本期覆盖 2026-05-29 至 2026-06-05，共收录高置信度文章 51 篇，边缘相关 3 篇，待人工核实 32 篇。

本周亮点

亮点 1：High-latitude Southern Ocean warming hotspot induced by ocean mesoscale eddies

期刊：Nature Climate Change ｜ DOI：https://doi.org/10.1038/s41558-026-02652-7

English summary

This Nature Climate Change study identifies a high-latitude Southern Ocean warming hotspot in the Indian sector, driven by ocean mesoscale eddies. Using model analyses, the authors show that eddies enhance upward heat transport, linked to a strengthening of the Antarctic Circumpolar Current. This finding challenges the traditional view that Southern Ocean heat uptake is primarily controlled by large-scale circulation, highlighting the critical role of eddies in regional climate change.

中文解读

这项《自然·气候变化》研究识别出南大洋高纬度印度洋扇区的一个增温热点，由海洋中尺度涡旋驱动。模型分析表明，涡旋增强了向上的热输送，并与南极绕极流的增强有关。这一发现挑战了传统认为南大洋热吸收主要由大尺度环流控制的观点，凸显了涡旋在区域气候变化中的关键作用。

亮点 2：Early Establishment of Far Eastern Pacific Warming Shapes Distinctive Air‐Sea Coupling in the 2023–2024 El Niño

期刊：GRL ｜ DOI：https://doi.org/10.1029/2026gl123227

English summary

This Geophysical Research Letters study examines the 2023–2024 El Niño, which featured early far eastern Pacific (FEP) warming and weak central Pacific westerly anomalies, unlike most post-1980 events. Linear decomposition reveals that a substantial portion of FEP variability is not explained by canonical ENSO dynamics, and this residual component shapes distinctive air-sea coupling. The findings challenge existing theories of El Niño development and have implications for seasonal prediction.

中文解读

这项《地球物理研究快报》研究分析了2023–2024年厄尔尼诺事件，其特点是远东太平洋（FEP）早期增温和中太平洋西风异常较弱，与1980年后的大多数事件不同。线性分解表明，FEP变率的很大一部分无法用经典ENSO动力学解释，这一残余成分塑造了独特的海气耦合。该发现挑战了现有的厄尔尼诺发展理论，并对季节预测具有重要意义。

文章详览

1. JPO — Lagrangian pair dispersion in the presence of high-frequency motions at the ocean surface

Abstract

Abstract We investigate the properties of relative dispersion of Lagrangian particles in a global-ocean simulation resolving both inertia-gravity waves (IGW) and meso and submesoscale (M/SM) turbulence. More specifically, we test if the dispersion laws depend on the shape of the Eulerian kinetic energy spectrum, as predicted from quasi-geostrophic turbulence theory. To this end, we focus on two areas, in the Kuroshio Extension and in the Gulf Stream, for which the relative importance of IGW compared to M/SM vary in summer and winter. In winter, Lagrangian statistical indicators return a picture in overall agreement with the shape of the kinetic energy spectrum. Conversely, in summer, when submesoscales are less energetic and higher-frequency internal waves gain importance, the expected relations between dispersion properties and spectra do not seem to hold. This apparent discrepancy is explained by decomposing the flow into nearly-balanced motions and internal gravity waves, and showing that the latter dominate the kinetic energy spectrum at small scales. Our results are consistent with the hypothesis that high-frequency IGWs do not impact relative dispersion, which is then controlled by the nearly-balanced, mainly rotational, flow component at larger scales. These results highlight that geostrophic velocities derived from wide-swath altimeters, such as SWOT, may present limits when estimating surface dispersion, and that current measuring satellite missions may provide the complementary information to do so.

中文摘要

摘要 我们研究了在全球海洋模拟中，解析惯性重力波（IGW）以及中尺度和次中尺度（M/SM）湍流时，拉格朗日粒子相对扩散的特性。更具体地说，我们检验了扩散规律是否如准地转湍流理论所预测的那样，依赖于欧拉动能谱的形状。为此，我们聚焦于黑潮延伸体和湾流两个区域，在这些区域中，IGW相对于M/SM的重要性在夏季和冬季有所不同。冬季，拉格朗日统计指标返回的结果与动能谱的形状总体一致。相反，在夏季，当次中尺度能量较弱且更高频率的内波重要性增加时，扩散特性与谱之间的预期关系似乎不再成立。通过将流场分解为准平衡运动和内重力波，并证明后者在小尺度上主导动能谱，可以解释这一明显的不一致性。我们的结果与以下假设一致：高频IGW不影响相对扩散，而相对扩散主要由较大尺度上的准平衡（主要是旋转）流分量控制。这些结果强调，从宽幅高度计（如SWOT）导出的地转速度在估算表面扩散时可能存在局限性，而当前的卫星测量任务可能提供补充信息以实现这一目标。

2. JPO — Full-Depth Scale-Dependent Eddy Diffusivities in the Kuroshio Extension

Abstract

Abstract In eddy-permitting models, only mixing induced by unresolved subgrid-scale eddies needs to be parameterized. Therefore, it is essential to study the diffusivity induced by eddies with spatial scales smaller than a separation scale L *, i.e., scale-specific eddy diffusivity. Using Lagrangian particle trajectories from high-resolution model solution (MITgcm LLC4320), we estimate full-depth and scale-dependent eddy diffusivities in the Kuroshio Extension region, and then develop a novel empirical formula to accurately represent their variations. Our results reveal significant variations in both magnitude and spatial structure of diffusivity with L * and depth. We find that Eady scale-based mixing length parameterization excels in the upper ocean, while GEOMETRIC and Topographic GEOMETRIC parameterizations better capture scale-dependent particle-based diffusivity in the depth range away from the ocean surface. At mid-depths and for L * ranging from 0.8° to 1.8°, the parameterization based on eddy size effectively represents both the spatial structure and magnitude of diffusivities. By combining the strengths of these parameterizations, our empirical formula provides an accurate representation of eddy diffusivity across the entire ocean depth. This study offers a promising approach for improving subgrid-scale eddy mixing parameterizations in eddy-permitting climate models.

中文摘要

摘要 在涡旋许可模型中，仅需参数化由未解析的次网格尺度涡旋引起的混合过程。因此，研究空间尺度小于分离尺度L的涡旋所导致的扩散率（即特定尺度涡旋扩散率）至关重要。利用高分辨率模式解（MITgcm LLC4320）中的拉格朗日粒子轨迹，我们估算了黑潮延伸体区域的全深度及尺度依赖的涡旋扩散率，并据此开发了一种新型经验公式以精确表征其变化。研究结果表明，扩散率的大小和空间结构随L及深度发生显著变化。我们发现，基于Eady尺度的混合长度参数化在上层海洋表现优异，而GEOMETRIC和Topographic GEOMETRIC参数化则能更好地捕捉远离海洋表面深度范围内尺度依赖的粒子扩散率。在中层深度且L*介于0.8°至1.8°时，基于涡旋尺度的参数化能有效表征扩散率的空间结构与量值。通过综合这些参数化的优势，我们的经验公式可精确表征整个海洋深度的涡旋扩散率。本研究为改进涡旋许可气候模式中的次网格尺度涡旋混合参数化提供了有前景的途径。

3. JPO — A frictional control mechanism of circumpolar transport in barotropic reentrant channel models

Abstract

Abstract Recent studies have reported that an increase in the bottom drag coefficient can enhance the volume transport of the Antarctic Circumpolar Current. Several mechanisms have been proposed to explain this frictional control, including the regulation of the geostrophic velocity by baroclinic instability and the influence of the form stress associated with standing meanders and wind-driven gyres. In this study, the role of momentum transport associated with Rossby wave radiations from disturbances is investigated as a potential frictional control mechanism. To highlight roles of the Rossby wave radiation, numerical experiments are conducted using barotropic reentrant channel models with topographic obstacles. In the high-drag regime, the circumpolar component is wind-driven, and the imbalance between the westerlies and topographic form stress sustains a net eastward transport. In contrast, in the low-drag regime, the eddy-driven westward circumpolar current is formed. In this case, the eastward flow at the center of the double gyre becomes unstable to barotropic instability. Analyses of the wave activity flux and momentum budget indicate that the Rossby wave transports westward momentum both northward and southward from the unstable region, which is responsible for the westward circumpolar current formation and maintenance. Although the direct application of the barotropic channel model to oceans requires caution, our findings imply that Rossby wave radiations from jets may play a role in the frictional control of the Antarctic Circumpolar Current.

中文摘要

摘要 近期研究报道，底部拖曳系数的增加可增强南极绕极流的体积输运。已有多种机制被提出用以解释这种摩擦控制作用，包括斜压不稳定性对地转流速的调控，以及伴随定常弯曲和风生涡旋的形态应力影响。本研究将扰动引起的罗斯贝波辐射所伴随的动量输运作为潜在的摩擦控制机制进行探讨。为突出罗斯贝波辐射的作用，采用带有地形障碍的正压再入通道模型开展数值实验。在高拖曳系数条件下，绕极分量由风驱动，西风带与地形形态应力之间的不平衡维持了净向东输运。相反，在低拖曳系数条件下，形成了涡旋驱动的向西绕极流。此时，双涡旋中心区域的东向流因正压不稳定性变得不稳定。波活动通量与动量收支分析表明，罗斯贝波从不稳定区域向北和向南输运西向动量，这导致了向西绕极流的形成与维持。尽管将正压通道模型直接应用于海洋需谨慎，但我们的研究结果表明，来自急流的罗斯贝波辐射可能在南极绕极流的摩擦控制中发挥作用。

4. JGR: Oceans — Springtime Intensification of Mesoscale Eddies in the Southeastern Tropical Indian Ocean

Abstract

Abstract Mesoscale eddies in the southeastern tropical Indian Ocean (SETIO) regulate regional circulation and heat redistribution. Using satellite altimetry and the GLORYS12V1 ocean reanalysis for 1993–2024, we identify a significant long‐term increase in eddy kinetic energy (EKE) in the SETIO. The trend exhibits pronounced seasonal asymmetry, with the intensification concentrated on austral spring (September–November), indicating an amplification of the seasonal EKE cycle. Energy diagnostics reveal that the springtime EKE intensification is primarily driven by enhanced baroclinic energy conversion rather than barotropic processes. The intensified baroclinic instability is associated with enhanced horizontal density gradients during late winter and spring. Further analyses suggest that strengthened coastal upwelling south of Java and increased wind energy input to the upper ocean likely contribute to the observed springtime EKE enhancement. These findings advance our understanding of eastern boundary eddy dynamics.

中文摘要

摘要 热带东南印度洋（SETIO）的中尺度涡旋调节区域环流和热量再分布。利用1993–2024年的卫星测高数据和GLORYS12V1海洋再分析资料，我们识别出SETIO区域涡旋动能（EKE）存在显著的长期增长趋势。该趋势表现出明显的季节性不对称性，增强集中在南半球春季（9–11月），表明EKE季节性循环有所放大。能量诊断显示，春季EKE增强主要由增强的斜压能量转换驱动，而非正压过程。增强的斜压不稳定性与冬末和春季期间水平密度梯度的增大有关。进一步分析表明，爪哇岛南部沿岸上升流的增强以及上层海洋风能输入的增大可能共同导致了观测到的春季EKE增强。这些发现推进了我们对东部边界涡旋动力学的理解。

5. JGR: Oceans — Cold Pool Formation Over the Taiwan Bank Driven by Shoaling Internal Tides

Abstract

Abstract Cold, saline, and chlorophyll‐rich surface waters are frequently observed over the Taiwan Bank in the southern Taiwan Strait, forming a distinct feature referred to as the Green–Cold Pool (GCP). Despite its ecological importance, the physical mechanisms sustaining this cold pool remain unclear. Using an integrated analysis of in situ hydrographic and microstructure observations, geostationary satellite measurements of sea surface temperature (SST) and chlorophyll‐a, and high‐resolution numerical simulations, we demonstrate that the GCP is primarily driven by shoaling and breaking semidiurnal internal tides. Internal tides generated in the Luzon Strait propagate northwestward and shoal over the continental slope south of the Taiwan Bank. As the internal tide trough encounters the steep slope, it steepens and evolves into internal tidal bores. These bores propagate upslope, inducing cold‐water run‐up from downslope regions and pushing previously uplifted cold water farther onto the bank. Strong turbulent diffusivity of O(10 −3 –10 −1 ) m 2 s −1 develops near the bore head and within the bottom boundary layer, promoting intense vertical mixing and irreversible upward transport of O(10 −3 ) m s −1 . This combined effect forms a bottom‐mixed layer (BML) that supplies cold, saline, and nutrient‐rich water onto the bank. Depending on the intensity and vertical extent of turbulence, the BML may remain capped by a thin warm surface layer or outcrop at the surface, producing the observed cold SST signal. Barotropic tidal currents modulate the semidiurnal migration of the cold pool but are insufficient to sustain its persistence.

中文摘要

摘要：在台湾海峡南部的台湾浅滩，经常观测到寒冷、高盐且富含叶绿素的表层水体，形成一种被称为“绿冷池”（GCP）的显著特征。尽管其具有重要的生态意义，但维持这一冷池的物理机制尚不清楚。通过整合现场水文与微结构观测、地球静止卫星的海表温度（SST）与叶绿素a测量数据以及高分辨率数值模拟，我们证明GCP主要由变浅和破碎的半日内潮驱动。源自吕宋海峡的内潮向西北方向传播，并在台湾浅滩以南的大陆坡上变浅。当内潮波谷遇到陡坡时，其会变陡并演变为内潮涌潮。这些涌潮沿坡向上传播，从下坡区域引发冷水上涌，并将先前抬升的冷水进一步推向浅滩。在涌潮头部附近及底部边界层内，形成了量级为O(10⁻³–10⁻¹) m² s⁻¹的强湍流扩散系数，促进了强烈的垂向混合和量级为O(10⁻³) m s⁻¹的不可逆向上输运。这种综合效应形成了一个底部混合层（BML），将寒冷、高盐且富含营养盐的水体输送到浅滩上。根据湍流的强度和垂向范围，BML可能被一层薄薄的温暖表层水覆盖，或出露于海表，从而产生观测到的冷SST信号。正压潮汐流调节了冷池的半日迁移，但不足以维持其持续性。

6. JGR: Oceans — Differences and Causes of Interannual Variations of Global Mean Sea Level Between Two El Niño Events in 2014–2016 and 2023–2024

Abstract

Abstract The interannual variation of global mean sea level is closely related to El Niño‐Southern Oscillation. During the 2014–2016 and 2023–2024 El Niño event development phases (October 2014–December 2015 and May 2023–December 2023, respectively), the interannual component of global mean sea level rose by approximately 9.16 and 7.70 mm, respectively. By combining satellite gravimetry and Argo gridded products, we show that barystatic sea level rise played a dominant role in the global mean sea level budget during both events. Although the barystatic sea level rise reached comparable magnitudes of 6.20 and 6.26 mm in the 2014–2016 and 2023–2024 development phases, respectively, the 2023–2024 surge was significantly more rapid, occurring over a much shorter duration. This accelerated rise was primarily driven by terrestrial water storage depletion in the America and Africa. Notably, South America exhibited a significantly faster rate of storage loss during the development phase of the 2023–2024 event compared to that of the 2014–2016 event. The steric sea level rise during the 2014–2016 and 2023–2024 development phases was 3.11 and 1.60 mm, respectively. Further analysis indicates that the steric sea level rise during the 2023–2024 development phase was predominantly driven by the thermosteric component, with a substantial contribution originating from the Indian Ocean. This regional anomaly was likely driven by the simultaneous occurrence of a peak positive Indian Ocean Dipole and El Niño.

中文摘要

摘要 全球平均海平面的年际变化与厄尔尼诺-南方涛动密切相关。在2014–2016年和2023–2024年厄尔尼诺事件的发展阶段（分别为2014年10月至2015年12月及2023年5月至2023年12月），全球平均海平面的年际分量分别上升了约9.16毫米和7.70毫米。通过结合卫星重力测量和Argo网格化产品，我们表明在这两次事件中，比容海平面上升在全球平均海平面收支中均占主导地位。尽管2014–2016年和2023–2024年发展阶段比容海平面上升的幅度相当，分别达到6.20毫米和6.26毫米，但2023–2024年的上升速度显著更快，持续时间更短。这种加速上升主要由美洲和非洲的陆地水储量消耗驱动。值得注意的是，与2014–2016年事件相比，南美洲在2023–2024年事件发展阶段的储量损失速率显著加快。2014–2016年和2023–2024年发展阶段的比容海平面上升分别为3.11毫米和1.60毫米。进一步分析表明，2023–2024年发展阶段的比容海平面上升主要由热比容分量驱动，其中印度洋贡献显著。这一区域异常很可能是由正印度洋偶极子峰值与厄尔尼诺事件同时发生所驱动的。

7. JGR: Oceans — Buoy Observations of Ocean Swell Propagation Across the Pacific Ocean

  • 作者：I. R. Young, A. Meucci, I. Houghton, C. Aguirre, A. BABANIN, M. Banner, T. Durrant, K. Ewans, H. Jiang, Q. LIU, J. Portilla‐Yandun, P. Smit, A. Toffoli
  • 发表日期：2026-05-31
  • DOI：https://doi.org/10.1029/2026jc024246

Abstract

Abstract A network of more than 300 drifting wave buoys is used to study the propagation of ocean swell across the Pacific Ocean. Swell events are identified at buoys in the Equatorial region and then tracked along Great Circle propagation paths both forward and backward in time. In this way, other buoys are identified at points along the propagation path and the generating storm can be determined by combining the assumed propagation path with spectral model hindcasts. Swell can be tracked over periods up to 12 days and propagation paths of 12,000 km. The analysis compares measured and predicted arrival times of swell between the buoys. The mean propagation times are well predicted by linear theory but with scatter up to hours. This range is consistent with the statistical uncertainty of the buoy spectral measurements. Decay rates of the swell are consistent with previous measurements and well modeled by the WAVEWATCH III spectral wave model. The analysis was conducted as a function of frequency, confirming that higher frequency swell decays more rapidly than lower frequencies.

中文摘要

摘要 一个由300多个漂流波浪浮标组成的网络被用于研究太平洋上海浪的传播。在赤道区域的浮标处识别出涌浪事件，随后沿大圆传播路径向前和向后追踪。通过这种方式，在传播路径上的其他浮标被识别出来，并且通过将假定的传播路径与谱模式后报相结合，可以确定生成风暴。涌浪可被追踪长达12天，传播路径达12000公里。分析比较了浮标之间涌浪的实测到达时间与预测到达时间。线性理论较好地预测了平均传播时间，但存在数小时的离散度。这一范围与浮标谱测量的统计不确定性一致。涌浪的衰减率与先前测量结果一致，且被WAVEWATCH III谱波浪模式很好地模拟。分析按频率进行，证实了高频涌浪比低频涌浪衰减更快。

8. JGR: Oceans — Vertical Decoupling of Marine Heatwaves in the Bay of Bengal: The Contrasting Roles of Atmospheric Forcing and Mesoscale Eddies

Abstract

Abstract Marine extreme temperature events pose severe threats to marine ecosystems. While existing research on extreme temperature events in the Bay of Bengal (BoB) has largely focused on sea surface conditions and large‐scale processes, the occurrence and drivers of subsurface extremes remain poorly constrained. To address this gap, an extensive data set combining uninterrupted mooring measurements (2008–2016) with diverse remote sensing products is utilized to elucidate the nature and forcing mechanisms of extreme temperature events within the northern Bay of Bengal (NBoB). The results reveal a clear vertical decoupling of subsurface marine heatwaves (MHWs) and cold spells (MCSs) from surface events. Surface extremes are principally forced by air‐sea heat fluxes and remotely modulated by El Niño‐Southern Oscillation through atmospheric teleconnections. In contrast, subsurface events are predominantly driven by mesoscale eddies, with over 50% of MHWs and MCSs co‐occurring with anticyclonic and cyclonic eddies, respectively. Furthermore, we find that the occurrence of subsurface eddy‐associated MHWs is modulated by the synchronization of La Niña with negative phases of the Indian Ocean Dipole during which anticyclonic eddy activity becomes anomalously active, leading to an increased frequency and enhanced intensity of these MHWs. This vertical dichotomy in governing mechanisms, with atmospheric processes dominating at the surface and eddy dynamics controlling the subsurface, advances our understanding of extreme temperature dynamics in tropical seas and provides crucial insights for predicting marine ecosystem responses under climate change.

