Journal of Geophysical Research-Oceans最新文献

{"title":"Distinguishing the Isotopic Signals of Nitrate Assimilation and Denitrification Along the GEOTRACES GP15 Pacific Meridional Transect","authors":"Dario Marconi,&nbsp;Daniel M. Sigman,&nbsp;Karen L. Casciotti,&nbsp;Rian M. Lawrence,&nbsp;Wentao Wang,&nbsp;Sergey Oleynik,&nbsp;Alfredo Martínez-García","doi":"10.1029/2024JC022084","DOIUrl":"https://doi.org/10.1029/2024JC022084","url":null,"abstract":"<p>The biogeochemical processes shaping the fluxes of nitrogen (N) in the tropical to subarctic Pacific are illuminated by nitrate isotope ratios (δ¹⁵N and δ¹⁸O) along the GEOTRACES GP15 section. In the equatorial and tropical Pacific, nitrate δ¹⁵N and δ¹⁸O are 2–4‰ higher in the thermocline than in deeper waters. This widespread elevation is driven by both nitrate assimilation in Southern Ocean surface waters and denitrification in the eastern tropical Pacific. In addition to this, a poleward increase in the δ¹⁵N of surface nitrate from the Equator to 10°S is generated by the progressive consumption of nitrate upwelled at the Equator and transported southward. This process leads to increases in the δ¹⁵N of phytoplankton biomass and a strong meridional nitrate isotopic gradient in the thermocline due to regeneration of sinking N. North of the Equator, an analogous gradient is barely detectable due to weaker northward flow and a compressed spatial scale for nitrate drawdown. By contrast, between 5°N and 40°N, the nitrate isotope gradients are dominated by the processes driving the oceanic fixed N budget: denitrification and N₂ fixation. High-δ¹⁵N and -δ¹⁸O nitrate in the tropics is advected from the oxygen deficient zone where denitrification occurs, whereas in the adjacent subtropics, low-δ¹⁵N thermocline nitrate suggests a response by N₂ fixation that is not observed in the south. The asymmetry of the north and south tropical Pacific gradients in thermocline nitrate isotopes has implications for efforts to reconstruct the N cycle in the past.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144220071","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":"Oxygen Minimum-Zone Expansion Controls Critical Metal Enrichment and Growth Rates in a Ferromanganese Crust From the Central Pacific Ocean","authors":"Jieqi Xing,&nbsp;Yinan Deng,&nbsp;Jiangbo Ren,&nbsp;James R. Hein,&nbsp;Haiyang Xian,&nbsp;Long Li,&nbsp;Xiaodong Jiang,&nbsp;Yiping Yang,&nbsp;Gaowen He,&nbsp;Haijun Qiu,&nbsp;Jianxi Zhu","doi":"10.1029/2025JC022450","DOIUrl":"https://doi.org/10.1029/2025JC022450","url":null,"abstract":"<p>Hydrogenetic ferromanganese crusts (FMCs) rich in critical metals [for example, cobalt (Co), nickel (Ni), and rare-earth elements plus yttrium (REY)] are known as promising mineral resources for the transition to a net-zero carbon emission future. The oxygen minimum zone (OMZ) has an important influence on the formation of FMCs, but its controlling mechanism for the enrichment of critical metals in FMCs is poorly constrained, hindering a fuller understanding of and exploration for critical metal-rich FMCs. The studied FMC (∼2,000 m depth) collected just below the oxygen minimum zone (OMZ; ∼300–1,000 m depth) in the central Pacific Ocean records the OMZ expansion during FMC formation; key evidence of this is changes in the size of the positive Ce anomaly and positive shifts in δ¹⁵N values. Our data indicate that OMZ expansion reduces FMCs growth rates over time, with texture transitions from dendritic to botryoidal. The OMZ expansion contributes to an increase in Mn oxides with Co and Ni enrichment and a decrease in the Fe oxyhydroxides and REY content. Our findings underscore the pivotal role of global OMZ expansion in influencing the growth dynamics of FMCs and the accumulation of critical metals, which is crucial for understanding the enrichment and cycling of critical metals in the deep ocean.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213815","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":"Mesoscale Ocean Processes: The Critical Role of Stratification in the Icelandic Region","authors":"Charly de Marez,&nbsp;Clara R. Vives,&nbsp;Esther Portela Rodriguez,&nbsp;Angel Ruiz-Angulo","doi":"10.1029/2025JC022664","DOIUrl":"https://doi.org/10.1029/2025JC022664","url":null,"abstract":"<p>The oceanic region around Iceland, a key component of the Atlantic meridional overturning circulation, plays a critical role in global climate through its complex system of surface and subsurface currents. Using high-resolution Surface Water and Ocean Topography (SWOT) satellite data, in situ observations, and idealized numerical simulations, this study reveals two distinct dynamical regimes in this region. South of Iceland, the mesoscale eddy field is energetic. In contrast, north of Iceland, the strong shallow stratification inhibits baroclinic instability and eddy generation, resulting in a low-energy “eddy desert”—a phenomenon observed synoptically for the first time at SWOT's unprecedented resolution. This new understanding of Iceland's dynamical regimes highlights the role of stratification in mesoscale variability. Analyzing Biogeochemical-Argo float data, it also suggests an impact of mesoscale regimes on the local biogeochemical cycles, with implications for primary production and carbon cycling as stratification patterns shift with climate change.