Journal of Geophysical Research-Oceans最新文献_第2页

Free Long Wave Generation: Breakpoint Forcing Versus Bound Wave Release 自由长波产生：断点强迫与束缚波释放

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-26 DOI: 10.1029/2025JC022377

Stephanie Contardo, Ryan J. Lowe, Francois Dufois, Jeff E. Hansen, Graham Symonds

{"title":"Free Long Wave Generation: Breakpoint Forcing Versus Bound Wave Release","authors":"Stephanie Contardo, Ryan J. Lowe, Francois Dufois, Jeff E. Hansen, Graham Symonds","doi":"10.1029/2025JC022377","DOIUrl":"https://doi.org/10.1029/2025JC022377","url":null,"abstract":"When wind waves break in the nearshore, free long (infragravity) waves are generated through two mechanisms: breakpoint forcing and bound wave release. Previous studies have highlighted that lower frequency groups breaking on steep slopes favor long wave generation by breakpoint forcing, whereas higher frequency groups breaking on mild slopes favor bound wave release. However, no study has established and demonstrated quantitative thresholds for when each mechanism will dominate. In this paper, we use a one-dimensional linear numerical model to quantify each mechanism and assess their relative dominance in free long wave generation, as a function of wave and bathymetry parameters. The results show that the individual contributions of breakpoint forcing and bound wave release do not add up linearly to the total long wave energy generated from both mechanisms due to the phase differences between free long waves generated from each mechanism. The combination of mechanisms always results in a net smaller long wave amplitude. The normalized bed slope parameter is shown to be effective in differentiating between the dominance of the breakpoint-forced and bound wave release mechanisms. The efficiency of breakpoint forcing is found to be independent of bed slope, wave group frequency and short-wave period. Therefore, the relative importance of each mechanism to long wave generation depends mainly on the efficiency of the bound wave release, which varies with these parameters. Overall, the bound wave release mechanism tends to dominate under most conditions, except for cases with low infragravity frequencies that occur on steep slopes (e.g., typical of reef environments).","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 7","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022377","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144482356","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}

引用次数: 0

Hydraulic Control of Submarine Glacial Melt in Greenlandic Fjords 格陵兰峡湾海底冰川融化的水力控制

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-26 DOI: 10.1029/2024JC021257

Jonathan Wiskandt, Johan Nilsson, Inga Monika Koszalka

{"title":"Hydraulic Control of Submarine Glacial Melt in Greenlandic Fjords","authors":"Jonathan Wiskandt, Johan Nilsson, Inga Monika Koszalka","doi":"10.1029/2024JC021257","DOIUrl":"https://doi.org/10.1029/2024JC021257","url":null,"abstract":"Ocean-driven submarine basal melt of the Greenland Ice Sheet remains a major source of uncertainty in climate projections of future sea level rise based on ice sheet modeling. State-of-the-art parameterizations focus on the properties of the ocean water reaching the marine-terminating glaciers, processes at the ice-ocean interface and subglacial discharge to estimate submarine basal melt. This study uses 2-dimensional, nonrotating, high-resolution ocean simulations complemented by theory and observations to quantify two effects of fjord bathymetry (sills) on the thermal forcing with consequences for the basal melt. These effects are the recirculation (reflux) of glacially modified water due to hydraulic control at the sill (which we study in detail) and the cooling of the inflow due to the restriction of the deepest and warmest Atlantic water inflow. For a fixed sill depth, an increase in subglacial discharge can make the exchange flow hydraulically controlled. Our results suggest that basal melt parameterizations should account for fjord bathymetry, and outline a road map to guide future parameterization developments relevant to narrow fjords.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 7","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC021257","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144482358","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}

引用次数: 0

Biogeochemical Implication of Massive Episodic Flood Deposition: Model-Data Integration 大规模幕式洪水沉积的生物地球化学意义：模式-数据整合

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-25 DOI: 10.1029/2025JC022414

