Journal of Geophysical Research-Oceans最新文献

{"title":"On the Stoichiometry of Degradable Fraction of Particulate Organic Matter Along a Diapycnal Mixing Path Using Dissolved Oxygen δ18O Approach","authors":"Zhuo-Yi Zhu,&nbsp;Guo-Dong Song,&nbsp;Zhi-Hao Zhang,&nbsp;Yu-Shan Luo,&nbsp;Su-Mei Liu,&nbsp;Jing Zhang","doi":"10.1029/2025JC022512","DOIUrl":"https://doi.org/10.1029/2025JC022512","url":null,"abstract":"<p>The stoichiometry of degradable fraction of particulate organic matter (POM) in the water column has long been one of the key fundamental parameters in chemical oceanography. In this work, we used a novel approach (δ¹⁸O of dissolved oxygen, DO) to verify the stoichiometry of degraded fraction of POM. A field survey was conducted in the northern South China Sea in 2024. Based on the observed DO and nutrients, we used an exhaustive inverse analysis to reveal all possible stoichiometric results of degradable POM in the 200–500 m zone, with the centroid (the most likely) result being C₁₀₄H_xO_yN_14.5P and the corresponding apparent oxygen utilization (AOU) as 140.5 O_2. Our result reveals that the H/O elemental ratio (x/y) is highly close to 2.8, which is closest to that of proteins. As for δ¹⁸O, it ranged from &lt;0 at the surface to a maximum of 7.5‰ at 277 m, with an overall apparent fractionation factor (<i>ε</i>) of 6.84. Based on the negative deviation between δ¹⁸O and DO concentration coupling, we quantified the DO_min (AOU_max) in the water columns when there had been no mixing. The average AOU_max was estimated as 265 μM, and the average AOU_max/nitrate_max (AOU_max/DIP_max) for all four stations was 10.1 ± 1.9 (151 ± 15), which agrees with the previous centroid result. Our work not only reveals the stoichiometry of degraded POM in this dynamic region but also provides a new method for the study of degraded POM stoichiometry in the ocean.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144367237","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":"Carbon Biomass Assessment for Microbial Plankton Groups Across a Young Anticyclonic Loop Current Eddy and Surrounding Waters in the Gulf of Mexico","authors":"L. Linacre,&nbsp;E. Pallàs-Sanz,&nbsp;J. A. Velásquez-Aristizábal,&nbsp;C. Sánchez-Robles,&nbsp;U. Mirabal-Gómez,&nbsp;V. Camacho-Ibar,&nbsp;J. R. Lara-Lara,&nbsp;C. Bazán-Guzmán,&nbsp;J. Sheinbaum-Pardo","doi":"10.1029/2025JC022705","DOIUrl":"https://doi.org/10.1029/2025JC022705","url":null,"abstract":"<p>Carbon biomass assessments are useful in quantifying carbon stored in key planktonic functional groups involved in biogeochemical processes in marine ecosystems. The microbial community inhabiting the open-ocean Gulf of Mexico comprises organisms that regulate carbon fluxes within this mesoscale-dominated ecosystem. The anticyclonic Loop Current Eddies (LCEs) are highly dynamic structures that harbor and transport significant microbial players in the ocean carbon cycle. This study focuses on characterizing the vertical and horizontal high-resolution carbon biomass distribution of the microbial community within the euphotic zone of a young LCE and the surrounding waters during a cruise conducted in the oceanic region of the Gulf of Mexico in November 2022. Carbon estimates were performed using cell abundance and variable carbon conversion factors per microbial group. The prevailing mesoscale dynamics modulated the biomass vertical distribution inside the LCE and at the external region. Sinking and rising of the microbial carbon to deeper and upper layers were discernible at the LCE center and edges, respectively. Upwelling and increase of carbon were evidenced in the cyclonic-influenced external region. Biotic factors, including habitat preferences, nutritional strategies, and ecological interactions among microorganisms, also shaped the biomass composition and distribution within the euphotic zone of mesoscale structures. Remarkably, the combined impact of the deep vertical mixing and the eddy interaction with strong northerly winds during the study period promoted phytoplankton vertical redistribution and carbon stock enhancement inside the LCE. The study's findings situate the LCEs as important dynamic structures regulating the microbial carbon pool within this open-ocean ecosystem.