Journal of Geophysical Research-Oceans最新文献

{"title":"The See-Saw Radiation of Semidiurnal Internal Tides From the Lesser Sunda Islands","authors":"Yuankai Zhou,&nbsp;Zhenhua Xu,&nbsp;Peiwen Zhang,&nbsp;Jia You,&nbsp;Yuanzheng Zhang,&nbsp;Zheng Wang,&nbsp;Adi Purwandana,&nbsp;Robin Robertson","doi":"10.1029/2026JC023982","DOIUrl":"https://doi.org/10.1029/2026JC023982","url":null,"abstract":"<p>The Lesser Sunda Islands (LSI) form a long chain over 1,000 km across major exits of the Indonesian Throughflow (ITF), through which Pacific waters enter the eastern Indian Ocean. The region hosts energetic internal tides and intense mixing that affect ITF water-mass transformation, with implications for Indo-Pacific exchange and global overturning circulation. Previous studies have focused on individual straits, leaving the island-chain-scale internal tide field poorly resolved. Using multi-satellite altimetry, we provide the first coherent mode-1 semidiurnal internal tide energy flux map across the LSI. A see-saw radiation pattern emerges across the island chain, shaped substantially by the combined strait-island-basin topography during generation and propagation. In the west side, internal tides from the Lombok Strait interact with those from the Australian Northwest Shelf, forming an interference pattern in the basin. In the central region, local generation near Benteng Island replenishes the diffracted northward Sape beam, allowing it to propagate over 500 km into the Gulf of Boni, highlighting a unique strait-basin-island-gulf long-range-traversed propagation. In the east side, the northward Ombai beam bifurcates and diffracts around the Wakatobi Islands, redirecting coherent energy into separate branches. Straits, islands, and basins combine to contribute to an asymmetric north–south internal tide radiation, with the southward semidiurnal coherent energy flux (2.5 GW) exceeding its northward component (1.8 GW). These results show how equatorial island chains organize and modulate multisource internal tides, advancing understanding of internal tide dynamics and energetics among global marginal seas and providing observational constraints for ocean and climate models.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205792","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":"Attribution of the 2013–2017 Subsurface Salinification Event in the South China Sea: The Role of Vertical Diffusion","authors":"Shuaichen Xin,&nbsp;Mingting Li,&nbsp;Junlu Li,&nbsp;Yaohua Zhu,&nbsp;Igor Belkin,&nbsp;Chunhua Qiu,&nbsp;Dongxiao Wang","doi":"10.1029/2026JC024732","DOIUrl":"https://doi.org/10.1029/2026JC024732","url":null,"abstract":"<p>Subsurface salinity variability in the South China Sea (SCS) plays a critical role in modulating circulation, stratification, and the water cycle, which remains poorly quantified, especially regarding budget closure and diffusion-related mixing. Observations indicate that the subsurface salinity in the SCS (100–300 m) increased by about 0.06 psu from 2013 to 2017, and this salinification event lagged surface salinity variability by approximately one year. Using a closed salinity budget analysis based on ECCO, multiple high-resolution data sets, and a one-dimensional diffusion experiment, we diagnose the processes controlling this salinification event. In the mean state, vertical diffusion acts as the dominant negative term in balancing advection. During the salinification event, advection initiates the subsurface salinity increase, while reduced vertical diffusion sustains the salinification when the surface signal weakening, generating the delayed subsurface maximum. One-dimensional diffusion experiment provides physical evidence supporting a diffusion-driven delayed subsurface salinity response. Further analysis based on both historical data and CMIP6 projections indicates that with the strengthening of stratification in the SCS under global warming, vertical diffusion will play an increasingly important role in regulating subsurface salinity. These results indicate that vertical diffusion is not merely a damping term but a key factor of subsurface salinity in the SCS, with implications for salinity budget analysis and water mass interpretation.