Stanley Nmor, Eric Viollier, Lucie Pastor, Bruno Lansard, Christophe Rabouille

{"title":"Biogeochemical Implication of Massive Episodic Flood Deposition: Model-Data Integration","authors":"Stanley Nmor, Eric Viollier, Lucie Pastor, Bruno Lansard, Christophe Rabouille","doi":"10.1029/2025JC022414","DOIUrl":"https://doi.org/10.1029/2025JC022414","url":null,"abstract":"During extreme flood events, coastal deltas experience large sediment deposition within a short time period. The biogeochemical consequences of these deposition-recycling-burial processes on carbon and nutrient cycles are not fully understood. Using a coupled data model approach, we explore the early diagenetic responses of deltaic sediments influenced by two intense floods (in spring and fall) on the Rhône River in 2008. The data set shows that sediment porewater composition responded abruptly to this almost instantaneous change in deposition. The model calculated that these flood-related depositions increased organic carbon mineralization by a factor of 2–4 compared to preflood levels, and were dominated by sulfate reduction (68%), and methanogenesis (16%). The two floods (organic-poor in spring and organic-rich in fall) cause different diagenetic effects in terms of dissolved inorganic carbon (DIC) fluxes—the 30-cm organic-poor flood deposition induced a large storage of DIC in porewaters, which largely decreased its flux to the water column, whereas the 10-cm organic-rich sediment induced a large efflux of DIC. The model reveals the absence of dissolved sulfide in porewaters after flood deposition due to iron bound precipitation. The sequential flood depositions caused a temporary memory effect (i.e., interaction between two successive floods), with stronger effect for methane (38%), whose longer relaxation timescale limits complete recovery before the next event separated by 6 months. Increasing the frequency and intensity of these events in the future could lead to memory accumulation of flood biogeochemical signatures.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022414","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144473230","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}

引用次数: 0

On the Stoichiometry of Degradable Fraction of Particulate Organic Matter Along a Diapycnal Mixing Path Using Dissolved Oxygen δ18O Approach 溶解氧δ18O法研究可降解颗粒有机物沿双周期混合路径的化学计量学

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-24 DOI: 10.1029/2025JC022512

Zhuo-Yi Zhu, Guo-Dong Song, Zhi-Hao Zhang, Yu-Shan Luo, Su-Mei Liu, Jing Zhang

{"title":"On the Stoichiometry of Degradable Fraction of Particulate Organic Matter Along a Diapycnal Mixing Path Using Dissolved Oxygen δ18O Approach","authors":"Zhuo-Yi Zhu, Guo-Dong Song, Zhi-Hao Zhang, Yu-Shan Luo, Su-Mei Liu, Jing Zhang","doi":"10.1029/2025JC022512","DOIUrl":"https://doi.org/10.1029/2025JC022512","url":null,"abstract":"The stoichiometry of degradable fraction of particulate organic matter (POM) in the water column has long been one of the key fundamental parameters in chemical oceanography. In this work, we used a novel approach (δ18O of dissolved oxygen, DO) to verify the stoichiometry of degraded fraction of POM. A field survey was conducted in the northern South China Sea in 2024. Based on the observed DO and nutrients, we used an exhaustive inverse analysis to reveal all possible stoichiometric results of degradable POM in the 200–500 m zone, with the centroid (the most likely) result being C104HxOyN14.5P and the corresponding apparent oxygen utilization (AOU) as 140.5 O2. Our result reveals that the H/O elemental ratio (x/y) is highly close to 2.8, which is closest to that of proteins. As for δ18O, it ranged from <0 at the surface to a maximum of 7.5‰ at 277 m, with an overall apparent fractionation factor (ε) of 6.84. Based on the negative deviation between δ18O and DO concentration coupling, we quantified the DOmin (AOUmax) in the water columns when there had been no mixing. The average AOUmax was estimated as 265 μM, and the average AOUmax/nitratemax (AOUmax/DIPmax) for all four stations was 10.1 ± 1.9 (151 ± 15), which agrees with the previous centroid result. Our work not only reveals the stoichiometry of degraded POM in this dynamic region but also provides a new method for the study of degraded POM stoichiometry in the ocean.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144367237","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}

引用次数: 0

Carbon Biomass Assessment for Microbial Plankton Groups Across a Young Anticyclonic Loop Current Eddy and Surrounding Waters in the Gulf of Mexico 墨西哥湾年轻反气旋环流、流涡和周围水域浮游微生物群的碳生物量评估

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-23 DOI: 10.1029/2025JC022705

L. Linacre, E. Pallàs-Sanz, J. A. Velásquez-Aristizábal, C. Sánchez-Robles, U. Mirabal-Gómez, V. Camacho-Ibar, J. R. Lara-Lara, C. Bazán-Guzmán, J. Sheinbaum-Pardo