中文摘要

摘要 海洋极端温度事件对海洋生态系统构成严重威胁。尽管现有关于孟加拉湾极端温度事件的研究主要聚焦于海表条件和大尺度过程，但次表层极端事件的发生机制及其驱动因素仍知之甚少。为弥补这一不足，本研究综合运用连续锚系观测数据（2008–2016年）与多种遥感产品组成的大规模数据集，揭示了孟加拉湾北部次表层海洋热浪与冷事件的本质及强迫机制。结果表明，次表层海洋热浪和冷事件与表层事件存在明显的垂直解耦现象。表层极端事件主要受海-气热通量强迫，并通过大气遥相关受到厄尔尼诺-南方涛动的远程调制。相比之下，次表层事件主要由中尺度涡旋驱动，超过50%的次表层热浪和冷事件分别与反气旋涡和气旋涡同时发生。此外，本研究发现与涡旋相关的次表层热浪的发生受拉尼娜与印度洋偶极子负位相协同作用的调制：在此背景下，反气旋涡活动异常活跃，导致此类热浪频率增加、强度增强。这种以大气过程主导表层、涡旋动力学控制次表层的垂直驱动机制二分性，深化了我们对热带海洋极端温度动力学的理解，并为预测气候变化下海洋生态系统响应提供了关键见解。

9. JPO — Escape of Near-Inertial Waves Trapped in Strong Fronts through Wave–Wave Interactions

Abstract

Abstract Wind-generated inertial motions are refracted by geostrophic vorticity gradients to propagate into the stratified ocean interior as near-inertial waves that can be trapped in anticyclonic regions of ocean fronts and eddies as subinertial waves. Here, we explore a nonlinear wave–wave interaction mechanism by which subinertial near-inertial waves trapped in a sharp front (vorticity Rossby number Ro ∼ −0.85, front gradient Froude number Fr ∼ 0.8) can escape as superinertial near-inertial waves. Inferences are drawn from spectral and cross-bispectral analyses of numerical solutions of a process study ocean model configured to represent a two-dimensional baroclinic front. The model is forced with a wind impulse. The resulting near-inertial wave fields are analyzed over the ensuing five inertial periods as the waves radiate downward. Resonant wave–wave interactions provide a pathway for trapped subinertial wave energy to radiate out of the front as free superinertial waves. Nonlinear interactions represent a significant component of the near-inertial wave energy budget, only a factor-of-2 smaller than dissipation. Escaping waves only occur for either large front vorticity Rossby number or large front gradient Froude number in the regime constrained by 0 < 1 + Ro − Fr 2 < 0.36.

中文摘要

摘要 风生惯性运动受地转涡度梯度折射，以近惯性波形式传播至层化海洋内部，这些波可被海洋锋面和涡旋的反气旋区域捕获为亚惯性波。本文探讨了一种非线性波-波相互作用机制，通过该机制，被强锋面（涡度罗斯贝数Ro ∼ −0.85，锋面梯度弗劳德数Fr ∼ 0.8）捕获的亚惯性近惯性波能够以超惯性近惯性波形式逃逸。基于过程研究海洋模式数值解的谱分析和交叉双谱分析得出推论，该模式被配置为表征二维斜压锋面，并以风脉冲驱动。在随后五个惯性周期内，随着波向下辐射，对产生的近惯性波场进行分析。共振波-波相互作用为被捕获的亚惯性波能量提供了一条路径，使其以自由超惯性波形式从锋面辐射出去。非线性相互作用是近惯性波能量预算的重要组成部分，其量级仅比耗散小一个因子。逃逸波仅发生在锋面涡度罗斯贝数较大或锋面梯度弗劳德数较大的情况下，且受限于0 < 1 + Ro − Fr² < 0.36的约束条件。

10. JPO — The Role of Wind in Driving the Subsurface Velocity Maxima of Makassar Strait Throughflow and Mindanao Current

Abstract

Abstract For most wind-driven ocean currents, velocity is typically surface-intensified with a peak at the surface. However, in a notable exception, the Makassar Strait throughflow (MST) and the Mindanao Current (MC)—two dynamically linked boundary currents—exhibit their maximum velocities in the subsurface (upper thermocline) layer. In this study, the driving mechanisms of subsurface velocity maxima are investigated, using mooring observations, ocean reanalysis products, and regional model simulations, with particular emphasis on the role of wind forcing. Both the in situ measurements and reanalysis data show that the subsurface velocity maxima in the MST and MC in boreal summer are stronger and shallower than in winter. We find that the higher-order baroclinic modes (modes 3 and 4) are crucial in shaping vertical structure of velocity and forming the subsurface velocity maximum. The meridional dynamic height difference along MC is identified as a driver of the subsurface velocity maximum, through balancing with frictional forces. The zonal density gradient, being negative at the surface but positive at depth, is consistent with the subsurface velocity maximum. Numerical experiments with a regional model indicate that the sea surface winds play an important role in driving the seasonality of subsurface velocity maxima of the MC and MST. Wind stress causes downwelling (upwelling) over the MC and deepens (lifts) zero contour of horizontal density gradient and leads to a deeper (shallower) subsurface velocity maximum. Wind forcing can also influence the subsurface velocity maximum of MST by modulating the seasonal freshwater transport from the South China Sea. Significance Statement The Indonesian Throughflow (ITF), which is mainly originated from Mindanao Current (MC), transfers mass and heat from the tropical Pacific Ocean into the Indian Ocean. The main heat transported by ITF is concentrated in thermocline layer, with the most notable feature of subsurface velocity maximum. In this study, we investigated the subsurface velocity maximum from the MC to the Makassar Strait (the main pathway of ITF), focusing on the wind-driven mechanisms and associated influences. Our analysis confirms that subsurface velocity maximum of the MC is governed by the meridional dynamic height gradient and the zonal density gradient, dominated by higher-order baroclinic modes. Sea surface winds play important roles in driving the seasonality of MC subsurface velocity maximum. The downwelling (upwelling) induced by wind stress curl over the MC deepens (lifts) zero contour of horizontal density gradient, producing a deeper (shallower) subsurface velocity maximum. The strength and depth variations of subsurface velocity maximum impact heat and salt exchanges between the Pacific and Indian Oceans, modulating the large-scale thermohaline structure and stratification of both oceans.

中文摘要

摘要 对于大多数风生海流而言，流速通常呈现表层增强特征，并在海面达到峰值。然而，一个显著的例外是望加锡海峡贯穿流（MST）和棉兰老流（MC）——这两支动力相连的边界流——其最大流速出现在次表层（上温跃层）。本研究利用锚系观测、海洋再分析产品和区域模式模拟，重点探讨风强迫的作用，揭示次表层流速最大值的驱动机制。现场观测和再分析数据均显示，北半球夏季MST和MC的次表层流速最大值比冬季更强且更浅。我们发现高阶斜压模态（第3和第4模态）对流速垂直结构的塑造及次表层流速最大值的形成至关重要。沿MC的经向动力高度差被识别为次表层流速最大值的驱动因子，其通过与摩擦力的平衡发挥作用。纬向密度梯度在海表为负值、在深层为正值，与次表层流速最大值一致。区域模式数值实验表明，海面风场在驱动MC和MST次表层流速最大值季节变化中起重要作用。风应力在MC区域引起下降流（上升流），使水平密度梯度零等值线加深（抬升），从而导致次表层流速最大值加深（变浅）。风强迫还可通过调节南海的季节性淡水输运影响MST的次表层流速最大值。意义声明 主要源自棉兰老流（MC）的印尼贯穿流（ITF）将热带太平洋的质量和热量输运至印度洋。ITF输送的主要热量集中在温跃层，其最显著特征为次表层流速最大值。本研究从MC到望加锡海峡（ITF主要通道）系统研究了次表层流速最大值，重点关注风驱动机制及其关联影响。我们的分析证实，MC的次表层流速最大值受经向动力高度梯度和纬向密度梯度控制，并由高阶斜压模态主导。海面风场在驱动MC次表层流速最大值季节变化中发挥重要作用。风应力旋度在MC区域诱导的下降流（上升流）使水平密度梯度零等值线加深（抬升），产生更深（更浅）的次表层流速最大值。次表层流速最大值的强度和深度变化影响太平洋与印度洋之间的热盐交换，调节两大洋的大尺度温盐结构及层结。

11. JPO — Wind Variability at Synoptic-to-Planetary Frequencies Enhances Front Asymmetry of Mesoscale Eddy

Abstract

Abstract Oceanic fronts at mesoscale eddy peripheries are critical for generating submesoscale processes that regulate upper-ocean transport and mixing. Previous studies have shown that large-scale wind forcing can induce asymmetry in frontal sharpness around mesoscale eddies, with sharpened (weakened) fronts on the down-front (up front) wind side. However, the response of these fronts and associated submesoscale processes to wind forcings at different oscillating frequencies remains poorly understood. Based on high-resolution idealized simulations of anticyclonic mesoscale eddy under various wind forcings, this study reveals that the modulation of frontal sharpness and asymmetry around an anticyclonic mesoscale eddy is most significant when the wind oscillation period matches the eddy’s rotational period. Analysis of Lagrangian particle tracking reveals that particles accumulate a net positive Ekman buoyancy flux (EBF) by experiencing an enhanced positive flux on the down-front wind side and a suppressed negative flux on the up-front wind side, which tends to strengthen the frontal asymmetry. Additionally, the submesoscale fronts sharpen significantly on the down-front wind side when wind stress relaxes. This frontal sharpening rate is driven by horizontal convergent flows, confirming the key role of submesoscale frontogenesis. Diagnosis of the horizontal divergence equation further reveals that local vorticity acceleration and nonlinear horizontal advection terms are primarily responsible for driving convergent flows and submesoscale frontogenesis. Given that 90% of mesoscale eddies exhibit rotational periods of 10–70 days, aligning with the dominant time scales of atmospheric variability, the mechanisms described above likely have significant influence on submesoscale frontal sharpness and asymmetry around mesoscale eddies across the global ocean. Significance Statement Wind forcing plays a crucial role in shaping oceanic fronts at mesoscale eddy peripheries; its influence has been primarily studied under steady winds, leaving the effects of oscillating winds poorly understood. This study revealed two mechanisms through idealized simulations. First, a resonance-like mechanism amplifies frontal asymmetry when the wind’s oscillation period matches the eddy’s rotational period. Second, we identify a frontogenesis mechanism modulated by wind-induced mixing: During wind relaxation, a reduction in mixing triggers a spontaneous momentum adjustment, leading to intense submesoscale frontogenesis driven primarily by local flow acceleration. These findings provide the physical basis for parameterizing the response of unresolved frontal dynamics to time-varying winds in climate models.

中文摘要

摘要 中尺度涡旋边缘的海洋锋面对于生成调控上层海洋输运和混合的次中尺度过程至关重要。已有研究表明，大尺度风强迫可导致中尺度涡旋周围锋面强度的不对称性，即在顺风侧锋面增强，在逆风侧锋面减弱。然而，这些锋面及其伴随的次中尺度过程对不同振荡频率风强迫的响应机制尚不明确。基于不同风强迫条件下反气旋式中尺度涡旋的高分辨率理想化数值模拟，本研究发现：当风振荡周期与涡旋旋转周期相匹配时，对反气旋式中尺度涡旋周围锋面强度及其不对称性的调制作用最为显著。拉格朗日粒子追踪分析表明，粒子通过经历顺风侧增强的正向埃克曼浮力通量和逆风侧抑制的负向通量，累积净正埃克曼浮力通量，从而强化锋面不对称性。此外，当风应力减弱时，顺风侧的次中尺度锋面显著增强，这种锋面增强速率由水平辐合流驱动，证实了次中尺度锋生过程的关键作用。水平散度方程的诊断进一步揭示，局地涡度加速度和非线性水平平流项是驱动辐合流和次中尺度锋生的主要机制。鉴于全球90%的中尺度涡旋旋转周期为10-70天，与大气变率的主导时间尺度相吻合，上述机制可能对全球海洋中尺度涡旋周围的次中尺度锋面强度及其不对称性产生显著影响。意义声明 风强迫在塑造中尺度涡旋边缘的海洋锋面中起关键作用，但现有研究主要关注稳态风的影响，对振荡风的作用认知不足。本研究通过理想化数值模拟揭示两种机制：其一，当风振荡周期与涡旋旋转周期匹配时，共振式机制会放大锋面不对称性；其二，我们识别出由风致混合调制的锋生机制——在风应力减弱期间，混合减弱触发自发动量调整，导致主要由局地流动加速驱动的强烈次中尺度锋生。这些发现为气候模式中参数化未解析锋面动力学对时变风强迫的响应提供了物理基础。

12. JPO — Importance of Geostrophic Shear on Eddy-Induced Ekman Pumping: Verification by Mesoscale Eddies in the Kuroshio Extension Region

Abstract

Abstract Vertical motion associated with mesoscale eddies subject to wind forcing is investigated. Previous studies have shown that the relative vorticity of eddies modifies Ekman pumping (i.e., vertical velocity within the frictional boundary layer that is associated with the divergence of frictionally forced currents) through an effective change in the Coriolis parameter, known as nonlinear Ekman pumping. In this study, a new formulation of Ekman pumping that considers both relative vorticity and geostrophic vertical shear, which is associated with horizontal density gradient and partially balances wind stress, is derived. The formulation is validated against the vertical velocity obtained from an eddy-resolving ocean model in the Kuroshio Extension (KE) region, where mesoscale activity prevails. Vertical velocity in the eddy interior comprises the “nonfrictional” component diagnosed by the quasigeostrophic omega equation and the residual “frictional” Ekman component. In winter, the frictional component at the depth where the ageostrophic shear becomes negligible is better explained by the new formulation than by the nonlinear Ekman pumping. In contrast, weak turbulent mixing and small eddy-induced sea surface temperature (SST) perturbations in summer make the geostrophic shear contribution negligible, so the nonlinear Ekman pumping explains the frictional component. The new formulation is furthermore applied to estimate Ekman pumping velocity in mesoscale eddies using satellite observations. This confirms the seasonal variation in the importance of geostrophic shear. Additionally, eddy-induced SST perturbations and surface ocean currents modify the surface wind stress, generating wind stress curl and hence Ekman pumping velocity.

中文摘要

摘要 本文研究了受风应力作用的中尺度涡旋相关的垂直运动。已有研究表明，涡旋的相对涡度通过科里奥利参数的有效变化（即非线性埃克曼抽吸）改变了埃克曼抽吸（即与摩擦驱动流辐散相关的摩擦边界层内的垂直速度）。本研究推导出一种新的埃克曼抽吸公式，该公式同时考虑了相对涡度和与水平密度梯度相关并部分平衡风应力的地转垂直切变。该公式通过与黑潮延伸体（KE）区域（中尺度活动盛行）涡旋分辨海洋模型获得的垂直速度进行验证。涡旋内部的垂直速度包括由准地转Omega方程诊断的“非摩擦”分量和残余的“摩擦”埃克曼分量。在冬季，当非地转切变可忽略的深度处的摩擦分量，新公式比非线性埃克曼抽吸能更好地解释。相比之下，夏季弱湍流混合和小的涡旋诱导海表温度（SST）扰动使得地转切变贡献可忽略，因此非线性埃克曼抽吸解释了摩擦分量。此外，新公式被应用于利用卫星观测估算中尺度涡旋中的埃克曼抽吸速度。这证实了地转切变重要性的季节变化。同时，涡旋诱导的海表温度扰动和表层洋流改变了海面风应力，产生风应力旋度，进而影响埃克曼抽吸速度。

13. JPO — Submesoscale Frontal SST Gradients from Airborne Collection during S-MODE: Wind Effects on Frontogenesis

  • 作者：Delphine Hypolite, Maarten Jeroen Molemaker, Louis Marié, Garrett Staller, James C. McWilliams, Ernesto Rodriguez, Alex Wineteer, Hector Torres
  • 发表日期：2026-06-01
  • DOI：https://doi.org/10.1175/jpo-d-25-0216.1

Abstract

Abstract During three airborne campaigns (2021–23) of NASA’s Submesoscale Ocean Dynamics Experiment (S-MODE) mission, infrared imagery was collected at resolution over of the California Current System, a hotspot for submesoscale activity. These observations reveal a complex surface temperature field, including high-frequency fine-scale variability, frontal “steps,” multifront convergence, and spatially heterogeneous roll cells. Probability density functions of horizontal sea surface temperature (SST) gradients, grouped by wind and wave conditions, show that strong winds are associated with reduced gradient intensity. Similarly, periods with large waves or visible roll cells tend to exhibit weaker gradients. Diagnoses of Ekman temperature flux, using Doppler scatterometer (DopplerScatt) winds, indicate that stabilizing conditions correspond to wider fronts, though wind speed exerts the dominant control. The cooccurrence of broader fronts and fewer sharp gradients under strong winds is consistent with a frontogenesis framework in which enhanced vertical mixing, in the presence of shear, opposes the sharpening of lateral temperature gradients, while weaker winds favor frontal intensification. We also report direct visual evidence of overshoots on the cold side of fronts, signatures of mixed layer deepening, and convergence.

中文摘要

摘要 在美国国家航空航天局（NASA）亚中尺度海洋动力学实验（S-MODE）任务的三次机载观测（2021–23年）期间，在加州海流系统（亚中尺度活动热点区域）上空以分辨率采集了红外图像。这些观测揭示了复杂的海表温度场，包括高频细尺度变率、锋面“阶梯”、多锋面汇聚以及空间异质性的滚动胞。按风浪条件分组的水平海表温度（SST）梯度概率密度函数显示，强风与梯度强度减弱相关。类似地，大浪或可见滚动胞时期往往表现出较弱的梯度。利用多普勒散射计（DopplerScatt）风场进行的埃克曼温度通量诊断表明，稳定条件对应更宽的锋面，尽管风速起主导控制作用。强风条件下较宽锋面与较少尖锐梯度同时出现，与锋生理论框架一致，即在存在切变的情况下增强的垂直混合会抑制侧向温度梯度的增强，而较弱的风则有利于锋面强化。我们还报告了锋面冷侧超调的直接视觉证据，以及混合层加深和辐合的标志。

14. JPO — Wintertime Convection in the Subpolar North Atlantic

Abstract

Abstract An oceanographic mooring south of Iceland includes turbulence measurements from 20 χ pods over a full winter (135 days) of nearly continuous surface cooling. During the wintertime cooling period, the mixed layer (depth D ) deepened to 500 m and cooled at a mean rate nearly equal to the sum of surface cooling ( Q ) plus cooling from below via mixing at its base ( ). The mean value of was about 0.15. Over the lower half of the mixed layer, mean profiles of turbulence dissipation rate ϵ were about (0.6–0.8)× the surface buoyancy flux, B . Mean values of and ϵ / B are roughly equal to those derived from measurements in the daytime atmospheric boundary layer, laboratory results, and large-eddy simulations. During convection, spectra of vertical velocity ( w ) measurements from an acoustic Doppler current profiler scale with inertial subrange turbulence. Rms values of w are well represented by both pure convective and rotational convective scalings, indicating at least partial influence of rotation or marginally deep convection. Despite advection by the energetic mesoscale eddy field, variable surface forcing, and subsurface stratification, the mixed layer deepened smoothly over 135 days. Simplified predictions of mixed layer deepening represent the observed deepening with considerable precision. A bulk estimate of the time ( t )-dependent mixed layer deepening suggests that D ( t ) ∝ t 1/2 . Significance Statement Few observations record full seasons of wintertime convection. None, until now, include measurements of turbulence. These measurements show that the mixed layer driven by convection over an entire winter in the subpolar ocean conforms with measurements from short time scale, convectively driven mixed layers in daytime atmospheres and nighttime oceans. In addition, and despite variations in surface forcing, thermocline stratification, and mesoscale advection, simple scalings demonstrate considerable precision in predicting the season-long mixed layer deepening.