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206903","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":"Increased Light Availability in the Northern Barents Sea Driven by Sea Ice Loss","authors":"Håkon Sandven,&nbsp;Mats A. Granskog,&nbsp;Anders Frugård Opdal,&nbsp;Stacey Connan-McGinty,&nbsp;Børge Hamre,&nbsp;David McKee","doi":"10.1029/2025JC022370","DOIUrl":"https://doi.org/10.1029/2025JC022370","url":null,"abstract":"<p>The Barents Sea region is a hotspot for global climate change, with larger-than-average temperature increase and sea ice loss. This has led to massive changes in the underwater light environment, which is a key environmental driver for polar marine ecosystems given the extreme seasonal variability. The ecosystem consequences of a changing underwater lightscape remains poorly characterized. Here, we model the changes in availability of photosynthetically available radiation <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>E</mi>\u0000 <mrow>\u0000 <mi>P</mi>\u0000 <mi>A</mi>\u0000 <mi>R</mi>\u0000 </mrow>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${E}_{PAR}$</annotation>\u0000 </semantics></math> in the Barents Sea from 1979 to 2022, using the underwater irradiance model HEIMDALL, which is developed and validated for use in the Barents Sea and has recently been expanded for use in ice-covered or ice-influenced waters. Our results show that the potential growth season for phytoplankton has become more than 1 month longer in large parts of the northern Barents Sea. The largest changes have been in the northeastern part of the region with up to 60 days. The primary environmental driver for light availability is the sea ice concentration (SIC), particularly in spring, with a Kendall rank correlation coefficient <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>τ</mi>\u0000 </mrow>\u0000 <annotation> $tau $</annotation>\u0000 </semantics></math> = −0.69. Cloud cover and phytoplankton are important second-order factors (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>τ</mi>\u0000 </mrow>\u0000 <annotation> $tau $</annotation>\u0000 </semantics></math> = −0.4 after controlling for SIC), whereas snow and ice thickness have a negligible effect after controlling for SIC due to strong interdependencies. We observe a partially stepwise change in the 2000s, but sea ice driven interannual variability has been large throughout the period. Sea ice and snow have a limited impact on the spectral quality of light, omitting any impurities or sea ice algae.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144191037","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":"Assessing Winter Phytoplankton Community Composition Dynamics and Their Response to Environmental Drivers in the Subarctic Northeast Pacific","authors":"Perumthuruthil Suseelan Vishnu,&nbsp;Justin Del Bel Belluz,&nbsp;M. Angelica Peña,&nbsp;Brian P. V. Hunt,&nbsp;Anna Vazhova,&nbsp;Midhun Shah Hussain,&nbsp;Hongyan Xi,&nbsp;Astrid Bracher,&nbsp;Maycira Costa","doi":"10.1029/2023JC020699","DOIUrl":"https://doi.org/10.1029/2023JC020699","url":null,"abstract":"<p>The subarctic northeast Pacific (SNEP) is a high-nutrient, low-chlorophyll region where primary productivity is limited by bioavailable iron during the spring through autumn, and by light limitation during winter. Here, we investigate the spatio-temporal distribution and drivers of SNEP surface phytoplankton biomass and community composition in the winters of 2019 and 2020 using in situ environmental data, chemotaxonomic analysis of phytoplankton pigment samples, and Sentinel-3A Ocean Land Color Instrument imagery. The utilized satellite-based algorithm showed promise replicating the expected trends of: (a) homogenous phytoplankton communities dominated by haptophytes, green algae, and pelagophytes in highly mixed light-limited oceanic waters and; (b) increased diatoms in coastal Haida Gwaii waters with reduced mixed-layer depth (MLD) and salinity. Unexpectedly, increases in cryptophytes were observed in the northern extents of the SNEP, which coincided with winter marine heatwave driven reductions in MLDs and also the presence of a mesoscale eddy. This finding highlights a deviation from expected homogeneous phytoplankton conditions, which may be systematically missed by spatially and temporally constrained in situ sampling. The further advancement and deployment of the satellite-based algorithm could significantly expand the understanding of winter phytoplankton dynamics in the SNEP, a critical period for Pacific salmon survival, improving the understanding of trophic linkages and match/mismatch dynamics, and contributing to improve the forecasting of salmon returns.