Journal of Geophysical Research-Oceans最新文献

{"title":"Dynamics of Surface Cold Patch off the Korean Peninsula Cape: Driven by Upwelling","authors":"Jiachen Zhang,&nbsp;Hao Huang,&nbsp;Xueen Chen,&nbsp;Zhen Gao,&nbsp;Chunxin Yuan,&nbsp;Zheen Zhang","doi":"10.1029/2024JC021965","DOIUrl":"https://doi.org/10.1029/2024JC021965","url":null,"abstract":"<p>Surface cold patches (SCPs) are important hydrological phenomena in the Yellow Sea (YS). We investigate the dynamics behind the appearance of the SCP off the Korean Peninsula Cape during summer. The numerical model results revealed that upwelling is the primary mechanism of SCP formation in this region. On one hand, the 3D vorticity balance of the dynamic processes of the SCP indicated that the combined effect of the tides and the baroclinic pressure gradient enhances dissipation in the bottom boundary layer, leading to seawater convergence in the bottom layer west of the tidal front and divergence east of the tidal front, forming a stable frontal secondary circulation and resulting in the formation of upwelling. On the other hand, the offshore transport, which is triggered by the Jeju Warm Current and persists throughout the year in the strait, leads to a divergence of seawater within the region. The joint effect of the above two processes ultimately contributes to the generation of upwelling. The presence of upwelling forces the thermocline to be changed. Strong tidal upwelling triggers the upward ventilating of the thermocline, which can bring cold water to the surface, and the dome-like upwarp of the thermocline isotherms caused by the current-induced upwelling, together lead to the formation of the SCP.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489958","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Asymmetric Changes of the Subtropical Gyre Circulation and Associated Sea Level Over 1960–2018 in the Pacific Ocean","authors":"Ruhui Huang,&nbsp;Xuebin Zhang,&nbsp;John A. Church,&nbsp;Jianyu Hu","doi":"10.1029/2024JC021785","DOIUrl":"https://doi.org/10.1029/2024JC021785","url":null,"abstract":"<p>Ocean circulations and sea level are undergoing long-term changes as part of anthropogenic global warming. Understanding these changes through the water column is important for comprehending the ocean's response to climate change. This study employs regional dynamic height (RDH) referenced to a no-motion layer (2,000 m) as a proxy to diagnose ocean circulations and sea levels using four observation-based datasets and 11 Ocean Model Intercomparison Project Phase 2 model simulations spanning from 1960 to 2018. Ocean Model Intercomparison Project Phase 2 simulations reproduce the major changes in ocean circulation indicated by observations, although regional differences are present, with certain regions exhibiting higher or lower RDH trends. North Pacific subtropical gyre shows positive RDH trends in the upper 400 m without a clear poleward shift but negative trends (spins down) below ∼400 m, while the South Pacific subtropical gyre shows positive RDH trends from surface to the no-motion layer and undergoes a poleward shift. These asymmetrical RDH trends between the North and South Pacific, are dominated by thermosteric components. The wind stress curl trends drive most changes of ocean circulations, resulting in asymmetric dynamic topography rise. Continued global warming in the 21st century is anticipated to intensify the asymmetric development of subtropical gyre circulations and associated sea levels in the Pacific Ocean.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tsunami Variability for the 2021 Megathrust and 2023 Outer Rise MW 7.7 Earthquakes Southeast of the Loyalty Islands","authors":"William H. Robert,&nbsp;Yoshiki Yamazaki,&nbsp;Kwok Fai Cheung,&nbsp;Thorne Lay","doi":"10.1029/2024JC021880","DOIUrl":"https://doi.org/10.1029/2024JC021880","url":null,"abstract":"<p>The 2021 shallow plate-boundary thrust-faulting and 2023 outer rise normal-faulting <i>M</i>_<i>W</i> 7.7 earthquakes southeast of the Loyalty Islands produced significant, well-recorded tsunamis around the North and South Fiji Basins. The two earthquakes occurred in close proximity on opposing sides of the Southern Vanuatu Trench with similar seismic moments and east-west rupture lengths but different faulting mechanisms. This provides a basis to examine tsunami sensitivity to source geometry and location for paths in the complex southwest Pacific region. Finite-fault models of the source processes for both events were inverted from teleseismic body wave data with constraints from forward, nonhydrostatic modeling of regional tide gauge and seafloor pressure sensor recordings. The wave motions are reversed in sign, with a