首页 > 最新文献

Ocean Science最新文献

英文 中文
Intraseasonal variability of the South Vietnam upwelling, South China Sea: influence of atmospheric forcing and ocean intrinsic variability 南海南越上升流的季节内变率:大气强迫和海洋固有变率的影响
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-04-17 DOI: 10.5194/os-19-453-2023
M. Herrmann, Thai To Duy, C. Estournel
Abstract. The South Vietnam upwelling (SVU) develops off the Vietnamese coast (SouthChina Sea, SCS) during the southwest summer monsoon over four main areas: thenorthern coastal upwelling (NCU), the southern coastal upwelling (SCU), theoffshore upwelling (OFU) and the shelf off the Mekong River mouth (MKU). Anensemble of 10 simulations with perturbed initial conditions were run withthe fine-resolution SYMPHONIE model (1 km inshore) to investigate the dailyto intraseasonal variability of the SVU and the influence of the oceanintrinsic variability (OIV) during the strong SVU of summer 2018. The intraseasonal variability is similar for the SCU, MKU and OFU, driven to thefirst order by the wind variability. The MKU and SCU are induced by stable oceandynamics (the northeastward then eastward boundary current) and have verylittle chaotic variability. The OIV has a stronger influence on OFU. InJuly, OFU mainly develops along the northern flank of the eastward jet. Theinfluence of the OIV is strongest and related to the chaotic variability of themeridional position of the jet. In August, this position is stable and OFUdevelops mainly in the area of positive wind curl and cyclonic eddies northof the jet. The influence of the OIV, weaker than in July, is related to theorganization of this mesoscale circulation. The NCU shows a behavior differentfrom that observed in the other areas. In the heart of summer, a large-scalecirculation formed by the eastward jet and eddy dipole is well establishedwith an alongshore current preventing the NCU development. In early and latesummer, this circulation is weaker, allowing a mesoscale circulation ofstrongly chaotic nature to develop in the NCU area. During those periods,the OIV influence on the NCU is very strong and related to the organization ofthis mesoscale circulation: the NCU is favored (annihilated) byoffshore-oriented (alongshore) structures.
摘要南越上升流(SVU)在西南夏季风期间在越南沿海(南中国海,SCS)发展,主要包括北部沿海上升流(NCU)、南部沿海上升流(SCU)、近海上升流(OFU)和湄公河河口外大陆架(MKU)四个区域。利用高分辨率SYMPHONIE模式(近海1 km)对初始扰动条件下的10次模拟进行了综合分析,探讨了2018年夏季强SVU期间SVU的日-季内变率和海洋固有变率(OIV)的影响。SCU、MKU和OFU的季内变率相似,由风变率驱动为一级。MKU和SCU是由稳定的海洋动力(先东北后东的边界流)引起的,混沌变率很小。OIV对OFU的影响更大。7月,OFU主要沿东急流北侧发展。OIV的影响是最强的,并且与喷流经向位置的混沌变化有关。8月,该位置较为稳定,ofu主要在急流以北的正风旋度和气旋涡旋区发展。OIV的影响较7月减弱,与中尺度环流的组织有关。NCU表现出不同于在其他区域观察到的行为。在夏季中心,一个由东向急流和涡旋偶极子形成的大尺度环流很好地建立起来,一个沿岸流阻止了NCU的发展。在初夏和夏末,该环流较弱,使NCU地区形成强混沌性质的中尺度环流。在这些时期,OIV对NCU的影响非常强,并且与这种中尺度环流的组织有关:NCU被近海导向(沿岸)结构所青睐(湮灭)。
{"title":"Intraseasonal variability of the South Vietnam upwelling, South China Sea: influence of atmospheric forcing and ocean intrinsic variability","authors":"M. Herrmann, Thai To Duy, C. Estournel","doi":"10.5194/os-19-453-2023","DOIUrl":"https://doi.org/10.5194/os-19-453-2023","url":null,"abstract":"Abstract. The South Vietnam upwelling (SVU) develops off the Vietnamese coast (South\u0000China Sea, SCS) during the southwest summer monsoon over four main areas: the\u0000northern coastal upwelling (NCU), the southern coastal upwelling (SCU), the\u0000offshore upwelling (OFU) and the shelf off the Mekong River mouth (MKU). An\u0000ensemble of 10 simulations with perturbed initial conditions were run with\u0000the fine-resolution SYMPHONIE model (1 km inshore) to investigate the daily\u0000to intraseasonal variability of the SVU and the influence of the ocean\u0000intrinsic variability (OIV) during the strong SVU of summer 2018. The intraseasonal variability is similar for the SCU, MKU and OFU, driven to the\u0000first order by the wind variability. The MKU and SCU are induced by stable ocean\u0000dynamics (the northeastward then eastward boundary current) and have very\u0000little chaotic variability. The OIV has a stronger influence on OFU. In\u0000July, OFU mainly develops along the northern flank of the eastward jet. The\u0000influence of the OIV is strongest and related to the chaotic variability of the\u0000meridional position of the jet. In August, this position is stable and OFU\u0000develops mainly in the area of positive wind curl and cyclonic eddies north\u0000of the jet. The influence of the OIV, weaker than in July, is related to the\u0000organization of this mesoscale circulation. The NCU shows a behavior different\u0000from that observed in the other areas. In the heart of summer, a large-scale\u0000circulation formed by the eastward jet and eddy dipole is well established\u0000with an alongshore current preventing the NCU development. In early and late\u0000summer, this circulation is weaker, allowing a mesoscale circulation of\u0000strongly chaotic nature to develop in the NCU area. During those periods,\u0000the OIV influence on the NCU is very strong and related to the organization of\u0000this mesoscale circulation: the NCU is favored (annihilated) by\u0000offshore-oriented (alongshore) structures.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"38 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76822481","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}
引用次数: 0
A simple diagnostic based on sea surface height with an application to central Pacific ENSO 基于海面高度的简单诊断及其对中太平洋ENSO的应用
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-04-14 DOI: 10.5194/os-19-421-2023
Jufen Lai, R. Greatbatch, M. Claus
Abstract. We use output from a freely running NEMO model simulation for the equatorial Pacific to investigate the utility of linearly removing the local influence of vertical displacements of the thermocline from variations in sea surface height. We show that the resulting time series of residual sea surface height, denoted ηnlti, measures variations in near-surface heat content that are independent of the local vertical displacement of the thermocline and can arise from horizontal advection, surface heat flux, and diapycnal mixing processes. We find that the variance of ηnlti and its correlation with sea surface temperature are focused on the Niño4 region. Furthermore, ηnlti averaged over the Niño4 region is highly correlated with indices of central Pacific El Niño–Southern Oscillation (CP ENSO), and its variance in 21-year running windows shows a strong upward trend over the past 50 years, corresponding to the emergence of CP ENSO following the 1976/77 climate shift. We show that ηnlti can be estimated from observations, using satellite altimeter data and a linear multi-mode model. The time series of ηnlti, especially when estimated using the linear model, show pronounced westward propagation in the western equatorial Pacific, arguing for an important role for zonal advective feedback in the dynamics of CP ENSO, in particular for cold events. We also present evidence that the role of the thermocline displacement in influencing sea surface height increased strongly after 2000 in the eastern part of the Niño4 region, at a time when CP ENSO was particularly active. Finally, the diagnostic is easy to compute and can be easily applied to mooring data or coupled climate models.
