Journal of Geophysical Research-Oceans最新文献

{"title":"Tidal Modulation of Two Interacting Mid-Field Bulges of the Pearl River Plume","authors":"Pengpeng Hu,&nbsp;Guang Zhang,&nbsp;Suan Hu,&nbsp;Heng Zhang,&nbsp;Wenping Gong","doi":"10.1029/2025JC022588","DOIUrl":"10.1029/2025JC022588","url":null,"abstract":"<p>River plumes are important pathways for transporting terrestrial materials to coastal oceans. Utilizing the Regional Ocean Modeling System, which has been well-validated against cruise observations and satellite data, we investigated the tidal modulation of the mid-field bulge in the Pearl River Estuary (PRE). Our findings reveal that the Pearl River plume exhibits two interacting bulges, forming a distinctive indented structure (i.e., isohalines curving toward shore) with periodic spring-neap tidal variation which is related to the tidal modulation of freshwater transport at the PRE mouth. Freshwater transport at the PRE mouth is primarily through two pathways: the West Shoal and the Lantau Channel. The Modaomen Estuary (adjacent to the PRE on its western side) and the West Shoal exhibit sustained downstream freshwater transport, forming a bulge in the west side of the PRE (the western bulge), while the freshwater within the Lantau Channel undergoes periodic anticyclonic motion modulated by tides, leading to the formation of a periodic indented structure. This process is governed by barotropic pressure gradient forces, manifesting as temporal variations in surface height gradients driven by freshwater accumulation. Furthermore, tidal forcing drives the fortnightly cyclic detachment of the bulge from the Lantau Channel (the eastern bulge) through its regulation on surface salinity distribution and vertical mixing intensity. Wind forcing suppresses the formation of this periodic indented structure in the plume by modulating freshwater flux. This study enhances our understanding of the periodic spring-neap tidal variation of the combined bulge and deepens our comprehension of the river plume's mid-field dynamics.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145062601","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":"Dual Coastal Downwelling Belts Over the Northwestern South China Sea in Winter","authors":"Xinmei Gong,&nbsp;Yeqiang Shu,&nbsp;Zhiqiang Liu,&nbsp;Tingting Zu,&nbsp;Danian Liu,&nbsp;Xuekun Shang,&nbsp;Binbin Guo","doi":"10.1029/2025JC022771","DOIUrl":"10.1029/2025JC022771","url":null,"abstract":"<p>This study explores a unique dual coastal downwelling belt in the northwestern South China Sea (NWSCS) during the winter northeasterly monsoon season. Employing both in situ observations and numerical simulations, we delineate how the topography of the Leizhou Peninsula and Hainan Island fundamentally shapes this phenomenon. The study reveals a westward alongshore current, propelled by downwelling-favorable winds and a buoyancy-driven river plume, which fosters seawater convergence on the western shelf. This process establishes a northeastward-directed pressure gradient force that triggers a stronger offshore flow than that driven by the northeasterly monsoon winds alone, as described by Ekman dynamics. On the inner shelf, warmer seawater driven by the northeasterly winds converges with colder, fresher coastal water near the 30-m isobath, forming a pronounced downwelling belt. In contrast, on the outer shelf, a landward reduction in the strength of the onshore current, which is counterbalanced by a landward enhancement of the eastward alongshore pressure gradient force with alongshore wind stress and the eastward Coriolis force, leads to water convergence and subsequent downwelling at the ∼60 m isobath. This dual-downwelling-belt structure, underscored by its dynamic mechanisms, not only deviates from traditional coastal downwelling theories but also highlights the dominant role of regional topography in modulating the downwelling dynamics in the NWSCS.