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205722","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":"Regional Sea-Level Variability Captures Low-Frequency Transport Through the Gulf of Mexico Gateways","authors":"Giovanni Durante,&nbsp;Julio Sheinbaum,&nbsp;Eric P. Chassignet,&nbsp;Yang Zhang,&nbsp;Marco Larrañaga,&nbsp;Homar Verdugo-Ortega","doi":"10.1029/2026JC024791","DOIUrl":"https://doi.org/10.1029/2026JC024791","url":null,"abstract":"<p>Transports through the Yucatan Channel, Florida Straits, and Bahamas passages form the western-boundary gateway connecting the Caribbean Sea, Gulf of Mexico, and North Atlantic. Their documented covariability with regional sea level suggests that satellite altimetry contains information about gateway transport variability, but its ability to recover section-integrated transport across this connected system has not been systematically evaluated. Here, we combine direct velocity-based transport estimates from the Canek mooring arrays, the Florida Cable record, and satellite altimetry to identify transport-sensitive sea-level modes and reconstruct low-frequency gateway transport. The observed records show substantial low-frequency variability, while finite-window experiments demonstrate that mean transport, seasonal amplitudes, and especially linear trends depend on the sampled period. Correlation analysis and covariance-targeted regression reveal coherent transport-related sea-level patterns spanning the northwestern Caribbean, Yucatan Channel, Cuba, Florida Straits, and Bahamas passages. Sea-level-based reconstructions reproduce much of the withheld observed variability, with validation <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>R</mi>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${R}^{2}$</annotation>\u0000 </semantics></math> values of 0.6–0.8 and RMSE of 0.74–2.0 Sv, comparable to observational uncertainty. Relative to local cross-section sea-level-gradient proxies, the regional reconstructions reduce validation RMSE by 36%–44% at the Canek sections, but only 14% at the Florida Cable, where local geostrophic control is stronger. Applied to the full satellite-altimetry era, the reconstructions provide empirical transport proxies from 1993 to 2025. These results show that regional sea-level variability contains recoverable transport information beyond local gradients, particularly across the Canek gateways.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JC024791","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205723","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":"Seasonal Phase Alignment Governs How Long Coastal High-Water Thresholds Are Exceeded Worldwide","authors":"Yi-Chun Kuo,&nbsp;Wei-Bo Chen","doi":"10.1029/2026JC024972","DOIUrl":"https://doi.org/10.1029/2026JC024972","url":null,"abstract":"<p>Coastal extreme sea level is conventionally characterized by exceedance frequency or height, with the seasonal cycle removed as a nuisance. Using hourly records from 730 tide gauges worldwide, we quantify how the annual sea-level cycle (ASLC) governs the time coastal thresholds spend exceeded. At each station we separate the astronomical tide, excluding the annual and semiannual constituents, reconstruct the ASLC, identify its annual-harmonic phase and the storm-surge season, and compare observations with a seasonally flattened counterfactual. The amplification of annual exceedance time increases monotonically with the ratio <i>r</i> of ASLC range to tidal range (Spearman <i>ρ</i> = 0.70) and weakens as <i>r</i> increases beyond about 1, ranging from negligible where the tide dominates to about +150% where the seasonal cycle does. After controlling for <i>r</i>, amplification decreases as the annual-harmonic and storm-season phases separate (partial <i>ρ</i> = −0.43, <i>p</i> &lt; 0.001); in the best-sampled <i>r</i> stratum, median amplification is 29% larger for in-phase than anti-phase stations (ratio 1.29, 95% CI 1.18–1.39). The association strengthens as co-located gauges are merged. At matched exceedance quantile the mean episode lengthens by only 1.8%: the seasonal cycle multiplies exposure chiefly by adding episodes, not extending them. The ASLC moves 43 stations (5.9%) across a threshold marking an annual-cycle-dominated intertidal regime. Two negative results bound the scope: alignment shows no coherent global trend, and it does not affect near-mean-sea-level emergence duration, which depends on amplitude alone. Seasonal phase alignment thus governs annual exceedance time in a way frequency-based metrics do not capture.