摘要我们使用赤道太平洋自由运行的NEMO模型模拟的输出来研究线性消除海洋表面高度变化对温跃层垂直位移的局部影响的效用。结果表明,所得的剩余海面高度(ηnlti)时间序列测量了与温跃层局部垂直位移无关的近地表热含量的变化,这些变化可能由水平平流、地表热通量和底流混合过程引起。结果表明,ηnlti的变化及其与海温的相关性主要集中在Niño4区域。此外,Niño4地区的平均ηnlti与中太平洋El Niño-Southern涛动(CP ENSO)指数高度相关,其21年运行窗口的方差在过去50年中呈现出强烈的上升趋势,与1976/77年气候变化后CP ENSO的出现相对应。利用卫星高度计数据和线性多模态模型,我们可以从观测中估计出ηnlti。ηnlti的时间序列,特别是使用线性模式估计时,显示出赤道西太平洋明显的向西传播,表明纬向平流反馈在CP ENSO动力学中起重要作用,特别是在寒冷事件中。我们还提供证据表明,2000年以后,在Niño4区域东部,当CP ENSO特别活跃时,温跃层位移对海面高度的影响作用增强。最后,该诊断方法易于计算,可方便地应用于系泊数据或耦合气候模型。
{"title":"A simple diagnostic based on sea surface height with an application to central Pacific ENSO","authors":"Jufen Lai, R. Greatbatch, M. Claus","doi":"10.5194/os-19-421-2023","DOIUrl":"https://doi.org/10.5194/os-19-421-2023","url":null,"abstract":"Abstract. We use output from a freely running NEMO model simulation for the equatorial Pacific to investigate the utility of linearly removing the local influence of vertical displacements of the thermocline from variations in sea surface height. We show that the resulting time series of residual sea surface height, denoted ηnlti, measures variations in near-surface heat content that are independent of the local vertical displacement of the thermocline and can arise from horizontal advection, surface heat flux, and diapycnal mixing processes. We find that the variance of ηnlti and its correlation with sea surface temperature are focused on the Niño4 region. Furthermore, ηnlti averaged over the Niño4 region is highly correlated with indices of central Pacific El Niño–Southern Oscillation (CP ENSO), and its variance in 21-year running windows shows a strong upward trend over the past 50 years, corresponding to the emergence of CP ENSO following the 1976/77 climate shift. We show that ηnlti can be estimated from observations, using satellite altimeter data and a linear multi-mode model. The time series of ηnlti, especially when estimated using the linear model, show pronounced westward propagation in the western equatorial Pacific, arguing for an important role for zonal advective feedback in the dynamics of CP ENSO, in particular for cold events. We also present evidence that the role of the thermocline displacement in influencing sea surface height increased strongly after 2000 in the eastern part of the Niño4 region, at a time when CP ENSO was particularly active. Finally, the diagnostic is easy to compute and can be easily applied to mooring data or coupled climate models.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"64 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80836088","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}
引用次数: 0
The sensitivity of primary productivity in Disko Bay, a coastal Arctic ecosystem, to changes in freshwater discharge and sea ice cover 北极沿海生态系统迪斯科湾初级生产力对淡水流量和海冰覆盖变化的敏感性
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-04-05 DOI: 10.5194/os-19-403-2023
E. Møller, A. Christensen, J. Larsen, K. Mankoff, M. Ribergaard, Mikael K. Sejr, P. Wallhead, M. Maar
Abstract. The Greenland ice sheet is melting, and the rate of iceloss has increased 6-fold since the 1980s. At the same time, the Arctic seaice extent is decreasing. Meltwater runoff and sea ice reduction bothinfluence light and nutrient availability in the coastal ocean, withimplications for the timing, distribution, and magnitude of phytoplanktonproduction. However, the integrated effect of both glacial and sea ice meltis highly variable in time and space, making it challenging to quantify. Inthis study, we evaluate the relative importance of these processes for theprimary productivity of Disko Bay, west Greenland, one of the most importantareas for biodiversity and fisheries around Greenland. We use ahigh-resolution 3D coupled hydrodynamic–biogeochemical model for 2004–2018 validated against in situ observations and remote sensing products. The model-estimated net primary production (NPP) varied between 90–147 gC m−2 yr−1 during 2004–2018, a period with variable freshwater dischargesand sea ice cover. NPP correlated negatively with sea ice cover andpositively with freshwater discharge. Freshwater discharge had a stronglocal effect within ∼ 25 km of the source-sustaining productive hotspots during summer. When considering the annual NPP at bay scale, sea icecover was the most important controlling factor. In scenarios with no seaice in spring, the model predicted a ∼ 30 % increase in annualproduction compared to a situation with high sea ice cover. Our studyindicates that decreasing ice cover and more freshwater discharge can worksynergistically and will likely increase primary productivity of the coastalocean around Greenland.