中文摘要

摘要 冰岛南部的一处海洋学锚系观测站，在整整一个冬季（135天）近乎连续的海面冷却过程中，利用20个χ探头进行了湍流测量。在冬季冷却期间，混合层（深度D）加深至500米，其平均冷却速率几乎等于海面冷却（Q）与底部混合引起的下方冷却之和。的平均值约为0.15。在混合层下半部分，湍流耗散率ϵ的平均廓线约为海面浮力通量B的0.6–0.8倍。和ϵ/B的平均值与白天大气边界层测量、实验室结果及大涡模拟得出的数值大致相当。在对流期间，声学多普勒流速剖面仪测量的垂直速度（w）谱与惯性子区湍流尺度一致。w的均方根值可由纯对流和旋转对流两种尺度较好地表示，表明旋转或边缘深对流至少存在部分影响。尽管受到高能中尺度涡旋场平流、变化的海面强迫及次表层层结的影响，混合层在135天内仍平稳加深。混合层加深的简化预测能以相当高的精度再现观测到的加深过程。对随时间（t）变化的混合层加深的总体估算表明，D(t) ∝ t^{1/2}。
意义声明 此前几乎没有观测记录整个冬季的对流过程，更无包含湍流测量的先例。本观测表明，在亚极地海洋整个冬季由对流驱动的混合层，与白天大气和夜间海洋中短时间尺度对流驱动混合层的测量结果一致。此外，尽管海面强迫、温跃层层结及中尺度平流存在变化，简单的尺度分析仍能以相当高的精度预测整个季节的混合层加深。

15. JPO — Pathways of Forward Energy Cascades in the Northern Bay of Bengal

  • 作者：Arjun Jagannathan, Kaushik Srinivasan, Pierre Damien, M. Jeroen Molemaker, Roy Barkan, Nikhil Patnaik, James C. McWilliams, Manikandan Mathur, Debasis Sengupta
  • 发表日期：2026-06-01
  • DOI：https://doi.org/10.1175/jpo-d-25-0219.1

Abstract

Abstract We investigate the governing pathways of energy cascades in the northern Bay of Bengal (BoB) region of the Indian Ocean using a hierarchy of nested Regional Ocean Modeling System (ROMS) simulations. The analysis is focused on 1 month each in the premonsoon (April) and postmonsoon (October) seasons, motivated by the contrasting upper-ocean dynamics in these months. In April, a swift, meandering western boundary current and its separation produces an energetic mesoscale eddy field in the northern BoB. By contrast, the postmonsoon month of October is characterized by an equatorward East India Coastal Current (EICC) and recurrent episodes of surface submesoscale frontogenesis driven by freshwater fluxes from monsoon rainfall and river runoff. Using a coarse-graining analysis for computing scale-to-scale kinetic energy fluxes, we find that at scales smaller than ≈15 km, surface forward fluxes in October are almost twice as large as in April, producing a fine-scale field of eddies, fronts, and filaments. We show that in both months, forward energy fluxes at submesoscales (⪅25 km) strongly correlate with convergent, frontogenetic mechanisms. Additionally, we provide evidence that remotely generated, semidiurnal internal tides have a crucial role in stimulating cross-scale energy fluxes in this region. Comparing simulations with and without barotropic tidal forcing, we demonstrate that internal tides are able to catalyze downscale cascades through three distinct mechanisms—direct energy extraction from the eddy field, scattering of the internal wave field by eddies, and nonlinear wave–wave interactions.

中文摘要

摘要 我们利用嵌套式区域海洋模式系统（ROMS）模拟的层级结构，研究了印度洋孟加拉湾北部区域能量级联的主导路径。分析聚焦于季风前期（4月）和季风后期（10月）各一个月，这是基于这两个月份上层海洋动力学的显著差异。4月，快速蜿蜒的西边界流及其分离在孟加拉湾北部产生了高能中尺度涡旋场。相比之下，季风后期的10月以向赤道的东印度沿岸流（EICC）以及由季风降雨和河流径流带来的淡水通量驱动的表层亚中尺度锋生反复事件为特征。通过用于计算尺度间动能通量的粗粒化分析，我们发现，在约15公里以下的尺度上，10月的表层正向通量几乎是4月的两倍，从而产生了细尺度的涡旋、锋面和丝状结构场。我们表明，在这两个月份中，亚中尺度（约25公里以下）的正向能量通量与辐合性锋生机制密切相关。此外，我们提供了证据，证明远程生成的半日内潮在该区域跨尺度能量通量中起着关键作用。通过比较有无正压潮汐强迫的模拟，我们证明内潮能够通过三种不同机制催化向下的级联——直接从涡旋场提取能量、涡旋对内波场的散射以及非线性波-波相互作用。

16. JPO — On Air–Sea Heat Flux, Subduction, and Ageostrophic Divergence in an Eddying Southern Ocean

Abstract

Abstract Subduction hotspots in the Southern Ocean transfer heat, carbon, and oxygen from the ocean’s mixed layer into the upper thermocline. In this study, we use an eddy-resolving global ocean–sea ice model, forced by an atmospheric reanalysis, to estimate the subduction due to the mean flow and also, for the first time, directly compute the horizontal and vertical eddy contributions to subduction in the Southern Ocean. This is in contrast to the earlier studies that parameterized the eddy-induced term. Our results also show the dominance of the mean flow on subduction because the eddy-induced lateral induction is anticorrelated with the vertical eddy bolus velocity, which reduces their combined effect on subduction. Meridional displacements of the Antarctic Circumpolar Current (ACC) modulate the subduction rate because the mean lateral injection of fluid is a dominant term. Moreover, the eddy-induced lateral induction is smaller than the mean lateral induction across most of the Southern Ocean. In addition, a comparison between subsurface vertical velocity and vertical Ekman velocity shows that the Ekman velocity is an order of magnitude smaller in energetic regions with strong ageostrophic divergence. These results suggest a possible mechanism in ACC meanders to explain the observed ventilation of Antarctic Intermediate Water in regions of steep bathymetry and high eddy kinetic energy. Finally, we note that the asymmetry in air–sea heat flux in the Southern Ocean contributes to the distribution of the subduction zones of mode and intermediate waters. Significance Statement This study uncovers crucial processes in how surface waters in the Southern Ocean penetrate into the interior ocean. This process is called subduction, and it is enhanced at subduction hotspots. These hotspots play a vital role in transferring heat, carbon, and oxygen from the surface to the interior ocean. Using a sophisticated ocean–sea ice model, our research calculates the contributions of both the time-averaged flow and eddies to this subduction, providing clearer insights into the role of eddies than in previous studies. The findings reveal that the meridional movement of the Antarctic Circumpolar Current significantly influences subduction rates, which are essential for understanding ocean ventilation and climate dynamics. This work is important because it enhances our understanding of oceanic processes that affect global climate, highlighting areas for further exploration of these mechanisms to inform climate models and policy efforts aimed at mitigating climate change.

中文摘要

南大洋的潜沉热点区域将热量、碳和氧气从海洋混合层输送到上层温跃层。本研究利用涡分辨率全球海洋-海冰模式，在大气再分析资料驱动下，估算了平均流引起的潜沉，并首次直接计算了南大洋中水平与垂直涡旋对潜沉的贡献。这与以往将涡旋诱导项参数化的研究形成对比。我们的结果还表明，平均流在潜沉中占主导地位，因为涡旋诱导的侧向吸入与垂直涡旋输送速度呈反相关，从而削弱了二者对潜沉的联合效应。南极绕极流（ACC）的经向位移调节着潜沉速率，因为平均侧向流体注入是主导项。此外，在南大洋大部分区域，涡旋诱导的侧向吸入小于平均侧向吸入。同时，次表层垂直速度与垂直埃克曼速度的比较显示，在强地转非对称辐散的能量活跃区域，埃克曼速度小一个量级。这些结果表明，ACC弯曲处可能存在一种机制，用以解释在陡峭地形和高涡动能区域观测到的南极中层水通风现象。最后，我们注意到南大洋海-气热通量的不对称性影响了模态水和中层水潜沉区的分布。意义声明：本研究揭示了南大洋表层水如何进入海洋内部的关键过程。这一过程称为潜沉，在潜沉热点区域得到增强。这些热点在将热量、碳和氧气从表层输送到海洋内部方面发挥着重要作用。通过使用先进的海洋-海冰模式，我们的研究计算了时间平均流和涡旋对潜沉的贡献，比以往研究更清晰地揭示了涡旋的作用。研究结果表明，南极绕极流的经向运动显著影响潜沉速率，这对理解海洋通风和气候动力学至关重要。这项工作之所以重要，是因为它加深了我们对影响全球气候的海洋过程的理解，并指出了进一步探索这些机制的领域，从而为气候模型和旨在减缓气候变化的政策努力提供信息。

17. JPO — Characteristics and Generation Mechanisms of Intrathermocline Eddies in the Southwestern South China Sea

Abstract

Abstract Intrathermocline eddies (ITEs), a distinct class of subsurface-intensified eddies, play a unique role in modulating subsurface dynamic and biogeochemical processes in the ocean. Based on temperature and salinity observations from 19 profiling floats collected in autumn 2019, an ITE was directly observed in the southwestern South China Sea (SW-SCS). This ITE exhibited a convex-lens-shaped thermohaline structure, characterized by low potential vorticity (PV) at its core depth of 30–80 m, with its radius of approximately 170 km. The isopycnal surfaces outcropped along the northwestern edge of the ITE, coinciding with the region where it encountered the strong Vietnam Offshore Current. Correspondingly, the ITE had subsurface-intensified anticyclonic swirl velocity on the southern and eastern sides, with a maximum magnitude of 37 cm s −1 at ∼50-m depth. Using eddy-resolving reanalysis data, 12 similar ITEs were identified during 1993–2019, indicating the common occurrence of such kind of ITEs. The generation mechanisms of ITEs were further investigated, and two key processes were proposed. First, the low-PV water within the ITEs originating from the upper boundary layer in the outcropping region is subducted into the thermocline through secondary circulations induced by frontogenesis. PV budget analysis revealed that PV destruction due to frictional forces associated with down-front winds constitutes the dominant mechanism for the low-PV formation. Second, upwelling driven by eddy–wind interactions induces doming of the upper-layer isopycnals, thereby further facilitating ITE formation. These findings demonstrate that ITEs are a common phenomenon in the SW-SCS and may exert considerable influence on subsurface processes. Significance Statement Intrathermocline eddies (ITEs) are typically convex-lens-shaped subsurface-intensified eddies in the ocean, showing great influence on the oceanic subsurface dynamic and biogeochemical processes. Based on profiling float observations, this study reports on an ITE in the southwestern South China Sea (SW-SCS) and presents a detailed analysis of its fundamental characteristics. Further analysis reveals that ITEs are a common phenomenon in the SW-SCS and are generated through two key processes: the doming of upper-layer isopycnals induced by local eddy–wind interactions and the subduction of low-PV water formed under down-front winds and frontogenesis-induced secondary circulations. These findings provide new dynamical insights into the characteristics and generation mechanisms of ITEs in this region, offering valuable implications for future targeted observations and investigations of ITEs.

中文摘要

摘要 温跃层内涡旋（ITEs）是一类独特的次表层强化涡旋，在调节海洋次表层动力与生物地球化学过程中发挥着独特作用。基于2019年秋季收集的19个剖面浮标的温盐观测数据，在南海南部西南部（SW-SCS）直接观测到一个ITE。该ITE呈现凸透镜状温盐结构，其核心深度30–80米处具有低位势涡度（PV）特征，半径约为170公里。等密面沿ITE西北边缘出露，与该区域遭遇强劲的越南离岸流的位置相吻合。相应地，该ITE在南侧和东侧具有次表层强化的反气旋式旋转流速，在约50米深度处最大流速达37厘米/秒。利用涡旋分辨再分析数据，在1993–2019年间识别出12个类似的ITE，表明此类ITE的普遍存在。进一步研究了ITE的生成机制，提出了两个关键过程。首先，源自出露区上层边界层的低PV水体，通过锋生引起的次级环流被潜沉至温跃层。PV收支分析表明，与顺风风应力相关的摩擦力导致的PV破坏是低PV形成的主导机制。其次，涡旋-风相互作用驱动的上升流引起上层等密面穹隆，从而进一步促进ITE形成。这些发现表明ITE是南海南部西南部的一种常见现象，可能对次表层过程产生显著影响。意义声明 温跃层内涡旋（ITEs）是海洋中典型的凸透镜状次表层强化涡旋，对海洋次表层动力和生物地球化学过程具有重要影响。基于剖面浮标观测，本研究报道了南海南部西南部的一个ITE，并详细分析了其基本特征。进一步分析揭示，ITE是南海南部西南部的常见现象，通过两个关键过程生成：局地涡旋-风相互作用引起的上层等密面穹隆，以及顺风风应力和锋生诱导次级环流作用下形成的低PV水体的潜沉。这些发现为该区域ITE的特征和生成机制提供了新的动力学见解，为未来针对ITE的观测和研究提供了有价值的参考。

18. JPO — Formation of Abyssal Downwelling-Favorable Prograde Flows via Mesoscale Eddy Potential Vorticity Mixing

Abstract

Abstract Observations and simulations have revealed widespread prograde mean flows (along-isobath currents in the direction of topographic wave propagation) over sloping topography in the abyssal ocean. While their emergence is consistent with quasi-two-dimensional turbulence theory, the factors governing their spatial variability remain poorly understood. Using a suite of eddy-resolving, process-oriented simulations, we investigate the driving mechanisms and parameter dependence of abyssal prograde flows. Consistent with previous studies, we find that prograde flows are driven by eddy momentum fluxes arising from eddy stirring of potential vorticity (PV), gradients of which are associated with the sloping seafloor. Moreover, we identify a nonmonotonic dependence of prograde flow strength on bottom steepness: Prograde flow initially strengthens with bottom slope but weakens once the slope becomes sufficiently steep, contradicting predictions from classical quasi-two-dimensional turbulence theories. Diagnostics of eddy PV diffusivity reveal that eddy PV stirring becomes much less efficient over steep slopes, where eddies propagate much faster relative to the background flow and tracer filaments are advected out of the eddy before significant stirring occurs. The suppressed eddy PV diffusivity results in reduced PV mixing despite larger topographic PV gradients over steep slopes. A scaling is proposed to constrain the eddy PV diffusivity, which, in turn, yields a scaling for prograde flow strength based on the leading-order momentum balance. The proposed scaling predicts stronger prograde flow with high eddy kinetic energy, intermediate slope Burger numbers, and weak friction. These findings improve our understanding of abyssal prograde flow distribution and highlight the joint role of topography and mesoscale eddies in regulating abyssal circulation. Significance Statement In the deep ocean, the sloping seafloor structures the pathways of large-scale currents, steering them to flow parallel to the slope with shallower (deeper) water to their right in the Northern (Southern) Hemisphere. Via the influence of Earth’s rotation, these currents produce secondary downhill flows along the seafloor and therefore may play an important role in shaping the pathways via which deep waters circulate back up to the ocean surface. Yet, how these deep currents depend on local environmental conditions remains poorly constrained. This study uses idealized simulation experiments and poses a novel theory to link key oceanic environmental parameters with the strength of deep, along-slope flows. These findings provide a key step toward assessing the impact of these currents on the global-scale circulation of deep-ocean waters.

中文摘要

摘要 观测与模拟研究揭示，深海倾斜地形上普遍存在顺向平均流（即沿等深线方向、与地形波传播方向一致的海流）。尽管其出现与准二维湍流理论一致，但控制其空间变异性的因素仍知之甚少。本研究利用一套涡分辨、过程导向的模拟实验，探究深海顺向流的驱动机制及其参数依赖性。与先前研究一致，我们发现顺向流由涡旋位势涡度（PV）搅拌产生的涡旋动量通量驱动，而PV梯度与倾斜海底相关。此外，我们识别出顺向流强度对海底陡度的非单调依赖性：顺向流随海底坡度增大先增强，但当坡度足够陡时反而减弱，这与经典准二维湍流理论的预测相矛盾。涡旋PV扩散率的诊断表明，在陡坡区域，涡旋PV搅拌效率显著降低——此处涡旋相对于背景流传播更快，示踪物细丝在显著搅拌发生前即被平流带出涡旋。尽管陡坡地形PV梯度更大，但受抑制的涡旋PV扩散率导致PV混合减弱。我们提出一个约束涡旋PV扩散率的标度律，进而基于主导动量平衡推导出顺向流强度的标度关系。该标度律预测：高涡动能、中等坡度Burger数及弱摩擦条件下顺向流更强。这些发现深化了对深海顺向流分布的理解，并凸显了地形与中尺度涡旋在调控深海环流中的协同作用。
意义声明 在深海中，倾斜海底结构塑造了大尺度环流的路径，使其沿坡平行流动，且北（南）半球浅水（深水）位于其右侧。受地球旋转影响，这些海流沿海底产生次级下坡流，因此可能在塑造深层水循环返回海洋表面的路径中发挥重要作用。然而，这些深层海流如何依赖局部环境条件仍缺乏约束。本研究通过理想化模拟实验，提出一种新理论，将关键海洋环境参数与深层沿坡流强度联系起来。这些发现为评估此类海流对全球尺度深海环流的影响提供了关键一步。

19. JPO — Overturning of Mixed Layer Eddies in a Submesoscale-Resolving Simulation of the North Atlantic

Abstract

Abstract To study submesoscale instabilities in the ocean mixed layer, this study uses the novel Icosahedral Nonhydrostatic (ICON)-Submesoscale Telescope (SMT) configuration that exploits a telescoping grid refinement to achieve a horizontal resolution finer than 1 km over wide areas of the North Atlantic. The model’s ability to simulate mesoscale-to-submesoscale turbulence is validated by comparing spatial power spectra of sea surface temperature and height with satellite data and a 10-km eddy-resolving simulation. We find more realistic variability in the refined grid simulation compared to the coarser simulation over a wide range of scales, including the mesoscale eddy regime. Furthermore, the high resolution permits submesoscale baroclinic instabilities at ocean fronts and we observe strong frontal overturning and restratification. Overturning rates are diagnosed from eddy buoyancy flux and mean front characteristics such as horizontal and vertical density gradients. To accurately capture the vertical extent of mixed layer eddy instabilities, commonly used threshold algorithms for identifying the mixed layer depth must be modified. We compare spatial and time filtering approaches for estimating submesoscale eddy fluxes and find qualitative similarity, although time filtering yields stronger fluxes. The diagnosed overturning rates are compared to two submesoscale baroclinic instability parameterizations. Both capture overturning magnitude at ocean fronts within an order of magnitude but overestimate it at eddy rims. Comparing submesoscale eddy fluxes in the entire study area shows two different regimes where the parameterizations slightly differ in the ability to capture the diagnosed eddy fluxes. Significance Statement In this study, we use the Icosahedral Nonhydrostatic (ICON) model with a novel configuration that allows to have a flexible horizontal resolution. With that configuration, we achieve a horizontal resolution finer than 1 km over large parts of the North Atlantic. This allows us to study so-called submesoscale ocean eddies that occur on small spatial scales at upper-ocean density fronts. Based on a comparison with high-resolution satellite data, we can show that our configuration better captures the variability on small scales compared with coarser configurations. Furthermore, we quantify how rapidly the submesoscale eddies turn over the density fronts and we evaluate how well parameterizations would be able to capture such a submesoscale eddy overturning. These findings advance understanding of submesoscale dynamics, their role in ocean energy transfer, and mixing.

