Journal of Geophysical Research-Oceans最新文献

{"title":"Phaeocystis Dominance of a Large-Scale Productivity Anomaly in the Northeast Atlantic Ocean During Spring 2024","authors":"S. C. Painter,&nbsp;E. Garcia-Martin,&nbsp;C. Feltham,&nbsp;R. Muliawan,&nbsp;E. Mawji,&nbsp;K. Peel,&nbsp;A. Elineau,&nbsp;G. Wallbridge,&nbsp;P. Kumari,&nbsp;A. Flohr,&nbsp;S. E. Hartman,&nbsp;A. R. Gates","doi":"10.1029/2026JC024018","DOIUrl":"https://doi.org/10.1029/2026JC024018","url":null,"abstract":"<p>Changes to the North Atlantic spring bloom phytoplankton community structure are expected in response to regional warming trends. In 2024 an extensive body of low chlorophyll water, covering approximately 720,000 km² in area, dominated the Northeast Atlantic during the peak of the spring bloom period. Picoplankton (&lt;2 μm) and small nanoplankton (2–10 μm) size fractions together accounted for ∼90% of total chlorophyll-<i>a</i> implying a significant contribution by smaller phytoplankton cells to net primary production. Flow imaging microscopy of the phytoplankton community confirmed the dominance of smaller phytoplankton (&lt;18 μm), whilst chemical taxonomy of phytoplankton pigments indicated the widespread presence of haptophyte species, most likely <i>Phaeocystis sp</i>. These results contrast markedly with recent descriptions of the North Atlantic spring bloom community structure which report larger nano- and micro-phytoplankton species dominance. However, these new results are consistent with model predictions showing a shift toward smaller sized phytoplankton species as water temperatures rise and with the appearance of increasingly favorable conditions for <i>Phaeocystis</i>. Our results further suggest that large scale regionally significant changes to the phytoplankton community can rapidly emerge in response to ocean warming which, in the case of a <i>Phaeocystis</i> dominated community, will likely have implications for carbon export fluxes due to changes in vertical flux attenuation efficiency.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JC024018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146075","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":"Ship-Based GNSS Tsunami Detection: Pilot Network Demonstration","authors":"James H. Foster,&nbsp;Todd L. Ericksen,&nbsp;Bruce E. O. Thomas,&nbsp;Jonathan Avery","doi":"10.1029/2026JC024024","DOIUrl":"https://doi.org/10.1029/2026JC024024","url":null,"abstract":"<p>We demonstrate the potential for ship-based GNSS systems to contribute to tsunami warning. We built a pilot network of 10 ships—8 commercial and 2 research vessels—equipped with a tsunami detection package consisting of a geodetic-grade GNSS antenna and receiver, and satellite internet communications. The ships we instrumented operated throughout the Pacific, and transmitted precise real-time positions to our onshore server from 2015 to 2018. We examine this data set to determine the potential performance of an operational GNSS system for tsunami detection. The accuracy for our real-time vertical position solutions is 5.6 cm, in line with the advertised accuracy of the positioning service we employed, indicating that it is reasonable to expect to observe the sea surface perturbations of a potentially dangerous 8+ cm amplitude tsunami. Although some long period (10s of minutes) non-tsunami excursions appear in the data, we find that the likelihood that these excursions might lead to a false corroboration of a possible tsunami event when using ship GNSS data is very small for a single ship, and negligible when 2 ships are involved. The density of commercial ships in the open oceans is shown to be well matched to the source regions of historical fatal tsunamis, with tsunamis from most historical sources encountering at least 10 ships within 30 min and at least 100 within 90 min. As ships effectively act as tide-gauges, providing a well-understood data type, this approach would provide valuable data, notably from currently under-observed regions, to augment tsunami warning efforts.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JC024024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149146579","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":"Two Daytime Variation Patterns of Phytoplankton Fluorescence Quantum Yield in the East China Sea Revealed by Geostationary Satellite Data","authors":"Zhiting Jiang,&nbsp;Yan Bai,&nbsp;Min Zhao,&nbsp;Xianqiang He,&nbsp;Qiang Hao,&nbsp;Qicheng Meng,&nbsp;Teng Li,&nbsp;Juntian Xu,&nbsp;Yifan Zhang","doi":"10.1029/2025JC023787","DOIUrl":"https://doi.org/10.1029/2025JC023787","url":null,"abstract":"<p>Phytoplankton fluorescence quantum yield (Φ_F) reveals energy allocation in photosynthesis, and serves as a direct metric quantifying the proportion of absorbed light energy emitted as fluorescence. Traditional in situ Φ_F measurements are limited by sparse spatial and temporal coverage and