leading crest generated by 1.31 m uplift on the upper plate slope for the 2021 tsunami and a leading trough from 2.37 m subsidence on the subducting plate near the trench for the 2023 tsunami. The more recent outer rise normal faulting produces narrower seafloor deformation beneath deeper water resulting in shorter period tsunami waves that shoal and refract more effectively along seamounts and island chains to produce a more elaborate radiation pattern. The source location relative to seamounts and small islands in the near field influences the energy lobes and directionality of the far-field tsunami to the north. In contrast, both events have very similar radiation patterns to the south due to absence of major bathymetric features immediately southward of the sources.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstruction of Global Ocean Surface pCO2 and Air-Sea CO2 Flux: Based on Multigrained Cascade Forest Model","authors":"Wanqin Zhong,&nbsp;Xin Ma,&nbsp;Tianqi Shi,&nbsp;Ge Han,&nbsp;Haowei Zhang,&nbsp;Wei Gong","doi":"10.1029/2024JC021483","DOIUrl":"https://doi.org/10.1029/2024JC021483","url":null,"abstract":"&lt;p&gt;Quantifying the role of air-sea CO&lt;sub&gt;2&lt;/sub&gt; exchange is essential for accurately estimating the global carbon balance, which is dependent on the spatial and temporal resolution of ocean surface carbon dioxide partial pressure (&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mtext&gt;sw&lt;/mtext&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${ptext{CO}}_{2(text{sw})}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;). When dealing with the global ocean as a vast and complex system, most existing studies tend to partition the global ocean into small-scale regions. To account for interactions of environmental variables across multiple regions, we used machine learning algorithms to holistically reconstruct a 20-year global &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mtext&gt;sw&lt;/mtext&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${ptext{CO}}_{2(text{sw})}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; map at a high resolution of 4 × 4 km based on products from the Moderate Resolution Imaging Spectroradiometer, reanalysis data, and Surface Ocean CO&lt;sub&gt;2&lt;/sub&gt; Atlas. Three machine learning methods were compared, with multigrained cascade forest (gcForest) demonstrating the highest accuracy in global reconstruction (r&lt;sup&gt;2&lt;/sup&gt; of 0.92, root mean square error of 13.46, and mean absolute error of 7.34 μatm). The global &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;msub&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;p&lt;/mi&gt;\u0000 &lt;mtext&gt;CO&lt;/mtext&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mn&gt;2&lt;/mn&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mo&gt;(&lt;/mo&gt;\u0000 &lt;mtext&gt;sw&lt;/mtext&gt;\u0000 &lt;mo&gt;)&lt;/mo&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;/msub&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${ptext{CO}}_{2(text{sw})}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; has shown a steady increase at an average annual growth rate of 1.95 ± 0.05 μa","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143481369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Observations of the Bottom Boundary Layer Beneath the World's Largest Internal Solitary Waves","authors":"J. H. Trowbridge,&nbsp;K. R. Helfrich,&nbsp;D. B. Reeder,&nbsp;G. E. Medley,&nbsp;M.-H. Chang,&nbsp;S. Jan,&nbsp;S. R. Ramp,&nbsp;Y.-J. Yang","doi":"10.1029/2024JC022028","DOIUrl":"https://doi.org/10.1029/2024JC022028","url":null,"abstract":"<p>Measurements in the South China Sea reveal the structure of the bottom boundary layer beneath onshore propagating highly nonlinear internal solitary waves of depression. Offshore directed free stream velocities beneath 13 waves with durations of 10–20 min and velocities up to 1.4 m/s are consistent with the solitary wave solution to the Korteweg-de Vries equation as are phase velocities estimated from pressures and free stream velocities. The measurements indicate a thin layer during free stream acceleration, a thicker layer with an inflected velocity during deceleration, and a long-lived sediment laden wake, after wave passage in the free stream, with velocities opposite to those at maximum flow strength. Reynolds-averaged Navier-Stokes simulations with the <i>k</i>-<i>ε</i> turbulence model reproduce the measured velocities and turbulent Reynolds shear stresses accurately during acceleration and early deceleration. However, differences between the simulations and the measurements during late deceleration and in the wake suggest energetic large-scale turbulence not represented by the simulations. This turbulence might be similar in origin to coherent vortices that have been observed in laboratory experiments and direct numerical simulations at much smaller Reynolds numbers, which have been attributed to absolute and global instabilities resulting from inflected velocity profiles.