Journal of Geophysical Research-Oceans最新文献

{"title":"Dominant Wind Patterns Under the Influence of Atmospheric Rivers: Implications for Coastal Upwelling off Central-Southern Chile","authors":"Yosvany Garcia-Santos,&nbsp;Diego A. Narváez,&nbsp;Martin Jacques-Coper,&nbsp;Gonzalo S. Saldías,&nbsp;Deniz Bozkurt,&nbsp;Benjamin M. Alessio","doi":"10.1029/2024JC021444","DOIUrl":"https://doi.org/10.1029/2024JC021444","url":null,"abstract":"<p>Atmospheric rivers (ARs) trigger intense precipitation and strong winds along the western coasts of mid-latitude continents. While the terrestrial impacts of ARs have been extensively studied, their influence on the ocean environment remains poorly understood. Here, we investigate several ARs affecting the Ekman dynamics along the coastal ocean off central-southern Chile from 1979 to 2018. A compositing method was applied to capture the general atmospheric and oceanographic responses to ARs, using reanalysis, satellite and in-situ data. Two primary patterns of ARs are described in the region: tilted (TAR), with a predominant northwest-southeast orientation and zonal (ZAR), with a prevailing west-east orientation. A total of 2480 events were quantified: 1243 TARs and 805 ZARs, with the remaining events being excluded from this study. The wind pattern associated with TARs induces stronger downwelling along the coastal ocean near the landfall areas, leading to increases in SST, southeastward surface currents, and higher sea levels. Additionally, a rise in sea level and SST north of the TAR axis suggests upwelling relaxation in areas farther north of the landfall. In contrast, ZARs have a minimal impact on downwelling, resulting in variable effects on SST and sea level. North of the ZAR axis, the intensification of atmospheric anticyclones triggers upwelling conditions along the coast, leading to a decrease in SST and sea level, accompanied by northwestward surface currents. The frequency of ZARs has shown an increasing trend in recent years, while TARs exhibit a decreasing trend, suggesting a potential increase in upwelling events associated with ARs.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143639263","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":"Tidal Corrections From and for SWOT Using a Spatially Coherent Variational Bayesian Harmonic Analysis","authors":"Thomas Monahan,&nbsp;Tianning Tang,&nbsp;Stephen Roberts,&nbsp;Thomas A. A. Adcock","doi":"10.1029/2024JC021533","DOIUrl":"https://doi.org/10.1029/2024JC021533","url":null,"abstract":"<p>The accuracy of global tidal models degrades significantly in coastal and estuarine regions. These models are important for correcting measurements from satellite altimetry and are used in numerous scientific and engineering applications. The new Surface Water Ocean Topography (SWOT) mission is providing measurements at unprecedented horizontal resolution in these regions. These data present both the opportunity and the necessity to quantify and correct the spatial variability in the model inaccuracies specific to these regions. We develop a variational Bayesian framework for tidal harmonic analysis which can be applied to SWOT, and is especially useful for exploting the data from the Cal/Val phase. The approach demonstrates superior robustness to different types of noise contamination in comparison to conventional least-squares approaches while providing full uncertainty estimation. By imposing a spatially coherent inductive bias on the model, we achieve superior harmonic constituent inference from temporally sparse but spatially dense data. Bayesian uncertainty estimation gives rise to statistical methods for outlier removal and constituent selection. Using our approach, we estimate a lower bound for the residual tidal variability for two SWOT Cal/Val passes (003 and 016) around the European Shelf to be <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>7</mn>\u0000 <mi>%</mi>\u0000 </mrow>\u0000 <annotation> $7%$</annotation>\u0000 </semantics></math> on average. We also show similar estimates cannot be produced using standard least-squares approaches. Tide gauge validation in the same region confirms the superiority of our empirical approach in coastal environments. Empirical corrections for the SWOT data products are provided alongside an open-source Python package, VTide.