Pub Date : 2023-10-04DOI: 10.1007/s10236-023-01578-4
Nan Yuan, Humio Mitsudera, Hideharu Sasaki
Abstract In this research, we studied the upwelling in the northwestern Gulf of Alaska using the climatological January mean and data from the output of the Ocean General Circulation Model for Earth Simulator (OFES2). Specifically, we analyzed the upwelling in the regions where the Alaska Coastal Current (ACC) flows out of the Shelikof Strait (especially the part to the west of Kodiak Island) and where the ACC and the Alaskan Stream (AS) are confluent. In both regions, strong geostrophic currents and downwelling-favorable wind predominate in winter. Furthermore, there are freshwater discharges along the Alaskan coast and an observed mean current vertical shear in the ACC. We revealed that when the internal water stress is larger than the wind stress inside the study regions, this could be decisive in terms of the local horizontal velocity divergence and further upwelling, even if the region is away from the coast and lacks upwelling-favorable wind conditions. Geostrophic stress is part of the internal water stress and is a product of the geostrophic current shear (due to the thermal wind relation) and the vertical viscosity coefficient. The analysis indicated that a front with a large geostrophic stress may act as a “virtual wall” and contribute to local upwelling within a depth of approximately 100 m in the study regions. This process could provide a heuristic for understanding the distribution of pollock in the areas during February and March, which corresponds to the simulated upwelling region.
{"title":"A study of the simulated climatological January mean upwelling in the northwestern Gulf of Alaska","authors":"Nan Yuan, Humio Mitsudera, Hideharu Sasaki","doi":"10.1007/s10236-023-01578-4","DOIUrl":"https://doi.org/10.1007/s10236-023-01578-4","url":null,"abstract":"Abstract In this research, we studied the upwelling in the northwestern Gulf of Alaska using the climatological January mean and data from the output of the Ocean General Circulation Model for Earth Simulator (OFES2). Specifically, we analyzed the upwelling in the regions where the Alaska Coastal Current (ACC) flows out of the Shelikof Strait (especially the part to the west of Kodiak Island) and where the ACC and the Alaskan Stream (AS) are confluent. In both regions, strong geostrophic currents and downwelling-favorable wind predominate in winter. Furthermore, there are freshwater discharges along the Alaskan coast and an observed mean current vertical shear in the ACC. We revealed that when the internal water stress is larger than the wind stress inside the study regions, this could be decisive in terms of the local horizontal velocity divergence and further upwelling, even if the region is away from the coast and lacks upwelling-favorable wind conditions. Geostrophic stress is part of the internal water stress and is a product of the geostrophic current shear (due to the thermal wind relation) and the vertical viscosity coefficient. The analysis indicated that a front with a large geostrophic stress may act as a “virtual wall” and contribute to local upwelling within a depth of approximately 100 m in the study regions. This process could provide a heuristic for understanding the distribution of pollock in the areas during February and March, which corresponds to the simulated upwelling region.","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135592560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-30DOI: 10.1007/s10236-023-01576-6
Wenfan Wu, Fangguo Zhai, Cong Liu, Yanzhen Gu, Peiliang Li
{"title":"Three-dimensional structure of summer circulation in the Bohai Sea and its intraseasonal variability","authors":"Wenfan Wu, Fangguo Zhai, Cong Liu, Yanzhen Gu, Peiliang Li","doi":"10.1007/s10236-023-01576-6","DOIUrl":"https://doi.org/10.1007/s10236-023-01576-6","url":null,"abstract":"","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136336583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The Bay of Campeche, located in the southern Gulf of Mexico (GoM), is characterized by a semi-permanent cyclonic circulation commonly referred to as the Campeche Gyre (CG). Several studies documenting its upper layer structure have suggested a possible relationship between its seasonal variability and the wind stress, and that non-seasonal variability arises mainly from the interaction of the gyre with Loop Current Eddies (LCEs) that arrive in the region. Nevertheless, a partition of the contributions of these forcings to the circulation of the CG in a statistically consistent manner is still needed. This study examines the wind- and eddy-driven circulation with long-term numerical simulations of the GoM using the HYbrid Coordinate Ocean Model. Our results show that, in the absence of LCEs, the wind can sustain a seasonal-modulated circulation in the CG, confined within the upper 600 m. When considering LCEs, high fluctuations on the flow at intraseasonal time scales are imposed. We found that the LCEs influence the western Bay of Campeche circulation through two main mechanisms: (a) by decelerating and inhibiting the CG through a positive vorticity flux out of the bay, leading to reversals in the flow if LCE southward penetration is large, or (b) by strengthening the CG when a big cyclone, accompanying the LCE, enters the region. It is proposed that the second mechanism is responsible for inducing a net weak cyclonic circulation in the Bay in the absence of wind. Furthermore, past studies have shown that the CG behaves as an equivalent-barotropic flow, with topography acting to confine the CG to the west of the bay. In our modeling results, the role of topography manifests similarly among the different numerical experiments, resulting in closed geostrophic contours to the west of the bay that confine an upper-layer, nearly-symmetric, equivalent-barotropic CG.