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022028","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the Budget of Local Sea Level Trends Along the Coast of Canada and Northern USA During 1958–2015","authors":"Li Zhai,&nbsp;Youyu Lu,&nbsp;Blair Greenan","doi":"10.1029/2024JC021000","DOIUrl":"https://doi.org/10.1029/2024JC021000","url":null,"abstract":"<p>Estimates of vertical land motion (VLM) from an updated Canadian crustal velocity model (NAD83v70VG) are used to evaluate the budget of contributions to trends of relative sea level (RSL) at tide gauge sites along the east and west coasts of Canada and northern USA during 1958–2015. The RSL trends result from a combination of the processes of sterodynamics (SD), glacial isostatic adjustment (GIA), and changes in earth Gravity, earth Rotation, and viscoelastic solid earth Deformation (GRD). For these contributions, we used data from a recent study on global RSL trends (Wang et al., 2021, https://doi.org/10.1029/2021gl094502). Incorporating the NAD83v70VG VLM in the derivation of the trends results in an improvement of the RSL budget. Estimates of SD contributions to the observed tide gauge water levels are obtained using this updated VLM, and are compared with the SD-component from the global ocean models used in Wang et al. (2021, https://doi.org/10.5281/zenodo.5554494). The comparison demonstrates the need to include interannual variations of river runoff for modeling the sea level changes in the St. Lawrence River and its estuary, and to improve the model's spatial resolution in the Gulf of St. Lawrence and on the open shelf of the Northwest Atlantic. Along the coast of the Northeast Pacific, the SD sea level changes are well simulated by the global models despite their coarse spatial resolutions and the use of river runoff climatology.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021000","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Decline in the Vertical Transport of Particulate Organic Carbon in the Global Open Ocean","authors":"Detong Tian,&nbsp;Xuegang Li,&nbsp;Jinming Song,&nbsp;Guorong Zhong,&nbsp;Jun Ma,&nbsp;Yanjun Wang,&nbsp;Huamao Yuan,&nbsp;Liqin Duan,&nbsp;Qidong Wang,&nbsp;Jianwei Xing,&nbsp;Baoxiao Qu,&nbsp;Jiajia Dai","doi":"10.1029/2024JC021478","DOIUrl":"https://doi.org/10.1029/2024JC021478","url":null,"abstract":"<p>In recent years, as the ocean absorbs increasing amounts of atmospheric CO₂, ocean acidification has intensified. Simultaneously, global warming and enhanced ocean stratification have led to the continuous expansion of the oceanic oxygen minimum zone (OMZ). Under the combined effects of these processes, a key question arises: How will the transport of particulate organic carbon (POC) to the deep ocean (&gt;1,000 m) be affected? Analysis of POC flux data from 547 stations, collected via global sediment traps since the 1980s, reveals that POC flux has increased only in the shallow ocean (&lt;300 m) but has significantly decreased in the deep ocean. These findings suggest that the expansion of the OMZ has not led to more carbon being transported to the deep ocean. Instead, more POC is being retained in the mid-upper ocean (&lt;1,000 m), where its degradation results in significant consumption of dissolved oxygen, contributing to the expansion of the OMZ.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Why Deep-Water Dissolved Oxygen Is Higher in G̱andaawuu.ngaay Xyangs (Juan Perez Sound), Haida Gwaii, Than Other British Columbia Fjords","authors":"Jennifer M. Jackson,&nbsp;Alex Hare,&nbsp;Charles G. Hannah,&nbsp;Andrea Hilborn,&nbsp;Skil Jáada Vanessa Zahner,&nbsp;Stephen Page,&nbsp;Sarah Rosen,&nbsp;Amanda H. V. Timmerman,&nbsp;Lynn Lee","doi":"10.1029/2024JC021826","DOIUrl":"https://doi.org/10.1029/2024JC021826","url":null,"abstract":"<p>G̱andaawuu.ngaay Xyangs (<i>Juan Perez Sound</i>) is a fjord-like area and ecological hotpot on the east coast of Haida Gwaii, British Columbia, within Gwaii Haanas National Park Reserve, National Marine Conservation Area Reserve, and Haida Heritage Site. A collaboration among the Council of the Haida Nation, Parks Canada, and Fisheries and Oceans Canada has been ongoing since 2017 to advance understanding of the oceanography and marine ecology within and around Gwaii Haanas. Oceanographic data collected year-round by subsurface moorings and annually on research cruises revealed