cannot capture high-frequency spatiotemporal variations. Based on long-term, large-area, hourly sea surface Φ_F retrieved from the Geostationary Ocean Color Imager (GOCI) over the East China Sea (2011–2020), this study systematically analyzed the hourly daytime variation patterns of phytoplankton Φ_F for the first time and explored their potential environmental controls. We constructed more than 4,000 quality-controlled daytime series of Φ_F, chlorophyll-<i>a</i>, and instantaneous photosynthetically active radiation (iPAR) from GOCI's eight observations per day. Using a multi-dimensional time series clustering method (K-MDTSC), two dominant Φ_F daytime variation patterns were identified: Type I (U-shape) and Type II (continuous decreasing). Analysis of the matched iPAR and modeled temperature and nutrient data suggested that light intensity and temperature are the primary environmental factors associated with these patterns: Type I dominates under strong summer irradiance, while Type II prevails under weak winter light and low seawater temperature, with both patterns coexisting in spring and autumn. Nutrient levels affect the Φ_F magnitude directly: under nutrient stress, reduced photosynthetic efficiency diverted more absorbed energy to fluorescence, thereby elevating Φ_F. Leveraging GOCI's high-frequency and large-area observation capabilities, this study establishes the first comprehensive perspective on phytoplankton Φ_F daytime variation patterns, providing mechanistic insights into phytoplankton physiological status and its response to environmental changes.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149205949","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":"Features of Kinetic Energy Exchange Between Balanced Motions and Near-Inertial Internal Waves in the Northeastern South China Sea","authors":"Zhe Feng,&nbsp;Mingfang Miao,&nbsp;Zhiwei Zhang,&nbsp;Jinchao Zhang,&nbsp;Kaiwen Zheng,&nbsp;Wei Zhao,&nbsp;Jiwei Tian","doi":"10.1029/2026JC024671","DOIUrl":"https://doi.org/10.1029/2026JC024671","url":null,"abstract":"<p>The energy exchange between balanced motions and near-inertial internal waves (NIWs) serves as a key pathway for cross-scale energy redistribution; however, its characteristics remain poorly understood. Based on a submesoscale-permitting simulation, the kinetic energy exchange rates (KER) between balanced motions (consisting of large- and mesoscale geostrophic motions, and high-frequency balanced motions) and NIWs are investigated in the northeastern South China Sea (NESCS). The results suggest that in the Luzon Strait, NIWs gain kinetic energy from balanced motions year-around, with an annual mean 0–1,000 m integrated KER of 1.15 × 10⁻⁶ m³/s³, accounting for 200.0% and 9.5% of wind work on NIWs and balanced motions, respectively. This indicates that energy exchange is an important source for NIWs and a corresponding sink for balanced motions. In the NESCS interior, the KER are substantially weaker than the wind work and slightly reverse seasonally, being positive in summer and negative in winter. The contributions of high-frequency balanced motions are quantified by comparing the KER between geostrophic motions and NIWs with those between balanced motions and NIWs. Their annual means are 5.51 × 10⁻⁷ m³/s³ in the Luzon Strait and 2.83 × 10⁻⁸ m³/s³ in the NESCS interior, respectively equivalent to 91.2% and 98.7% of the magnitude of KER between geostrophic motions and NIWs. Further analysis reveals that high-frequency balanced motions enhance the kinetic energy transfer from balanced motions to NIWs by increasing the strain rates and elevating positive Okubo-Weiss parameter. These results emphasize the crucial role of high-frequency balanced motions in facilitating energy transfer from balanced motions to NIWs.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942873","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":"Submarine Landslides Could Cause Wide-Spread Tsunami Impact in the East Sea (Sea of Japan)","authors":"Deniz Cukur,&nbsp;Xiaoming Wang,&nbsp;Senay Horozal,&nbsp;Aaaron Micallef,&nbsp;In-Kwon Um,&nbsp;Seong-Pil Kim,&nbsp;Gee-Soo Kong","doi":"10.1029/2026JC024179","DOIUrl":"https://doi.org/10.1029/2026JC024179","url":null,"abstract":"<p>The East Sea (Sea of Japan) is a seismically active back-arc basin with a history of devastating tsunamis, yet regional hazard assessments and mitigation planning often overlook the tsunamigenic potential of submarine landslides. This study investigates the tsunami impact of large-scale mass failures along the southwest (SW) margin of the East Sea, where prominent submarine landslide scarps and related mass-transport deposits are mapped. Using high-resolution seismic reflection and multibeam echosounder data, we reconstructed the pre-failure morphology of a major landslide involving approximately 25 km³ of material. Landslide runout and subsequent tsunami were