摘要格陵兰冰盖正在融化,自20世纪80年代以来,冰盖融化的速度增加了6倍。与此同时,北极的海冰面积正在减少。融水径流和海冰减少都会影响沿海海洋的光照和养分有效性,从而影响浮游植物生产的时间、分布和规模。然而,冰川和海冰融化的综合影响在时间和空间上都是高度可变的,因此很难进行量化。在这项研究中,我们评估了这些过程对西格陵兰岛迪斯科湾初级生产力的相对重要性,迪斯科湾是格陵兰岛周围生物多样性和渔业最重要的地区之一。我们使用了2004-2018年高分辨率三维耦合水动力-生物地球化学模型,并根据现场观测和遥感产品进行了验证。在2004-2018年期间,模型估计的净初级产量(NPP)在90-147 gC m−2 yr−1之间变化,这是一个淡水排放量和海冰覆盖变化的时期。NPP与海冰覆盖负相关,与淡水流量正相关。夏季,淡水流量在维持水源的生产热点约25公里范围内具有强烈的局部效应。在海湾尺度上考虑年NPP时,海冰覆盖是最重要的控制因子。在春季没有海冰的情况下,该模型预测,与海冰覆盖率高的情况相比,年产量将增加~ 30%。我们的研究表明,减少冰覆盖和增加淡水排放可以协同工作,并可能提高格陵兰岛周围沿海海洋的初级生产力。
{"title":"The sensitivity of primary productivity in Disko Bay, a coastal Arctic ecosystem, to changes in freshwater discharge and sea ice cover","authors":"E. Møller, A. Christensen, J. Larsen, K. Mankoff, M. Ribergaard, Mikael K. Sejr, P. Wallhead, M. Maar","doi":"10.5194/os-19-403-2023","DOIUrl":"https://doi.org/10.5194/os-19-403-2023","url":null,"abstract":"Abstract. The Greenland ice sheet is melting, and the rate of ice\u0000loss has increased 6-fold since the 1980s. At the same time, the Arctic sea\u0000ice extent is decreasing. Meltwater runoff and sea ice reduction both\u0000influence light and nutrient availability in the coastal ocean, with\u0000implications for the timing, distribution, and magnitude of phytoplankton\u0000production. However, the integrated effect of both glacial and sea ice melt\u0000is highly variable in time and space, making it challenging to quantify. In\u0000this study, we evaluate the relative importance of these processes for the\u0000primary productivity of Disko Bay, west Greenland, one of the most important\u0000areas for biodiversity and fisheries around Greenland. We use a\u0000high-resolution 3D coupled hydrodynamic–biogeochemical model for 2004–2018 validated against in situ observations and remote sensing products. The model-estimated net primary production (NPP) varied between 90–147 gC m−2 yr−1 during 2004–2018, a period with variable freshwater discharges\u0000and sea ice cover. NPP correlated negatively with sea ice cover and\u0000positively with freshwater discharge. Freshwater discharge had a strong\u0000local effect within ∼ 25 km of the source-sustaining productive hot\u0000spots during summer. When considering the annual NPP at bay scale, sea ice\u0000cover was the most important controlling factor. In scenarios with no sea\u0000ice in spring, the model predicted a ∼ 30 % increase in annual\u0000production compared to a situation with high sea ice cover. Our study\u0000indicates that decreasing ice cover and more freshwater discharge can work\u0000synergistically and will likely increase primary productivity of the coastal\u0000ocean around Greenland.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"37 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77742928","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}
引用次数: 2
Water mass transformation variability in the Weddell Sea in ocean reanalyses 海洋再分析中威德尔海的水团转化变率
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-04-04 DOI: 10.5194/os-19-381-2023
Shanice Bailey, S. Jones, R. Abernathey, A. Gordon, X. Yuan
Abstract. This study investigates the variability of water mass transformation (WMT) within the Weddell Gyre (WG).The WG serves as a pivotal site for the Meridional Overturning Circulation (MOC) and ocean ventilation because it is the primary origin of the largest volume of water mass in the global ocean: Antarctic Bottom Water (AABW).Recent mooring data suggest substantial seasonal and interannual variability of AABW properties exiting the WG, and studies have linked the variability to the large-scale climate forcings affecting wind stress in the WG region.However, the specific thermodynamic mechanisms that link variability in surface forcings to variability in water mass transformations and AABW export remain unclear.This study explores how current state-of-the-art data-assimilating ocean reanalyses can help fill the gaps in our understanding of the thermodynamic drivers of AABW variability in the WG via WMT volume budgets derived from Walin's classic WMT framework. The three ocean reanalyses used are the following: Estimating the Circulation and Climate of the Ocean state estimate (ECCOv4), Southern Ocean State Estimate (SOSE) and Simple Ocean Data Assimilation (SODA).From the model outputs, we diagnose a closed form of the water mass budget for AABW that explicitly accounts for transport across the WG boundary, surface forcing, interior mixing and numerical mixing.We examine the annual mean climatology of the WMT budget terms, the seasonal climatology and finally the interannual variability. Our finding suggests that the relatively coarse resolution of these models did not realistically capture AABW formation, export and variability.In ECCO and SOSE, we see strong interannual variability in AABW volume budget.In SOSE, we find an accelerating loss of AABW during 2005–2010, driven largely by interior mixing and changes in surface salt fluxes.ECCO shows a similar trend during a 4-year time period starting in late 2007 but also reveals such trends to be part of interannual variability over a much longer time period.Overall, ECCO provides the most useful time series for understanding the processes and mechanisms that drive WMT and export variability in the WG.SODA, in contrast, displays unphysically large variability in AABW volume, which we attribute to its data assimilation scheme.We also examine correlations between the WMT budgets and large-scale climate indices, including El Niño–Southern Oscillation (ENSO) and Southern Annular Mode (SAM), and find no strong relationships.