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021533","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143639262","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":"Thank You to Our 2024 Peer Reviewers","authors":"Lisa M. Beal,&nbsp;Léon Chafik,&nbsp;Sarah Fawcett,&nbsp;Xin Wang,&nbsp;Mar Flexas,&nbsp;Chellappan Gnanaseelan,&nbsp;Nathalie F. Goodkin,&nbsp;Zouhair Lachkar,&nbsp;Yuanlong Li,&nbsp;Ryan P. Mulligan,&nbsp;Takeyoshi Nagai,&nbsp;Joanne O’Callaghan,&nbsp;Hannah E. Power,&nbsp;Karina von Schuckmann,&nbsp;Christopher Sherwood,&nbsp;Arvind Singh,&nbsp;Lars Umlauf,&nbsp;Martin Vancoppenolle,&nbsp;Anna Wahlin,&nbsp;Fanghua Xu","doi":"10.1029/2025JC022585","DOIUrl":"https://doi.org/10.1029/2025JC022585","url":null,"abstract":"<p>On behalf of our ocean community of authors and readers, the editors at JGR-Oceans would like to sincerely thank all those who gave their valuable time to review manuscripts for the journal in 2024. Thank YOU!</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022585","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143639264","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":"Kı̄lauea Volcanic Ash Induced a Massive Phytoplankton Bloom in the Nutrient-Poor North Pacific Subtropical Gyre","authors":"C. H. Chow,&nbsp;W. Cheah,&nbsp;R. M. Letelier,&nbsp;D. M. Karl,&nbsp;J.-H. Tai","doi":"10.1029/2023JC020676","DOIUrl":"https://doi.org/10.1029/2023JC020676","url":null,"abstract":"<p>Kı̄lauea volcano is one of the most active volcanoes in the world with nearly continuous seismic activity from 1983 to 2018. In May 2018, the Kı̄lauea volcano erupted and released volcanic ash into the atmosphere. Carried by easterly winds, the volcanic ash plume dispersed westward and by June 2018, the plume was observed over the central part (150<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>E to 160<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math>W) of the nutrient-poor North Pacific Subtropical Gyre (NPSG). Coincident with precipitation during the same period, anomalously high dust deposition comprised mostly of wet dust was observed over the same region. Consequently, patches of high chlorophyll <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>a</mi>\u0000 </mrow>\u0000 <annotation> $a$</annotation>\u0000 </semantics></math> (chl <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>a</mi>\u0000 </mrow>\u0000 <annotation> $a$</annotation>\u0000 </semantics></math>) waters were observed approximately 5<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> ${}^{circ}$</annotation>\u0000 </semantics></math> north of the high dust deposition area from the middle of June to early August 2018 via satellite images. The phytoplankton bloom peaked in July encompassing <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 </mrow>\u0000 <annotation> ${ &gt;} $</annotation>\u0000 </semantics></math>1.5 million <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mtext>km</mtext>\u0000 <mn>2</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${text{km}}^{2}$</annotation>\u0000 </semantics></math>, about 5 or 50 times the size of Malaysia or Taiwan, respectively. In addition to the large dust deposition, shoaling of the mixed layer in the range of 25–50 m is believed to have concentrated the bloom within the optical depth detected by satellite. Net primary production and export production estimated from satellite observations show that the July 2018 bloom generated an additional 1.91 Tg C of net carbon production, and 0.34 Tg C was exported from the euphotic zone.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143622418","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":"Modeling the Dissolution and Transport of Bubbles Emitted From Hydrocarbon Seeps Within the Hydrate Stability Zone of the Oceans","authors":"Inok Jun,&nbsp;Binbin Wang,&nbsp;Jonas Gros,&nbsp;Anusha L. Dissanayake,&nbsp;Scott A. Socolofsky","doi":"10.1029/2024JC021942","DOIUrl":"https://doi.org/10.1029/2024JC021942","url":null,"abstract":"<p>Quantifying the vertical distribution of dissolved gases entering the oceans from natural seeps is important to understand biogeochemical cycling of these gases and to constrain their emissions to the atmosphere. The fate and