{"title":"Carbon Biomass Assessment for Microbial Plankton Groups Across a Young Anticyclonic Loop Current Eddy and Surrounding Waters in the Gulf of Mexico","authors":"L. Linacre, E. Pallàs-Sanz, J. A. Velásquez-Aristizábal, C. Sánchez-Robles, U. Mirabal-Gómez, V. Camacho-Ibar, J. R. Lara-Lara, C. Bazán-Guzmán, J. Sheinbaum-Pardo","doi":"10.1029/2025JC022705","DOIUrl":"https://doi.org/10.1029/2025JC022705","url":null,"abstract":"Carbon biomass assessments are useful in quantifying carbon stored in key planktonic functional groups involved in biogeochemical processes in marine ecosystems. The microbial community inhabiting the open-ocean Gulf of Mexico comprises organisms that regulate carbon fluxes within this mesoscale-dominated ecosystem. The anticyclonic Loop Current Eddies (LCEs) are highly dynamic structures that harbor and transport significant microbial players in the ocean carbon cycle. This study focuses on characterizing the vertical and horizontal high-resolution carbon biomass distribution of the microbial community within the euphotic zone of a young LCE and the surrounding waters during a cruise conducted in the oceanic region of the Gulf of Mexico in November 2022. Carbon estimates were performed using cell abundance and variable carbon conversion factors per microbial group. The prevailing mesoscale dynamics modulated the biomass vertical distribution inside the LCE and at the external region. Sinking and rising of the microbial carbon to deeper and upper layers were discernible at the LCE center and edges, respectively. Upwelling and increase of carbon were evidenced in the cyclonic-influenced external region. Biotic factors, including habitat preferences, nutritional strategies, and ecological interactions among microorganisms, also shaped the biomass composition and distribution within the euphotic zone of mesoscale structures. Remarkably, the combined impact of the deep vertical mixing and the eddy interaction with strong northerly winds during the study period promoted phytoplankton vertical redistribution and carbon stock enhancement inside the LCE. The study's findings situate the LCEs as important dynamic structures regulating the microbial carbon pool within this open-ocean ecosystem.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144339632","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}

引用次数: 0

Improved Theoretical Estimates of the Zonal Propagation of Global Nonlinear Mesoscale Eddies 全球非线性中尺度涡旋纬向传播的改进理论估计

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-21 DOI: 10.1029/2025JC022518

Ran Liu, Yan Wang, Xiaoming Zhai, Dhruv Balwada, Julian Mak

{"title":"Improved Theoretical Estimates of the Zonal Propagation of Global Nonlinear Mesoscale Eddies","authors":"Ran Liu, Yan Wang, Xiaoming Zhai, Dhruv Balwada, Julian Mak","doi":"10.1029/2025JC022518","DOIUrl":"https://doi.org/10.1029/2025JC022518","url":null,"abstract":"Mesoscale eddies are essential for transport and mixing processes in the global ocean, with their characteristic westward propagation being a significant finding from the satellite altimetry era. Traditional predictions of their zonal propagation rely on the theoretical phase speed of long baroclinic Rossby waves; however, this approach is known to overestimate eddy speeds equatorward of approximately <math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>35</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $35{}^{circ}$</annotation>\u0000 </semantics></math> latitudes. To address this issue, we incorporate local eddy wavelengths inferred from satellite-based eddy radii into the estimation of global eddy speeds, thereby significantly reducing the overestimation biases in mid-to low-latitude regions. This improvement is consistent with the observation that mesoscale eddies in these latitudes have length scales comparable to the local deformation scales and thus refrain from satisfying the long-wave approximation, whereas the long baroclinic Rossby wave phase speed remains useful for capturing the most energetic but less abundant eddies. The remaining discrepancies between the revised theoretical speeds and observations primarily stem from uncertainties in the background zonal flow, spatial variability of vertical modal structures (and the associated deformation radii), and estimation of local eddy length scales. These findings have important implications for understanding long-range mesoscale eddy propagation and eddy-driven mixing in the global ocean, which are anticipated to benefit future ocean model developments and enhance predictions of mesoscale eddy dynamics.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022518","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144336101","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}

引用次数: 0

Energetics of (Super)Tidal Baroclinic Modes in a Realistically Forced Global Ocean Simulation 真实强迫全球海洋模拟中（超）潮汐斜压模态的能量学

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-20 DOI: 10.1029/2025JC022460

Maarten C. Buijsman, Mujeeb Abdulfatai, Brian K. Arbic, Eric P. Chassignet, Luna Hiron, Jay F. Shriver, Miguel Solano, Dheeraj Varma, Xiaobiao Xu