摘要本文研究了威德尔环流(WG)内水团转化(WMT)的变异性。WG是经向翻转环流(MOC)和海洋通风的关键站点,因为它是全球海洋中最大体积的水质量的主要来源:南极底水(AABW)。最近的系泊数据表明,离开WG的AABW属性存在大量的季节和年际变化,并且研究将这种变化与影响WG地区风应力的大尺度气候强迫联系起来。然而,将地表强迫的变异性与水质量转化和AABW输出的变异性联系起来的具体热力学机制仍不清楚。本研究探讨了当前最先进的数据同化海洋再分析如何通过从Walin的经典WMT框架中得出的WMT体积预算,帮助填补我们对WG中AABW变率的热力学驱动因素的理解空白。使用的三种海洋再分析是:估计环流和气候的海洋状态估计(ecco4)、南大洋状态估计(SOSE)和简单海洋资料同化(SODA)。从模型输出中,我们诊断出AABW的水质量预算的封闭形式,该形式明确地考虑了跨WG边界的输送、地表强迫、内部混合和数值混合。我们考察了WMT预算项的年平均气候学、季节气候学和年际变率。我们的发现表明,这些模型相对粗糙的分辨率并不能真实地捕捉到AABW的形成、输出和变化。在ECCO和sse中,我们看到AABW体积预算的年际变化很强。在SOSE,我们发现2005-2010年间AABW的加速损失,主要是由内部混合和地表盐通量的变化驱动的。ECCO在2007年末开始的4年期间显示了类似的趋势,但也表明这种趋势是年际变率的一部分,而且时间更长。总的来说,ECCO为理解驱动WMT的过程和机制提供了最有用的时间序列,并在WG中导出可变性。相比之下,SODA在AABW体积上表现出非物理上的大变异性,我们将其归因于其数据同化方案。我们还研究了WMT预算与大尺度气候指数(包括El Niño-Southern涛动(ENSO)和南环模(SAM))之间的相关性,发现没有很强的相关性。
{"title":"Water mass transformation variability in the Weddell Sea in ocean reanalyses","authors":"Shanice Bailey, S. Jones, R. Abernathey, A. Gordon, X. Yuan","doi":"10.5194/os-19-381-2023","DOIUrl":"https://doi.org/10.5194/os-19-381-2023","url":null,"abstract":"Abstract. This study investigates the variability of water mass transformation (WMT) within the Weddell Gyre (WG).\u0000The WG serves as a pivotal site for the Meridional Overturning Circulation (MOC) and ocean ventilation because it is the primary origin of the largest volume of water mass in the global ocean: Antarctic Bottom Water (AABW).\u0000Recent mooring data suggest substantial seasonal and interannual variability of AABW properties exiting the WG, and studies have linked the variability to the large-scale climate forcings affecting wind stress in the WG region.\u0000However, the specific thermodynamic mechanisms that link variability in surface forcings to variability in water mass transformations and AABW export remain unclear.\u0000This study explores how current state-of-the-art data-assimilating ocean reanalyses can help fill the gaps in our understanding of the thermodynamic drivers of AABW variability in the WG via WMT volume budgets derived from Walin's classic WMT framework. The three ocean reanalyses used are the following: Estimating the Circulation and Climate of the Ocean state estimate (ECCOv4), Southern Ocean State Estimate (SOSE) and Simple Ocean Data Assimilation (SODA).\u0000From the model outputs, we diagnose a closed form of the water mass budget for AABW that explicitly accounts for transport across the WG boundary, surface forcing, interior mixing and numerical mixing.\u0000We examine the annual mean climatology of the WMT budget terms, the seasonal climatology and finally the interannual variability. Our finding suggests that the relatively coarse resolution of these models did not realistically capture AABW formation, export and variability.\u0000In ECCO and SOSE, we see strong interannual variability in AABW volume budget.\u0000In SOSE, we find an accelerating loss of AABW during 2005–2010, driven largely by interior mixing and changes in surface salt fluxes.\u0000ECCO shows a similar trend during a 4-year time period starting in late 2007 but also reveals such trends to be part of interannual variability over a much longer time period.\u0000Overall, ECCO provides the most useful time series for understanding the processes and mechanisms that drive WMT and export variability in the WG.\u0000SODA, in contrast, displays unphysically large variability in AABW volume, which we attribute to its data assimilation scheme.\u0000We also examine correlations between the WMT budgets and large-scale climate indices, including El Niño–Southern Oscillation (ENSO) and Southern Annular Mode (SAM), and find no strong relationships.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"64 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86881468","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}
引用次数: 0
Global submesoscale diagnosis using along-track satellite altimetry 利用轨道卫星测高技术进行全球亚中尺度气象诊断
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-03-31 DOI: 10.5194/os-19-363-2023
O. Vergara, R. Morrow, M. Pujol, G. Dibarboure, C. Ubelmann
Abstract. The ocean's sea surface height (SSH) field is a complex mix of motions ingeostrophic balance and unbalanced motions including high-frequency tides,internal tides, and internal gravity waves. Barotropic tides are wellestimated for altimetric SSH in the open ocean, but the SSH signals ofinternal tides remain. The transition scale,Lt, at which these unbalancedageostrophic motions dominate balanced geostrophic motions is estimatedforthe first time using satellite altimetry. Lt is critical todefine thespatial scales above which surface geostrophic currents can be inferredfromSSH gradients. We use a statistical approach based on the analysis of 1 Hzaltimetric SSH wavenumber spectra to obtain four geophysical parametersthatvary regionally and seasonally: the background error, the spectral slope inthe mesoscale range, a second spectral slope at smaller scales, andLt. Themesoscale slope and error levels are similar to previous studies based onsatellite altimetry. The break in the wavenumber spectra to a flatterspectral slope can only be estimated in midlatitude regions where thesignal exceeds the altimetric noise level. Small values of Ltare observedin regions of energetic mesoscale activity, while larger values areobservedtowards low latitudes and regions of lower mesoscale activity. Theseresultsare consistent with recent analyses of in situ observations andhigh-resolution models. Limitations of our results and implications forreprocessed nadir and future swath altimetric missions are discussed.