中文摘要

摘要 为研究海洋混合层中的亚中尺度不稳定性，本研究采用新型二十面体非静力（ICON）-亚中尺度望远镜（SMT）配置，该配置利用望远镜式网格加密技术，在北大西洋广阔海域实现优于1公里的水平分辨率。通过将海表温度与海面高度的空间功率谱与卫星数据及10公里涡旋分辨模拟结果进行对比，验证了模型模拟中尺度至亚中尺度湍流的能力。我们发现，相较于较粗分辨率模拟，加密网格模拟在包括中尺度涡旋尺度在内的广泛尺度范围内呈现出更真实的变率。此外，高分辨率使得海洋锋面处的亚中尺度斜压不稳定性得以解析，并观测到强烈的锋面翻转与再层化过程。翻转速率通过涡旋浮力通量及平均锋面特征（如水平与垂直密度梯度）进行诊断。为准确捕捉混合层涡旋不稳定性的垂直范围，需对常用的混合层深度阈值识别算法进行修正。我们比较了空间滤波与时间滤波两种估算亚中尺度涡旋通量的方法，发现两者在定性上相似，但时间滤波产生的通量更强。将诊断的翻转速率与两种亚中尺度斜压不稳定性参数化方案进行对比，两者均能在量级上捕捉海洋锋面处的翻转幅度，但在涡旋边缘处存在高估。对整个研究区域亚中尺度涡旋通量的比较显示，存在两种不同状态，参数化方案在捕捉诊断涡旋通量的能力上略有差异。意义声明 本研究采用具有新型配置的二十面体非静力（ICON）模型，该配置可实现灵活的水平分辨率。通过该配置，我们在北大西洋大部分区域实现了优于1公里的水平分辨率，从而能够研究发生在海洋上层密度锋面小空间尺度上的所谓亚中尺度海洋涡旋。基于与高分辨率卫星数据的对比，我们证明该配置相较于较粗分辨率配置能更好地捕捉小尺度变率。此外，我们量化了亚中尺度涡旋翻转密度锋面的速率，并评估了参数化方案捕捉此类亚中尺度涡旋翻转的能力。这些发现增进了对亚中尺度动力学及其在海洋能量传递与混合中作用的理解。

20. JPO — Sea Ice Effects on Stratification in Barrow Strait: A Potential Energy Anomaly Framework

Abstract

Abstract Using a one-dimensional potential energy anomaly (PEA) framework, we examine the development and erosion of density stratification in Barrow Strait within the Canadian Arctic Archipelago. PEA is the amount of work per unit volume required to completely mix the water column, given a particular density profile. Many processes modify PEA, including surface buoyancy fluxes such as heating and cooling, ice melt and growth, precipitation and evaporation, and vertical mixing processes driven by the tides, winds, and ice drift. Using full-depth mooring data from Barrow Strait, augmented by reanalysis products, we quantify the one-dimensional surface fluxes and vertical mixing processes that affect PEA in this seasonally ice-covered region. Significant seasonality in PEA was observed, with interannual variability. The PEA analysis shows that sea ice melt and growth played a major role in setting stratification year-round. Mixing by drifting sea ice and wind became seasonally important during summer periods, as did surface heating and cooling and precipitation and evaporation, though to a lesser extent. Other common shallow shelf sea processes like tidal mixing generally contributed the least. Our analysis also indicates that mechanisms, such as advection, influence stratification at this site. Despite the acknowledged caveats and assumptions made in our approach, the findings suggest that Barrow Strait stratification is shaped not only by local processes mediated by sea ice but also by upstream changes, underscoring the region’s sensitivity to broader Arctic dynamics. Significance Statement Oceanic water column stratification regulates the vertical transport of oceanic properties and hence plays a critical role in the climate and environment. We examine the development and erosion of density stratification in Barrow Strait, Canadian Arctic Archipelago—a region of global and local significance. We find that sea ice melt and growth played a major role year-round. Mixing by ice drift and wind, and to a smaller degree heating and cooling and precipitation and evaporation, was seasonally important. Tidal mixing contributed the least. We address uncertainties in our analysis and highlight the likely importance of lateral advection on stratification. In conclusion, stratification in Barrow Strait is sensitive to both local processes mediated by sea ice and to upstream changes.

中文摘要

摘要 利用一维势能异常（PEA）框架，我们研究了加拿大北极群岛巴罗海峡密度层结的形成与消退过程。PEA是指在给定密度剖面条件下，完全混合水柱所需的单位体积功。许多过程会改变PEA，包括加热与冷却等表面浮力通量、海冰融化与生长、降水与蒸发，以及由潮汐、风和海冰漂移驱动的垂直混合过程。利用巴罗海峡全深度锚系观测数据，并结合再分析产品，我们量化了影响该季节性海冰覆盖区域PEA的一维表面通量和垂直混合过程。观测到PEA具有显著的季节性变化及年际变率。PEA分析表明，海冰融化与生长在全年层结形成中起主导作用。夏季期间，漂移海冰和风的混合作用变得季节性重要，表面加热与冷却、降水与蒸发的影响次之。其他常见的浅海陆架过程（如潮汐混合）贡献最小。我们的分析还表明，平流等机制也影响该站点的层结。尽管我们的方法存在已知的局限性和假设，但研究结果表明，巴罗海峡的层结不仅受海冰介导的局地过程影响，还受上游变化的影响，凸显了该区域对更广泛北极动力学的敏感性。意义声明 海洋水柱层结调节着海洋属性的垂向输运，因此在气候与环境中起着关键作用。我们研究了加拿大北极群岛巴罗海峡——一个具有全球和局地重要性的区域——密度层结的形成与消退过程。研究发现，海冰融化与生长在全年中起主导作用。冰漂移和风的混合作用在夏季具有季节性重要性，而加热与冷却、降水与蒸发的影响较小。潮汐混合的贡献最小。我们讨论了分析中的不确定性，并强调了侧向平流对层结的可能重要性。总之，巴罗海峡的层结既对海冰介导的局地过程敏感，也受上游变化的影响。

21. JPO — Formation of a Quasi-Universal Internal Wave Spectrum by Wind Forcing Alone: Idealized Modeling and Mooring Observations

  • 作者：Qian Zhang, Zhiwu Chen, Zhiyu Liu, Lixin Qu, Huaihao Lu, Yuhan Sun, Qingyou He, Jiexin Xu, Yankun Gong, Shuqun Cai
  • 发表日期：2026-06-01
  • DOI：https://doi.org/10.1175/jpo-d-25-0199.1

Abstract

Abstract Oceanic internal waves (IWs) play a key role in diapycnal mixing that sustains the global overturning circulation. Their energy follows a quasi-universal Garrett–Munk (GM) spectrum, traditionally attributed to nonlinear wave–wave interactions under combined wind and tidal forcing. However, growing evidence points to the importance of eddy–wave interactions, but the specific energy contributions from mesoscale and submesoscale motions to this GM spectrum remain unclear. More importantly, the generation of this GM spectrum by eddy–wave interactions has not been observed in the real ocean. In the present work, an idealized numerical model is used to simulate the formation of a GM-like spectrum by eddy–wave interaction under wind forcing alone. Energy transfers are diagnosed in both Eulerian and Lagrangian coordinates using a multiscale energy and vorticity analysis. It is found that IW energy supplied by mesoscale eddies is comparable to that from submesoscale motions in Lagrangian coordinate, whereas this mesoscale contribution appears much weaker in Eulerian coordinate. Vertically, mesoscale eddies transfer energy to IWs in the upper ocean, while this energy transfer is reversed in the pycnocline. In situ mooring observations from the Southern Ocean further support the role of eddies in facilitating the generation of a GM-like spectrum under wind forcing alone. Together, these findings clarify the energy pathways through which mesoscale and submesoscale dynamics energize IWs and offer new insight into the dynamical processes that help maintain the GM spectrum. Significance Statement A quasi-universal internal wave (IW) spectrum is traditionally thought to be created by wave–wave interactions through simultaneous wind and tidal forcing. Using idealized simulations and Southern Ocean observations, this study provides evidence that wind forcing over an eddying ocean can generate a Garrett–Munk (GM)-like spectrum. Lagrangian energy transfer analyses reveal comparable mesoscale and submesoscale contributions to IW energy, whereas direct extraction of mesoscale energy is less apparent in Eulerian coordinate. Vertically, mesoscale eddies energize IWs in the upper ocean, while IWs return energy to mesoscale eddies in the pycnocline, thus limiting the penetration of wind-induced IWs. These results clarify the dynamical pathways feeding IWs, providing new insights into the formation of a GM-like spectrum under wind forcing alone.

中文摘要

摘要 海洋内波在维持全球翻转环流的跨密度面混合中起着关键作用。其能量遵循准普遍的Garrett–Munk (GM)谱，传统上归因于风和潮汐共同强迫下的非线性波-波相互作用。然而，越来越多的证据表明涡-波相互作用的重要性，但中尺度和次中尺度运动对该GM谱的具体能量贡献仍不清楚。更重要的是，在真实海洋中尚未观测到由涡-波相互作用产生该GM谱的过程。本研究利用理想化数值模型，模拟了仅由风强迫下涡-波相互作用形成类GM谱的过程。通过多尺度能量和涡度分析，在欧拉和拉格朗日坐标系中诊断了能量传递。结果发现，在拉格朗日坐标系中，中尺度涡旋提供给内波的能量与次中尺度运动相当，而在欧拉坐标系中，这一中尺度贡献显得弱得多。在垂向上，中尺度涡旋在上层海洋向内波传递能量，而在跃层中能量传递方向相反。来自南大洋的现场锚系观测进一步支持了仅风强迫下涡旋促进类GM谱生成的作用。这些发现共同阐明了中尺度和次中尺度动力学为内波提供能量的路径，并为维持GM谱的动力过程提供了新见解。意义声明 传统上认为准普遍的内波谱是由风和潮汐共同强迫下的波-波相互作用产生的。本研究通过理想化模拟和南大洋观测，提供了证据表明在涡旋活跃的海洋中，仅风强迫即可生成类Garrett–Munk (GM)谱。拉格朗日能量传递分析显示，中尺度和次中尺度对内波能量的贡献相当，而在欧拉坐标系中，中尺度能量的直接提取则不那么明显。在垂向上，中尺度涡旋在上层海洋为内波提供能量，而在跃层中内波将能量返还给中尺度涡旋，从而限制了风生内波的穿透深度。这些结果阐明了为内波供能的动力学路径，为仅风强迫下类GM谱的形成提供了新见解。

22. JGR: Oceans — Structure and Dynamics of the Antarctic Slope and Weddell Fronts Along the SR04 WOCE Section Based on Four Oceanographic Cruises (2007–2022)

Abstract

Abstract The Antarctic Slope Current (ASC) and the Weddell Front‐associated Current (WFC) form a system of bottom‐intensified jets found in the continental slope of the Antarctic peninsula, acting as major conduits for the export of dense Weddell Sea waters into the global overturning circulation. We investigate the structure, transport, and multiyear variability of these boundary currents in the northwestern Weddell Sea using hydrographic and velocity data. These include four occupations of the WOCE SR04 section: three RV Polarstern reoccupations between 2016 and 2022, complemented by an earlier occupation in 2007. Our multiyear observations reveal previously unquantified variability in the strength, vertical structure, and water‐mass composition of the jets. ASC transport ranges from 0.4 ± 0.2 Sv in 2017 to 7.4 ± 0.3 Sv in 2019, while transport associated with the WFC varies from 5.2 ± 0.6 Sv in 2019 to 8.5 ± 0.7 Sv in 2017. Two key mechanisms emerge as drivers of this variability: (a) enhanced ASC flow associated with dense bottom water, steepening isopycnals and intensifying baroclinic shear, dominating during strong stratification events; and (b) wind‐driven barotropic adjustment, indicated by negative wind stress curl aligned with steeper absolute dynamic topography gradients, dominating under strong wind forcing conditions. These findings highlight the combined role of stratification and wind forcing in regulating boundary current variability and establish a novel baseline for evaluating the climate sensitivity of dense water export in the northwestern Weddell Sea.

中文摘要

摘要 南极坡流（ASC）与威德尔锋相关流（WFC）构成了南极半岛大陆坡上的一组底部增强型急流系统，是稠密威德尔海水输出至全球翻转环流的主要通道。我们利用水文和流速数据研究了西北威德尔海这些边界流的结构、输运量及多年变率。数据包括WOCE SR04断面的四次观测：2016年至2022年间三次”极星号”调查船的重复观测，以及2007年的一次早期观测。我们的多年观测揭示了这些急流在强度、垂直结构和水团组成方面此前未被量化的变率。ASC输运量从2017年的0.4±0.2 Sv变化至2019年的7.4±0.3 Sv，而WFC相关输运量则从2019年的5.2±0.6 Sv变化至2017年的8.5±0.7 Sv。驱动这种变率的两个关键机制为：(a) 与稠密底层水相关的ASC增强流动，导致等密面变陡和斜压切变增强，在强层结事件中占主导地位；(b) 风驱正压调整，表现为与更陡的绝对动力地形梯度相一致的负风应力旋度，在强风强迫条件下占主导地位。这些发现揭示了层结和风强迫在调节边界流变率中的联合作用，并为评估西北威德尔海稠密水输出的气候敏感性建立了新的基准。

23. JGR: Oceans — Distribution and Export of Particulate 3‐Hydroxy Fatty Acids in the Northwestern Pacific Ocean: Implications for Seawater Temperature Reconstructions

Abstract

Abstract Bacterial 3‐hydroxy fatty acids (3‐OH‐FAs) have emerged as promising biomarkers for reconstructing seawater temperatures. However, uncertainties regarding their production and transportation from water column to sediments have hindered accurate interpretation of temperature signals reconstructed by sedimentary 3‐OH‐FAs. Here, we present a comprehensive analysis of particulate 3‐OH‐FAs from two water column profiles and corresponding surface sediments in the Northwestern Pacific Ocean (NWP). Particulate 3‐OH‐FA concentrations ranged from 0.69 to 2.95 μg L −1 , peaking in the surface layer coinciding with elevated particulate organic carbon (POC) concentrations and higher temperatures. Seawater temperature was the primary factor controlling 3‐OH‐FA distributions in the water column, supported by its highest variable importance in projection score in the partial least squares analysis. Temperature showed a significant negative correlation with relative abundance of branched homologs, consistent with homeoviscous adaptation. An export model based on depth‐specific molecular index Br 13+17 % (proportion of branched C 13 and C 17 homologs) indicated that 3‐OH‐FAs in the study area are primarily exported from the subsurface layer (∼200 m), where production and aggregation/packaging efficiency are optimally coupled. The sedimentary 3‐OH‐FA‐based seawater temperature index RAN 13 effectively captured the variability of subsurface seawater temperature, consistent with the export model results. Overall, these findings suggest that 3‐OH‐FAs in deep NWP sediments are mainly sourced from subsurface waters, thereby highlighting their potential as a proxy for subsurface temperature reconstructions in this region.

中文摘要

摘要 细菌3-羟基脂肪酸（3-OH-FAs）已成为重建海水温度的重要生物标志物。然而，关于其在水柱中产生及向沉积物输送过程的不确定性，阻碍了对沉积物中3-OH-FAs所重建温度信号的准确解读。本文对西北太平洋（NWP）两个水柱剖面及对应表层沉积物中的颗粒态3-OH-FAs进行了综合分析。颗粒态3-OH-FA浓度范围为0.69至2.95 μg L⁻¹，在表层达到峰值，与颗粒有机碳（POC）浓度升高及较高温度相对应。偏最小二乘分析中，海水温度具有最高的变量投影重要性得分，表明其是控制水柱中3-OH-FA分布的主要因素。温度与支链同系物相对丰度呈显著负相关，这与恒黏适应机制一致。基于深度特异性分子指数Br₁₃₊₁₇%（支链C₁₃和C₁₇同系物比例）的输运模型表明，研究区3-OH-FAs主要从次表层（约200米）输出，该层位中生产与聚集/包裹效率达到最优耦合。基于沉积物3-OH-FAs的海水温度指数RAN₁₃有效捕捉了次表层海水温度的变化，与输运模型结果一致。总体而言，这些发现表明西北太平洋深层沉积物中的3-OH-FAs主要来源于次表层水体，从而凸显其作为该区域次表层温度重建代用指标的潜力。

24. JC — Trends in atmospheric radiative cooling from satellite, reanalyses and CMIP6 datasets

  • 作者：Caroline Jouan, Rachael Byrom, Gunnar Myhre, Camilla W. Stjern, Birthe Marie Steensen, Norman G. Loeb, Seiji Kato, Piers Forster
  • 发表日期：2026-06-04
  • DOI：https://doi.org/10.1175/jcli-d-25-0511.1

Abstract

Abstract Atmospheric radiative cooling (Q) is closely tied to latent heat release during precipitation, and its changes offer critical insight into how changes in the Earth’s energy balance might impact future rainfall. This study analyzes trends in Q (dQ) over 2001-2024 period using CERES observation-constrained estimates, two reanalysis datasets (ERA5 and MERRA2) and the CMIP6 multi-model mean. The datasets show significant divergence in global mean dQ. CERES indicates a negative trend of −0.21 ± 0.45 W m −2 decade −1 (shifting to +0.19 after 2006), ERA5 shows a positive trend of +0.56 ± 0.27 W m −2 decade −1 , while MERRA2 and CMIP6 display weaker trends. These differences arise from divergent longwave radiative cooling trends over land, driven by surface temperature biases prior to 2006 and strong temperature and water vapor anomalies associated with ENSO events. Shortwave radiative cooling generally decreases, although regional aerosol variability, including intense Amazonian fires in 2024, may further influence global trends. In reanalyses, cloud representations often mask aerosol radiative effects, complicating attribution. While consistent trends across independent datasets would suggest a robust signal, our results highlight the limitations that influence dQ, including input dataset inconsistencies, differing treatments of compensating radiative effects of key drivers such as near-surface temperature and water vapor—which amplify Q variability under strong forcing—and the realistic or unrealistic representation of cloud and aerosol trends. As a result, both measurements and simulations of a dQ indicate a positive trend, but the reliability of its magnitude remains uncertain, highlighting the need to reconcile differences across multiple datasets.

中文摘要

摘要 大气辐射冷却（Q）与降水过程中的潜热释放密切相关，其变化为理解地球能量平衡变化如何影响未来降雨提供了关键见解。本研究利用CERES观测约束估算、两个再分析数据集（ERA5和MERRA2）以及CMIP6多模式均值，分析了2001-2024年期间Q的趋势（dQ）。各数据集在全球平均dQ上显示出显著差异。CERES显示负趋势为−0.21 ± 0.45 W m⁻² decade⁻¹（2006年后转为+0.19），ERA5显示正趋势为+0.56 ± 0.27 W m⁻² decade⁻¹，而MERRA2和CMIP6则呈现较弱趋势。这些差异源于陆地长波辐射冷却趋势的分歧，其驱动因素包括2006年之前的地表温度偏差以及与ENSO事件相关的强温度和水汽异常。短波辐射冷却总体呈下降趋势，尽管区域气溶胶变率（包括2024年亚马逊地区强烈火灾）可能进一步影响全球趋势。在再分析中，云的表征常掩盖气溶胶辐射效应，使归因复杂化。虽然独立数据集间一致的趋势可能表明稳健信号，但我们的结果凸显了影响dQ的局限性，包括输入数据集的不一致性、对关键驱动因子（如近地表温度和水汽）补偿辐射效应的不同处理方式——这些因子在强强迫下会放大Q变率——以及云和气溶胶趋势表征的真实性或非真实性。因此，dQ的测量和模拟均显示正趋势，但其量值的可靠性仍不确定，这凸显了协调多个数据集间差异的必要性。

25. JC — New Insights into Dynamic Feedback from Sea Surface Temperature Gradient to Summer Monsoon Intraseasonal Oscillations over the South China Sea

Abstract

Abstract During the South China Sea summer monsoon (SCSSM), 30-60-day monsoon intraseasonal oscillations (MISOs) represent the dominant mode of monsoon variability. While air-sea interactions are pronounced on this timescale, the specific oceanic feedback on MISO deep convection remains inadequately quantified and requires further investigation. This study investigates an ocean dynamic feedback mechanism during MISOs over the SCS. Composite analysis of observations and ERA5 reanalysis reveals distinct phase relationships: warm intraseasonal sea surface temperatures (SSTs) precede deep convection by approximately 10 days, while cold SSTs lag. This creates a pronounced meridional SST gradient that enhances low-level wind convergence ahead of convection. Crucially, warm SST anomalies strengthen vertical momentum transfer, initially accelerating easterly winds (∼10 days before convection) and subsequently intensifying westerlies near the convective center. These wind changes generate cyclonic vorticity anomalies ahead of convection, promoting wind convergence and triggering new convection to the north. Simultaneously, cold SST anomalies suppress convection to the south through weakened vertical mixing and westerlies, and the generation of anticyclonic vorticity. To quantify these mechanisms, we conducted turbulent flux-locking experiments using a coupled climate model. Results demonstrate that both oceanic dynamic (momentum flux) and thermal (heat flux) feedbacks account for approximately 70% of the total oceanic contribution to intraseasonal wind convergence and relative vorticity, with each mechanism playing a comparable role within that share. This challenges the conventional view that thermal feedback through warm SST-induced heat flux dominates the coupled ocean-convection dynamics. We demonstrate that SST gradients play a pivotal role in modulating low-level winds and vorticity, offering a more comprehensive explanation for MISO propagation. The findings underscore the need to capture both dynamic and ocean thermal feedbacks in climate models to improve simulations and predictions of monsoon variability and change.