{"title":"Contribution of the wind, Loop Current Eddies, and topography to the circulation in the southern Gulf of Mexico","authors":"Erick R. Olvera-Prado, Rosario Romero-Centeno, Jorge Zavala-Hidalgo, Efraín Moreles, Angel Ruiz-Angulo","doi":"10.1007/s10236-023-01569-5","DOIUrl":"https://doi.org/10.1007/s10236-023-01569-5","url":null,"abstract":"Abstract The Bay of Campeche, located in the southern Gulf of Mexico (GoM), is characterized by a semi-permanent cyclonic circulation commonly referred to as the Campeche Gyre (CG). Several studies documenting its upper layer structure have suggested a possible relationship between its seasonal variability and the wind stress, and that non-seasonal variability arises mainly from the interaction of the gyre with Loop Current Eddies (LCEs) that arrive in the region. Nevertheless, a partition of the contributions of these forcings to the circulation of the CG in a statistically consistent manner is still needed. This study examines the wind- and eddy-driven circulation with long-term numerical simulations of the GoM using the HYbrid Coordinate Ocean Model. Our results show that, in the absence of LCEs, the wind can sustain a seasonal-modulated circulation in the CG, confined within the upper 600 m. When considering LCEs, high fluctuations on the flow at intraseasonal time scales are imposed. We found that the LCEs influence the western Bay of Campeche circulation through two main mechanisms: (a) by decelerating and inhibiting the CG through a positive vorticity flux out of the bay, leading to reversals in the flow if LCE southward penetration is large, or (b) by strengthening the CG when a big cyclone, accompanying the LCE, enters the region. It is proposed that the second mechanism is responsible for inducing a net weak cyclonic circulation in the Bay in the absence of wind. Furthermore, past studies have shown that the CG behaves as an equivalent-barotropic flow, with topography acting to confine the CG to the west of the bay. In our modeling results, the role of topography manifests similarly among the different numerical experiments, resulting in closed geostrophic contours to the west of the bay that confine an upper-layer, nearly-symmetric, equivalent-barotropic CG.","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135200166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-27DOI: 10.1007/s10236-023-01568-6
John Ssebandeke, Jin-Song von Storch, Nils Brüggemann
Abstract We re-examine the Lorenz energy cycle (LEC) for the global ocean by assessing its sensitivity to model and forcing differences. We do so by comparing LECs derived from two simulations based on different eddy-rich ocean models, ICON-O and MPI-OM, both driven by NCEP/NCAR reanalysis, and by comparing LECs derived from two simulations generated using ICON-O model but driven by two different reanalyses, NCEP/NCAR and ERA5. Regarding model difference, we find weaker eddy kinetic energy, $$k_e$$ ke , in the ICON-O simulation than in the MPI-OM simulation. We attribute this to the higher horizontal resolution of MPI-OM in the Southern Ocean. The weaker $$k_e$$ ke in ICON-O is not caused by the lack of eddy available potential energy, $$p_e$$ pe , but by the strong dissipation of $$p_e$$ pe and the resulting weak conversion from $$p_e$$ pe to $$k_e$$ ke . Regarding forcing difference, we find that considerably more mechanical energy is generated by the ERA5 forcing, which has a higher spatial-temporal resolution compared to the NCEP/NCAR forcing. In particular, the generation of $$k_e$$ ke , which also contains the resolved part of the internal wave spectrum, is enhanced by about 1 TW (40%). However, the dominance of the baroclinic and the barotropic pathways forces the enhanced generation of $$k_e$$ ke to be balanced by an enhanced dissipation in the surface layer. The gross features of LEC are insensitive to both model and forcing differences, picturing the ocean as an inefficient “windmill” that converts only a small portion of the inputted mechanical energy into the interior mean and transient circulations.
通过评估全球海洋的洛伦兹能量循环对模式和强迫差异的敏感性，我们重新审视了全球海洋的洛伦兹能量循环。我们通过比较基于NCEP/NCAR再分析驱动的ICON-O和MPI-OM两种不同富涡海洋模型的模拟结果得出的LECs，以及通过比较由ICON-O模型生成但由NCEP/NCAR和ERA5两种不同再分析驱动的两个模拟结果得出的LECs。在模式差异方面，ICON-O模拟的涡动能$$k_e$$ ke比MPI-OM模拟的弱。我们将此归因于南大洋MPI-OM的水平分辨率较高。ICON-O中较弱的$$k_e$$ ke不是由于缺乏涡动有效势能$$p_e$$ p e造成的，而是由于$$p_e$$ p e的强耗散以及由此产生的从$$p_e$$ p e到$$k_e$$ ke的弱转换。在强迫差异方面，ERA5强迫产生的机械能明显高于NCEP/NCAR强迫，且具有更高的时空分辨率。特别是，$$k_e$$ k e的生成，也包含了内波谱的分解部分，增强了约1 TW (40)%). However, the dominance of the baroclinic and the barotropic pathways forces the enhanced generation of $$k_e$$ k e to be balanced by an enhanced dissipation in the surface layer. The gross features of LEC are insensitive to both model and forcing differences, picturing the ocean as an inefficient “windmill” that converts only a small portion of the inputted mechanical energy into the interior mean and transient circulations.