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144339632","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":"Improved Theoretical Estimates of the Zonal Propagation of Global Nonlinear Mesoscale Eddies","authors":"Ran Liu,&nbsp;Yan Wang,&nbsp;Xiaoming Zhai,&nbsp;Dhruv Balwada,&nbsp;Julian Mak","doi":"10.1029/2025JC022518","DOIUrl":"https://doi.org/10.1029/2025JC022518","url":null,"abstract":"<p>Mesoscale eddies are essential for transport and mixing processes in the global ocean, with their characteristic westward propagation being a significant finding from the satellite altimetry era. Traditional predictions of their zonal propagation rely on the theoretical phase speed of long baroclinic Rossby waves; however, this approach is known to overestimate eddy speeds equatorward of approximately <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>35</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $35{}^{circ}$</annotation>\u0000 </semantics></math> latitudes. To address this issue, we incorporate local eddy wavelengths inferred from satellite-based eddy radii into the estimation of global eddy speeds, thereby significantly reducing the overestimation biases in mid-to low-latitude regions. This improvement is consistent with the observation that mesoscale eddies in these latitudes have length scales comparable to the local deformation scales and thus refrain from satisfying the long-wave approximation, whereas the long baroclinic Rossby wave phase speed remains useful for capturing the most energetic but less abundant eddies. The remaining discrepancies between the revised theoretical speeds and observations primarily stem from uncertainties in the background zonal flow, spatial variability of vertical modal structures (and the associated deformation radii), and estimation of local eddy length scales. These findings have important implications for understanding long-range mesoscale eddy propagation and eddy-driven mixing in the global ocean, which are anticipated to benefit future ocean model developments and enhance predictions of mesoscale eddy dynamics.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022518","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336101","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":"Energetics of (Super)Tidal Baroclinic Modes in a Realistically Forced Global Ocean Simulation","authors":"Maarten C. Buijsman,&nbsp;Mujeeb Abdulfatai,&nbsp;Brian K. Arbic,&nbsp;Eric P. Chassignet,&nbsp;Luna Hiron,&nbsp;Jay F. Shriver,&nbsp;Miguel Solano,&nbsp;Dheeraj Varma,&nbsp;Xiaobiao Xu","doi":"10.1029/2025JC022460","DOIUrl":"https://doi.org/10.1029/2025JC022460","url":null,"abstract":"<p>In this study, we diagnose the spatial variability in the energetics of tidally generated diurnal, semidiurnal, and supertidal (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 <mn>2.5</mn>\u0000 </mrow>\u0000 <annotation> ${ &gt;} 2.5$</annotation>\u0000 </semantics></math> cycles per day) internal wave vertical modes (up to mode 6) in a 30-day forward global ocean model simulation with a 4-km grid spacing and 41 layers. The simulation is forced with realistic tides and atmospheric fields. Diurnal modes are resolved beyond mode 6, semidiurnal modes are resolved up to mode 4, and supertidal modes are resolved up to mode 2, in agreement with a canonical horizontal resolution criterion. The meridional trends in the kinetic to available potential energy ratios of these resolved modes agree with an internal wave consistency relation. The supertidal band is dominated by the higher harmonics of the diurnal and semidiurnal tides. Its higher harmonic energy projects on the internal wave dispersion curves in frequency-wavenumber spectra and is captured mostly by the terdiurnal and quarterdiurnal mode-1 waves. Terdiurnal modes are mostly generated in the west Pacific, where diurnal internal tides are strong. In contrast, quarterdiurnal modes occur at all longitudes near strong semidiurnal generation sites. The globally integrated energy in the supertidal band is about one order of magnitude smaller than the energy in the tidal band. The supertidal energy as a fraction of the tidal energy is elevated along semidiurnal internal wave beams in the tropics. We attribute this to near-resonant interactions between tidal modes of the same mode number.