摘要海洋的海面高度场是一个复杂的运动混合体,包括高频潮汐、内部潮汐和内部重力波等运动。正压潮可以很好地估计出公海的高度计超高温,但内部潮汐的超高温信号仍然存在。利用卫星测高首次估算了这些不平衡地转运动支配平衡地转运动的过渡尺度Lt。定义空间尺度是至关重要的,在空间尺度之上,地表地转流可以从mssh梯度推断出来。通过对1赫兹高程短波波数光谱的分析,采用统计方法得到了背景误差、中尺度光谱斜率、小尺度第二次光谱斜率和高程光谱等4个具有区域和季节变化特征的地球物理参数。中尺度坡度和误差水平与以前基于卫星测高的研究相似。只有在中纬度地区,当信号超过高程噪声电平时,才能估计波数谱向平坦谱斜率的断裂。在中尺度活动强烈的区域观测到较小的温度值,而在低纬度和中尺度活动较低的区域观测到较大的温度值。这些结果与最近对原位观测和高分辨率模型的分析一致。讨论了我们的研究结果的局限性和重新处理的最低点和未来的条带测高任务的意义。
{"title":"Global submesoscale diagnosis using along-track satellite altimetry","authors":"O. Vergara, R. Morrow, M. Pujol, G. Dibarboure, C. Ubelmann","doi":"10.5194/os-19-363-2023","DOIUrl":"https://doi.org/10.5194/os-19-363-2023","url":null,"abstract":"Abstract. The ocean's sea surface height (SSH) field is a complex mix of motions in\u0000geostrophic balance and unbalanced motions including high-frequency tides,\u0000internal tides, and internal gravity waves. Barotropic tides are well\u0000estimated for altimetric SSH in the open ocean, but the SSH signals of\u0000internal tides remain. The transition scale,\u0000Lt, at which these unbalanced\u0000ageostrophic motions dominate balanced geostrophic motions is estimated\u0000for\u0000the first time using satellite altimetry. Lt is critical to\u0000define the\u0000spatial scales above which surface geostrophic currents can be inferred\u0000from\u0000SSH gradients. We use a statistical approach based on the analysis of 1 Hz\u0000altimetric SSH wavenumber spectra to obtain four geophysical parameters\u0000that\u0000vary regionally and seasonally: the background error, the spectral slope in\u0000the mesoscale range, a second spectral slope at smaller scales, and\u0000Lt. The\u0000mesoscale slope and error levels are similar to previous studies based on\u0000satellite altimetry. The break in the wavenumber spectra to a flatter\u0000spectral slope can only be estimated in midlatitude regions where the\u0000signal exceeds the altimetric noise level. Small values of Lt\u0000are observed\u0000in regions of energetic mesoscale activity, while larger values are\u0000observed\u0000towards low latitudes and regions of lower mesoscale activity. These\u0000results\u0000are consistent with recent analyses of in situ observations and\u0000high-resolution models. Limitations of our results and implications for\u0000reprocessed nadir and future swath altimetric missions are discussed.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"73 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83731831","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}
引用次数: 4
The signature of NAO and EA climate patterns on the vertical structure of the Canary Current upwelling system NAO和EA气候模式对加那利海流上升流系统垂直结构的影响
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-03-30 DOI: 10.5194/os-19-351-2023
Tina Georg, M. C. Neves, P. Relvas
Abstract. The current study aims to analyse the vertical structureof the ocean during upwelling events using in situ and modelled data.Additionally, the influence of climate patterns, namely the North AtlanticOscillation (NAO) and the East Atlantic (EA) pattern, on the verticalstructure and their impact on the upwelling activity are assessed for aperiod of 25 years (1993–2017). The study focuses on the central part ofthe Canary Current (25–35∘ N) with persistent upwellingthroughout the year, with an annual cycle and the strongest events from June toSeptember. Upwelling is determined using two different approaches: one index iscalculated based on temperature differences between the coastal and theoffshore area, and the other is calculated based on wind data and the resulting Ekmantransport. Different datasets were chosen according to the indices. Stable coastal upwelling can be observed in the study area for the analysedtime span, with differences throughout the latitudes. A deepening of theisothermal layer depth and a cooling of temperatures are observed in thevertical structure of coastal waters, representing a deeper mixing of theocean and the rise of cooler, denser water towards the surface. During years of a positive NAO, corresponding to a strengthening of theAzores High and the Icelandic Low, stronger winds lead to an intensificationof the upwelling activity, an enhanced mixing of the upper ocean, and adeeper (shallower) isothermal layer along the coast (offshore). The oppositeis observed in years of negative NAO. Both effects are enhanced in yearswith a coupled, opposite phase of the EA pattern and are mainly visibleduring winter months, where the effect of both indices is the greatest. The study therefore suggests that upwelling activities are stronger in winters ofpositive North Atlantic Oscillation coupled with a negative East Atlanticpattern and emphasizes the importance of interactions between the climatepatterns and upwelling.
摘要目前的研究旨在利用现场和模拟数据分析上升流事件期间海洋的垂直结构。此外,评估了25年(1993-2017)期间北大西洋涛动(NAO)和东大西洋(EA)气候模式对垂直结构的影响及其对上升流活动的影响。这项研究的重点是金丝雀海流(25-35°N)的中部,该海流全年持续上涌,每年循环一次,6月至9月是最强的一次。上升流是用两种不同的方法来确定的:一种是根据沿海和近海地区之间的温差来计算的,另一种是根据风数据和由此产生的埃克曼运输来计算的。根据指标选择不同的数据集。在分析的时间跨度内,研究区可以观测到稳定的海岸上升流,但各纬度存在差异。在沿海水域的垂直结构中观察到等温层深度的加深和温度的冷却,这表明海洋的深度混合和较冷、密度较大的水向表面上升。在正的NAO期间,对应于亚速尔高压和冰岛低压的增强,强风导致上升流活动的增强,上层海洋的混合增强,以及沿海(近海)更深(更浅)的等温层。相反,在负NAO年份观察到。这两种效应都在EA型相相反的年份中增强,并且主要在冬季月份可见,在冬季两个指数的影响最大。因此,该研究表明,在北大西洋正振荡与东大西洋负振荡相结合的冬季,上升流活动更强,并强调了气候模式与上升流之间相互作用的重要性。
{"title":"The signature of NAO and EA climate patterns on the vertical structure of the Canary Current upwelling system","authors":"Tina Georg, M. C. Neves, P. Relvas","doi":"10.5194/os-19-351-2023","DOIUrl":"https://doi.org/10.5194/os-19-351-2023","url":null,"abstract":"Abstract. The current study aims to analyse the vertical structure\u0000of the ocean during upwelling events using in situ and modelled data.\u0000Additionally, the influence of climate patterns, namely the North Atlantic\u0000Oscillation (NAO) and the East Atlantic (EA) pattern, on the vertical\u0000structure and their impact on the upwelling activity are assessed for a\u0000period of 25 years (1993–2017). The study focuses on the central part of\u0000the Canary Current (25–35∘ N) with persistent upwelling\u0000throughout the year, with an annual cycle and the strongest events from June to\u0000September. Upwelling is determined using two different approaches: one index is\u0000calculated based on temperature differences between the coastal and the\u0000offshore area, and the other is calculated based on wind data and the resulting Ekman\u0000transport. Different datasets were chosen according to the indices. Stable coastal upwelling can be observed in the study area for the analysed\u0000time span, with differences throughout the latitudes. A deepening of the\u0000isothermal layer depth and a cooling of temperatures are observed in the\u0000vertical structure of coastal waters, representing a deeper mixing of the\u0000ocean and the rise of cooler, denser water towards the surface. During years of a positive NAO, corresponding to a strengthening of the\u0000Azores High and the Icelandic Low, stronger winds lead to an intensification\u0000of the upwelling activity, an enhanced mixing of the upper ocean, and a\u0000deeper (shallower) isothermal layer along the coast (offshore). The opposite\u0000is observed in years of negative NAO. Both effects are enhanced in years\u0000with a coupled, opposite phase of the EA pattern and are mainly visible\u0000during winter months, where the effect of both indices is the greatest. The study therefore suggests that upwelling activities are stronger in winters of\u0000positive North Atlantic Oscillation coupled with a negative East Atlantic\u0000pattern and emphasizes the importance of interactions between the climate\u0000patterns and upwelling.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"34 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88013914","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}