{"title":"Energetics of (Super)Tidal Baroclinic Modes in a Realistically Forced Global Ocean Simulation","authors":"Maarten C. Buijsman, Mujeeb Abdulfatai, Brian K. Arbic, Eric P. Chassignet, Luna Hiron, Jay F. Shriver, Miguel Solano, Dheeraj Varma, Xiaobiao Xu","doi":"10.1029/2025JC022460","DOIUrl":"https://doi.org/10.1029/2025JC022460","url":null,"abstract":"In this study, we diagnose the spatial variability in the energetics of tidally generated diurnal, semidiurnal, and supertidal (<math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>></mo>\u0000 <mn>2.5</mn>\u0000 </mrow>\u0000 <annotation> ${ >} 2.5$</annotation>\u0000 </semantics></math> cycles per day) internal wave vertical modes (up to mode 6) in a 30-day forward global ocean model simulation with a 4-km grid spacing and 41 layers. The simulation is forced with realistic tides and atmospheric fields. Diurnal modes are resolved beyond mode 6, semidiurnal modes are resolved up to mode 4, and supertidal modes are resolved up to mode 2, in agreement with a canonical horizontal resolution criterion. The meridional trends in the kinetic to available potential energy ratios of these resolved modes agree with an internal wave consistency relation. The supertidal band is dominated by the higher harmonics of the diurnal and semidiurnal tides. Its higher harmonic energy projects on the internal wave dispersion curves in frequency-wavenumber spectra and is captured mostly by the terdiurnal and quarterdiurnal mode-1 waves. Terdiurnal modes are mostly generated in the west Pacific, where diurnal internal tides are strong. In contrast, quarterdiurnal modes occur at all longitudes near strong semidiurnal generation sites. The globally integrated energy in the supertidal band is about one order of magnitude smaller than the energy in the tidal band. The supertidal energy as a fraction of the tidal energy is elevated along semidiurnal internal wave beams in the tropics. We attribute this to near-resonant interactions between tidal modes of the same mode number.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022460","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331989","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}

引用次数: 0

Phase-Locked Internal-Wave Triads Observed in the Izu-Ogasawara Ridge: Implications for Interplay Between Tides and Winds 在伊豆-小笠原海岭观测到的锁相内波三联：潮汐和风之间相互作用的含义

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-20 DOI: 10.1029/2025JC022501

Takashi Ijichi, Ryuichiro Inoue, Yasuo Furushima

{"title":"Phase-Locked Internal-Wave Triads Observed in the Izu-Ogasawara Ridge: Implications for Interplay Between Tides and Winds","authors":"Takashi Ijichi, Ryuichiro Inoue, Yasuo Furushima","doi":"10.1029/2025JC022501","DOIUrl":"https://doi.org/10.1029/2025JC022501","url":null,"abstract":"The Ogasawara subregion of the Izu-Ogasawara-Mariana arc system in the western North Pacific is recognized as one of the most notable hotspots for thermocline turbulent mixing. Although parametric subharmonic instability (PSI) is generally considered a primary driver of enhanced turbulence by facilitating energy transfer from low-mode semidiurnal internal tides to high-mode near-inertial waves (NIWs), recent observations suggest that NIWs remotely induced by winds also contribute to significant seasonal variations in thermocline turbulence in this region. Here, 3-day velocity and density yo-yo measurements, conducted near the PSI critical latitude of 28.8°N opportunistically after several storm passages, reveal the coexistence of PSI-induced high-mode NIWs and wind-induced low-mode NIWs. Two distinct pairs of upward- and downward-propagating NIWs are identified, each forming a phase-locked triad with locally generated upward-propagating semidiurnal internal tides. In a mid-depth layer, a pair of high-mode upward- and downward-propagating NIWs forms a scale-separated PSI triad with the internal tides, whereas in an overlying layer, a pair of low-mode downward-propagating NIWs and intermediate-mode upward-propagating NIWs forms a distinct non-scale-separated triad. Consequently, turbulent dissipation is enhanced at the boundary between these distinct near-inertial velocity layers. These findings are not inconsistent with the view that wind-induced low-mode NIWs interact with internal tides, promoting the growth of intermediate-mode NIWs and eventually contributing to the enhanced thermocline turbulence, thus suggesting an overlooked pathway to turbulence in the ocean interior.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JC022501","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323549","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}