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022460","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331989","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":"Phase-Locked Internal-Wave Triads Observed in the Izu-Ogasawara Ridge: Implications for Interplay Between Tides and Winds","authors":"Takashi Ijichi,&nbsp;Ryuichiro Inoue,&nbsp;Yasuo Furushima","doi":"10.1029/2025JC022501","DOIUrl":"https://doi.org/10.1029/2025JC022501","url":null,"abstract":"<p>The Ogasawara subregion of the Izu-Ogasawara-Mariana arc system in the western North Pacific is recognized as one of the most notable hotspots for thermocline turbulent mixing. Although parametric subharmonic instability (PSI) is generally considered a primary driver of enhanced turbulence by facilitating energy transfer from low-mode semidiurnal internal tides to high-mode near-inertial waves (NIWs), recent observations suggest that NIWs remotely induced by winds also contribute to significant seasonal variations in thermocline turbulence in this region. Here, 3-day velocity and density yo-yo measurements, conducted near the PSI critical latitude of 28.8°N opportunistically after several storm passages, reveal the coexistence of PSI-induced high-mode NIWs and wind-induced low-mode NIWs. Two distinct pairs of upward- and downward-propagating NIWs are identified, each forming a phase-locked triad with locally generated upward-propagating semidiurnal internal tides. In a mid-depth layer, a pair of high-mode upward- and downward-propagating NIWs forms a scale-separated PSI triad with the internal tides, whereas in an overlying layer, a pair of low-mode downward-propagating NIWs and intermediate-mode upward-propagating NIWs forms a distinct non-scale-separated triad. Consequently, turbulent dissipation is enhanced at the boundary between these distinct near-inertial velocity layers. These findings are not inconsistent with the view that wind-induced low-mode NIWs interact with internal tides, promoting the growth of intermediate-mode NIWs and eventually contributing to the enhanced thermocline turbulence, thus suggesting an overlooked pathway to turbulence in the ocean interior.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022501","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323549","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":"Longshore Sediment Transport and Morphological Changes Under Climate Change—A Comparison Between CMIP5- and CMIP6-Derived Forcings and the Use of Wave Climate Bias Correction","authors":"G. Vieira da Silva,&nbsp;D. Strauss,&nbsp;T. Murray,&nbsp;F. Alvarez,&nbsp;M. Hemer,&nbsp;A. Meucci,&nbsp;O. Repina","doi":"10.1029/2024JC022212","DOIUrl":"https://doi.org/10.1029/2024JC022212","url":null,"abstract":"<p>Changes in wave climate can impact coastal zones by altering the sediment supplied to coastal compartments via longshore sediment transport (LST). Estimating these changes is challenging, and biases and uncertainty in wave climate projections contribute to uncertainty in LST and morphological change projections. This paper compares wave climate, LST projections, and morphological changes derived from two iterations of the Coupled Model Intercomparison Project (CMIP), and the implications of applying wave climate bias correction in these projections for the late 21st century under high emission scenarios. LST and morphological changes were simulated in a process-based model calibrated with data from a sand bypassing system. Bias correction improved representation of wave climate, including extremes, and reduced variance between climate models. Although bias correction did not change projected mean LST, it reduced the spread of model ensembles by 20% and 10% for CMIP5 and CMIP6, respectively. Both CMIP5 and CMIP6 suggest a future reduction of LST in the study area. However, CMIP6-derived projections show: (a) 50% less variance in wave forcing; (b) greater consistency between ensemble members; and (c) double the reduction in LST. This reduction is attributed to changes in the frequency, intensity and direction of modal and extreme waves. Morphological changes suggest steepening of the beach profiles in line with the historical record. This contribution highlights the value of a bias-corrected model ensemble and improvements in CMIP iterations in providing coherent projections of future wave climate change and its impacts on regional coastal processes.