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146330","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":"Global Patterns of Marine Phytoplankton Pigment Package and Composition Influencing Light Absorption","authors":"Yu Huan,&nbsp;Deyong Sun,&nbsp;Shengqiang Wang,&nbsp;Qiwei Hu,&nbsp;Jiawen Fang","doi":"10.1029/2026JC024447","DOIUrl":"https://doi.org/10.1029/2026JC024447","url":null,"abstract":"<p>Phytoplankton are fundamental to marine ecosystems, influencing global biogeochemical cycles and climate. A key to understanding their abundance and function lies in their light absorption properties (<i>a</i>_ph), which are primarily governed by two intrinsic factors: the package effect (<i>Q</i>_<i>a</i>*, the efficiency loss in specific absorption caused by cellular self-shading) and pigment composition (<i>a</i>_pig*). However, our understanding of the non-linear bio-optical relationships between <i>a</i>_ph, <i>a</i>_pig*, and <i>Q</i>_<i>a</i>* has been largely constrained by localized studies, leaving a significant gap in our knowledge of their dynamics and interactions across the global ocean. This study aims to quantify the global-scale (60°S–60°N) causal relationships between <i>a</i>_ph and its drivers, <i>Q</i>_<i>a</i>* and <i>a</i>_pig*, based on 22 years of satellite data by refining the bio-optical models. Our results reveal a latitudinal structuring of influence: the package effect was the dominant driver of <i>a</i>_ph variability in mid-latitudes, contributing 40%–50% of the changes in the Atlantic, while its influence was minimal in tropical regions. Pigment composition acted to reduce uncertainty in <i>a</i>_ph, particularly in subtropical zones. Overall, the package effect demonstrated a more active and significant interaction with phytoplankton absorption than pigment composition on a global scale. This work provides a global causal perspective on the mechanisms controlling phytoplankton optical properties. It moves beyond local correlations to reveal a coherent latitudinal pattern in bio-optical control. By elucidating these global latitudinal causal patterns, this study provides a mechanistic basis for refining regionally parameterized bio-optical schemes in Earth System Models, and enhances the interpretation of satellite ocean color data.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146450","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":"Local Surface and ENSO Forcings Induce Predictable Temperature and Salinity Responses in the Coastal Gulf of Alaska","authors":"Seth L. Danielson,&nbsp;Tyler D. Hennon,&nbsp;David F. Hill,&nbsp;Kay McMonigal","doi":"10.1029/2026JC024703","DOIUrl":"https://doi.org/10.1029/2026JC024703","url":null,"abstract":"<p>We assess temperature and salinity vertical profile (1970–2025) and mooring time series (1999–2025) data for structure, trends, and variability at northern Gulf of Alaska coastal oceanographic station GAK1 (59° 50.7′N, 149° 28.0′W). The whole water column (0–250 m) is warming, though marginally faster at the surface (+0.21 ± 0.05°C decade⁻¹) than at the seafloor (+0.16 ± 0.03°C decade⁻¹), and with seasonally greatest warming in winter. Near-surface waters are freshening (−0.05 ± 0.02 decade⁻¹) while near-bottom waters show salinization (+0.04 ± 0.01 decade⁻¹). The surface and seafloor opposing trends are consistent with half-century trends of increasing winter coastal freshwater discharge and diminished downwelling-favorable wind forcing. At the surface, warm anomalies coincide with fresh anomalies, driven by elevated runoff from snow and glacier melt. Near the seafloor, relatively large anomalies of both paramaters tend to be induced in winter, when stratification is annually weakest. Projection of downwelling winds, surface heat fluxes and freshwater discharge on temperature and salinity fields reveals seasonally- and depth-dependant coupling between the drivers and water column structure. Composite analysis of El Niño Southern Oscillation events reveals up to 24 months of forward predictability for coastal Gulf of Alaska ocean conditions during La Niñas (which induce cooling and salinization), and Central Pacific (CP) and Eastern Pacific (EP) El Niños (which both induce warming and freshening). EP events generate larger responses than CP events. The environmental variations documented here can inform our understanding of ecosystem processes, including bottom-up trophic cascades triggered by marine heat waves.