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145037835","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":"A Unified, Data-Informed Model for Shoreline Evolution Due To Longshore and Cross-Shore Processes","authors":"M. A. Davidson,&nbsp;E. Hunt,&nbsp;N. G. Valiente","doi":"10.1029/2025JC022379","DOIUrl":"10.1029/2025JC022379","url":null,"abstract":"<p>Due partially to a changing global climate, there is an increasing need to develop a modeling approach capable of providing warnings of coastal evolution, including erosion at storm, interannual, and decadal timescales and in complex coastal settings. This research presents a reduced-complexity model with a common approach to predicting shoreline change due to cross-shore and longshore processes. The model architecture is designed to be flexible and data-informed, incorporating an extended Kalman filter (eKF) for the assimilation of field measurements of shoreline change. Depending on the values of the optimized model-free parameters resulting from the eKF assimilation, the longshore and cross-shore shoreline model components can resemble either new, established, or hybrid versions of previously reported models. Thus, the model also provides new insight into the dynamics of shoreline change. The model is tested and demonstrated via a series of numerical tests and applied to field data collected at a complex coastal setting, showing good performance with R.M.S. shoreline prediction errors of &lt;6 m. The eKF data assimilation suggests that a hybrid cross-shore transport model, combining the characteristics of two established semiempirical models and a new disequilibrium longshore transport model, effectively describes the shoreline evolution at the swash-aligned field site. The computational efficiency, stability, and versatility of the ForCE-LX model provides a promising tool for the prediction of shoreline evolution on time-scales of days to decades, in widespread coastal settings.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022379","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145022004","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":"Variability and Dynamics of Wave Effects on Upwelling Circulation off the Pearl River Estuary","authors":"Shangfei Lin,&nbsp;Jianping Gan","doi":"10.1029/2025JC022928","DOIUrl":"10.1029/2025JC022928","url":null,"abstract":"<p>We employed a coupled wave-circulation model to investigate the variability and dynamics of surface gravity wave effects on the upwelling circulation within the estuary-shelf system of the Pearl River Estuary and its adjacent shelf. Our analyses demonstrated that waves produce shoreward Stokes transports, cumulatively raising the surface elevation in nearshore regions and reducing the surface elevation in offshore regions even though the anti-Stokes current due to the Stokes Coriolis force partially counteracts this effect. Subsequently, changes in the cross-isobath barotropic pressure gradient force (PGF) weaken the along-isobath flow and the upwelling. Meanwhile, wave-induced shoreward advection of the river plume notably alters the cross-isobath density gradients, modulating the baroclinic geostrophic flow. Wave effects on the alongshore flow are dominated by competing these barotropic and baroclinic effects of the geostrophic adjustment. Wave affects the cross-isobath flow governed intricately by Stokes forces, geostrophic adjustment, and weakened turbulent stress in the surface, interior, and bottom layers of the water column, respectively. A more pronounced reduction in the upwelling circulation occurs east of the continental shelf compared to the region west of the shelf and offshore compared to nearshore with reductions in depth-integrated along-isobath and cross-isobath Lagrangian transports. This spatial variation is primarily associated with wave-modulated PGF over different topography.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145022005","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":"Blue Carbon Ecosystems Modulate the Air-Sea CO2 Exchange and Coastal Acidification in Tropical Estuaries","authors":"Jianzhong Su,&nbsp;Shimin Xiao,&nbsp;Cong Tan,&nbsp;Zhixiong Huang,&nbsp;Min Nina Xu,&nbsp;Ehui Tan,&nbsp;Liguo Guo,&nbsp;Guizhi Wang,&nbsp;Wei-Jun Cai,&nbsp;Shuh-Ji Kao","doi":"10.1029/2025JC023089","DOIUrl":"10.1029/2025JC023089","url":null,"abstract":"<p>The diverse and productive blue carbon ecosystems (mangrove, seagrass, salt marsh, and macroalgae) provide many ecosystem services and play an important role in climate change mitigation