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022212","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331988","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":"On the Ambiguity of Oceanic Eddy Polarity","authors":"Ge Chen,&nbsp;Xiaoyan Chen","doi":"10.1029/2024JC022239","DOIUrl":"https://doi.org/10.1029/2024JC022239","url":null,"abstract":"<p>Polarity is a fundamental feature of oceanic eddies, which defines many aspects of its hydrodynamics and thermodynamics. Polarity ambiguity is a challenging and sometimes puzzling issue for the classification of eddies and analysis of their dynamics. Here, we propose a new methodology combining drifter-measured currents and temperatures to evaluate the validity of altimeter-derived eddy polarity. Different from previous schemes based purely on assessing oceanic temperature ambiguity of eddies from either satellite or Argo observations, our approach integrates the concurrent vector flow and surface temperature measured by drifters riding on altimeter-tracked eddies. The idea is to examine the consistency between the rotation of drifter trajectory and the spinning of eddy motion on the assumption that the looping and circulating directions are identical for a normal eddy and otherwise for an “ambiguous” or “abnormal” one. For a special class of radial drifter trajectory with respect to the eddy centroid, the temperature trend along its path is used to judge its polarity, that is, warmer toward the core for a normal anticyclonic eddy and colder for cyclonic. Our results reveal that many eddies previously classified as “abnormal” are in fact dynamically or thermally ambiguous due to distortions in their upper-layer structures rather than being genuinely misclassified by altimeter. After excluding such ambiguous cases, only ∼3% of eddies show polarity inconsistency in both aspects. These findings suggest that altimeter-derived eddy polarity is highly reliable, and that combining a multi-parameter, Lagrangian-informed approach offers more accurate interpretations of eddy structures by distinguishing intrinsic anomalies from superficial distortions.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022239","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323647","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":"Observed and Model-Simulated Dramatic Bottom Temperature Variations During a Weakened Typhoon in the Northern Yellow Sea","authors":"Hang Yu,&nbsp;Nan Wang,&nbsp;Yang Ding,&nbsp;Rui Li,&nbsp;Xianwen Bao,&nbsp;Guandong Gao,&nbsp;Congcong Bi,&nbsp;Lingling Zhou,&nbsp;Zhigang Yao,&nbsp;Kai Wan","doi":"10.1029/2025JC022401","DOIUrl":"https://doi.org/10.1029/2025JC022401","url":null,"abstract":"<p>Observations and a high-resolution ocean model were utilized to investigate the significant bottom temperature response in the north Yellow Sea (NYS) during the weakening of Typhoon Lekima in August 2019. The cyclonic typhoon winds generated prominent cyclonic currents, with eastward (westward) currents along the southern (northern) coast of the NYS. Concurrently, high sea levels occurred along the northern and southern coasts, whereas low sea levels were present in the central NYS. This sea level pattern persisted for a week after the typhoon's dissipation, maintaining the eastward (westward) currents along the southern (northern) coast. The sustained eastward alongshore current transported warm bottom water along the northern coast of the Shandong Peninsula, resulting in a significant bottom temperature increase over 10°C during 4 days. Simultaneously, the westward alongshore current carried cold water from the Yellow Sea Cold Water Mass (YSCWM) along the southern coast of the Liaodong Peninsula, leading to a prominent bottom temperature decrease of 13°C over 6 days. Near-inertial oscillations disturbed the thermocline and created favorable conditions for the bottom warm water advection. Temperature budget analysis further confirmed the dominant role of horizontal temperature advection in these dramatic bottom temperature anomalies. The relatively weaker wind disturbance could still drive strong bottom temperature change in the YSCWM boundary with sharp temperature gradient, which underscores the impact of weaker synoptic weather systems on significant bottom temperature variations in coastal regions with sharp temperature front, which are often ignored compared to much stronger weather events such as typhoons.