中文摘要

摘要 在南海夏季风期间，30-60天季风内振荡是季风变异的主导模态。尽管海气相互作用在此时间尺度上显著，但海洋对季风内振荡深对流的具体反馈机制尚未得到充分量化，仍需进一步研究。本研究探讨了南海季风内振荡期间的一种海洋动力反馈机制。基于观测和ERA5再分析资料的合成分析揭示了明确的位相关系：暖的季风内海表温度超前深对流约10天，而冷的海表温度则滞后。这形成了显著的经向海表温度梯度，在对流前方增强低层风辐合。关键的是，暖海表温度异常增强了垂直动量输送，最初加速了东风（对流前约10天），随后增强了对流中心附近的西风。这些风场变化在对流前方产生气旋性涡度异常，促进风辐合并触发北部新对流。同时，冷海表温度异常通过减弱垂直混合和西风以及产生反气旋涡度，抑制了南部的对流。为量化这些机制，我们利用耦合气候模式开展了湍流通量锁定实验。结果表明，海洋动力（动量通量）和热力（热通量）反馈共同贡献了季风内风辐合和相对涡度总海洋贡献的约70%，且两种机制在此份额中作用相当。这挑战了传统观点，即暖海表温度诱导热通量的热力反馈主导耦合海洋-对流动力学。我们证明海表温度梯度在调节低层风和涡度中起关键作用，为季风内振荡传播提供了更全面的解释。研究结果强调，气候模式需同时捕捉海洋动力和热力反馈，以改进季风变异与变化的模拟和预测。

26. JC — Antarctic extreme precipitation variability from 1979 to 2022: Role of atmospheric rivers and tropical western Pacific convection

Abstract

Abstract Extreme precipitation (EP) exerts an important impact on Antarctic mass changes, and consequent global sea level changes. However, its drivers and remote influences remain insufficiently understood. Validation against in situ observations shows that ERA5 reanalysis robustly captures Antarctic EP events. Using ERA5, we examine the spatiotemporal variability in annual and seasonal Antarctic EP from 1979 to 2022, and explore the underlying mechanisms involving atmospheric rivers (ARs) and large-scale circulation modes. Antarctic ice sheet (AIS)-averaged EP intensity and frequency have increased significantly since 1979, with strong seasonal and regional contrasts linked to the Southern Annular Mode (SAM) and the two Pacific South American (PSA1 and PSA2) patterns. AR landfalls contribute 53.4% of annual EP totals and explain 72% of interannual EP variability. Notably, large-scale EP events affecting >20% of the ice sheet are preceded by enhanced deep convection over the tropical western Pacific (TWP). This tropical heating anomaly generates upper-level divergence that excites stationary Rossby wave trains. The resulting wave responses project onto zonal wave 3 (ZW3) and zonal wave 4 (ZW4) circulation patterns over the Southern Ocean, establishing multiple meridional moisture corridors toward Antarctica, thereby intensifying AR activity and promoting large-scale EP occurrence. These findings underscore ARs and tropical-polar teleconnections as critical drivers of Antarctic hydroclimatic variability, with implications for ice-sheet mass balance projections.

中文摘要

极端降水（EP）对南极冰盖质量变化及全球海平面变化具有重要影响，然而其驱动机制与远程影响仍未被充分认知。通过与实地观测数据的验证表明，ERA5再分析资料能够稳健捕捉南极极端降水事件。基于ERA5数据，我们分析了1979至2022年间南极年际与季节性极端降水的时空变化特征，并探讨了大气河流（ARs）与大尺度环流模态的潜在作用机制。自1979年以来，南极冰盖（AIS）平均的极端降水强度与频率显著增加，其强烈的季节性与区域性差异与南半球环状模（SAM）及两种太平洋-南美遥相关型（PSA1和PSA2）密切相关。大气河流登陆事件贡献了年极端降水总量的53.4%，并解释了72%的年际极端降水变率。值得注意的是，影响冰盖面积超过20%的大尺度极端降水事件发生前，热带西太平洋（TWP）区域均出现增强的深对流活动。这一热带加热异常激发高层辐散，进而触发准定常罗斯贝波列。由此产生的波动响应投射到南大洋上空形成纬向波数3（ZW3）与纬向波数4（ZW4）环流型，构建起多条指向南极的经向水汽通道，从而增强大气河流活动并促进大尺度极端降水事件的发生。这些发现揭示了大气河流与热带-极地遥相关作为南极水文气候变率关键驱动因子的作用，对冰盖物质平衡预估具有重要启示。

27. JC — On the role of ocean dynamics in polar amplified climate change

Abstract

Abstract Coupled general circulation models (GCMs) ubiquitously predict polar amplified surface warming in response to increasing CO 2 concentrations, but with significant variation in the magnitude of polar temperature rises. Here we develop a simplified model of climate change over the global ocean to better understand the fundamental physics underpinning polar amplification and untangle the role of ocean dynamics in modulating its strength. Our model is composed of a forcing-feedback formulation for the surface energy balance coupled to the ocean circulation, with the atmosphere slaved to the ocean. Our results suggest that polar amplified warming is a fundamental property of any climate where the poles are colder than the equator, due largely to the variation of the (negative) evaporative and (positive) longwave feedbacks with temperature. The evaporative feedback weakens more rapidly than the longwave feedback as temperature decreases, leading to larger temperature changes at the poles than the equator. In our model the polar oceans are highly sensitive to feedbacks associated with ocean dynamics, which we decompose into circulation and mixing. We find that the amplification of warming in both the Southern Ocean and Arctic Ocean is most sensitive to strength of the Atlantic Meridional Overturning Circulation at centennial timescales, and near-surface mixing at decadal timescales. There is also significant sensitivity of Southern Ocean temperature changes to the strength of the abyssal overturning, as well as the deep diapycnal mixing. As such, our results suggest that the differing representation of ocean dynamics in GCMs may partly explain their significant variation in the meridional structure of warming under CO 2 forcing.

中文摘要

摘要 耦合环流模式普遍预测，在CO₂浓度增加的情况下，极地表面增温会放大，但极地温度升高的幅度存在显著差异。本文建立了一个全球海洋气候变化简化模型，以更好地理解极地放大效应的基本物理机制，并厘清海洋动力学在调节其强度中的作用。该模型由耦合海洋环流的强迫-反馈海表能量平衡方程组成，其中大气从属于海洋。结果表明，极地增温放大是任何极地温度低于赤道气候的基本属性，这主要归因于（负的）蒸发反馈和（正的）长波反馈随温度的变化。随着温度降低，蒸发反馈的减弱速度快于长波反馈，导致极地温度变化大于赤道。在该模型中，极地海洋对与海洋动力学相关的反馈高度敏感，我们将这些反馈分解为环流和混合两部分。研究发现，南大洋和北冰洋的增温放大在百年时间尺度上对大西洋经向翻转环流强度最为敏感，在十年时间尺度上对近表层混合强度最为敏感。此外，南大洋温度变化对深层经向翻转环流强度以及深层等密度面混合强度也表现出显著敏感性。因此，我们的结果表明，不同耦合环流模式对海洋动力学的表征差异，可能部分解释了它们在CO₂强迫下增温经向结构上的显著差异。

28. GRL — Early Establishment of Far Eastern Pacific Warming Shapes Distinctive Air‐Sea Coupling in the 2023–2024 El Niño

Abstract

Abstract This study investigates the role of far eastern Pacific (FEP) sea surface temperature anomalies (SSTA) in shaping El Niño development, focusing on the 2023–2024 event. Unlike most post‐1980 El Niño events, which are characterized by central–eastern Pacific–dominated growth and strong air–sea coupling, the 2023–2024 event featured early FEP warming and weak central Pacific westerly anomalies during its development. Linear decomposition shows that a substantial portion of FEP variability is not explained by canonical El Niño–Southern Oscillation dynamics, and this residual FEP component plays a key role in the evolution of the 2023–2024 event. This FEP warming is accompanied by subtropical northeastern Pacific cooling and suppressed convection, inducing off‐equatorial northeasterlies that weaken central Pacific westerlies. Such FEP‐dominant characteristics occurred more frequently in pre‐1980 El Niño events, consistent with decadal thermocline changes that may modulate the relative sensitivity of eastern and central Pacific SSTA growth.

中文摘要

摘要 本研究探讨了远东太平洋（FEP）海表温度异常（SSTA）在塑造厄尔尼诺发展过程中的作用，重点关注2023–2024年事件。与1980年后大多数以中东太平洋主导增长和强海气耦合为特征的厄尔尼诺事件不同，2023–2024年事件在发展初期呈现出FEP增暖和中太平洋西风异常偏弱的特点。线性分解表明，FEP变率的相当一部分无法由经典厄尔尼诺-南方涛动动力学解释，而这一残余FEP分量在2023–2024年事件的演变中发挥了关键作用。该FEP增暖伴随副热带东北太平洋冷却和抑制的对流，诱发赤道外东北风，从而削弱中太平洋西风。此类FEP主导特征在1980年前的厄尔尼诺事件中出现更为频繁，这与可能调节东太平洋和中太平洋SSTA增长相对敏感性的年代际温跃层变化相一致。

29. GRL — Glacial Ice‐Front Calving: Internal Wave Generation and Melting

Abstract

Abstract Small, frequent calving events dominate the behavior of most Arctic marine‐terminating glaciers, yet their oceanographic impacts remain largely unquantified. We present the first direct observations of internal waves generated by modest ice‐fall calving at Kronebreen, Svalbard. High‐resolution current meter and microstructure measurements show that each event excites weakly nonlinear multi‐modal internal wave packets with ∼4 m vertical displacements and mode 1 propagation speeds of 0.35–0.42 ms −1 . These waves enhance shear and turbulence in the upper 15 m and modify local stratification. Idealized numerical simulations reproduce the observed wave characteristics and confirm their sensitivity to fjord stratification. Given the high frequency of small calving events across Arctic glaciers, calving‐generated internal waves may represent an under‐recognized mechanism contributing to submarine melt and fjord‐scale mixing.

中文摘要

摘要 小型、频繁的崩解事件主导了大多数北极海洋末端冰川的行为，但其海洋学影响在很大程度上尚未被量化。我们首次提供了斯瓦尔巴群岛克朗布雷恩冰川因小型冰崩解产生的内波的直接观测数据。高分辨率海流计和微结构测量显示，每次事件激发弱非线性多模态内波包，垂直位移约4米，模态1传播速度为0.35–0.42米/秒。这些波增强了上层15米内的剪切和湍流，并改变了局部层结。理想化数值模拟再现了观测到的波特征，并证实其对峡湾层结的敏感性。鉴于北极冰川小型崩解事件的高频发生，崩解生成的内波可能是一种未被充分认识的机制，对水下融化和峡湾尺度混合具有贡献。

30. GRL — The Lifecycle of Tracer Variance in the North Atlantic

  • 作者：Espe Broullón, R Graham Williams, Alberto C. Naveira Garabato, Louis Clément, Bieito Fernández Castro
  • 发表日期：2026-06-02
  • DOI：https://doi.org/10.1029/2026gl122823

Abstract

Abstract Oceanic tracer distributions are shaped by turbulent mixing, which may be understood via a traver variance budget. There is a tracer variance lifecycle: variance production by turbulent flows stirring large‐scale gradients, redistribution by currents, and variance dissipation by molecular diffusion. A comprehensive tracer variance budget, including variance transport, is diagnosed from North Atlantic hydrographic observations and reveals three different regimes. In the subtropical thermocline, there is a local balance between diapycnal production by microscale turbulence and molecular dissipation. In intermediate waters and the subpolar gyre, the local balance is between isopycnal production by mesoscale stirring and dissipation. Near gyre boundaries, a three‐way balance emerges between isopycnal production by mesoscale stirring, variance transport by currents, and dissipation downstream. Transitions between mixing regimes are determined by water‐mass contrasts and circulation strength. Our expectation is that these different mixing regimes apply to the global ocean and affect how the ocean sequesters and redistributes anthropogenic heat.

中文摘要

摘要 海洋示踪物分布受湍流混合塑造，这可通过示踪物方差预算加以理解。示踪物方差存在生命周期：湍流搅动大尺度梯度产生方差，洋流重新分布方差，分子扩散耗散方差。基于北大西洋水文观测资料，本文诊断了包含方差输运在内的完整示踪物方差预算，揭示了三种不同机制。在副热带温跃层中，微尺度湍流的跨等密度面产生与分子耗散之间存在局地平衡。在中层水和副极地环流中，中尺度搅动的等密度面产生与耗散之间呈现局地平衡。在环流边界附近，中尺度搅动的等密度面产生、洋流方差输运与下游耗散之间形成三重平衡。混合机制的转换由水团对比度和环流强度共同决定。我们预期这些不同混合机制适用于全球海洋，并影响海洋对人为热量的封存与再分布过程。

31. GRL — Tropical Pacific Variability Drives Quasi‐Decadal Sea Ice Fluctuations Off East Greenland

Abstract

Abstract The sea ice off East Greenland exhibits pronounced quasi‐decadal fluctuations superimposed on its long‐term decline. Here we show that this low‐frequency variability is tightly phase‐coherent with tropical Pacific quasi‐decadal variability (TPQD), revealing a teleconnection from the tropics to the Arctic. Using observations together with targeted pacemaker experiments, we demonstrate that convective anomalies during positive TPQD phases generate Rossby wave energy propagation along a Pacific–North American pathway, establishing a positive North Atlantic Oscillation (NAO)‐like circulation that enhances northward ocean heat transport into the Greenland–Iceland–Norwegian Seas. The resulting upper ocean warming drives sea ice loss along East Greenland, whereas the opposite circulation pattern during negative phases promotes cooling and sea ice growth, together producing quasi‐decadal fluctuations in local sea ice. These findings reveal a previously underappreciated tropical influence on Arctic climate and highlight a potential source of decadal predictability for Arctic change.

中文摘要

摘要 东格陵兰海域的海冰在长期衰退趋势上叠加了显著的准十年尺度波动。本研究表明，这种低频变率与热带太平洋准十年变率（TPQD）在相位上高度一致，揭示了从热带到北极的遥相关机制。通过结合观测数据与定向步进器实验，我们证实：在TPQD正位相期间，对流异常沿太平洋-北美路径激发罗斯贝波能量传播，形成类似正位相北大西洋涛动（NAO）的环流型，从而增强向北进入格陵兰-冰岛-挪威海的海表热输送。由此引发的上层海洋增温驱动东格陵兰海冰消融，而负位相期间的相反环流型则促进冷却与海冰增长，共同导致该区域海冰的准十年尺度波动。这些发现揭示了此前被低估的热带对北极气候的影响，并凸显了北极变化十年可预测性的潜在来源。

32. GRL — SamudrACE: Fast and Accurate Coupled Climate Modeling With 3D Ocean and Atmosphere Emulators

  • 作者：James Duncan, Elynn Wu, Surya Dheeshjith, Adam Subel, Troy Arcomano, Spencer K. Clark, Brian Henn, Anna Kwa, Jeremy McGibbon, W. A. Perkins, William K. Gregory, Carlos Fernandez-Granda, Julius Busecke, Oliver Watt‐Meyer, William J. Hurlin, Alistair Adcroft, Laure Zanna, Christopher S. Bretherton
  • 发表日期：2026-05-30
  • DOI：https://doi.org/10.1029/2025gl119340

Abstract

Abstract Traditional numerical global climate models simulate the full Earth system by exchanging boundary conditions between separate simulators of the atmosphere, ocean, sea ice, land surface, and other geophysical processes. This paradigm allows for distributed development of individual components within a common framework, unified by a coupler that handles translation between realms via spatial or temporal alignment and flux exchange. Following a similar approach adapted for machine learning‐based emulators, we present SamudrACE: a coupled global climate model emulator which produces centuries‐long simulations at 1‐degree horizontal, 6‐hourly atmospheric, and 5‐daily oceanic resolution, with 145 2D fields spanning 8 atmospheric and 19 oceanic vertical levels, plus sea ice, surface, and top‐of‐atmosphere variables. SamudrACE is highly stable and has low climate biases comparable to those of its components with prescribed boundary forcing, with realistic variability in coupled climate phenomena such as ENSO that is not possible to simulate in uncoupled mode.

中文摘要

摘要 传统数值全球气候模式通过在大气、海洋、海冰、陆面及其他地球物理过程的独立模拟器之间交换边界条件，实现对完整地球系统的模拟。这一范式允许在统一框架内对各组件进行分布式开发，并通过耦合器实现不同领域间的空间或时间对齐及通量交换。基于适用于机器学习模拟器的类似方法，我们提出SamudrACE：一个耦合的全球气候模式模拟器，能够以1度水平分辨率、6小时间隔的大气及5天间隔的海洋分辨率生成百年尺度模拟，涵盖145个二维场，跨越8个大气层和19个海洋层，以及海冰、地表和大气顶变量。SamudrACE具有高度稳定性，其气候偏差与采用指定边界强迫的组件相当，并在厄尔尼诺-南方涛动等耦合气候现象中展现出非耦合模式无法模拟的现实变率。

33. GRL — The Global Contribution of Individual Submarine Groundwater Discharge Components to the Ocean

Abstract

Abstract Saline submarine groundwater discharge (SSGD) contributes to ocean chemistry through water‐rock interactions as seawater circulates in coastal aquifers. Its components, driven by different mechanisms, exhibit varying residence times and degrees of chemical alteration, so constraining solute fluxes requires quantifying each component. We estimated global density‐driven and tidally driven SSGD and solute fluxes using numerical modeling and geospatial data. The modeled global fluxes of density‐driven circulation, nearshore tidal circulation, and tidal pumping are 23 (3–219) km 3 /yr, 254 (173–275) km 3 /yr, and 388 (179–1,032) km 3 /yr, respectively. Groundwater flow models often underestimate density‐driven circulation because aquifer heterogeneity creates complex salinity distributions that can increase fluxes by orders of magnitude. Accounting for heterogeneity and hydraulic conductivity uncertainty, the revised estimate for density‐driven circulation is 523 (181–1,705) km 3 /yr, comparable to the total tidal‐driven SGD. This water flux delivers ∼3 Tmol/yr Ca 2+ to the ocean, a significant fraction of the global riverine calcium input.

中文摘要

摘要 含盐海底地下水排放（SSGD）通过海水在沿海含水层中循环时的水-岩相互作用影响海洋化学。其不同组分由不同机制驱动，具有不同的滞留时间和化学改造程度，因此约束溶质通量需要量化每个组分。我们利用数值模拟和地理空间数据估算了全球密度驱动和潮汐驱动的SSGD及溶质通量。模拟的全球密度驱动环流、近岸潮汐环流和潮汐泵送通量分别为23（3–219）km³/yr、254（173–275）km³/yr和388（179–1,032）km³/yr。地下水流动模型常低估密度驱动环流，因为含水层非均质性会产生复杂的盐度分布，从而可能使通量增加数个数量级。考虑非均质性和水力传导率不确定性后，密度驱动环流的修正估计值为523（181–1,705）km³/yr，与总潮汐驱动SGD相当。这一水通量向海洋输送约3 Tmol/yr的Ca²⁺，占全球河流钙输入量的显著比例。

34. JC — Atmospheric Rivers Linking Tropical Forcing to Winter Precipitation over Southern China

Abstract

Abstract Significant winter [December–February (DJF)] precipitation over southern China (SC) is one of the key features of the East Asian winter monsoon, accounting for nearly 20% of annual precipitation in the area. While oceanic drivers of its interannual variability are extensively studied, the influence of atmospheric rivers (ARs), contributing approximately 30%–40% of the climatological wintertime precipitation in SC, remains unclear. Additionally, how seasonal forecast models capture the impact of tropical sea surface temperature (SST) variations on winter precipitation through ARs requires further investigation using objective metrics. This study identifies a tropical SST pattern involving El Niño–Southern Oscillation (ENSO), the Indian Ocean dipole, and the SST anomalies over the western North Pacific (WNP), whose coevolving structure rapidly develops from the preceding summer to winter. This anomalous SST configuration generates a hemispheric-scale circulation pattern from the tropics to the subtropics, which enhances vertical wind shear and meridional moisture transport over SC, favoring increased AR intrusion into the region. Consequently, significant precipitation anomalies occur particularly near SC along 20°–30°N, explaining over 50% of the interannual DJF precipitation variability. These ENSO-driven precipitation changes, mediated by AR activity, are reasonably predicted by two operational seasonal forecast systems, suggesting that ENSO and its interaction with WNP SST anomalies serve as the primary sources of forecast skill for winter ARs and SC precipitation. Furthermore, a screening scheme based on the observed SST and circulation states during October and November preceding the target winter is developed to determine the years in which the dynamical model forecast skill for SC DJF precipitation is higher than in other winters. Significance Statement A coupling pattern between atmospheric rivers (ARs), accounting for one-third of December–February (DJF) precipitation in climatology, and large-scale circulation plays a critical role in shaping the winter (DJF) precipitation variability in southern China (SC). This mode, characterized by a low pressure anomaly over central China and more active ARs steered into the region, explains at least 50% of the region’s total DJF precipitation variability. El Niño–Southern Oscillation (ENSO), along with related sea surface temperature anomalies in the western North Pacific, acts as the primary driver of this large-scale circulation–AR coupling. As this ENSO-driven process is reasonably well captured by current seasonal forecast systems, this process could be the main source enabling an improved seasonal forecast of SC winter precipitation.