and adaptation. However, less is known about how different biogeochemical processes within blue carbon ecosystems can influence seawater carbonate dynamics especially on the partial pressure of carbon dioxide (<i>p</i>CO₂) and pH. Through underway <i>p</i>CO₂ measurements and discrete water samples, we examined the spatial and temporal distributions of the carbonate system in two tropical mangrove estuaries and one benthic-macroalgae-vegetated lagoon. In early summer, the mangrove estuaries behaved as weak CO₂ sources of 2.0–4.0 mmol m⁻² d⁻¹, whereas the tropical lagoon became a CO₂ sink of −6.4 mmol m⁻² d⁻¹. The chemical stoichiometry, stable carbon isotope, and other geochemical tracers reveal that carbonate dissolution and sulfate reduction followed by aerobic respiration are dominant controls on carbonate dynamics in mangrove estuaries. Without alkalinity enhancement driven by carbonate dissolution and sulfate reduction mainly from mangrove sediments, CO₂ emission would be 23 times larger than current observation, and pH would decrease by 0.39 units on an estuary-wide scale. However, in macroalgae-inhabited lagoon primary production followed by carbonate formation could draw <i>p</i>CO₂ down to 70 μatm and raise pH to 8.8, which are significantly distinct from the normal estuarine water. This study demonstrates that lateral export of alkalinity from mangrove sediments and the in situ metabolism of macroalgae can significantly influence the estuarine air-sea CO₂ flux and acidification status, and emphasizes the importance of protecting and restoring the blue carbon ecosystems.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012142","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":"Response of Oceanic Meridional Overturning Circulation to Vegetation Removal on Different Continents","authors":"Jiaqi Guo,&nbsp;Yonggang Liu,&nbsp;Shuai Yuan,&nbsp;Xiang Li,&nbsp;Yue Liu,&nbsp;Yongyun Hu","doi":"10.1029/2025JC022978","DOIUrl":"10.1029/2025JC022978","url":null,"abstract":"<p>Vegetation on different continents is often subject to substantial changes due to climate change, anthropogenic activities, or vegetation evolution, but how it affects the oceanic meridional overturning circulation (MOC) is unclear. This study explores both the transient evolution and equilibrium response of MOCs to vegetation removal on each continent except Antarctica using an atmosphere-ocean general circulation model, CESM1.2.2, under preindustrial climate conditions. The results indicate that at equilibrium, removing Eurasian vegetation slightly weakens the Atlantic MOC (AMOC) (−2.5 Sv, −16.5%) but enhances the Pacific MOC (PMOC) (+6.0 Sv, +58.3%). Conversely, removing North American vegetation strengthens the AMOC (+2.7 Sv, +17.6%) while weakening the PMOC (−1.8 Sv, −17.7%). Vegetation removal over low-latitude regions produces minimal impact on either AMOC or PMOC. Global vegetation removal causes a substantial weakening of AMOC (−5.7 Sv, −36.9%) and a pronounced strengthening of PMOC (+4.8 Sv, +47.3%), different from the linear sum of individual effects described above. The transient evolution of both AMOC and PMOC is complex, exhibiting distinct (even opposite) responses in the multidecadal timescale and centennial or millennial timescale. Abrupt changes in both AMOC (by ∼10 Sv) and PMOC (by ∼2 Sv) occur around 2700 years after the global vegetation removal. This highlights the long timescale of surface-climate responses to external forcings, which is easily overlooked in shorter simulations. Process diagnostics show that salinity anomalies—modulated by net precipitation and sea ice melt—govern the AMOC response, whereas surface temperature anomalies dominate the PMOC response.