引用次数: 0

Longshore Sediment Transport and Morphological Changes Under Climate Change—A Comparison Between CMIP5- and CMIP6-Derived Forcings and the Use of Wave Climate Bias Correction 气候变化下的海岸输沙与地貌变化——CMIP5-与CMIP5-强迫的比较及波浪气候偏差校正的应用

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-20 DOI: 10.1029/2024JC022212

G. Vieira da Silva, D. Strauss, T. Murray, F. Alvarez, M. Hemer, A. Meucci, O. Repina

{"title":"Longshore Sediment Transport and Morphological Changes Under Climate Change—A Comparison Between CMIP5- and CMIP6-Derived Forcings and the Use of Wave Climate Bias Correction","authors":"G. Vieira da Silva, D. Strauss, T. Murray, F. Alvarez, M. Hemer, A. Meucci, O. Repina","doi":"10.1029/2024JC022212","DOIUrl":"https://doi.org/10.1029/2024JC022212","url":null,"abstract":"Changes in wave climate can impact coastal zones by altering the sediment supplied to coastal compartments via longshore sediment transport (LST). Estimating these changes is challenging, and biases and uncertainty in wave climate projections contribute to uncertainty in LST and morphological change projections. This paper compares wave climate, LST projections, and morphological changes derived from two iterations of the Coupled Model Intercomparison Project (CMIP), and the implications of applying wave climate bias correction in these projections for the late 21st century under high emission scenarios. LST and morphological changes were simulated in a process-based model calibrated with data from a sand bypassing system. Bias correction improved representation of wave climate, including extremes, and reduced variance between climate models. Although bias correction did not change projected mean LST, it reduced the spread of model ensembles by 20% and 10% for CMIP5 and CMIP6, respectively. Both CMIP5 and CMIP6 suggest a future reduction of LST in the study area. However, CMIP6-derived projections show: (a) 50% less variance in wave forcing; (b) greater consistency between ensemble members; and (c) double the reduction in LST. This reduction is attributed to changes in the frequency, intensity and direction of modal and extreme waves. Morphological changes suggest steepening of the beach profiles in line with the historical record. This contribution highlights the value of a bias-corrected model ensemble and improvements in CMIP iterations in providing coherent projections of future wave climate change and its impacts on regional coastal processes.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022212","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144331988","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}

引用次数: 0

On the Ambiguity of Oceanic Eddy Polarity 论海洋涡旋极性的模糊性

IF 3.3 2区地球科学

Journal of Geophysical Research-Oceans Pub Date : 2025-06-20 DOI: 10.1029/2024JC022239

Ge Chen, Xiaoyan Chen

{"title":"On the Ambiguity of Oceanic Eddy Polarity","authors":"Ge Chen, Xiaoyan Chen","doi":"10.1029/2024JC022239","DOIUrl":"https://doi.org/10.1029/2024JC022239","url":null,"abstract":"Polarity is a fundamental feature of oceanic eddies, which defines many aspects of its hydrodynamics and thermodynamics. Polarity ambiguity is a challenging and sometimes puzzling issue for the classification of eddies and analysis of their dynamics. Here, we propose a new methodology combining drifter-measured currents and temperatures to evaluate the validity of altimeter-derived eddy polarity. Different from previous schemes based purely on assessing oceanic temperature ambiguity of eddies from either satellite or Argo observations, our approach integrates the concurrent vector flow and surface temperature measured by drifters riding on altimeter-tracked eddies. The idea is to examine the consistency between the rotation of drifter trajectory and the spinning of eddy motion on the assumption that the looping and circulating directions are identical for a normal eddy and otherwise for an “ambiguous” or “abnormal” one. For a special class of radial drifter trajectory with respect to the eddy centroid, the temperature trend along its path is used to judge its polarity, that is, warmer toward the core for a normal anticyclonic eddy and colder for cyclonic. Our results reveal that many eddies previously classified as “abnormal” are in fact dynamically or thermally ambiguous due to distortions in their upper-layer structures rather than being genuinely misclassified by altimeter. After excluding such ambiguous cases, only ∼3% of eddies show polarity inconsistency in both aspects. These findings suggest that altimeter-derived eddy polarity is highly reliable, and that combining a multi-parameter, Lagrangian-informed approach offers more accurate interpretations of eddy structures by distinguishing intrinsic anomalies from superficial distortions.","PeriodicalId":54340,"journal":{"name":"Journal of Geophysical Research-Oceans","volume":"130 6","pages":""},"PeriodicalIF":3.3,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JC022239","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144323647","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}

引用次数: 0