引用次数: 1
Surface circulation in the Gulf of Thailand from remotely sensed observations: seasonal and interannual timescales 来自遥感观测的泰国湾地面环流:季节和年际时间尺度
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-03-30 DOI: 10.5194/os-19-335-2023
A. Anutaliya
Abstract. The Gulf of Thailand (GoT), a shallow semi-enclosed basin located in the western equatorial Pacific, undergoes much wind variabilities on both seasonal and interannual timescales that produce complex surface circulation. The local Ekman pumping modifies sea level in the northern GoT, while remote wind forcing influences sea level variability at the GoT western boundary, potentially through the coastal trapped Kelvin waves. The importance of the Ekman current on ageostrophic current is also important; the stronger influence of the Ekman current is found toward the southern part of the GoT. The GoT circulation reverses its direction seasonally following the monsoon wind reversal which is well-captured by the most dominant complex empirical orthogonal function explaining 28 % of the total circulation variance. During the monsoon transition, a strong meridional current along the western boundary that connects to the flow at the GoT southeastern entrance is observed. This implies high exchange between the GoT and the South China Sea and thus modification of the GoT water. On the interannual timescale, the GoT circulation is directly impacted by both the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). Interestingly, the two climate modes have different spatial influences on the GoT circulation. The IOD dominates the interannual current along the GoT western boundary and the southern boundary of the observing domain (8∘ N), while the ENSO correlates with that in the interior. The results highlight the complex circulation pattern as being contributed by different dynamics over each region of the GoT.
摘要泰国湾(GoT)是位于赤道西太平洋的一个浅半封闭盆地,在季节和年际时间尺度上都经历了很多风的变化,产生了复杂的地面环流。局地的Ekman泵送改变了北半球的海平面,而遥远的风强迫可能通过沿海被困的开尔文波影响北半球西部边界的海平面变化。埃克曼流对地转流的重要性也很重要;埃克曼海流的影响更强的方向是赤道以南。随着季风的反转,GoT环流的方向发生了季节性的反转,这被最主要的复杂经验正交函数很好地捕获,解释了总环流方差的28%。在季风过渡期间,观察到沿西部边界有一股强经向气流,与东南入口气流相连。这意味着GoT和南海之间的高交换,从而改变了GoT水。在年际尺度上,大气环流受到El Niño-Southern涛动(ENSO)和印度洋偶极子(IOD)的直接影响。有趣的是,两种气候模态对GoT环流有不同的空间影响。观测区(8°N)西边界和南边界的年际流主要由IOD主导,而内部的年际流主要由ENSO主导。结果表明,复杂的环流模式是由GoT各区域的不同动力所造成的。
{"title":"Surface circulation in the Gulf of Thailand from remotely sensed observations: seasonal and interannual timescales","authors":"A. Anutaliya","doi":"10.5194/os-19-335-2023","DOIUrl":"https://doi.org/10.5194/os-19-335-2023","url":null,"abstract":"Abstract. The Gulf of Thailand (GoT), a shallow semi-enclosed basin located in the western equatorial Pacific, undergoes much wind variabilities on both seasonal and interannual timescales that produce complex surface circulation. The local Ekman pumping modifies sea level in the northern GoT, while remote wind forcing influences sea level variability at the GoT western boundary, potentially through the coastal trapped Kelvin waves. The importance of the Ekman current on ageostrophic current is also important; the stronger influence of the Ekman current is found toward the southern part of the GoT. The GoT circulation reverses its direction seasonally following the monsoon wind reversal which is well-captured by the most dominant complex empirical orthogonal function explaining 28 % of the total circulation variance. During the monsoon transition, a strong meridional current along the western boundary that connects to the flow at the GoT southeastern entrance is observed. This implies high exchange between the GoT and the South China Sea and thus modification of the GoT water. On the interannual timescale, the GoT circulation is directly impacted by both the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). Interestingly, the two climate modes have different spatial influences on the GoT circulation. The IOD dominates the interannual current along the GoT western boundary and the southern boundary of the observing domain (8∘ N), while the ENSO correlates with that in the interior. The results highlight the complex circulation pattern as being contributed by different dynamics over each region of the GoT.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"46 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79673234","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}
引用次数: 1
Revisiting the global mean ocean mass budget over 2005–2020 回顾2005-2020年全球平均海洋质量预算
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-03-23 DOI: 10.5194/os-19-321-2023
A. Barnoud, J. Pfeffer, A. Cazenave, Robin Fraudeau, V. Rousseau, M. Ablain
Abstract. We investigate the performances of Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) satellite gravimetry missions in assessing the ocean mass budget at the global scale over 2005–2020. For that purpose, we focus on the last years of the record (2015–2020) when GRACE and GRACE Follow-On faced instrumental problems. We compare the global mean ocean mass estimates from GRACE and GRACE Follow-On to the sum of its contributions from Greenland, Antarctica, land glaciers, terrestrial water storage and atmospheric water content estimated with independent observations. Significant residuals are observed in the global mean ocean mass budget at interannual timescales. Our analyses suggest that the terrestrial water storage variations based on global hydrological models likely contribute in large part to the misclosure of the global mean ocean mass budget at interannual timescales. We also compare the GRACE-based global mean ocean mass with the altimetry-based global mean sea level corrected for the Argo-based thermosteric contribution (an equivalent of global mean ocean mass). After correcting for the wet troposphere drift of the radiometer on board the Jason-3 altimeter satellite, we find that mass budget misclosure is reduced but still significant. However, replacing the Argo-based thermosteric component by the Ocean Reanalysis System 5 (ORAS5) or from the Clouds and the Earth's Radiant Energy System (CERES) top of the atmosphere observations significantly reduces the residuals of the mass budget over the 2015–2020 time span. We conclude that the two most likely sources of error in the global mean ocean mass budget are the thermosteric component based on Argo and the terrestrial water storage contribution based on global hydrological models. The GRACE and GRACE Follow-On data are unlikely to be responsible on their own for the non-closure of the global mean ocean mass budget.