transport of gas bubbles in seawater depend on their rise velocity and their rate of mass exchange with ambient water. In the deep ocean, clathrate hydrates may form as skins on bubbles of natural gases. Although it is known that hydrate skins reduce mass transfer rates, it is unclear how quickly they form and to what extent they may slow mass transfer. In this study, we develop an empirical equation to predict the time scale for hydrates to affect mass transfer, and we apply a Lagrangian particle numerical model to predict the height of rise of natural seep bubbles observed in echo sounder data. We calibrate an equation for hydrate transition time by comparing to field observations in Rehder et al. (2009, https://doi.org/10.1029/2001gl013966), and we validate to other field and laboratory observations. We apply the model to predict the rise heights of bubbles emitted from natural seeps. When comparing to acoustic data, we show that bubbles become acoustically transparent when their sizes fall below a critical size near the resonant frequency of the insonified bubble. Using this insight, our model predicts the rise heights observed in acoustic data of seven natural seeps spanning source depths from 890 to 2,890 m with an <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> of 0.98, bias of 41 m, and absolute relative percentage error of 4.7%.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021942","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612521","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":"Mesopelagic Particle Layers in the Dynamic Hypoxic Northern Benguela Are Shaped by Zooplankton Activity","authors":"Elisa Lovecchio,&nbsp;Stephanie Henson,&nbsp;Filipa Carvalho,&nbsp;Nathan Briggs,&nbsp;Hans Hilder,&nbsp;George A. Wolff,&nbsp;Sarah L. C. Giering,&nbsp;Kathryn Cook,&nbsp;Chelsey A. Baker,&nbsp;Sophie Fielding,&nbsp;Calum Preece,&nbsp;Mark Stinchcombe","doi":"10.1029/2024JC021039","DOIUrl":"https://doi.org/10.1029/2024JC021039","url":null,"abstract":"<p>Hypoxic (O₂ &lt; 60 μmol kg⁻¹) waters are found below 27% of the ocean surface and are predicted to expand in the near future; however, the organic carbon cycle in these regions is far from understood. Here we study the origin, composition, and temporal variability of mesopelagic particle layers in the hypoxic northern Benguela. We combine ship measurements, 4 months of glider data, and a high-resolution 3D coupled model. Glider data show deep particle layers between 250 and 500 m, in the hypoxic oxygen minimum zone (OMZ), often giving rise to “deep export” events. Our data point toward biological processes generating the particle layers within the OMZ itself. Between 250 and 500 m, large particulate organic matter is fresh, small particles are more refractory, and image data show a local increase in aggregates and fecal pellets. Ship data suggest that large particles and deep export events are generated both by vertically migrating organisms importing organic carbon from the near-surface to the OMZ and by mesozooplankton constantly inhabiting the OMZ and transforming the particles there. Small suspended particles accumulate above and within the OMZ. This is likely contributed to by fragmentation via zooplankton partial feeding and reduced remineralization rates. Near-shore currents drive the temporal variability in hypoxia and the associated deep particle layers, hence modulating biological activity and export events in the mesopelagic. Our results highlight how the interplay of biological and physical processes drive the carbon dynamics of widespread hypoxic OMZs and provide insight into how to improve models in these regions.