中文摘要

摘要：冬季（12月至次年2月）中国南方显著降水是东亚冬季风的关键特征之一，约占该地区年降水量的20%。尽管其年际变率的海洋驱动因素已被广泛研究，但贡献了气候态冬季降水约30%–40%的大气河流的影响仍不明确。此外，季节预报模式如何通过大气河流捕捉热带海表温度变化对冬季降水的影响，仍需借助客观指标进一步探究。本研究识别出一种涉及厄尔尼诺-南方涛动、印度洋偶极子及西北太平洋海表温度异常的热带海温模态，其协同演变结构从前夏至冬季快速形成。这种异常海温配置在热带至副热带区域激发出半球尺度的环流型，增强了中国南方的垂直风切变和经向水汽输送，有利于更多大气河流侵入该区域。因此，显著降水异常主要出现在20°–30°N的中国南方附近，解释了超过50%的冬季降水年际变率。由厄尔尼诺-南方涛动驱动、经大气河流活动介导的这些降水变化，被两套业务化季节预报系统合理预测，表明厄尔尼诺-南方涛动及其与西北太平洋海温异常的相互作用是冬季大气河流和中国南方降水预报技巧的主要来源。此外，基于目标冬季前10月和11月观测到的海温和环流状态，本研究建立了一套筛选方案，用于判定动力模式对中国南方冬季降水预报技巧高于其他年份的年份。意义声明：大气河流（气候态上贡献了冬季降水约三分之一）与大尺度环流之间的耦合模态，在塑造中国南方冬季降水变率中起关键作用。该模态以中国中部低压异常和更多大气河流被引导进入该区域为特征，解释了该区域冬季降水总变率的至少50%。厄尔尼诺-南方涛动及其相关的西北太平洋海温异常，是这种大尺度环流-大气河流耦合的主要驱动因素。由于当前季节预报系统能合理捕捉这一厄尔尼诺-南方涛动驱动过程，该过程可能是提升中国南方冬季降水季节预报的主要来源。

35. JC — Evaluation of Variability in GOME-2 Total Water Vapor and Nitrogen Dioxide Columns Associated with Natural Oscillations

Abstract

Abstract This study presents the variability of total water (H 2 O) vapor and nitrogen dioxide (NO 2 ) columns associated with natural oscillations [quasi-biennial oscillation (QBO), El Niño–Southern Oscillation (ENSO), North Atlantic Oscillation (NAO)], based on monthly Global Ozone Monitoring Experiment (GOME)-2 level-3 trace gas column data produced under the Atmospheric Composition Satellite Application Facility (AC SAF) project. The periods studied are January 2007–December 2018 for GOME-2A, January 2013–May 2025 for GOME-2B, and January 2019–May 2025 for GOME-2C. The QBO-type periodicity in total NO 2 is strongest in the tropics with a measurable amplitude of a few percent. Going from low- to midlatitudes, there is a phase shift in the QBO impact seen in total NO 2 . Variability of total H 2 O is not significantly correlated with the QBO. The effects of ENSO on total H 2 O are clearly seen in the tropics, while the effect of NAO is evident in the northern midlatitudes. Variability in total H 2 O from GOME-2 in regions affected by ENSO and NAO is compared with that from Copernicus Atmosphere Monitoring Service (CAMS) reanalysis and the European Centre for Medium-Range Weather Forecasts (ECMWF)-Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model results, and good agreement is found between the datasets. Overall, our results show that the total column NO 2 and H 2 O data from GOME-2 capture well the variability associated with large-scale natural fluctuations in the recent past, supporting that QBO/ENSO/NAO–tracer correlations can serve as a diagnostic tool for model and reanalysis evaluations. This provides confidence that data from the newer versions of the GOME-2 instrument (GOME-2B, GOME-2C) can be quite useful for monitoring the response of NO 2 and H 2 O to potential anomalies in the QBO/ENSO/NAO signals in the near future and can significantly help in evaluating the representation of these natural cycles in climate model simulations of trace gases in the coming years. Significance Statement Quasi-biennial oscillation, El Niño–Southern Oscillation, and North Atlantic Oscillation are known natural fluctuations that affect meteorological and climatic variables around the world. Here, we examine the ability of water vapor and nitrogen dioxide total column retrievals from the Global Ozone Monitoring Experiment-2 satellite instrument to capture variability associated with these natural perturbations and use this information to evaluate chemistry–climate model simulations and reanalysis data from the Copernicus Atmosphere Monitoring Service. Our findings indicate that the newer versions of the Global Ozone Monitoring Experiment-2 can be quite useful for monitoring the response of total column nitrogen dioxide and water vapor to potential anomalies or changes in the signals of these natural oscillations in the near future and can significantly help to improve our knowledge for better representation of these natural oscillations in future climate model simulations of trace gases.

中文摘要

摘要 本研究基于大气成分卫星应用设施（AC SAF）项目下生成的月度全球臭氧监测实验（GOME）-2三级痕量气体柱浓度数据，分析了与水汽（H₂O）和二氧化氮（NO₂）总柱浓度相关的自然振荡[准两年振荡（QBO）、厄尔尼诺-南方涛动（ENSO）、北大西洋涛动（NAO）]的变率。研究时段分别为：GOME-2A为2007年1月至2018年12月，GOME-2B为2013年1月至2025年5月，GOME-2C为2019年1月至2025年5月。NO₂总柱浓度的QBO型周期在热带地区最强，可测量振幅达百分之几。从低纬度到中纬度，NO₂总柱浓度中QBO影响的相位发生偏移。H₂O总柱浓度的变率与QBO无显著相关性。ENSO对H₂O总柱浓度的影响在热带地区清晰可见，而NAO的影响则在北半球中纬度地区显著。将受ENSO和NAO影响区域的GOME-2 H₂O总柱浓度变率与哥白尼大气监测服务（CAMS）再分析数据及欧洲中期天气预报中心（ECMWF）-汉堡（ECHAM）/模块化地球子模型系统（MESSy）大气化学（EMAC）模式结果进行比较，发现各数据集之间具有良好一致性。总体而言，我们的结果表明，GOME-2的NO₂和H₂O总柱浓度数据能够很好地捕捉近期与大规模自然波动相关的变率，支持QBO/ENSO/NAO-示踪物相关性可作为模式和再分析评估的诊断工具。这增强了信心，即GOME-2仪器新版本（GOME-2B、GOME-2C）的数据对于监测近期NO₂和H₂O对QBO/ENSO/NAO信号潜在异常的响应非常有用，并能显著帮助评估未来气候模式模拟痕量气体时对这些自然循环的表征。意义声明 准两年振荡、厄尔尼诺-南方涛动和北大西洋涛动是已知的影响全球气象和气候变量的自然波动。本文检验了全球臭氧监测实验-2卫星仪器反演的水汽和二氧化氮总柱浓度捕捉与这些自然扰动相关变率的能力，并利用此信息评估化学-气候模式模拟及哥白尼大气监测服务的再分析数据。我们的发现表明，全球臭氧监测实验-2的新版本对于监测近期NO₂和H₂O总柱浓度对这些自然振荡信号潜在异常或变化的响应非常有用，并能显著帮助提升认知，以便在未来气候模式模拟痕量气体时更好地表征这些自然振荡。

36. JC — Decadal Spiciness Variability in the Subtropical–Tropical Pacific in the CESM2 Large Ensemble

Abstract

Abstract Tropical Pacific decadal variations impact weather and climate around the world and are also linked to variations in the global warming trend. The mechanisms driving these long-term modulations, particularly the role of subsurface ocean dynamics, are still debated. Here, we investigate the dynamics of spiciness (density-compensated temperature and salinity) anomalies in the tropical and subtropical Pacific, which are hypothesized as a possible driving mechanism of decadal climate variability. Based on the analysis of 100 realizations from the Community Earth System Model, version 2, Large Ensemble (CESM2-LE), we demonstrate a coupling between the subtropics and the equatorial Pacific by propagating spiciness anomalies at decadal time scales. The CESM2-LE simulates spiciness variability along a subduction path from the subtropics to the equator with frequency spectra that show the highest power at low frequencies and a power decay proportional to a −4 slope for frequencies greater than 0.01 cycles per month, corresponding to periods smaller than ∼8.5 years. Signals that originate in the Southern Hemisphere (SH) dominate and arrive with a larger magnitude at the equator compared to spiciness anomalies from the Northern Hemisphere (NH). Spiciness anomalies from the SH have shorter propagation times and are strengthened along their pathway as stochastic wind stress curl forcing generates anomalous baroclinic ocean pressure gradients. These pressure gradients generate spiciness anomalies via anomalous advection across climatological spiciness gradients in the SH. We conclude that the observed spiciness variance at decadal time scales is consistent with a forcing by stochastic wind variations that are low-pass filtered by ocean dynamics.

中文摘要

摘要 热带太平洋年代际变化影响着全球天气与气候，并与全球增暖趋势的变化密切相关。驱动这些长期调制的机制，特别是次表层海洋动力学的作用，仍存在争议。本文研究了热带和副热带太平洋中”辛辣度”（密度补偿的温度和盐度）异常的动力学特征，该异常被认为是年代际气候变率的可能驱动机制之一。基于对社区地球系统模型第二版大集合（CESM2-LE）中100个样本的分析，我们证明了副热带与赤道太平洋之间通过年代际时间尺度上辛辣度异常的传播存在耦合。CESM2-LE模拟了沿副热带至赤道潜沉路径的辛辣度变率，其频谱显示低频段功率最强，且对于频率大于0.01周/月（对应周期小于约8.5年）的信号，功率衰减符合-4次方斜率。源自南半球的信号占主导地位，且与北半球辛辣度异常相比，其到达赤道时振幅更大。南半球辛辣度异常传播时间更短，并在传播过程中因随机风应力旋度强迫产生异常斜压海洋压力梯度而增强。这些压力梯度通过穿越南半球气候态辛辣度梯度的异常平流生成辛辣度异常。我们得出结论：观测到的年代际时间尺度辛辣度方差与海洋动力学低通滤波后的随机风变率强迫相一致。

37. JC — Characteristics of Springtime Surface Energy Budget Anomalies and Their Relation to Arctic Melt Onset Dates

Abstract

Abstract The timing of sea ice melt onset (MO) strongly influences the length of the melt season and the subsequent summer ice evolution of Arctic sea ice. However, the atmospheric mechanisms governing the pronounced interannual and regional variability in MO remain incompletely understood. Here, we investigate the atmospheric contribution to the spatiotemporal variability of MO dates across the Arctic sea ice during spring (April–June) over 1980–2017. Using passive microwave satellite-derived MO dates and ERA5 reanalysis, we identify regions of extreme positive surface energy budget (SEB) anomalies (SEB events) as markers of episodic atmospheric influence and relate their occurrence and airmass origin to locally anomalous MO timings in a pixel-based framework. Very early MO occurs preferentially in the Beaufort, Kara, and Barents Seas and is associated with strongly enhanced frequency of SEB events during the 24 days preceding melt, with peak occurrence both near the melt date and about 3 weeks earlier. Earlier melt is further characterized by larger-than-usual anomalies in downward longwave and turbulent fluxes and predominantly associated with SEB events of Pacific and Atlantic airmass origin. In contrast, very late MO is located more widespread across the eastern Arctic Ocean and coincides with a significant absence of SEB events before melt, weaker downward longwave fluxes, positive downward shortwave anomalies under clear-sky conditions, and continental airmass inflows. These results demonstrate that synoptic-scale atmospheric processes are a key driver of regional MO variability and highlight the need for improved representation of springtime atmosphere–ice interactions in climate models to properly capture the seasonal transition in the Arctic. Significance Statement The start of the sea ice melt affects the Arctic ice evolution, but the mechanisms responsible for the melt transition are not well understood. Suggested triggers are short-time episodes of earlier ice melt, associated with positive surface energy budget (SEB) anomalies. This study aims to characterize positive SEB-anomaly extremes (SEB events) and use them to investigate the atmosphere’s role in the inhomogeneity of sea ice melt dates. Earlier melt onset is associated with Pacific airflows and enhanced occurrence of SEB events, dominated by increased longwave and turbulent fluxes and decreased shortwave fluxes, whereas later onset favors continental airmass origins and opposite radiative fluxes. These findings emphasize the importance of adequately representing atmospheric processes to capture the melt transition and predict the changing Arctic climate.

中文摘要

摘要 海冰融化开始时间（MO）强烈影响北极海冰融化季节的长度及随后的夏季冰况演变。然而，控制MO显著年际和区域变化的大气机制仍不完全清楚。本文研究了1980–2017年春季（4–6月）期间大气对北极海冰MO日期时空变化的贡献。利用被动微波卫星反演的MO日期和ERA5再分析资料，我们将极端正地表能量收支（SEB）异常区域（SEB事件）识别为间歇性大气影响的标志，并在像元框架下将其发生频率和气团来源与局地异常MO时间相关联。极早MO主要出现在波弗特海、喀拉海和巴伦支海，与融化前24天内SEB事件频率显著增强有关，其峰值出现时间既接近融化日期也约提前三周。更早的融化还表现为向下长波和湍流通量异常大于常年，且主要与太平洋和大西洋气团来源的SEB事件相关。相反，极晚MO更广泛分布于北冰洋东部，与融化前SEB事件显著缺失、向下长波通量较弱、晴空条件下向下短波正异常以及大陆气团流入有关。这些结果表明，天气尺度大气过程是区域MO变化的关键驱动因素，并强调气候模式需改进春季大气-冰相互作用的表征，以准确捕捉北极的季节转换。意义声明 海冰融化开始时间影响北极冰况演变，但融化转换的机制尚不明确。已有研究提出，与正地表能量收支（SEB）异常相关的短期冰融提前事件可能是触发因素。本研究旨在表征正SEB异常极端事件（SEB事件），并利用其探究大气在海冰融化日期非均匀性中的作用。更早的融化开始与太平洋气流及SEB事件频率增加相关，其主导因素为长波和湍流通量增加及短波通量减少；而更晚的融化则有利于大陆气团来源及相反的辐射通量特征。这些发现强调了充分表征大气过程对于捕捉融化转换及预测北极气候变化的重要性。

38. JC — Natural Variability Dominates Precipitation Variability over the Past 800 Years in Eastern Europe

  • 作者：Cătălin-Constantin Roibu, Viorica Nagavciuc, Ciprian Palaghianu, Andrei Mursa, Cosmin-Mihai Andriescu, Mihai-Gabriel Cotos, Marian-Ionuț Știrbu, Tomasz Wazny, Victor Sfeclă, Monica Ionita
  • 发表日期：2026-06-01
  • DOI：https://doi.org/10.1175/jcli-d-25-0626.1

Abstract

Abstract Tree-ring chronologies are frequently used to gain invaluable insights into past climate variability. In this study, we developed a unique 804-yr oak ring width chronology network from eastern Europe to reconstruct annual hydroclimate variability with a particular focus on the 12 July month standardized precipitation index (SPI). The SPI reconstruction captures pronounced interannual-to-multidecadal fluctuations in moisture availability, revealing sequences of persistent droughts and pluvials. These reconstructed hydroclimatic extremes align with documented historical episodes of agricultural failure, famine, and population displacement, underscoring the SPI’s potential for identifying long-term climate–society linkages. Here, we show that the hydroclimate in the eastern part of Europe has largely remained stationary from 1221 to 2019, despite exhibiting substantial variability across interannual-to-multidecadal time scales. Wet years correspond to negative geopotential height anomalies over eastern Europe, promoting cyclonic flow and rainfall, while dry years align with persistent high pressure systems that suppress precipitation and shift storm tracks northward. These circulation anomalies cooccur with coherent Atlantic sea surface temperature (SST) patterns, warm subtropical and tropical anomalies during wet years, and cold anomalies during dry years, highlighting the coupled role of blocking and ocean variability in shaping multiyear droughts and floods across eastern Europe. Comparison with bias-corrected regional climate simulations suggests little change in mean annual hydroclimate through the twenty-first century, but a broadening range of possible outcomes increases risks of persistent extremes. Our study combines tree-ring reconstructions with documentary archives to place recent and future hydroclimatic extremes in a long-term context, offering critical insights for water management, agriculture, and forestry. Significance Statement The purpose of this study is to provide an eight-century reconstruction of annual hydroclimate for eastern Europe and to identify the processes and risks behind persistent extremes. Using a replication-rich oak network, we produce a robust drought record (1221–2019) that is stable across Romania, Moldova, and Ukraine. The reconstruction reveals pronounced interannual-to-multidecadal variability, including megadroughts in the fourteenth, fifteenth, and eighteenth centuries corroborated by documentary evidence that have repeatedly disrupted harvests and livelihoods. Mechanistic analyses link extremes to large-scale circulation and Atlantic sea surface temperature (SST) anomalies, with no consistent volcanic signal—implicating internal variability as the dominant driver. Projections show stable means but wider swings, heightening risks of persistent extremes and requiring adaptive water, farm, and hazard planning.

中文摘要

摘要：树木年轮年表常被用于获取过去气候变率的宝贵信息。本研究利用东欧地区独特的804年橡树年轮宽度年表网络，重建了年际水文气候变率，重点关注7月12日标准化降水指数（SPI）。SPI重建结果捕捉到水分可用性在年际至多年代际尺度上的显著波动，揭示了持续干旱与多雨期的序列。这些重建的水文气候极端事件与历史记载的农业歉收、饥荒及人口迁移事件相吻合，凸显了SPI在识别长期气候-社会关联方面的潜力。研究表明，尽管东欧地区水文气候在年际至多年代际时间尺度上表现出显著变率，但1221年至2019年间其整体状态基本保持平稳。湿润年份对应东欧上空负位势高度异常，促进气旋性环流与降水；干旱年份则与抑制降水并使风暴路径北移的持续高压系统一致。这些环流异常与大西洋海表温度（SST）的相干模态同时出现——湿润年份副热带和热带区域为暖异常，干旱年份则为冷异常——揭示了阻塞作用与海洋变率在塑造东欧地区多年干旱与洪水中的耦合作用。与偏差校正后的区域气候模拟对比表明，21世纪年平均水文气候变化甚微，但可能结果的区间扩大增加了持续极端事件的风险。本研究将树木年轮重建与文献档案相结合，将近期及未来的水文气候极端事件置于长期背景中，为水资源管理、农业和林业提供了关键见解。意义声明：本研究旨在提供东欧地区八百年尺度的年际水文气候重建，并识别持续极端事件背后的过程与风险。利用高重复性橡树年轮网络，我们生成了覆盖罗马尼亚、摩尔多瓦和乌克兰的稳健干旱记录（1221–2019年）。重建结果揭示了显著的年代际至多年代际变率，包括14、15和18世纪的巨型干旱，这些干旱得到文献证据的佐证，曾反复破坏收成与生计。机制分析将极端事件与大尺度环流和大西洋海表温度（SST）异常联系起来，未发现一致的火山信号——表明内部变率是主导驱动因子。预估结果显示均值稳定但波动幅度增大，加剧了持续极端事件的风险，需要适应性水资源、农业和灾害规划。

39. JC — The Influence of Arctic Stratospheric Ozone Variations on North Atlantic Ocean Currents

Abstract

Abstract Using reanalysis and the Community Earth System Model (CESM) experiments, this study investigates the effects of Arctic stratospheric ozone (ASO) on North Atlantic Ocean currents and compares them with those in the North Pacific. We found that the variation of North Atlantic surface ocean current is significantly related to the ASO in March. An increased ASO accompanies anomalous westward (southeastward) ocean current and the deceleration (acceleration) of ocean current in high-latitude (midlatitude) North Atlantic in the shallow layer in March, and vice versa. The increased ASO weakens Arctic stratospheric polar vortex via the radiative process, which facilitates the tropospheric negative Arctic Oscillation (AO−)-like circulation anomaly through stratosphere–troposphere coupling. The lower-tropospheric wind changes associated with this AO− anomaly force the above ocean current anomalies in the North Atlantic via the friction of wind and the Coriolis force. These influences are reproduced by the CESM experiments forced by high- and low-ozone scenarios. We also compare the influence of ASO on the North Atlantic with that on the North Pacific. In the North Pacific, ASO-related zonal and meridional ocean current changes are both significant. The meridional ocean current change further contributes to Victoria mode–like sea surface temperature (SST) anomalies in the North Pacific by heat transport. By contrast, the ASO-related meridional (zonal) ocean current anomaly is small (large) in the North Atlantic, and the zonal ocean current is relatively inefficient in temperature advection. Consequently, the responses in North Atlantic SST to ASO are weak. Therefore, although both the North Pacific and the North Atlantic are located in the Northern Hemisphere, their responses to ASO are apparently different. Significance Statement The stratosphere, troposphere, and ocean form a coupled system. However, our understanding of stratospheric impact on the ocean is relatively poor, especially in the Northern Hemisphere. This study shows that the Arctic stratospheric ozone exerts significant effects on the surface ocean current in the North Atlantic via modulating stratospheric polar vortex and tropospheric winds in both reanalysis and CESM experiments. These results highlight that Arctic stratosphere–troposphere coupling is important for the better simulation and prediction of ocean current variations in the North Atlantic.