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JC024703","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146101","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":"Global Distribution and Decadal Trends of Coastal Marine Cold Spells: Insights From an Ensemble of Satellite Sea Surface Temperature Products","authors":"Tianxiao Cui,&nbsp;Jiaxiang Li,&nbsp;Wenjin Sun,&nbsp;Jingsong Yang,&nbsp;Changming Dong","doi":"10.1029/2025JC023960","DOIUrl":"https://doi.org/10.1029/2025JC023960","url":null,"abstract":"<p>Marine cold spells (MCSs) exert severe impacts on coastal ecosystems, yet global assessments in coastal regions, which host diverse and complex marine systems, remain limited. Here we integrate four satellite sea surface temperature (SST) products to quantify the spatial distribution and decadal trends of coastal MCS worldwide. We further assess the relative contributions of long-term SST change and internal variability. Hotspots of MCS cumulative intensity are concentrated in mid- to high-latitude coastal cold-water zones, particularly along the Gulf of Alaska and the North American west coast, the Peru–Chile upwelling system, the Kuroshio–Oyashio and Okhotsk–Bering margins, and the southeast Australian shelf. Over 1992–2021, coastal MCS generally weakened, with frequency and duration decreasing by 0.62 ± 0.48 events/decade and 1.15 ± 2.53 days/decade, respectively. Cumulative cold stress also weakened, as indicated by a spatial mean cumulative-intensity trend of 1.69 ± 5.97°C days/decade. Long-term SST change is more strongly associated with trends in MCS frequency, duration, and annual cumulative days, whereas internal variability plays a comparable role in shaping intensity trends. Multiple SST products show broad agreement in the mean state and trends of coastal MCS, but differ markedly in the inferred balance between long-term SST change and internal variability. The average OISST-referenced event-scale co-identification rate across the four products is 28.47% ± 13.84%, highlighting substantial inter-product uncertainty in MCS detection and underscoring the value of multi-product ensemble approaches for characterizing consistent large-scale patterns and long-term trends in coastal MCS assessments.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146174","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":"Internal Solitary Waves in the Xisha Areas: Evidence From SWOT Observations","authors":"Sheng Wang,&nbsp;Zheen Zhang,&nbsp;Yonggang Guo,&nbsp;Hanyu Chen,&nbsp;Xueen Chen,&nbsp;Chongyue Li,&nbsp;Xiaoming Li,&nbsp;Jianjun Liang,&nbsp;Yongguo Chang","doi":"10.1029/2026JC024164","DOIUrl":"https://doi.org/10.1029/2026JC024164","url":null,"abstract":"<p>The Xisha Islands, situated in the northwestern South China Sea, are characterized by diverse topography conducive to a wide range of oceanic dynamic processes. Internal solitary waves (ISWs), large-amplitude nonlinear waves in continuously-stratified oceans, are pivotal for oceanic energy transport, vertical seawater mixing, and material exchange. This research leverages Surface Water and Ocean Topography (SWOT) mission data to investigate ISWs near the Xisha Islands. Contrary to previous views, SWOT data reveal numerous ISWs in the vicinity of the Xisha Islands and their surroundings, originating from various sources such as the Luzon Strait, the Beibu Gulf, and the local Xisha Islands. The study explores the occurrence patterns, propagation characteristics, and energy features of ISWs from different sources. ISWs from the Luzon Strait are influenced by tides, mesoscale eddies, and local stratification. Those from the Beibu Gulf persist throughout the year, while ISWs from the Xisha Islands are affected by the background current field during propagation. Comparing ISWs from different sources, it is evident that those from the Beibu Gulf are the most frequently observed in the Xisha Islands region during the study period. However, ISWs originating from the Luzon Strait exhibit comparable amplitude, maximum isopycnal displacement, and depth-integrated energy flux upon reaching the area. Despite encountering various influences during propagation, ISWs from the Luzon Strait significantly impact the marine environment of the Xisha Islands. Locally generated ISWs in the Xisha Islands have lower energy but enhance the complexity of local marine dynamic processes.