winter dissolved oxygen concentrations (DO) greater than 5 mLL⁻¹ (217 μmol kg⁻¹) as deep as 350 m in G̱andaawuu.ngaay Xyangs and no evidence of hypoxia throughout the water column. This observation differs from other British Columbia fjords, where maximum deep DO is generally observed in summer and values can be hypoxic or anoxic in winter. To explain this high DO, potential energy in the water column was calculated and compared with wind energy. Strong winds and weak stratification facilitated mixing of the water column each winter enabling ventilation. Oxygen loss from the winter high was caused by both frequent episodes of advection of dense, DO-poor water from shelf waters into G̱andaawuu.ngaay Xyangs, and by remineralization. In comparison, in Rivers Inlet, weak winds and strong stratification prevented full water column mixing and ventilation. Although climate-driven changes such as intensified upwelling, enhanced stratification, and region-wide deoxygenation could cause future hypoxia, protecting the integrated land-ocean ecosystem in G̱andaawuu.ngaay Xyangs is more important than ever before.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021826","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489679","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the Relative Roles of Dynamics and Thermodynamics in Sea-Ice Volume Changes in the Canada Basin","authors":"Elizabeth Bailey,&nbsp;Mary-Louise Timmermans","doi":"10.1029/2024JC022075","DOIUrl":"https://doi.org/10.1029/2024JC022075","url":null,"abstract":"<p>The Canada Basin (CB) has seen significant sea-ice loss in recent decades. We use output from the Pan-Arctic Ice-Ocean Modeling and Assimilation System to examine the 1979–2023 evolution of seasonal sea-ice volume (SIV) changes in the CB partitioned into advective and thermodynamic changes. In winter, some years show net convergence into the region that is of comparable magnitude to the SIV change attributed to sea-ice growth. In summer, melt/ablation dominates the change each year. In both seasons, 44 year trends in seasonal SIV changes are driven primarily by thermodynamic processes. The inferred thermodynamic growth each year is nearly equal to the inferred melt consistent with SIV at the end of the melt season declining more rapidly than SIV at the end of the growth season. Increased melt season atmospheric heating of the ice-ocean system over 1979–2023, estimated from ERA5 reanalysis, is consistent with the ice-albedo feedback. In the growth season, net cumulative atmospheric heat release from the ice-ocean system shows no trend, suggesting increases in inferred thermodynamic ice growth can be attributed to more rapid growth of thinner ice. In each season, cumulative atmospheric heat input exceeds that required for ice melt/growth resulting in a residual that influences ocean heat content (OHC). Seasonal OHC changes, inferred from ocean observations, are equal to approximately one-third of this residual, although limited ocean observations leave the total heat budget poorly constrained, highlighting a need for more water column observations.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143475781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Weakening and Poleward Migration of the Southeastern Front Associated With the South Indian Countercurrent From 1980 to 2023","authors":"Weihao Liang,&nbsp;Siyuan Ding,&nbsp;Keyao Wang,&nbsp;Shang-Min Long,&nbsp;Qinyu Liu,&nbsp;Yishuai Jin,&nbsp;Lixiao Xu","doi":"10.1029/2024JC021961","DOIUrl":"https://doi.org/10.1029/2024JC021961","url":null,"abstract":"<p>The Southeast Indian Subantarctic Mode Water (SEISAMW), a thick water layer located between the seasonal and permanent pycnoclines, is important for climate variability in the Southern Ocean. However, its impact on long-term changes of the Southeastern Front (SEF) associated with the South Indian Countercurrent has not been clearly revealed. By analyzing data from observations, objective products and an eddy resolving ocean general circulation model, the present study shows that the SEISAMW has shifted poleward (0.56° ± 0.12°) and weakened from 1980 to 2023, which causes the poleward migration (0.52° ± 0.12°) and weakening of the SEF in recent 44 years. The SEISAMW changes are associated with a significant shallowing and poleward shifting trend of the austral winter deep mixed layer in the Southeast Indian Ocean, as well as the poleward-shifted SEISAMW's outcrop lines, all of which are mainly driven by the poleward migrated westerlies in recent decades.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 2","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143456066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}