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JC020699","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190994","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":"Directional Variations in Tidal Flow Multifractality and Intermittency","authors":"Shyuan Cheng,&nbsp;Vincent S. Neary,&nbsp;Leonardo P. Chamorro","doi":"10.1029/2025JC022463","DOIUrl":"https://doi.org/10.1029/2025JC022463","url":null,"abstract":"<p>We explored distinct directional variations of multifractal and intermittent characteristics of ebb and flood flow velocities at nodule point, WA, tidal energy site, and complementary inspection on the East River, NY using scaling exponents of the structure function, distribution flatness, detrending moving average (DMA) analysis, multifractal detrended fluctuation analysis (MF-DFA), and high-order spectral moments. Our findings reveal that tidal flow presents higher long-range dependence (LRD) and intermittent levels for the ebb flow sections, whereas the flood flow sections exhibit a higher degree of multifractality and greater sensitivity to larger magnitude of turbulent fluctuations. We demonstrate that long-range dependence predominantly contributes to multifractal behavior in both ebb and flood flows, as evidenced by the significantly reduced multifractal spectrum width for temporally randomly permuted time series. Moreover, spectral kurtosis analysis uncovers a higher intermittent level across all frequency scales for ebb flow sections and reveals a distinct pattern of tidal flow intermittency differing from the monotonically increasing intermittent level observed in wall-bounded and grid turbulence. Finally, we demonstrate that DMA, MF-DFA, and high-order spectral moments provide more comprehensive insights than structure function scaling exponents and PDF flatness methods.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022463","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144185887","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":"Winter Storm Surge Event Long-Term Variability in the North Atlantic","authors":"Simon Barbot,&nbsp;Lucia Pineau-Guillou,&nbsp;Jean-Marc Delouis","doi":"10.1029/2024JC022204","DOIUrl":"https://doi.org/10.1029/2024JC022204","url":null,"abstract":"<p>Changes in storm surge events are investigated using the Event CHARacterization method, which identifies and quantifies the various dynamical structures of a typical storm surge event. This method was applied yearly, using a 20 year sliding window, to a set of 41 long-term tide gauges in the North Atlantic. Storm surge events were investigated on the basis of four key parameters: the amplitude and duration of two structures related to atmospheric pressure (Gaussian structure) and wind stress (Laplace structure). The analysis reveals large changes in 71% of the tide gauges, located in the eastern North Sea, the Baltic Sea, and in specific regions of North America. Changes are more important for the duration <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 <mn>16</mn>\u0000 <mi>%</mi>\u0000 </mrow>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation> $(pm 16%)$</annotation>\u0000 </semantics></math> of the events than for the amplitude <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>(</mo>\u0000 <mrow>\u0000 <mo>±</mo>\u0000 <mn>7</mn>\u0000 <mi>%</mi>\u0000 </mrow>\u0000 <mo>)</mo>\u0000 </mrow>\u0000 <annotation> $(pm 7%)$</annotation>\u0000 </semantics></math>. In Europe, the pressure-induced structure (Gaussian) is more affected by changes than the wind-stress-induced structure (Laplace). In addition, the changes in North America show patterns with significant linear trends that lacked discernible geographical coherence, while in Europe, the changes exhibit cyclic patterns with more obvious geographical coherence.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022204","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179017","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":"Identification of Southern Ocean Upwelling From Biogeochemical-Argo Floats","authors":"D. Stappard,&nbsp;B. Fernández Castro,&nbsp;A. Naveira Garabato,&nbsp;T. Tyrrell","doi":"10.1029/2023JC020597","DOIUrl":"https://doi.org/10.1029/2023JC020597","url":null,"abstract":"<p>The Southern Ocean surrounds the continent of Antarctica, linking the southern regions of the Atlantic, Indian, and Pacific Oceans. It plays a fundamental role in the global overturning circulation, and is a location of intense upwelling of deep water. The deep water that upwells is rich in nutrients, depleted in oxygen (O₂), and enriched in carbon dioxide (CO₂). Southern Ocean upwelling is thus important to the global carbon cycle through its impact on global ocean productivity and through its influence on air-sea CO₂ exchange. However, because of its widespread nature in time and space, and its underpinning weak vertical flows, it is challenging to detect Southern Ocean upwelling from observations. In a novel approach, we utilize measurements from Biogeochemical-Argo floats deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling project, to identify Southern Ocean upwelling through its biogeochemical fingerprint. Our approach detects upwelling by examining surface carbon dioxide ([CO₂]) and oxygen ([O₂]) concentration Relative to Saturation (CORS). Differences between observed (calculated from pH for CO₂) and saturating gas concentrations are used to fingerprint upwelling. Spatial analysis of the identified upwelling reveals a latitudinal gradient in upwelling, with the maximum toward the south of the Antarctic Circumpolar Current. Furthermore, our observational diagnostics provides some support of previous model-based propositions of a focalization of Southern Ocean upwelling on hotspots of complex topography. Ongoing analysis with our approach can provide further insight into the nature and spatio-temporal variability of Southern Ocean upwelling.