中文摘要

摘要 利用再分析资料和社区地球系统模式（CESM）试验，本研究探讨了北极平流层臭氧（ASO）对北大西洋洋流的影响，并与北太平洋进行了对比。我们发现，北大西洋表层洋流的变化与3月的ASO显著相关。ASO增加伴随着3月北大西洋高纬度（中纬度）浅层出现异常向西（东南向）的洋流以及洋流减速（加速），反之亦然。ASO增加通过辐射过程减弱了北极平流层极涡，进而通过平流层-对流层耦合引发对流层负位相北极涛动（AO−）型环流异常。与这种AO−异常相关的对流层低层风场变化，通过风应力和科里奥利力强迫出上述北大西洋洋流异常。这些影响在高臭氧和低臭氧情景强迫的CESM试验中得到了再现。我们还比较了ASO对北大西洋和北太平洋的影响。在北太平洋，与ASO相关的纬向和经向洋流变化均显著。经向洋流变化进一步通过热输送贡献了北太平洋维多利亚模态型的海表温度（SST）异常。相比之下，在北大西洋，与ASO相关的经向（纬向）洋流异常较小（较大），且纬向洋流在温度平流中效率相对较低。因此，北大西洋SST对ASO的响应较弱。因此，尽管北太平洋和北大西洋均位于北半球，但它们对ASO的响应存在明显差异。意义陈述 平流层、对流层和海洋构成一个耦合系统。然而，我们对平流层影响海洋的理解相对薄弱，尤其是在北半球。本研究表明，在再分析资料和CESM试验中，北极平流层臭氧通过调节平流层极涡和对流层风场，对北大西洋表层洋流产生显著影响。这些结果强调，北极平流层-对流层耦合对于更好地模拟和预测北大西洋洋流变化具有重要意义。

40. JC — Revealing Weekly Scale Drivers of North American Winter Storm-Track Variability Using a Causal Discovery Framework

Abstract

Abstract Storm tracks frequently produce winter weather extremes across North America. However, their weekly scale variability remains challenging to explain, since atmospheric and oceanic processes, both local and remote, interact in complex ways. This study uses a causal discovery framework to pinpoint and evaluate the drivers of the North American winter storm-track activity on a weekly scale. Unlike correlation-based statistical methods, causal discovery methods factor in confounders and time dependence, enabling them to distinguish true drivers from spurious associations. By incorporating a resampling procedure, the framework quantifies the degree of confidence for candidate drivers, thus revealing the most probable pathways influencing the storm-track variability. The two strongest pathways are analyzed. The first arises from anomalous atmospheric circulation over the North Pacific. This anomaly excites a quasi-stationary Rossby wave train to affect the vertical wind shear over the U.S. West Coast 1 week later. Hence, the downstream baroclinic development changes, thereby altering the storm-track activity over central–eastern North America. The second pathway involves rapid air–sea coupling over the North Atlantic, where the low-level wind anomalies related to the North Atlantic Oscillation alter surface heat fluxes to induce a tripolar pattern of sea surface temperature (SST) anomalies 1 week later. This SST tripole then affects the baroclinicity upstream and thus the storm-track activity over northern North America. By isolating different processes that drive storm-track variability, the framework could enhance our understanding and prediction of midlatitude weather as well as climate. Significance Statement We aim to understand why storm tracks, which shape much of the winter weather in North America, vary from week to week. These variations arise from many interacting factors, making it difficult to pinpoint the true causes of the variations. Using a causal discovery method, we identify two processes driving the variations. One involves atmospheric wave propagation from the North Pacific and the other involves rapid air–sea feedback in the North Atlantic. These results demonstrate the method’s potential to unravel complex interactions, to rank different physical processes, and to identify useful predictors. With uncertainty estimates, the method also provides a way to evaluate whether different datasets reflect the same processes or diverge.

中文摘要

摘要 风暴轴频繁导致北美冬季极端天气事件。然而，其周尺度变异性仍难以解释，因为局地和遥相关的大气与海洋过程以复杂方式相互作用。本研究采用因果发现框架，在周尺度上识别并评估北美冬季风暴轴活动的驱动因子。与基于相关性的统计方法不同，因果发现方法考虑了混杂因子和时间依赖性，能够区分真实驱动因子与虚假关联。通过引入重采样程序，该框架量化了候选驱动因子的置信度，从而揭示影响风暴轴变率的最可能路径。分析得出两条最强路径：第一条源于北太平洋异常大气环流，该异常激发准定常罗斯贝波列，一周后影响美国西海岸的垂直风切变，进而改变下游斜压发展，最终影响北美中东部风暴轴活动；第二条路径涉及北大西洋快速海气耦合过程，与北大西洋涛动相关的低层风异常改变海表热通量，一周后引发海表温度异常的三极型分布，该海温三极型随后影响上游斜压性，从而影响北美北部风暴轴活动。通过分离驱动风暴轴变率的不同过程，该框架可增强我们对中纬度天气及气候的理解与预测能力。意义声明 本研究旨在理解塑造北美冬季天气的风暴轴为何呈现周际变化。这些变化源于众多相互作用因子，使得难以确定变率的真实成因。通过因果发现方法，我们识别出驱动变率的两条过程：其一涉及北太平洋大气波传播，其二涉及北大西洋快速海气反馈。这些结果展示了该方法在解析复杂相互作用、排序不同物理过程及识别有效预测因子方面的潜力。结合不确定性估计，该方法还可评估不同数据集是否反映相同过程或存在分歧。

41. JC — Intermodel Spread in Indian Ocean Basin Mode Simulation: Roles of Indian Ocean Winds and Pacific Cold Tongue

Abstract

Abstract The Indian Ocean basin mode (IOBM) is a major component of interannual sea surface temperature (SST) variability in the tropical Indian Ocean and acts as an atmospheric–oceanic bridge extending El Niño–Southern Oscillation (ENSO)’s climate influence into the boreal summer of its decay phase—known as the capacitor effect. Despite advancements, state-of-the-art climate models continue to show systematic biases in simulating the IOBM during ENSO decay summers. Analyzing historical simulations from 56 models in the Coupled Model Intercomparison Project phases 5 and 6 (CMIP5/6), this study identifies two dominant modes of intermodel spread in IOBM simulations: an Indian Ocean dipole (IOD)-like mode linked to climatological easterly wind biases over the equatorial Indian Ocean and an eastern Indian Ocean (EIO)-centered mode associated with equatorial Pacific cold tongue biases. The IOD-like spread pattern arises from easterly wind biases that weaken SST–thermocline coupling in the southwestern Indian Ocean, suppressing IOBM amplitude. The EIO-centered pattern stems from cold tongue biases that shift ENSO anomalies westward, altering EIO SSTs through Indo-Pacific interactions. Using statistical relationships between the spread modes and historical mean-state biases, we refine CMIP5/6 projections of the IOBM and its capacitor effect under warming, revealing a stronger and more consistent enhancement than previously estimated. These findings highlight the role of background climatological wind and SST biases in shaping model spread and underscore the importance of improving Indo-Pacific mean-state simulations for more reliable IOBM representation and future climate projections. Significance Statement This study investigates why climate models struggle to simulate the Indian Ocean basin mode (IOBM), a key feature that helps extend El Niño’s climate influence into the summer following its peak. Analyzing historical simulations from 56 models in the Coupled Model Intercomparison Project phases 5 and 6 (CMIP5/6), we identify two main sources of model disagreement: biases in tropical Indian Ocean winds and Pacific cold tongue sea surface temperatures. These mean-state biases not only distort the simulated IOBM but also weaken projections of the “capacitor effect,” in which the IOBM enables the Indian Ocean to relay El Niño’s influence. By correcting for these biases, we find that future IOBM responses and associated climate impacts may be stronger than previously thought, highlighting the need to reduce background biases in climate models.

中文摘要

摘要 印度洋海盆模态（IOBM）是热带印度洋海表温度（SST）年际变化的主要组成部分，它作为连接厄尔尼诺-南方涛动（ENSO）气候影响的大气-海洋桥梁，将其影响延伸至ENSO衰减阶段的北半球夏季——即所谓的电容器效应。尽管取得了进展，但最先进的气候模式在模拟ENSO衰减夏季的IOBM时仍存在系统性偏差。通过分析耦合模式比较计划第五和第六阶段（CMIP5/6）中56个模式的历史模拟，本研究识别出IOBM模拟中模式间差异的两种主导模态：一种是与赤道印度洋气候态东风偏差相关的类印度洋偶极子（IOD）模态，另一种是与赤道太平洋冷舌偏差相关的以东印度洋（EIO）为中心的模态。类IOD的差异模态源于东风偏差削弱了西南印度洋的SST-温跃层耦合，从而抑制了IOBM的振幅。以东印度洋为中心的模态则源于冷舌偏差使ENSO异常向西偏移，通过印太相互作用改变东印度洋SST。利用差异模态与历史平均态偏差之间的统计关系，我们修正了CMIP5/6对增暖条件下IOBM及其电容器效应的预估，发现其增强幅度比先前估计更强且更一致。这些发现突显了背景气候态风场和SST偏差在塑造模式差异中的作用，并强调了改进印太平均态模拟对于更可靠地再现IOBM及未来气候预估的重要性。意义声明 本研究探讨了气候模式为何难以模拟印度洋海盆模态（IOBM）——这一关键特征有助于将厄尔尼诺的气候影响延伸至其峰值后的夏季。通过分析耦合模式比较计划第五和第六阶段（CMIP5/6）中56个模式的历史模拟，我们识别出模式分歧的两个主要来源：热带印度洋风场偏差和太平洋冷舌海表温度偏差。这些平均态偏差不仅扭曲了模拟的IOBM，还削弱了对“电容器效应”（即IOBM使印度洋能够传递厄尔尼诺影响）的预估。通过修正这些偏差，我们发现未来IOBM响应及相关气候影响可能比先前认为的更强，这凸显了减少气候模式中背景偏差的必要性。

42. JC — Processes Driving Interannual Variability of Deep Convection in the Nordic Seas from an Ensemble of Earth System Model Historical Simulations

Abstract

Abstract The Nordic seas play an important role in the polar and global climate system, connecting the subpolar North Atlantic to the Arctic Ocean, while also being the primary region for the formation of lower North Atlantic Deep Water, a key contributor to the Atlantic meridional overturning circulation. Oceanic deep convection in the Nordic seas undergoes considerable interannual variability, as indicated by local observational and reanalysis studies and by the variability of the observed transport of the Denmark Strait overflow. In this paper, we investigate the oceanic and atmospheric processes associated with this variability using results from a global, fully coupled Earth system model configuration with regional refinement of the horizontal resolution in the Arctic and subarctic in all model components (ocean, sea ice, atmosphere, and land models). We consider an ensemble of five simulations with historical variations of greenhouse gases over the period 1950–2014. In these experiments, Nordic seas convection features strong interannual variability. We find that high convection winters are accompanied by two separate scenarios with active drivers in the ocean and the atmosphere, respectively, occurring partly independently and partly at the same time: enhanced salinity advection via the Atlantic Water inflow into the Nordic seas and an increased frequency of synoptic cyclonic circulation patterns over Scandinavia and the Norwegian Sea with associated northerly winds across the Nordic seas. Both scenarios lead to similar conditions that enhance oceanic deep convection: sea ice reduction (in the Greenland–Iceland Seas) and increased heat flux exchanges in the ocean interior. Significance Statement The purpose of this work is to study processes in the ocean and atmosphere that affect the intensity of deep convection in the Nordic seas. This is important because deep convection is associated with the formation of water masses that feed into the Atlantic meridional overturning circulation, which, in turn, helps redistribute heat within Earth system. We find that the primary trigger for deep convection in the Nordic seas is enhanced advection of warm and saline Atlantic Water, which, combined with more frequent cold northerly winds, leads to enhanced heat fluxes between the warm upper ocean and the colder atmosphere on top. On the Greenland side of the Nordic seas, this process is also modulated by sea ice.

中文摘要

摘要 北欧海在极地和全球气候系统中扮演着重要角色，它连接着亚极地北大西洋与北冰洋，同时也是北大西洋深层水下层形成的主要区域，而北大西洋深层水下层是大西洋经向翻转环流的关键贡献者。北欧海的海洋深层对流存在显著的逐年变率，这一点已由局地观测和再分析研究以及丹麦海峡溢流观测输运量的变率所证实。本文利用一个全球全耦合地球系统模式配置的结果，该模式在北极和亚北极区域的所有模式分量（海洋、海冰、大气和陆地模式）中均采用了水平分辨率的区域细化，研究了与这种变率相关的海洋和大气过程。我们考虑了一个由五次模拟组成的集合，这些模拟涵盖了1950-2014年期间温室气体的历史变化。在这些实验中，北欧海的对流表现出强烈的逐年变率。我们发现，高对流冬季伴随着两种不同的情景，其驱动因素分别来自海洋和大气，这两种情景部分独立发生，部分同时出现：通过大西洋水流入北欧海而增强的盐度平流，以及斯堪的纳维亚半岛和挪威海上空气旋性环流天气尺度模式的频率增加，并伴随横跨北欧海的偏北风。这两种情景都导致了增强海洋深层对流的相似条件：海冰减少（在格陵兰-冰岛海）以及海洋内部热通量交换的增加。意义声明 本研究的目的是探讨影响北欧海深层对流强度的海洋和大气过程。这一点至关重要，因为深层对流与形成水团的过程相关，这些水团汇入大西洋经向翻转环流，进而有助于地球系统内部的热量再分配。我们发现，北欧海深层对流的主要触发因素是温暖且高盐的大西洋水平流增强，这与更频繁的寒冷偏北风相结合，导致温暖的上层海洋与上方较冷大气之间的热通量增强。在北欧海的格陵兰一侧，这一过程还受到海冰的调节。

43. JC — Ocean Meridional Heat Transport Estimated from Energy Budget Constraint

  • 作者：Yuying Pan, Lijing Cheng, Andrea Storto, Michael Mayer, Sergey Gulev, Yuanlong Li, Kewei Lyu, Huayi Zheng, Huifeng Yuan
  • 发表日期：2026-06-01
  • DOI：https://doi.org/10.1175/jcli-d-25-0522.1

Abstract

Abstract Oceanic meridional heat transport (MHT), a key component of Earth’s energy flow, fundamentally shapes climate variability by redistributing heat between hemispheres and across latitudes, thereby regulating surface energy exchange, atmospheric circulation, and hydrological patterns. However, accurate quantification of the global MHT remains challenging. Here, we use the energy budget approach to derive MHT from 1985 to 2023 based on sea surface heat fluxes (Fs), ocean heat content tendency (OHCT), and heat changes related to sea ice melt/formation ( Q ice ), with objective adjustment applied to these components under an ocean energy budget constraint. This approach enables an improved estimate of the MHT climatology, variability, and trend for the global ocean, Indo-Pacific Ocean, and Atlantic Ocean. With good agreement with RAPID and Overturning in the Subpolar North Atlantic Program (OSNAP) mooring array observation time series, our estimates indicate realistic northward MHT at all latitudes in the North Atlantic with a peak of 1.22 ± 0.07 PW at 24.5°N. In contrast, the Indo-Pacific MHT is poleward with a peak of −1.67 ± 0.06 PW at 13.5°S. Regional energy budgets reveal that Fs dominates the mean state of MHT, while OHCT controls its interannual variability. After 2000, when the data quality of both OHC and Fs improved a lot, the Indo-Pacific Ocean exhibited a statistically significant increase in MHT, whereas the Atlantic Ocean showed a basinwide weakening of MHT, particularly between 25°S and 18°N. The derived ocean MHT data in this study provide a basis to evaluate model and reanalysis data and support a better understanding of Earth’s energy flow. Significance Statement Quantifying ocean meridional heat transport (MHT) is essential for understanding Earth’s energy balance and climate variability, yet it remains challenging due to data uncertainties and methodological limitations. This study introduces a novel constrained energy budget approach to derive MHT by combining multiple estimates of OHC, Fs, and sea ice volume changes. Unlike previous methods, it applies an objective adjustment based on uncertainty covariance and considering the spatial correlation. The resulting MHT time series (1985–2023) aligns well with independent observations [e.g., RAPID, Overturning in the Subpolar North Atlantic Program (OSNAP)] and captures both climatology and variability across basins. This approach enables more accurate diagnostics of heat redistribution and provides a robust benchmark for evaluating climate models and reanalysis.

中文摘要

摘要 海洋经向热输送（MHT）作为地球能量流动的关键组成部分，通过重新分配半球间和跨纬度的热量，从根本上塑造了气候变率，从而调节地表能量交换、大气环流和水文格局。然而，全球MHT的精确量化仍具挑战性。本研究基于海表热通量（Fs）、海洋热含量趋势（OHCT）以及与海冰融化/形成相关的热量变化（Q_ice），采用能量收支方法推导1985—2023年的MHT，并在海洋能量收支约束下对这些分量进行客观调整。该方法能够改进全球海洋、印度洋-太平洋和大西洋的MHT气候态、变率及趋势估算。与RAPID和亚极地北大西洋翻转计划（OSNAP）锚系阵列观测时间序列的良好一致性表明，我们的估算结果呈现北大西洋所有纬度上真实的向北MHT，在24.5°N处达到峰值1.22 ± 0.07 PW。相比之下，印度洋-太平洋的MHT为向极方向，在13.5°S处达到峰值−1.67 ± 0.06 PW。区域能量收支揭示，Fs主导MHT的平均态，而OHCT控制其年际变率。2000年后，当OHC和Fs的数据质量显著提升时，印度洋-太平洋的MHT呈现统计显著的增强趋势，而大西洋则显示全海盆尺度的MHT减弱，尤其在25°S至18°N之间。本研究导出的海洋MHT数据为评估模式和再分析资料提供了基础，并有助于更深入理解地球能量流动。意义陈述 量化海洋经向热输送（MHT）对于理解地球能量平衡和气候变率至关重要，但由于数据不确定性和方法局限性，这一任务仍具挑战性。本研究引入一种新颖的约束能量收支方法，通过结合OHC、Fs和海冰体积变化的多重估算来推导MHT。与以往方法不同，该方法基于不确定性协方差并考虑空间相关性进行客观调整。由此得到的MHT时间序列（1985—2023年）与独立观测（如RAPID、亚极地北大西洋翻转计划（OSNAP））高度吻合，并能够捕捉各海盆的气候态和变率。该方法能够更精确地诊断热量再分配，并为评估气候模式和再分析资料提供稳健的基准。

44. JC — Effect of the Boreal Summer Intraseasonal Oscillation on Interannual Variation of Rainy Season Onset in Southwest China

Abstract

Abstract Southwest China (SWC) is a significant disaster-prone area, where approximately 80% of the annual precipitation is concentrated during the rainy season. The rainy season onset date (RSOD) in SWC directly influences the precipitation amount during the rainy season, which has crucial implications for drought and flood conditions, as well as geological disasters such as landslides and debris flows. Based on meteorological station data and reanalysis data from 1981 to 2023, this study reveals that the rainy season in SWC advances from east to west, with an average RSOD of 27 May superimposed with interannual variations. It is found that the first component of the boreal summer intraseasonal oscillation (BSISO1) plays a phase-locked role in the interannual variation of RSOD in SWC. Phases 1–3 of BSISO1 are conducive to the late RSOD, while phases 4–6 are conducive to the early RSOD. BSISO1 affects the moisture and dynamic conditions over SWC through whether convection propagates northward or not, resulting in an early or late onset of the rainy season in SWC. Moreover, in negative phase years of the Indian Ocean dipole (IOD), the longitudinal asymmetry of water vapor and convergence anomalies at the convective center is conducive to the northward propagation of BSISO1 convection and thereby the rainy season onsets earlier, which is the opposite in positive IOD years. These results shed some light on the mechanisms for interannual variations and the prediction of RSOD in SWC. Significance Statement Southwest China (SWC) is a region seriously affected by droughts, floods, and landslides, with most of its annual rain falling during the rainy season. The rainy season onset date (RSOD) in SWC shows strong interannual variations with an average start date around 27 May. This study finds that the first component of boreal summer intraseasonal oscillation (BSISO1) plays a key role in these variations. When BSISO1 convection is over the equatorial Indian Ocean (phases 1–3), the rainy season starts later. When it moves to the Bay of Bengal (phases 4–6), the RSOD begins earlier. BSISO1 can modulate moisture and dynamic conditions over SWC by regulating the northward propagation of convection, thereby determining an early or late rainy season onset. Furthermore, the negative Indian Ocean dipole (IOD) years promote BSISO1 convection spread north, leading to an earlier RSOD, while positive IOD years block this movement, causing delays. These findings advance the understanding of RSOD interannual variability and provide insights for improving its predictability in SWC.

