Journal of Geophysical Research-Oceans最新文献

{"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":"https://doi.org/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":"https://doi.org/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":"https://doi.org/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":"https://doi.org/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":"https://doi.org/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":"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":"https://doi.org/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":"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":"https://doi.org/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}

{"title":"Characterization of the Spatiotemporal Distribution of Shear Stress and Bedload Flux Within a Mobile, Rippled Bed","authors":"Savannah R. DeVoe,&nbsp;Meagan E. Wengrove,&nbsp;Diane L. Foster,&nbsp;Daniel S. Hagan","doi":"10.1029/2025JC022369","DOIUrl":"https://doi.org/10.1029/2025JC022369","url":null,"abstract":"<p>Mobile sediment layer dynamics and the distribution of shear stress within mobile fluid-sediment mixtures are not well understood, particularly for oscillatory flows over rippled boundaries. This article provides insight into bed shear stress at and within a mobile, rippled bedform at high spatiotemporal resolution for the purpose of improving estimates of bedload transport. Data from a coupled Large Eddy Simulation (LES) and Discrete Particle Model (DPM) is used to characterize the spatiotemporal distribution of shear stress within the bed. Estimates of stress within the mobile layer are obtained using a new momentum integral method expression for oscillatory flow over mobile, porous, non-planar boundaries that makes no a priori assumptions about the boundary layer shape. Shear stress within the mobile layer and the resulting bedload flux show a strong response to the near-bed flow. Two local maxima occur within the mobile layer shear stress distribution during each half-oscillation period that coincide with near-bed fluid acceleration and the formation of a lee-side ripple vortex. The depth-averaged mobile layer Shields parameter, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mrow>\u0000 <msub>\u0000 <mover>\u0000 <mi>θ</mi>\u0000 <mo>˜</mo>\u0000 </mover>\u0000 <mrow>\u0000 <mi>M</mi>\u0000 <mi>L</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${widetilde{theta }}_{ML}$</annotation>\u0000 </semantics></math>, obtained by depth-averaging across the mobile layer of grains, is approximately one-half the magnitude of the Shields parameter at the top of the mobile layer, and may serve as a better indicator of bedform motion for rippled beds subjected to oscillatory flow. Findings highlight the implications of the assumed bed elevation on the resulting magnitude and direction of estimated shear stress, as well as discrepancies in the magnitude and phase of bedload flux estimated with existing semi-empirical formulae.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022369","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927681","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":"The Impact of Antarctic Sea Ice on Southern Ocean Water Mass Transformation in Coupled Climate Models","authors":"Zijin Chen,&nbsp;William Hobbs,&nbsp;Zanna Chase,&nbsp;Jan Zika","doi":"10.1029/2025JC022445","DOIUrl":"https://doi.org/10.1029/2025JC022445","url":null,"abstract":"<p>The Southern Ocean is a critical heat and carbon sink due to the interaction between the atmosphere and deep ocean that occurs there. Antarctic sea ice is essential for maintaining this interaction by transforming ventilated deep-water into both denser and lighter water masses. However, the representation of sea ice in climate models is variable, and its impact on water mass transformation remains unclear. We evaluate the contribution of sea ice to surface water mass transformation in the Southern Ocean in 16 models from Phase 6 of the Coupled Model Intercomparison Project (CMIP6). We find that sea ice redistributes freshwater from the Antarctic coast to offshore, acting as a pump, driving 10.2 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 </mrow>\u0000 <annotation> $pm $</annotation>\u0000 </semantics></math> 8.8 Sv of deep-water ventilation across the ensemble. Variations in ventilation between models are driven by biases both in sea ice production and the ocean state. Firstly, the models' sea ice biases directly affect the net freshwater flux into the ocean. Secondly, the impact of surface freshwater flux on water mass transformation depends also on the ocean's surface density and salinity, so that biases in the model ocean state also play a role. We find that heat fluxes can partially compensate for variations in the sea ice contribution, so that models with lower sea-ice driven ventilation have higher heat flux driven ventilation. Therefore, sea ice is an important but not the sole determinant of the interaction between the atmosphere and deep ocean in models of the Southern Ocean.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022445","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144927682","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":"In Situ Observations of Tide-Dominated Fluid-Mud Generation and Transport on the Central Jiangsu Tidal Flat","authors":"Yun Peng,&nbsp;Qian Yu,&nbsp;Jianhua Gao,&nbsp;Yunwei Wang,&nbsp;Shu Gao","doi":"10.1029/2025JC022783","DOIUrl":"https://doi.org/10.1029/2025JC022783","url":null,"abstract":"<p>Fluid mud (FM), a near-bed layer of high suspended sediment concentration, can be transported offshore in the form of gravity flow under the support of waves and currents, playing a critical role in sediment transport and geomorphological evolution. Wave-supported FM has been extensively studied, whereas research on the transport processes of tide-dominated FM remains insufficient. Here, we conducted four field campaigns on the central Jiangsu tidal flats, revealing that FM events occur frequently during winter, spring, and summer. The FM can be transported offshore as a gravity flow, with gravity-driven velocities ranging from 0.01 to 0.06 m s⁻¹. <i>In situ</i> measurements combined with theoretical modeling indicate that FM generation and transport in the central Jiangsu tidal flats are tide-dominated. On a tidal cycle scale, the tide-dominated FM pattern was divided into four stages. Stage I: during flood tides, fine sediment is transported landward from offshore waters to the tidal flat; Stage II: sediment settles from the overlying water column to the bed during flood slack tide, leading to the formation of FM; Stage III: ebb currents facilitate the downslope transport of FM as a gravity flow; Stage IV: ebb currents disperse the sediment within the FM layer, ultimately causing its dissipation. The tide-dominated FM presented in this study significantly differs from wave-supported FM, advancing the understanding of sediment dynamics on tidal flats and underscoring the importance of observing tide-dominated FM in similar coastal environments globally.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 9","pages":""},"PeriodicalIF":3.4,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144923525","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}