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145012299","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":"Hf-Nd-Sr Isotopic Constraints on the Sources of Pelagic Clays and Silicate Residues of Ferromanganese Crusts in the Central Indian Basin","authors":"N. P. Sukumaran,&nbsp;G. Parthiban,&nbsp;V. K. Banakar,&nbsp;B. Nagender Nath","doi":"10.1029/2025JC022607","DOIUrl":"10.1029/2025JC022607","url":null,"abstract":"<p>The sources of pelagic clays and the silicate residues of ferromanganese (Fe-Mn) crusts from the Central Indian Basin remain unclear. Here, we present combined Hf-Nd-Sr isotopic compositions for a suite of clays and silicate residues of Fe-Mn crusts from the Afanasiy-Nikitin Seamount (ANS) to constrain their sources and the process influencing their variability. Our results show large and systematic variations with a range of 0.70788–0.73051 for ⁸⁷Sr/⁸⁶Sr, from −15.68 to −7.55 for εNd, and from −3.9 to 6.72 for εHf. Detrital clays are characterized by radiogenic ⁸⁷Sr/⁸⁶Sr, unradiogenic εNd, and εHf. Siliceous clays have less radiogenic ⁸⁷Sr/⁸⁶Sr, radiogenic εNd, and εHf. The silicate residues of ANS Fe-Mn crusts have unradiogenic ⁸⁷Sr/⁸⁶Sr, radiogenic εNd, and highly radiogenic εHf. Despite variable lithologies and depositional environments, all data display highly correlating trends in Nd-Sr and Nd-Hf space suggesting mixing of two common enriched and depleted end-members. Mixing relationships in Nd-Sr space define the sources as the Himalayas and the Indonesian Volcanic Arc (IVA). In the Nd-Hf space, the highly radiogenic Hf isotopic compositions of our sedimentary archives resolve the IVA source, but not the Himalayas that are plagued by zircon effects. Calculated ∆εHf clay ranges from 2.3 to 8.53 suggesting an unlikely presence of zircons in these sedimentary archives. Our results demonstrate that the clays and the silicate residues of ANS Fe-Mn crusts primarily originate from the Himalayas and the IVA, with the Himalayas supplying 47%–98% of the detrital clays and the IVA contributing 46%–62% to the siliceous clays and silicate residues of crusts.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144998862","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":"Benefits of a Landfast Ice Representation on Simulated Antarctic Sea Ice and Coastal Polynya Dynamics","authors":"N. Pirlet,&nbsp;T. Fichefet,&nbsp;M. Vancoppenolle,&nbsp;A. D. Fraser,&nbsp;P. Mathiot,&nbsp;C. Rousset,&nbsp;A. Barthélemy,&nbsp;P.-Y. Barriat,&nbsp;C. Pelletier,&nbsp;G. Madec,&nbsp;C. Kittel","doi":"10.1029/2024JC022032","DOIUrl":"10.1029/2024JC022032","url":null,"abstract":"<p>The Antarctic coastal marine region is a unique and highly complex environment, of which landfast ice and polynyas are key features, especially in the context of dense water formation. Current large-scale ocean-sea ice models used in climate studies simulate hardly any Antarctic landfast ice, which has presumably negative implications on sea ice and polynya dynamics. Here we develop, implement, and evaluate an empirical circumpolar Antarctic landfast-ice representation for large-scale ocean-sea ice models. This representation is based on the restoring of sea ice velocity to zero where and when landfast ice is observed, according to a recently released circum-Antarctic landfast ice database. Using 2001–2017 hindcast simulations with the NEMO-<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mtext>SI</mtext>\u0000 <mn>3</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${text{SI}}^{3}$</annotation>\u0000 </semantics></math> model, we demonstrate that prescribing landfast ice not only ensures accurate landfast ice coverage, as expected, but also largely improves the simulated landfast ice thickness and polynya dynamics. This includes more realistic polynya coverage, individual polynya shape, frequency, and ice production rates. Additionally, the model low bias in summer ice extent is reduced, as prescribing landfast ice locks thicker ice near the coast, taking longer to melt. Our simulations also give the first estimate of landfast ice volume, representing 10.6% of the pan-Antarctic total, compared to 3.8% of the total Antarctic sea ice extent. We argue that velocity restoring is appropriate for some investigations of the Antarctic landfast ice over the recent past, but not for the remote past or future projections, for which a physical representation of landfast ice drivers, particularly iceberg-sea ice interactions, is necessary.