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JC020597","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144179016","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":"Asymmetric Response of the North Atlantic Gyres to the North Atlantic Oscillation","authors":"Dhruv Bhagtani,&nbsp;Andrew McC. Hogg,&nbsp;Ryan M. Holmes,&nbsp;Navid C. Constantinou,&nbsp;Hemant Khatri","doi":"10.1029/2024JC021997","DOIUrl":"https://doi.org/10.1029/2024JC021997","url":null,"abstract":"<p>The North Atlantic Oscillation (NAO) is a leading mode of atmospheric variability, affecting the North Atlantic Ocean on sub-seasonal to multi-decadal timescales. The NAO changes the atmospheric forcing at the ocean's surface, including winds and surface buoyancy fluxes, both of which are known to impact large-scale gyre circulation. However, the relative role of other physical processes (such as mesoscale eddies and topography) in influencing gyre circulation under NAO variability is not fully understood. Here, we analyze a series of ocean-sea ice simulations using a barotropic vorticity budget to understand the long-term response of the North Atlantic gyre circulation to NAO forcing. We find that for each standard deviation increase in the NAO index, the subtropical and subpolar gyres intensify by 0.90 and 3.41 Sv (1<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mspace></mspace>\u0000 <mi>S</mi>\u0000 <mi>v</mi>\u0000 <mspace></mspace>\u0000 <mo>≡</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>6</mn>\u0000 </msup>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>m</mi>\u0000 <mn>3</mn>\u0000 </msup>\u0000 <mspace></mspace>\u0000 <msup>\u0000 <mi>s</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> $,mathrm{S}mathrm{v} equiv 1{0}^{6},{mathrm{m}}^{3},{mathrm{s}}^{-1}$</annotation>\u0000 </semantics></math>), respectively. The NAO-induced wind stress anomalies drive approximately 90% of the change in the subtropical gyre's interior flow. However, in the subpolar gyre's interior, in addition to wind stress, flow-topography interactions, stratification (influenced by surface heat fluxes), and non-linear advection significantly influence the circulation. Along the western boundary the bottom pressure torque plays a key role in steering the flow, and the vorticity input by the bottom pressure torque is partly redistributed by non-linear advection. Our study highlights the importance of both atmospheric forcing and oceanic dynamical processes in driving long-term gyre circulation responses to the NAO.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021997","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171917","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":"Influence of the Advection of Labrador Sea Water on the Decadal Variability of the Eastern Subpolar North Atlantic","authors":"C. Herbaut,&nbsp;M.-N. Houssais,&nbsp;A. C. Blaizot,&nbsp;S. Close","doi":"10.1029/2024JC022269","DOIUrl":"https://doi.org/10.1029/2024JC022269","url":null,"abstract":"<p>The upper ocean heat content of the eastern subpolar North Atlantic (ESPNA) displays large decadal variations, in particular, a warming starting in the mid-1990s followed by a cooling trend from the mid-2000s to the mid-2010s. Using an eddy permitting ice-ocean model, we find a relationship between the eastward propagation of dense water formed in the Labrador and Irminger Seas, the barotropic horizontal circulation and the advective heat convergence in the ESPNA. The time evolution of the 3-year average anomalies of the barotropic streamfunction (BSF) shows a strong resemblance to that of the depth of the deep isopycnals. In particular, the propagation of dense water drives a response of the BSF in the intergyre gyre region. During the warming period, the advection of dense water is associated with a southeastward expansion of the subpolar gyre and a reduction of the supply of cold water from the western subpolar North Atlantic to the upper layers of the ESPNA. Sensitivity experiments suggest that atmospheric forcing can also enhance the trends in the heat content, but the latter cannot be related to trends of the local wind curl. However, circulation changes induced by the wind curl on some specific years can amplify the heat content changes.</p>","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022269","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171985","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}