中文摘要

摘要 西南地区是中国重要的灾害易发区，年降水量约80%集中在雨季。西南地区雨季开始日期直接影响雨季降水量，对旱涝状况以及滑坡、泥石流等地质灾害具有关键影响。基于1981—2023年气象站资料和再分析资料，本研究发现西南地区雨季自东向西推进，平均雨季开始日期为5月27日，并叠加有年际变化。研究表明，北半球夏季季节内振荡第一模态对西南地区雨季开始日期的年际变化起位相锁定作用：BSISO1位相1—3有利于雨季偏晚，位相4—6有利于雨季偏早。BSISO1通过对流是否向北传播来影响西南地区的水汽和动力条件，从而导致西南地区雨季提前或推迟。此外，在印度洋偶极子负位相年，对流中心水汽和辐合异常的经向不对称性有利于BSISO1对流北传，进而使雨季提前；而在印度洋偶极子正位相年则相反。这些结果揭示了西南地区雨季开始日期年际变化的机制，并为其预测提供了启示。意义声明 西南地区是受干旱、洪涝和滑坡严重影响的中国区域，其年降水量大部分集中在雨季。西南地区雨季开始日期表现出强烈的年际变化，平均开始日期约为5月27日。本研究发现北半球夏季季节内振荡第一模态在这些变化中起关键作用：当BSISO1对流位于赤道印度洋（位相1—3）时，雨季开始偏晚；当对流移至孟加拉湾（位相4—6）时，雨季开始偏早。BSISO1通过调节对流的北向传播来调控西南地区的水汽和动力条件，从而决定雨季的提前或推迟。此外，印度洋偶极子负位相年促进BSISO1对流北传，导致雨季提前；而印度洋偶极子正位相年则阻碍这一传播，导致雨季推迟。这些发现深化了对西南地区雨季开始日期年际变化的理解，并为其可预测性提升提供了依据。

45. GRL — Decadal Predictions of the Link Between European Hot‐Dry Compound Summers and North Atlantic Sea Surface Temperature

Abstract

Abstract We assess MPI‐ESM 1.2‐LR decadal hindcasts (lead year 1–5) to evaluate the prediction of European compound hot and dry summers with help of North Atlantic sea surface temperature (SST). Using a 64‐member ensemble and detrended data, we isolate extremes driven by internal variability. We find that initialization is crucial for capturing the 2m‐temperature‐precipitation correlation found in observational data. While the occurrence probability of hot summers correlates positively with North Atlantic SST in time, the impact of North Atlantic SST on precipitation varies. The occurrence probability of compound hot and dry summers shows no significant correlation with North Atlantic SST. Although warmer North Atlantic SST increases the predicted occurrence probability of hot summers, the Brier Skill Score indicates that these decadal predictions do not outperform climatology for rare extreme events. Utilizing North Atlantic SST shows promise for predicting hot summers, but its impact on compound summers is still unclear.

中文摘要

摘要 我们评估了MPI-ESM 1.2‐LR十年际后报（提前1–5年），以借助北大西洋海表温度（SST）评估欧洲复合型高温干旱夏季的预测能力。利用64个集合成员和去趋势数据，我们分离出由内部变率驱动的极端事件。研究发现，初始化对于捕捉观测数据中2米气温-降水相关性至关重要。尽管高温夏季的发生概率在时间上与北大西洋SST呈正相关，但北大西洋SST对降水的影响存在差异。复合型高温干旱夏季的发生概率与北大西洋SST无显著相关性。尽管较暖的北大西洋SST提高了高温夏季的预测发生概率，但Brier技巧评分表明，这些十年际预测在罕见极端事件上并未优于气候态预测。利用北大西洋SST在预测高温夏季方面显示出潜力，但其对复合型夏季的影响仍不明确。

46. Nature Climate Change — High-latitude Southern Ocean warming hotspot induced by ocean mesoscale eddies

Abstract

Nature Climate Change, Published online: 03 June 2026; doi:10.1038/s41558-026-02652-7 The Southern Ocean is important for anthropogenic heat uptake, and this regional analysis shows an area with enhanced warming in the high-latitude Indian sector. Model analyses indicate that mesoscale eddies drive upward heat transport, linked to a strengthening of the Antarctic Circumpolar Current.

中文摘要

《自然·气候变化》，在线发表：2026年6月3日；doi:10.1038/s41558-026-02652-7。南大洋对人为热量吸收至关重要，本区域分析显示，高纬度印度洋扇区存在一个增温加剧的区域。模式分析表明，中尺度涡旋驱动了向上的热量输送，这与南极绕极流的增强有关。

47. GRL — Crustal Deformation and Gravitational Effects From Dynamic Ocean Mass Redistribution Impact Projected Sea‐Level Change

Abstract

Abstract As the climate warms, associated changes in ocean dynamics will redistribute sea‐water mass within the ocean, contributing to relative sea‐level change. This mass redistribution will cause additional sea‐level changes due to gravitational self‐attraction, deformation of the solid Earth, and shifts in the Earth’s rotation axis (GRD), which are not incorporated in sea‐level projections. Using CMIP6 climate model output, we quantify relative sea‐level changes induced by GRD from ocean‐dynamic mass loading through 2100. These effects act to amplify projected ocean‐dynamic sea‐level patterns, causing sea‐level rise in coastal regions, particularly along wide continental shelves and at high latitudes. On average, the magnitude of such GRD‐induced sea‐level change is equivalent to ∼15% of the signal due to dynamic ocean mass redistribution. Although our results show substantial inter‐model spread, they reveal that GRD‐induced relative sea‐level changes from ocean mass redistribution represent a non‐negligible component of regional sea‐level change and should be considered in projections.

中文摘要

摘要 随着气候变暖，海洋动力学的相关变化将导致海水质量在海洋内部重新分布，从而引起相对海平面变化。这种质量重新分布会因重力自吸引、固体地球形变以及地球自转轴偏移（GRD）而产生额外的海平面变化，而这些效应尚未被纳入海平面预估中。利用CMIP6气候模式输出结果，我们量化了至2100年由海洋动力质量加载引起的GRD所导致的相对海平面变化。这些效应会放大预估的海洋动力海平面空间格局，导致沿海地区（尤其是宽阔大陆架和高纬度区域）的海平面上升。平均而言，此类GRD引起的海平面变化幅度相当于海洋动力质量重新分布信号的约15%。尽管我们的结果显示模式间存在显著差异，但揭示了由海洋质量重新分布引起的GRD相对海平面变化是区域海平面变化中不可忽略的组成部分，应在预估中予以考虑。

48. GRL — The Anatomy of Convection Under Lake Ice: Reynolds Stresses and Convective Energy Budget From In Situ Observations

Abstract

Abstract We present the first in situ observations of the full turbulence tensor of free convection under lake ice, obtained using an original method based on a set of two synchronized acoustic Doppler profilers to measure all six turbulent stress components. Convection revealed strong anisotropy, with prevailing horizontal transport components. Convective energy closely followed buoyancy flux scaling modified for spatially distributed buoyancy production by solar radiation under ice. The scaling coefficients, however, differ from those known in atmospheric convection driven by surface buoyancy flux, indicating stronger horizontal fluctuations. Local non‐stationarity due to diurnal variations in solar radiation contributed about 10% of the total energy budget. Direct quantification of convective energy components and shear transport in free convection provides a framework for estimating ice–water heat exchange in lakes and for testing convection models with applications to a wide range of geo‐ and astrophysical flows.

中文摘要

摘要 我们首次展示了湖冰下自由对流全湍流张量的原位观测结果，该结果基于一种原创方法，利用两台同步声学多普勒剖面仪测量所有六个湍流应力分量。对流表现出强烈的各向异性，水平输运分量占主导地位。对流能量紧密遵循浮力通量标度关系，该关系针对冰下太阳辐射引起的空间分布浮力产生进行了修正。然而，标度系数与由表面浮力通量驱动的大气对流中已知的系数不同，表明水平波动更强。太阳辐射日变化导致的局部非平稳性约占总能量预算的10%。自由对流中对流能量分量和剪切输运的直接量化，为估算湖泊中冰-水热交换以及测试适用于广泛地球物理和天体物理流的对流模型提供了框架。

49. GRL — Reconstructing Marine Boundary Layer Jets Over the South China Sea Using Machine Learning

Abstract

Abstract Marine boundary layer jets (MBLJs) over the South China Sea (SCS) play a critical role in coastal heavy rainfall, yet their structure remains uncertain due to limited wind observations over the ocean. Here, we develop a U‐Net–based reconstruction framework to estimate 950‐hPa winds from satellite‐derived sea surface winds, providing a satellite‐driven depiction of MBLJs. The model is trained using four decades of ERA5 data and evaluated against independent shipborne Doppler wind LiDAR observations. Relative to ERA5, the reconstructed winds reduce RMSE from 3.34 to 2.69 m s −1 for wind speed and from 2.87 to 2.45 m s −1 for meridional wind. During identified MBLJ events, the reconstruction produces stronger and more spatially extensive jets than ERA5. These results demonstrate that satellite‐informed machine learning can effectively mitigate systematic underestimation of MBLJs in reanalysis products and improve representation of boundary‐layer winds over data‐sparse oceanic regions.

中文摘要

摘要 南海海洋边界层急流（MBLJs）在沿海强降雨中起着关键作用，但由于海洋上风场观测数据有限，其结构仍存在不确定性。本文开发了一种基于U-Net的重建框架，利用卫星反演的海面风场估算950百帕风场，从而提供卫星驱动的MBLJs描述。该模型使用四十年ERA5数据进行训练，并利用独立船载多普勒测风激光雷达观测进行验证。与ERA5相比，重建风场将风速均方根误差从3.34米/秒降至2.69米/秒，经向风均方根误差从2.87米/秒降至2.45米/秒。在识别的MBLJ事件期间，重建结果显示出比ERA5更强且空间范围更广的急流。这些结果表明，卫星信息驱动的机器学习能够有效缓解再分析产品中MBLJs的系统性低估，并改善数据稀疏海洋区域边界层风场的表征。

50. JC — A Signal-to-Noise Problem in Model Simulation of Decadal Climate Modes

Abstract

Abstract Regional modes of climate variability, modes with consequential impacts on temperature and rainfall over land, have historically been understood as natural, internal fluctuations in the ocean–atmosphere system. There is, however, growing evidence of the influence of external radiative forcing on these modes. Here, we use large ensembles of simulations of the historical period with over 50 climate models to estimate the magnitude of the radiatively forced response, here termed “signal,” compared with internal fluctuations, termed “noise,” in both models and observations. We examine three major modes of decadal variability collectively: Atlantic multidecadal variability (AMV), the North Atlantic Oscillation (NAO), and the Pacific decadal oscillation (PDO). We find strong agreement in recent decades between the observed time history of all these modes and their response to radiative forcing as simulated in climate models, suggesting that the signal of radiative forcing is an important part of their observed behavior. However, the amplitude of the radiatively forced signal is smaller in models than in observations for all three regional climate modes. This erroneously small, forced signal is overwhelmed by internally generated noise in any single run of a climate model. This is the signal-to-noise problem in climate models. This error leads to the mistaken impression that these decadal climate modes vary unpredictably, despite the radiatively forced trends in recent decades. Without this error in climate models, our understanding of the nature of regional decadal climate variability, both historically and into the future, would be very different.

中文摘要

摘要 区域气候变率模态——即对陆地温度和降水产生重要影响的模态——历来被视为海洋-大气系统内部自然波动。然而，越来越多的证据表明外部辐射强迫对这些模态存在影响。本研究利用50多个气候模式的历史时期大集合模拟，估算辐射强迫响应（本文称为”信号”）相对于内部波动（称为”噪声”）的幅度，并同时分析模式与观测数据。我们综合考察了三种主要的年代际变率模态：大西洋多年代际变率（AMV）、北大西洋涛动（NAO）和太平洋年代际振荡（PDO）。研究发现，近几十年来，这些模态的观测时间序列与气候模式模拟的辐射强迫响应之间存在高度一致性，表明辐射强迫信号是其观测行为的重要组成部分。然而，对于所有三种区域气候模态，模式中辐射强迫信号的振幅均小于观测值。这种被低估的强迫信号在气候模式的任何单次运行中都会被内部生成噪声所淹没——这就是气候模式中的信噪比问题。该误差导致人们误以为这些年代际气候模态呈现不可预测的变率，尽管近几十年来存在辐射强迫趋势。若消除气候模式中的这一误差，我们对区域年代际气候变率本质（无论是历史时期还是未来）的理解将截然不同。

51. Communications Earth & Environment — Asymmetric cross-hemispheric climate response to extratropical forcing mediated by tropical Pacific coupling

Abstract

Communications Earth & Environment, Published online: 04 June 2026; doi:10.1038/s43247-026-03706-6 Southern Hemisphere extratropical cooling induces strong temperature responses in the Northern Hemisphere whereas equivalent Northern Hemisphere cooling remains more localized, primarily due to hemispheric asymmetries in tropical air-sea coupling, revealed by climate model experiments.

中文摘要

《通讯-地球与环境》，在线发表：2026年6月4日；doi:10.1038/s43247-026-03706-6。气候模式实验揭示，南半球中纬度地区的冷却会引发北半球强烈的温度响应，而同等强度的北半球冷却则主要局限于本地，这主要归因于热带海气耦合的半球不对称性。

边缘相关条目

命中物理海洋学关键词，但同时涉及其他学科领域，仅供参考。

  • JAMES — Strongly Coupled Data Assimilation for Paleoclimate Reconstruction Using Deep Learning‐Based Models（DOI: https://doi.org/10.1029/2025ms005686）
    • 命中: SST, sea surface temperature, data assimilation
    • 排除: paleoclimate
  • GRL — Revealing Coastal Storm‐Wave Transformations From SWOT HR Observation: The English Channel Case Study（DOI: https://doi.org/10.1029/2025gl121115）
    • 命中: reanalysis
    • 排除: sediment
  • Communications Earth & Environment — Changing sea ice cover led to marine biodiversity shifts in the Late Quaternary（DOI: https://doi.org/10.1038/s43247-026-03696-5）
    • 命中: sea ice
    • 排除: biodiversity

待人工核实

元数据缺失（摘要 / DOI / 作者），需人工核查后再纳入。

  • Ocean Modelling — Quantifying Wave-Current Interaction Effects on Wave Energy Resources of High Energy Sites
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102773
  • Ocean Modelling — OCSMesh and an Automated Creek-to-Ocean Mesh Generation Workflow
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102774
  • Ocean Modelling — Inferring upper-ocean submesoscale ageostrophic dyna-mics using a physics-informed constrained deep learning framework
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102771
  • Ocean Modelling — Seamless hydro-morphological simulation of nearshore sandbar migration across storm phases
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102769
  • JPO — Journal Information and Table of Contents
    • 缺失项: 摘要缺失或过短; 作者列表缺失
    • 链接: https://doi.org/10.1175/jpo-566cover
  • Ocean Modelling — Source inversion and trans-Pacific simulation of the 2025 Kamchatka Mw 8.8 tsunami
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102733
  • Ocean Modelling — Tsunami warning cancellation based on data assimilation with a nonlinear propagation model: Application to the 2025 Mw 8.8 Kamchatka earthquake
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102747
  • Ocean Modelling — A robust sponge layer relaxation scheme for complex open boundary regional ocean model
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102744
  • Ocean Modelling — On the application of the two-time stepping Euler forward Runge-Kutta schemes to the shallow water equations: Global truncation error, numerical viscosity, consistency, energy conservation, inertial stability and phase error
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102735
  • Ocean Modelling — The mechanism of the ENSO diversity predictability paradox
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102745
  • Ocean Modelling — Evaluation of parametric tropical cyclone wind models for representing storm surge and wave heights in the Queensland region
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102737
  • Ocean Modelling — On the effect of grid resolution and mixing schemes on mesoscale dynamics in coastal ocean models: Studies in a mid-latitude marginal sea (northern Adriatic Sea)
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102748
  • Ocean Modelling — Effects of horizontal discretization on triangular and hexagonal grids on linear baroclinic and symmetric instabilities
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102751
  • Ocean Modelling — IW-PPM: A BP neural network model with feature engineering for internal wave propagation prediction in the Northern South China Sea
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102746
  • Ocean Modelling — Three-dimensional structural characteristics and geometric morphology of marine heatwaves in the South China Sea
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102752
  • Ocean Modelling — Tropical cyclone catalyzes seasonal transition of marginal sea: premature dissipation of cold pool
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102739
  • Ocean Modelling — Impact of parameterized wind-driven boundary layer turbulence on the development and evolution of submesoscale mixed layer eddies in an idealized front
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102741
  • Ocean Modelling — Impact of wave-current interaction on Hurricane Ian storm surge simulation
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102734
  • Ocean Modelling — Surface wave impacts on turbulent roughness length parameterization
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102742
  • Ocean Modelling — Method for extracting the core of jet streams based on streamline ensemble analysis and its verification using the Kuroshio (Kuroshio and Kuroshio Extension) as an example
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102730
  • Ocean Modelling — Energetically consistent rotated diffusion and lateral stirring surfaces in the ocean
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102722
  • Ocean Modelling — Impact of assimilating CFOSAT SWIM omnidirectional spectra on tropical cyclone wind–wave modeling
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102743
  • Ocean Modelling — Numerical simulations of ocean surface waves in the China Seas
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102718
  • Ocean Modelling — Editorial Board
    • 缺失项: 摘要缺失或过短; 作者列表缺失
    • 链接: https://doi.org/10.1016/s1463-5003(26)00083-1
  • Ocean Modelling — Deep evaluation of numerical simulation of long-time tsunami propagation utilizing tsunami source constrained by offshore tsunami waveforms: Application to the 2016 Mw 6.9 off-Fukushima earthquake, Japan
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102732
  • Ocean Modelling — Toward a digital twin of the Great Barrier Reef: Impact of extreme model resolution on tidal simulations
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102723
  • Ocean Modelling — Parameterization of bottom friction coefficient depending on sediment types and its application in tide simulation in the Eastern China Marginal Seas
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102721
  • Ocean Modelling — Offshore Algal bloom triggered by the detachment of an isolated low-salinity water lens from the Changjiang River plume
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102736
  • Ocean Modelling — The Australian Climate Service Coupled circulation-wave Coastal Hazards Prediction System (CCHaPS): Development, implementation, and validation
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102731
  • Ocean Modelling — Under data‐scarce conditions, rapid acquisition of regional tidal characteristics is achieved by combining physical constraints with extremely randomized trees
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102740
  • Ocean Modelling — Flashrip dynamics in the surfzone: Contrasting wave- and group-resolving models
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102750
  • Ocean Modelling — Offshore windfarm monopiles attenuate wave action compensating for shear-induced sediment resuspension
    • 缺失项: 摘要缺失或过短
    • 链接: https://doi.org/10.1016/j.ocemod.2026.102738