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144935301","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":"ENSO Influences Subsurface Marine Heatwave Occurrence in the Kuroshio Extension","authors":"Mitchell Chandler,&nbsp;Janet Sprintall,&nbsp;Nathalie V. Zilberman","doi":"10.1029/2025JC022899","DOIUrl":"10.1029/2025JC022899","url":null,"abstract":"<p>Extreme ocean temperature events, also known as marine heatwaves (MHWs), can have devastating consequences for ecosystems, communities, and economies. However, the ability to understand and predict MHWs beneath the sea surface is limited by a scarcity of subsurface observations. Here, we combined in situ temperature observations from a High-Resolution eXpendable BathyThermograph (HR-XBT) transect in the northwest Pacific Ocean with satellite observations to produce a multidecadal (1993–2022) subsurface temperature time series with 10-day temporal resolution. This novel time series was used to examine MHWs between the surface and 800-m deep in the Kuroshio-Kuroshio Extension region east of Japan. The length of this 30-year time series also permitted exploration of long-term trends and interannual variability in subsurface temperature. Variability in the Kuroshio-Kuroshio Extension system is found to exert a strong control on the occurrence of MHWs along the transect. Throughout the upper 800-m of the water column, Kuroshio warming drove a significant increase in Kuroshio MHW days per year. Notably, the largest mean MHW event intensities were observed in the subsurface at every location along the transect rather than at the sea surface. Strengthening of the Kuroshio Extension and its southern recirculation gyre during El Niño drove a significant increase in subsurface MHWs where the intensified current system intersected the transect. In contrast, surface MHW occurrence along the transect was not influenced by the El Niño-Southern Oscillation (ENSO). Clearly, relying only on sea surface temperature observations does not provide the full picture of MHWs in this highly dynamic region.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022899","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929710","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":"Future Summertime Marine Heatwaves in the Indian Ocean in Response to Enhanced Variability of the Western North Pacific Subtropical High Under Warming Climate","authors":"Jayarathna W. N. D. Sandaruwan,&nbsp;Wen Zhou,&nbsp;Mat Collins,&nbsp;Xuan Wang","doi":"10.1029/2025JC022626","DOIUrl":"10.1029/2025JC022626","url":null,"abstract":"<p>Marine heatwaves (MHWs) pose significant threats to marine ecosystems and associated services, necessitating a deeper understanding of their driving mechanism. This study examines how the intensification of the Western North Pacific Subtropical High (WNPSH) influences future summer MHW occurrences in the Indian Ocean through complex ocean-atmosphere coupling. Over two thirds of CMIP6 models project more frequent an intense strong WNPSH years by the end of the 21st century, resulting in prolonged and extreme summer MHWs in the future. Westward extension of stronger WNPSH generates pronounced anomalous anticyclonic circulation, producing easterly winds that extend into the north and equatorial Indian Ocean and oppose climatological monsoon winds. While these anomalous easterlies suppress key cooling mechanisms, such as wind driven evaporative cooling and upwelling, the westward propagating downwelling Rossby waves dynamically precondition the warming in the western Indian Ocean by deepening the thermocline. This coupled system creates sustained surface and subsurface warming extending from preceding seasons into summer. Regional differences emerge in future summer MHWs through cloud-sea surface temperature (SST) feedback mechanisms. The central and northeastern Indian Ocean experiences more extreme MHWs due to reduced cloud cover, enhanced solar radiation exposure, and suppressed evaporative cooling through positive low cloud-SST feedback. Conversely, the western Indian Ocean exhibits enhanced convection and cloud formation, moderating extreme warming through negative SST-cloud feedback, exposing the region only to strong-moderate MHWs. These findings highlight the critical role of multiseasonal, coupled ocean-atmospheric interactions in shaping future summer MHW patterns, emphasizing the enhanced vulnerability of marine ecosystems.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144929711","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}