摘要研究了重力恢复与气候实验(GRACE)和GRACE后续卫星重力测量任务(GRACE- fo)在2005-2020年全球尺度海洋质量预算评估中的表现。为此,我们将重点放在GRACE和GRACE后续项目面临仪器问题的最后几年(2015-2020年)。我们将GRACE和GRACE Follow-On估算的全球平均海洋质量与独立观测估算的格陵兰岛、南极洲、陆地冰川、陆地储水和大气含水量的贡献之和进行了比较。在年际时间尺度上观测到全球平均海洋质量收支的显著残差。我们的分析表明,基于全球水文模型的陆地储水量变化可能在很大程度上导致年际时间尺度上全球平均海洋质量收支的误闭合。我们还比较了基于grace的全球平均海洋质量与基于argo的热阻贡献校正的基于海拔的全球平均海平面(相当于全球平均海洋质量)。在对Jason-3高度计卫星上的辐射计的湿对流层漂移进行校正后,发现质量预算误闭有所减少,但仍然很明显。然而,用海洋再分析系统5 (ORAS5)或云和地球辐射能系统(CERES)的大气观测数据取代基于argo的热静态分量,将大大减少2015-2020年期间质量预算的剩余。我们得出结论,全球平均海洋质量收支的两个最可能的误差来源是基于Argo的热阻分量和基于全球水文模型的陆地储水贡献。GRACE和GRACE后续数据本身不太可能对全球平均海洋质量预算不闭合负责。
{"title":"Revisiting the global mean ocean mass budget over 2005–2020","authors":"A. Barnoud, J. Pfeffer, A. Cazenave, Robin Fraudeau, V. Rousseau, M. Ablain","doi":"10.5194/os-19-321-2023","DOIUrl":"https://doi.org/10.5194/os-19-321-2023","url":null,"abstract":"Abstract. We investigate the performances of Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) satellite gravimetry missions in assessing the ocean mass budget at the global scale over 2005–2020. For that purpose, we focus on the last years of the record (2015–2020) when GRACE and GRACE Follow-On faced instrumental problems. We compare the global mean ocean mass estimates from GRACE and GRACE Follow-On to the sum of its contributions from Greenland, Antarctica, land glaciers, terrestrial water storage and atmospheric water content estimated with independent observations. Significant residuals are observed in the global mean ocean mass budget at interannual timescales. Our analyses suggest that the terrestrial water storage variations based on global hydrological models likely contribute in large part to the misclosure of the global mean ocean mass budget at interannual timescales. We also compare the GRACE-based global mean ocean mass with the altimetry-based global mean sea level corrected for the Argo-based thermosteric contribution (an equivalent of global mean ocean mass). After correcting for the wet troposphere drift of the radiometer on board the Jason-3 altimeter satellite, we find that mass budget misclosure is reduced but still significant. However, replacing the Argo-based thermosteric component by the Ocean Reanalysis System 5 (ORAS5) or from the Clouds and the Earth's Radiant Energy System (CERES) top of the atmosphere observations significantly reduces the residuals of the mass budget over the 2015–2020 time span. We conclude that the two most likely sources of error in the global mean ocean mass budget are the thermosteric component based on Argo and the terrestrial water storage contribution based on global hydrological models. The GRACE and GRACE Follow-On data are unlikely to be responsible on their own for the non-closure of the global mean ocean mass budget.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"45 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84140028","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}
引用次数: 2
Effects of including the adjoint sea ice rheology on estimating Arctic Ocean–sea ice state 纳入伴随海冰流变对估算北冰洋-海冰状态的影响
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-03-17 DOI: 10.5194/os-19-305-2023
G. Lyu, Armin Koehl, Xinrong Wu, Meng Zhou, D. Stammer
Abstract. The adjoint assimilation method has been applied to coupled ocean and sea ice models for sensitivity studies and Arctic state estimations. However, the accuracy of the adjoint model is degraded by simplifications of the adjoint of the sea ice model, especially the adjoint sea ice rheologies. As part of ongoing developments in coupled ocean and sea ice estimation systems, we incorporate and approximate the adjoint of viscous-plastic sea ice dynamics (adjoint-VP) and compare it with the adjoint of free-drift sea ice dynamics (adjoint-FD) through assimilation experiments. Using the adjoint-VP results in a further cost reduction of 7.9 % in comparison to adjoint-FD, with noticeable improvements in the ocean temperature over the open water and the intermediate layers of the Arctic Ocean. Adjoint-VP adjusts the model input more efficiently than adjoint-FD does by involving different sea ice retreat processes. For instance, adjoint-FD melts the sea ice up to 1.0 m in the marginal seas from May to June by overadjusting air temperature (>8 ∘C); adjoint-VP reproduces the sea ice retreat with smaller adjustments to the atmospheric state within their prior uncertainty range. These developments of the adjoint model here lay the foundation for further improving Arctic Ocean and sea ice estimations by comprehensively adjusting the initial conditions, atmospheric forcings, and parameters of the model.