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143612520","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":"Reef Community Productivity and Calcification – Spatial and Temporal Variability in Recovering Coral Reefs","authors":"Alexandra Khrizman,&nbsp;Mathilde Lindhart,&nbsp;David A. Mucciarone,&nbsp;Yuichiro Takeshita,&nbsp;Stephen G. Monismith,&nbsp;Elisabeth L. Boles,&nbsp;Robert B. Dunbar","doi":"10.1029/2024JC021592","DOIUrl":"https://doi.org/10.1029/2024JC021592","url":null,"abstract":"<p>Coral reefs are currently under threat due to multiple anthropogenic stressors, with increasing temperatures leading to more frequent bleaching events. We assessed reef Net Community Production (NCP) and Net Community Calcification (NCC), measures of reef ecosystem functioning, using a benthic gradient-flux approach on forereef and lagoon coral reefs recovering from the major 2015–2016 bleaching event in the Chagos Archipelago, Indian Ocean. Hard coral cover at the lagoon was higher (44% vs. 21% at the forereef, 3 years post-bleaching) and increased by ∼60% at both reefs 6 years post-bleaching. Calcification, computed using Structure-from-Motion photogrammetry, increased by 34%, and rugosity by ∼10% over this period. Biogeochemical measurements show net heterotrophy at both reefs 3 years within the recovery, with the lagoon reef exhibiting particularly high rates. Six years into the recovery process, productivity and calcification rates at the forereef more than doubled compared with the rates 3 years prior. Large day-to-day variability was documented. This included a transition in the lagoon reef from net calcification to dissolution within days, despite the long-term trend of net CaCO₃ accumulation. On the forereef, heterotrophy increased by 51% on cloudy days, while a shift to autotrophy (147% increase in NCP) and 47% higher calcification were found on sunny days that directly followed cloudy days. An internal wave event presumably led to enhanced production on one of the days on the forereef. Our findings highlight the importance of combining long-term reef health indicators with short-term measurements of reef functioning to capture the dynamics of reef recovery.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143602520","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":"Seasonal Variation of Air-Sea CO2 Flux and Contribution of Biological Processes to Carbon Source/Sink in a Large River-Dominated Shelf Sea","authors":"Kui Wang,&nbsp;Kai Cai,&nbsp;Jianfang Chen,&nbsp;Feng Zhou,&nbsp;Haiyan Jin,&nbsp;Hongliang Li,&nbsp;Bin Xue,&nbsp;Peisong Yu,&nbsp;Yifan Zhang","doi":"10.1029/2025JC022329","DOIUrl":"https://doi.org/10.1029/2025JC022329","url":null,"abstract":"<p>Productive shelf seas are often considered hotspots for absorbing atmospheric CO₂. However, the contribution of biological processes to carbon source or sink remains unclear in global large river-dominated shelf seas. As a case study, we applied a three end-members mixing model to quantify the contribution of biological processes (including the release of CO₂ from organic matter degradation by microbes and CO₂ uptake by phytoplankton) to the variations of air-sea CO₂ flux (F) in the Changjiang plume-impacted shelf area (CPS). We also established a 1-D mass budget model to quantitatively assess the factors controlling of the partial pressure of carbon dioxide (<i>p</i>CO₂) during seasonal transitions. Our results showed that CPS acted as a source of atmospheric CO₂ in summer (2.0 ± 13.9 mmol m⁻² d⁻¹) and autumn (5.4 ± 8.6 mmol m⁻² d⁻¹), but as a sink in winter (−6.8 ± 9.4 mmol m⁻² d⁻¹) and spring (−1.0 ± 4.8 mmol m⁻² d⁻¹). Biological processes significantly influence <i>p</i>CO₂ variability. It is worth noting that during the winter-to-spring transition, biological processes contributed 36% (the largest among the four transition periods) to the <i>p</i>CO₂ decrease. In the CPS, the air-sea CO₂ flux caused by biological processes in winter, spring, summer, and autumn are 2.6 ± 4.1, −15.1 ± 22.0, 2.2 ± 8.2, and −2.0 ± 4.9 mmol m⁻² d⁻¹, respectively, with relative contributions of biological processes to F of 13.5%, −53.9%, 5.0%, and −11.0%, respectively. These findings suggest biological uptake of dissolved inorganic carbon in global continental shelf seas significantly enhance carbon sequestration and contribute to mitigating global warming.