simulated using a dynamically coupled landslide–tsunami model in COMCOT. Results indicate that such an event triggers extreme hydrodynamic response, with coastal wave amplitudes reaching 9.3 m and current speeds of 13.3 m s⁻¹ along the coast of Korean Peninsula. These waves cause significant onshore inundation, with flow depth reaching 3 m and penetration distances up to 1.5 km inland. In Japan, coastal amplitudes could reach up to 16.8 m. Crucially, tsunami arrival times to densely populated cities like Ulsan and Busan range from only 25 to 50 min, providing a narrow window for emergency response. Compared to earthquake-generated tsunamis in the region, landslide-induced tsunamis exhibit higher amplitudes, stronger currents, and shorter travel times, producing widespread regional impacts. These findings highlight the critical need to integrate submarine landslides into regional tsunami hazard assessments and early warning systems.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JC024179","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942957","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":"Intensification of the Winter South China Sea Western Boundary Current During 2014–2024","authors":"Xuwen Wang,&nbsp;Qiang Wang,&nbsp;Lili Zeng,&nbsp;Rui Shi,&nbsp;Yikai Yang,&nbsp;Ju Chen,&nbsp;Yunkai He","doi":"10.1029/2026JC024035","DOIUrl":"https://doi.org/10.1029/2026JC024035","url":null,"abstract":"<p>Understanding the low-frequency variability of the western boundary current (WBC) is essential for the redistribution of heat, salt and energy in the South China Sea (SCS). Long-term acoustic Doppler current profiler (ADCP) mooring observations show a strengthening trend in the winter SCS WBC from 2014 to 2024. Diagnosis of the vorticity budget suggests that the trend is primarily attributed to the enhanced basin-scale wind stress curl and secondarily to the weakening of the joint effect of baroclinicity and relief (JEBAR), which overall serves as a vorticity sink. The trend of JEBAR is associated with a warming center west of the Luzon Strait, which enhances the baroclinic effect along the northern SCS continental slope, leading to a positive trend of JEBAR and weakening of vorticity consumption.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942885","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":"Wave Climate Signals Are Obscured by Observational Errors and Sampling Bias of Voluntary Observing Ships","authors":"Guixuan Lin,&nbsp;Qisheng Du,&nbsp;Alexander Babanin,&nbsp;Haoyu Jiang","doi":"10.1029/2026JC024252","DOIUrl":"https://doi.org/10.1029/2026JC024252","url":null,"abstract":"<p>Visual wave observations from Voluntary Observing Ships (VOSs) have long been regarded as a useful data source for studying the long-term evolution of the global wave climate due to their unique multi-decadal continuity. However, by integrating satellite altimetry, buoy records, and an ERA5-based Virtual Observation framework, this study demonstrates that the observational errors and sampling bias significantly obscure long-term trends in ocean waves in VOS data. Results reveal substantial intrinsic uncertainties in VOS observations, with overall significant wave height uncertainty exceeding 1.0 m and exceeding 2 m in some regions. While the Law of Large Numbers allows for reasonable approximations of long-term mean sea states in high-traffic corridors, high-percentiles (90th and 99th percentiles) are systematically underestimated due to the inherent statistical challenges of capturing transient extreme events through sparse sampling. Crucially, even if the uncertainty of VOS observations is ignored, VOS sampling patterns can introduce substantial discrepancies in ERA5-derived long-term trend estimates, with sampling-induced artifacts sometimes comparable to climate signals in the reference field. We conclude that while VOSs remain an invaluable historical record for the pre-satellite era, they possess severe limitations for monitoring global wave climate changes.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149044473","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":"Near-Surface Ocean Current and Its Response to Wind Forcing","authors":"Junzhe Liu,&nbsp;Christopher J. Zappa,&nbsp;Nathan J. M. Laxague","doi":"10.1029/2026JC024663","DOIUrl":"https://doi.org/10.1029/2026JC024663","url":null,"abstract":"<p>Ocean currents near the air-sea interface are critical for understanding boundary layer processes and advancing coupled models. The near-surface currents mediate air–sea fluxes and govern the transport of buoyant materials, yet the uppermost meter of the ocean remains sparsely observed and poorly represented in models. This study reconstructs ocean current profiles within the uppermost centimeters of the ocean using multiple remote-sensing techniques collected during the ASIT-2019 field campaign. The retrieved flows span three distinct