摘要伴随同化方法已应用于耦合海洋和海冰模型的敏感性研究和北极状态估计。然而,伴随模式的精度由于对伴随模式的简化而降低,尤其是伴随海冰流变。作为海洋和海冰耦合估计系统持续发展的一部分,我们合并并近似粘塑性海冰动力学的伴随(伴随vp),并通过同化实验将其与自由漂移海冰动力学的伴随(伴随fd)进行比较。与伴随式fd相比,使用伴随式vp可进一步降低7.9%的成本,并显著改善了北冰洋开放水域和中间层的海洋温度。通过引入不同的海冰退缩过程,联合vp比联合fd更有效地调整模型输入。例如,从5月到6月,联合fd通过过度调节气温(bbb80°C)使边缘海域的海冰融化1.0米;伴随vp在其先前的不确定性范围内对大气状态进行较小的调整后再现了海冰退缩。伴随模式的这些发展为通过综合调整模式的初始条件、大气强迫和参数进一步改进北冰洋和海冰估算奠定了基础。
{"title":"Effects of including the adjoint sea ice rheology on estimating Arctic Ocean–sea ice state","authors":"G. Lyu, Armin Koehl, Xinrong Wu, Meng Zhou, D. Stammer","doi":"10.5194/os-19-305-2023","DOIUrl":"https://doi.org/10.5194/os-19-305-2023","url":null,"abstract":"Abstract. The adjoint assimilation method has been applied to coupled ocean and sea ice models for sensitivity studies and Arctic state estimations. However, the accuracy of the adjoint model is degraded by simplifications of the adjoint of the sea ice model, especially the adjoint sea ice rheologies. As part of ongoing developments in coupled ocean and sea ice estimation systems, we incorporate and approximate the adjoint of viscous-plastic sea ice dynamics (adjoint-VP) and compare it with the adjoint of free-drift sea ice dynamics (adjoint-FD) through assimilation experiments. Using the adjoint-VP results in a further cost reduction of 7.9 % in comparison to adjoint-FD, with noticeable improvements in the ocean temperature over the open water and the intermediate layers of the Arctic Ocean. Adjoint-VP adjusts the model input more efficiently than adjoint-FD does by involving different sea ice retreat processes. For instance, adjoint-FD melts the sea ice up to 1.0 m in the marginal seas from May to June by overadjusting air temperature (>8 ∘C); adjoint-VP reproduces the sea ice retreat with smaller adjustments to the atmospheric state within their prior uncertainty range. These developments of the adjoint model here lay the foundation for further improving Arctic Ocean and sea ice estimations by comprehensively adjusting the initial conditions, atmospheric forcings, and parameters of the model.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"33 4 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88350976","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}
引用次数: 0
A numerical investigation on the energetics of a current along an ice-covered continental slope 沿冰层覆盖的大陆斜坡水流能量学的数值研究
IF 3.2 3区 地球科学 Q2 METEOROLOGY & ATMOSPHERIC SCIENCES Pub Date : 2023-03-14 DOI: 10.5194/os-19-289-2023
Hengling Leng, Hailun He, M. Spall
Abstract. The Chukchi Slope Current is a westward-flowing currentalong the Chukchi slope, which carries Pacific-origin water from the Chukchishelf into the Canada Basin and helps set the regional hydrographicstructure and ecosystem. Using a set of experiments with an idealizedprimitive equation numerical model, we investigate the energetics of theslope current during the ice-covered period. Numerical calculations showthat the growth of surface eddies is suppressed by the ice friction, whileperturbations at mid-depths can grow into eddies, consistent with linearinstability analysis. However, because the ice stress is spatially variable,it is able to drive Ekman pumping to decrease the available potential energy(APE) and kinetic energy of both the mean flow and mesoscale eddies over avertical scale of 100 m, well outside the frictional Ekman layer. The rateat which the APE changes is determined by the vertical density flux, whichis negative as the ice-induced Ekman pumping advects lighter (denser) waterupward (downward). A scaling analysis shows that Ekman pumping will dominatethe release of APE for large-scale flows, but the effect of baroclinicinstability is also important when the horizontal scale of the mean flow isthe baroclinic deformation radius and the eddy velocity is comparable to themean flow velocity. Our numerical results highlight the importance of icefriction in the energetics of the slope current and eddies, and this may berelevant to other ice-covered regions.
摘要楚科奇斜坡流是沿楚科奇斜坡向西流动的水流,它将来自楚科奇海架的太平洋水带入加拿大盆地,并有助于形成区域水文结构和生态系统。本文利用一组具有理想原始方程数值模型的实验,研究了冰期坡流的能量特性。数值计算表明,表面涡流的增长受到冰摩擦的抑制,而中深度的扰动可以发展成涡流,这与线性不稳定性分析一致。然而,由于冰应力在空间上是可变的,它能够驱动Ekman泵送,从而降低100 m垂直尺度上的平均流和中尺度涡旋的有效势能(APE)和动能,远远超出摩擦Ekman层。APE变化的速率由垂直密度通量决定,垂直密度通量为负,因为冰诱导的Ekman泵送将较轻(密度较大)的水向上(向下)平流。尺度分析表明,对于大尺度流动,Ekman泵送将主导APE的释放,但当平均流的水平尺度为斜压变形半径时,涡动速度与平均流速度相当时,斜压不稳定性的影响也很重要。我们的数值结果强调了冰摩擦在斜坡流和漩涡的能量学中的重要性,这可能与其他冰雪覆盖地区有关。
{"title":"A numerical investigation on the energetics of a current along an ice-covered continental slope","authors":"Hengling Leng, Hailun He, M. Spall","doi":"10.5194/os-19-289-2023","DOIUrl":"https://doi.org/10.5194/os-19-289-2023","url":null,"abstract":"Abstract. The Chukchi Slope Current is a westward-flowing current\u0000along the Chukchi slope, which carries Pacific-origin water from the Chukchi\u0000shelf into the Canada Basin and helps set the regional hydrographic\u0000structure and ecosystem. Using a set of experiments with an idealized\u0000primitive equation numerical model, we investigate the energetics of the\u0000slope current during the ice-covered period. Numerical calculations show\u0000that the growth of surface eddies is suppressed by the ice friction, while\u0000perturbations at mid-depths can grow into eddies, consistent with linear\u0000instability analysis. However, because the ice stress is spatially variable,\u0000it is able to drive Ekman pumping to decrease the available potential energy\u0000(APE) and kinetic energy of both the mean flow and mesoscale eddies over a\u0000vertical scale of 100 m, well outside the frictional Ekman layer. The rate\u0000at which the APE changes is determined by the vertical density flux, which\u0000is negative as the ice-induced Ekman pumping advects lighter (denser) water\u0000upward (downward). A scaling analysis shows that Ekman pumping will dominate\u0000the release of APE for large-scale flows, but the effect of baroclinic\u0000instability is also important when the horizontal scale of the mean flow is\u0000the baroclinic deformation radius and the eddy velocity is comparable to the\u0000mean flow velocity. Our numerical results highlight the importance of ice\u0000friction in the energetics of the slope current and eddies, and this may be\u0000relevant to other ice-covered regions.\u0000","PeriodicalId":19535,"journal":{"name":"Ocean Science","volume":"52 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82901230","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}
引用次数: 0
期刊
Ocean Science
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1