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143602462","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":"Insights Into Protistan Plankton Blooms in the Highly Dynamic Patagonian Shelf and Adjacent Ocean Basin in the Southwestern Atlantic","authors":"Carola Ferronato,&nbsp;Valeria A. Guinder,&nbsp;Martín Rivarossa,&nbsp;Martin Saraceno,&nbsp;Federico Ibarbalz,&nbsp;Urban Tillmann,&nbsp;Gastón O. Almandoz,&nbsp;Guillaume Bourdin,&nbsp;Valeria D’Agostino,&nbsp;Azul S. Gilabert,&nbsp;Rocío Loizaga,&nbsp;Celeste López-Abbate,&nbsp;Ariadna C. Nocera,&nbsp;Ricardo Silva,&nbsp;Pedro Flombaum","doi":"10.1029/2024JC021412","DOIUrl":"https://doi.org/10.1029/2024JC021412","url":null,"abstract":"<p>Blooms of phototrophic protists play a crucial role in marine biogeochemical cycles, significantly impacting carbon fluxes and overall ecosystem productivity. Eukaryotes of the nano- and microplankton are responsible for the large spring and summer blooms visible from space in the highly dynamic southwestern Atlantic Ocean. Here, we investigated the composition and abundance of protistan plankton during late spring 2021 across three contrasting oceanographic regions of the southwestern Atlantic Ocean: the Patagonian continental shelf, the core of the Malvinas Current (MC), and the adjacent energetic open ocean in the Argentine basin. Using a combination of in situ sampling and satellite-derived chlorophyll-<i>a</i>, particulate inorganic carbon, sea surface temperature, and geostrophic currents, we identified marked differences in water masses and plankton communities. High chlorophyll-<i>a</i> concentration over the outer continental shelf was related to blooms of phototrophic and mixotrophic dinoflagellates and large diatoms. This plankton accumulation over the shelf was associated with the permanent thermohaline front that develops along the shelf-break, with upwelling as the main driver of high productivity. However, in waters of the MC and the open ocean protists exhibited lower biomass and diversity, with prevalence of nanoflagellates and coccolithophores. The results suggest that the water column stability and the N:Si and N:P nutrient ratios shape the distinct bloom-forming functional types. This study contributes with data on taxonomic diversity identified by microscopy which, along with remote sensing approaches, provide insights into how protists respond to environmental changes at different spatial and temporal scales.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595675","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":"Basal Melting and Oceanic Observations Beneath Central Fimbulisen, East Antarctica","authors":"Katrin Lindbäck,&nbsp;Elin Darelius,&nbsp;Geir Moholdt,&nbsp;Irena Vaňková,&nbsp;Tore Hattermann,&nbsp;Julius Lauber,&nbsp;Laura de Steur","doi":"10.1029/2023JC020506","DOIUrl":"https://doi.org/10.1029/2023JC020506","url":null,"abstract":"<p>Basal melting of ice shelves is fundamental to Antarctic ice sheet mass loss, yet direct observations remain sparse. We present the first year-round melt record (2017–2021) from a phase-sensitive radar on Fimbulisen, one of the fastest flowing ice shelves in Dronning Maud Land, East Antarctica. The observed long-term mean ablation rate at 350 m depth below the central ice shelf was 1.0 ± 0.5 m yr⁻¹, marked by substantial sub-weekly variability ranging from 0.4 to 3.5 m yr⁻¹. 36-h filtered basal melt rate fluctuations closely align with ocean velocity. On seasonal time scales, melt rates peak during austral spring to autumn (September–March), driven by both elevated ocean velocities and thermal driving near the base. The combined effect of thermal driving and current speed explains the majority of the melt rate variability (<i>r</i> = 0.84), highlighting the dominant role of shear-driven turbulence. This relationship enables parameterization of melt rates for the decade-long ocean record (2010–2021), although deviations appear under low and high forcing conditions. Both observed and parameterized melt rates show similar yearly mean magnitudes compared to satellite-derived melt rates but with a tenfold lower seasonal amplitude and a 3-month delay in seasonality. These detailed concurrent ice–ocean observations provide essential validation data for remote sensing and numerical models that aim to quantify and project ice-shelf response to a change in ocean forcing. In situ measurements and continued monitoring are crucial for accurately assessing and modeling future basal melt rates, and for understanding the complex dynamics driving ice-shelf stability and sea-level change.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 3","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JC020506","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143595074","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}