layers: (a) the viscous sublayer <i>O</i>(10 μm); (b) the top of the logarithmic layer <i>O</i>(1 mm–1 cm); and (c) a 2-m reference layer. This unique data set enables examination of wind–wave–current interactions in the ocean surface boundary layer. We revisit the wind-driven near-surface current parameterizations. The along-wind skin drift is found to be 3.70% ± 0.34% of the wind speed; and the quasi-Eulerian current at the top of the logarithmic layer reaches 2.45% ± 0.56% of the wind speed. From the reconstructed profiles, we quantify near-surface shear and infer viscous stress, which are consistent with previous laboratory measurements. These results highlight the importance of resolving vertical flow structure for future data assimilation and modeling in the near-surface layer. In addition, the cross-wind near-surface flow is found to be, on average, of the same order of magnitude as the along-wind component, and its forcing reflects a complex interplay of multiple potential processes.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JC024663","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942877","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":"Abnormally Increased Summer Bottom SSC: A Case Study in the Northern East China Sea","authors":"Sichen Zhang,&nbsp;Lulu Qiao,&nbsp;Lu Zhang,&nbsp;Guangxue Li","doi":"10.1029/2026JC024254","DOIUrl":"https://doi.org/10.1029/2026JC024254","url":null,"abstract":"<p>An anomalous bottom high suspended sediment concentration (SSC) in summer, which even higher than bottom values in winter, has been widely observed on several stratified continental shelves. However, the in-depth mechanism remains insufficiently constrained. Combining winter and summer field observations in the northern East China Sea, offshore wave records, and regional and idealized Finite-Volume Community Ocean Model (FVCOM) experiments, this study elucidates how seasonal stratification regulates bottom SSC. The synchrony between bottom SSC and tidal currents, together with the similarity between the summer particle size distribution and nearby muddy seabed sediment, indicates that current induced resuspension is a major source of the elevated summer bottom SSC. Field observations further reveal the enhanced baroclinic tidal currents in summer. Typhoon waves were unlikely to dominate resuspension during the observation period. Regional FVCOM experiments show little seasonal difference under barotropic simulations, whereas the baroclinic simulation produces stronger summer currents with a clearer vertical structure. Idealized experiments indicate that the presence of a thermocline is the main condition for current enhancement and that thermocline depth exerts a stronger control on the velocity profile than its intensity. These results suggest that summer stratification can increase bottom SSC by suppressing turbulent mixing, reducing tidal kinetic energy dissipation, strengthening baroclinic current responses, and enhancing near bottom bed shear stress. The findings reveal that stratification fundamentally affects current dynamics and bottom SSC seasonality, providing a new potential mechanism of material distribution for stratified and muddy continental shelf seas.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942884","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":"Decadal Coherence of Arctic Thermohaline Staircases","authors":"Mikhail G. Schee,&nbsp;Erica Rosenblum,&nbsp;Jonathan M. Lilly,&nbsp;Luca Haines,&nbsp;Nicolas Grisouard","doi":"10.1029/2026JC024055","DOIUrl":"https://doi.org/10.1029/2026JC024055","url":null,"abstract":"<p>Thermohaline staircase layers residing above the relatively warm Atlantic Water layer have been consistently observed in the Arctic Ocean for over 50 years. Previous studies demonstrate that these structures exhibit large-scale spatial coherence. However, on time scales beyond a few years, both the coherence and evolution of these basin-wide layers are unknown. Using Ice-Tethered Profiler data from 2005 to 2022 in the Beaufort Gyre Region, we track staircase layers across time and space with an unsupervised clustering method. Individual layers are found to be coherent across the entire 17-year time period, with properties that would evolve on 40 to 50-year timescales if the current observed trend continues. This quantifies, for the first time, the decadal-scale coherence of basin-wide thermohaline staircases in the Arctic Ocean. These results raise important questions regarding the interplay of small-scale processes driving staircase stability and large-scale oceanic changes in response to a rapidly changing Arctic.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"131 9","pages":""},"PeriodicalIF":3.3,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2026JC024055","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942986","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}