{"title":"Sensitivity of the Lorenz energy cycle of the global ocean","authors":"John Ssebandeke, Jin-Song von Storch, Nils Brüggemann","doi":"10.1007/s10236-023-01568-6","DOIUrl":"https://doi.org/10.1007/s10236-023-01568-6","url":null,"abstract":"Abstract We re-examine the Lorenz energy cycle (LEC) for the global ocean by assessing its sensitivity to model and forcing differences. We do so by comparing LECs derived from two simulations based on different eddy-rich ocean models, ICON-O and MPI-OM, both driven by NCEP/NCAR reanalysis, and by comparing LECs derived from two simulations generated using ICON-O model but driven by two different reanalyses, NCEP/NCAR and ERA5. Regarding model difference, we find weaker eddy kinetic energy, $$k_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> , in the ICON-O simulation than in the MPI-OM simulation. We attribute this to the higher horizontal resolution of MPI-OM in the Southern Ocean. The weaker $$k_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> in ICON-O is not caused by the lack of eddy available potential energy, $$p_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> , but by the strong dissipation of $$p_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> and the resulting weak conversion from $$p_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>p</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> to $$k_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> . Regarding forcing difference, we find that considerably more mechanical energy is generated by the ERA5 forcing, which has a higher spatial-temporal resolution compared to the NCEP/NCAR forcing. In particular, the generation of $$k_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> , which also contains the resolved part of the internal wave spectrum, is enhanced by about 1 TW (40%). However, the dominance of the baroclinic and the barotropic pathways forces the enhanced generation of $$k_e$$ <mml:math xmlns:mml=\"http://www.w3.org/1998/Math/MathML\"> <mml:msub> <mml:mi>k</mml:mi> <mml:mi>e</mml:mi> </mml:msub> </mml:math> to be balanced by an enhanced dissipation in the surface layer. The gross features of LEC are insensitive to both model and forcing differences, picturing the ocean as an inefficient “windmill” that converts only a small portion of the inputted mechanical energy into the interior mean and transient circulations.","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135536985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-21DOI: 10.1007/s10236-023-01574-8
Yue Xu, Xiping Yu
{"title":"Dynamic interdependence of wind stress and sea state under action of a tropical cyclone moving from deep to shallow waters","authors":"Yue Xu, Xiping Yu","doi":"10.1007/s10236-023-01574-8","DOIUrl":"https://doi.org/10.1007/s10236-023-01574-8","url":null,"abstract":"","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136155663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-11DOI: 10.1007/s10236-023-01573-9
Tal Ezer
{"title":"In memoriam: Prof. Dr. Jörg-Olaf Wolff (1959–2023)","authors":"Tal Ezer","doi":"10.1007/s10236-023-01573-9","DOIUrl":"https://doi.org/10.1007/s10236-023-01573-9","url":null,"abstract":"","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135981982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-11DOI: 10.1007/s10236-023-01572-w
Tapajyoti Chakraborty, Sandeep Pattnaik, Sudheer Joseph
{"title":"Influence of tropical cyclone Jawad on the surface and sub-surface circulation in the Bay of Bengal: ocean–atmosphere feedback","authors":"Tapajyoti Chakraborty, Sandeep Pattnaik, Sudheer Joseph","doi":"10.1007/s10236-023-01572-w","DOIUrl":"https://doi.org/10.1007/s10236-023-01572-w","url":null,"abstract":"","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135982094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-29DOI: 10.1007/s10236-023-01570-y
T. Ezer
{"title":"Evaluation of the applicability of the Ekman theory for wind-driven ocean currents: a comparison with the Mellor–Yamada turbulent model","authors":"T. Ezer","doi":"10.1007/s10236-023-01570-y","DOIUrl":"https://doi.org/10.1007/s10236-023-01570-y","url":null,"abstract":"","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76083556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-25DOI: 10.1007/s10236-023-01571-x
Rafael Ricardo Torres, Sadid Latandret, Jhon Salon, Claudia Dagua
{"title":"Correction to: Water masses in the Caribbean Sea and sub‑annual variability in the Guajira upwelling region","authors":"Rafael Ricardo Torres, Sadid Latandret, Jhon Salon, Claudia Dagua","doi":"10.1007/s10236-023-01571-x","DOIUrl":"https://doi.org/10.1007/s10236-023-01571-x","url":null,"abstract":"","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73362092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-01DOI: 10.1007/s10236-023-01567-7
Yu Yan, Yuqing Zhou, Yingjun Xu, W. Gu
{"title":"Assessment of the spatiotemporal variability of seawater temperature and salinity in the Yellow and Bohai seas from multiple high-resolution reanalysis datasets","authors":"Yu Yan, Yuqing Zhou, Yingjun Xu, W. Gu","doi":"10.1007/s10236-023-01567-7","DOIUrl":"https://doi.org/10.1007/s10236-023-01567-7","url":null,"abstract":"","PeriodicalId":19387,"journal":{"name":"Ocean Dynamics","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91304283","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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