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331987","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":"Absolute Velocity, Transport and Stability of the Polar Front Downstream of the Southeast Indian Ridge","authors":"Annie Foppert,&nbsp;Stephen R. Rintoul,&nbsp;Helen E. Phillips","doi":"10.1029/2024JC021853","DOIUrl":"https://doi.org/10.1029/2024JC021853","url":null,"abstract":"<p>The fronts of the Antarctic Circumpolar Current (ACC) influence the growth and instability of eddies, eddy-mean flow interaction, and the development of submesoscale processes. We use in situ hydrography and directly measured velocity from a comprehensive shipboard survey of the Polar Front (PF) south of Tasmania to characterize the synoptic mean velocity and transport structure of the PF. A stream-coordinate system, based on dynamic height anomaly (<i>ϕ</i>), is constructed to create an along- and across-stream perspective of the PF that naturally follows the current. We find the surface-intensified along-stream flow carries a full-depth transport of 80.5 Sv over a width of 90 km, with roughly two-thirds carried by the baroclinic flow. The across-stream velocities are largely depth-independent; the mean depth-averaged flow across the PF core is 0.08 m s⁻¹ in the quasi-northward direction, associated with along-isopyncal downwelling and cold water advection. We calculate potential vorticity (PV) to investigate the stability of the PF and find it is susceptible to both baroclinic and barotropic instability. Mean PV is dominated by the thickness PV term <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mfenced>\u0000 <mfrac>\u0000 <mrow>\u0000 <mi>f</mi>\u0000 <msup>\u0000 <mi>N</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <mi>g</mi>\u0000 </mfrac>\u0000 </mfenced>\u0000 </mrow>\u0000 <annotation> $left(frac{f{N}^{2}}{g}right)$</annotation>\u0000 </semantics></math>, that is PV is controlled by changes in stratification. While strong upper-ocean PV gradients indicate a barrier to mixing, weaker PV gradients and relatively elevated mixing lengths at mid-depth (≈2,000–2,500 m depth) suggest a deep steering level where eddies can efficiently mix properties across the PF.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021853","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144332004","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":"High Frequency Radar Observations of East India Coastal Current Eddies","authors":"Pooja Patel,&nbsp;P. N. Vinayachandran,&nbsp;Deepak Subramani","doi":"10.1029/2024JC022154","DOIUrl":"https://doi.org/10.1029/2024JC022154","url":null,"abstract":"<p>The East India Coastal Current (EICC) flows poleward along the east coast of India during spring and equatorward during winter. In the summer, it flows equatorward in the northern bay and poleward in the south, converging in the central part of the coast. Data from three pairs of HF radars located at three stations, Odisha (ORCO), Andhra Pradesh (APCO), and Tamil Nadu (TNCO), along the east coast of India are used in this study to present the characteristics and dynamics of eddies for a decade, from 2010 to 2020. The seasonal reversal of the EICC occurs through a gentle transition in the north, marked by strong offshore flows in the middle part of the coast, and eddies of different signs in the south. Eddy formation peaks in winter and most frequent off TNCO, followed by APCO and ORCO. Cyclonic eddies have longer lifespans and larger sizes in winter, while anticyclonic eddies show similar characteristics in spring. Most eddies have a radius between 10–30 km and life of 5 days. Seasonal mean Eddy Kinetic Energy (EKE) is higher in spring and winter, when EICC is well organized. Barotropic (BT) energy conversion takes place for all three stations for all seasons. Baroclinic (BC) energy transfer occurs in winter for all three stations and additionally off ORCO during summer. Spatial patterns of energy conversion occur in both mean-to-eddy and eddy-to-mean directions; they are spatially non-uniform and show marked differences between coastal and offshore regions.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144315104","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}