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149145850","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":"Surface Chlorophyll-a Trends in the Mediterranean Sea: Seasonal Bloom Dynamics and Drivers","authors":"Christian Marchese,&nbsp;Simon Oiry,&nbsp;Emanuele Organelli,&nbsp;Maria Laura Zoffoli","doi":"10.1029/2025JC023779","DOIUrl":"https://doi.org/10.1029/2025JC023779","url":null,"abstract":"<p>Chlorophyll<i>-a</i> (Chl<i>-a</i>) is the most widely used proxy for phytoplankton biomass, bloom intensity, and trophic status in marine ecosystems. We analyzed 27 years (1998–2024) of 1 km-resolution satellite-derived Chl<i>-a</i> data across the Mediterranean Sea and evaluated long-term trends, bloom phenology, and seasonal variability in relation to sea surface temperature, mixed-layer depth, and nutrient dynamics. A Mediterranean-specific Chl<i>-a</i> algorithm was also used to accurately represent both open and optically complex coastal waters. Before assessing trends, we compared three central-tendency metrics to account for the right-skewed nature of Chl<i>-a</i> distributions. The geometric mean best represents typical conditions by reducing the influence of extreme values and was therefore selected as it enhances the robustness of basin-scale trend detection. Trend analysis revealed a basin-wide decline in surface Chl<i>-a</i> over the 27-year study period, with negative trends across all seasons and localized increases in some coastal areas. The longer satellite record reconciles previously reported spatially heterogeneous trends. The clustering of Chl<i>-a</i> variability delineated a gradient from productive, seasonally dynamic regions to persistently oligotrophic regimes. Regionally, the spring bloom magnitude declined in the Gulf of Lion (northwestern Mediterranean) and the southern Adriatic Sea, whereas biomass in the Levantine Sea (eastern basin) remained persistently low. Overall, these patterns suggest a shift toward increased oligotrophy, as warming-induced stratification suppresses nutrient resupply. By combining long-term satellite observations, robust Chl<i>-a</i> statistics, and phenological analysis, this study provides an update and comprehensive assessment of phytoplankton variability and its drivers in the Mediterranean Sea.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC023779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149145773","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":"Circumpolar Effects of a Velocity-Restoring Scheme for Antarctic Fast Ice on Shelf Waters and Ice Shelf Melt Simulated by NEMO4-SI3","authors":"N. Pirlet,&nbsp;T. Fichefet,&nbsp;M. Vancoppenolle,&nbsp;C. de Lavergne,&nbsp;N. C. Jourdain","doi":"10.1029/2025JC023673","DOIUrl":"https://doi.org/10.1029/2025JC023673","url":null,"abstract":"<p>Dense water formation in the Southern Ocean plays a key role in the global ocean overturning circulation, affecting the distribution of heat, carbon, oxygen, and nutrients. Fast ice stays immobile while blocking sea ice flow, favoring the opening of coastal polynyas, where intense air-sea exchanges drive sea ice production and ocean densification. Antarctic fast ice representation is notoriously poor in Earth system models, and is thus considered a potential cause of model biases in dense water formation. Here we assess the impact of a sea ice velocity-restoring representation of Antarctic fast ice on Antarctic shelf water properties and ice shelf melt using NEMO4-<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> simulations with and without velocity-restoring. By improving the location and shape of coastal polynyas, fast ice redistributes sea ice production and promotes Dense Shelf Water formation in several key source regions. In contrast, beneath extensive fast ice tongues, the reduced brine rejection associated with lower sea ice production limits mixed layer deepening, leading to fresher surface waters, which are then advected into downstream polynyas. The enhanced upper-ocean stratification beneath fast ice isolates warm subsurface waters from the surface and favors their intrusion into nearby ice shelf cavities, increasing ice shelf basal melt. As a result, ice shelf basal melt increases overall by 15.8% in the simulation including fast ice. These results support that ESMs studies with an Antarctic focus would gain from a physically-based representation of Antarctic fast ice.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 10","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC023673","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149145729","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}