Journal of Physical Oceanography最新文献

Vertical Velocity Dynamics in the North Atlantic and Implications for AMOC 北大西洋垂直速度动力学及其对 AMOC 的影响

Journal of Physical Oceanography Pub Date : 2024-07-15 DOI: 10.1175/jpo-d-23-0229.1

N. Fraser, Alan Fox, Stuart A. Cunningham, Willi Rath, F. Schwarzkopf, Arne Biastoch

{"title":"Vertical Velocity Dynamics in the North Atlantic and Implications for AMOC","authors":"N. Fraser, Alan Fox, Stuart A. Cunningham, Willi Rath, F. Schwarzkopf, Arne Biastoch","doi":"10.1175/jpo-d-23-0229.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0229.1","url":null,"abstract":"\u0000The Atlantic meridional overturning circulation (MOC) is traditionally monitored in terms of zonally-integrated transport either in depth space or density space. While this view has the advantage of simplicity, it obscures the rich and complex three-dimensional structure, so that the exact physics of the downwelling and upwelling branch remains poorly understood. The near-equivalence of the depth- and density-space MOC in the subtropics suggests that vertical and diapycnal volumes transports are intimately coupled, whereas the divergence of these two metrics at higher latitudes indicates that any such coupling is neither instantaneous nor local. Previous work has characterised the surface buoyancy forcing and mixing processes which drive diapycnal volume transport. Here, we develop a new analytical decomposition of vertical volume transport based on the vorticity budget. We show that most terms can be estimated from observations, and provide additional insights from a high-resolution numerical simulation of the North Atlantic. Our analysis highlights the roles (1) of relative vorticity advection for the sinking of overflow water at the northern subpolar North Atlantic boundaries and (2) the geostrophic β-effect for the sinking of dense waters in the inter-gyre region. These results provide insights into the coupling between density- and depth-space overturning circulations.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"29 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141649343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","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 model for multiple equilibria in ice-covered oceans 冰封海洋多重平衡的简单模型

Journal of Physical Oceanography Pub Date : 2024-07-15 DOI: 10.1175/jpo-d-24-0022.1

M. Spall

引用次数: 0

Dynamics of bubble plumes produced by breaking waves 破浪产生的气泡羽流动力学

Journal of Physical Oceanography Pub Date : 2024-07-02 DOI: 10.1175/jpo-d-23-0261.1

D. Pelaez-Zapata, V. Pakrashi, Frédéric Dias

{"title":"Dynamics of bubble plumes produced by breaking waves","authors":"D. Pelaez-Zapata, V. Pakrashi, Frédéric Dias","doi":"10.1175/jpo-d-23-0261.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0261.1","url":null,"abstract":"\u0000Bubble plumes play a significant role in the air-sea interface by influencing processes such as air-sea gas exchange, aerosol production, modulation of oceanic carbon and nutrient cycles, and the vertical structure of the upper ocean. Using Acoustic Doppler Current Profiler (ADCP) data collected off the west coast of Ireland, we investigate the dynamics of bubble plumes and their relationship with sea state variables. In particular, we describe the patterns of bubble plumes vertical extension, duration and periodicity. We establish a power-law relationship between the average bubble penetration depth and wind speed, consistent with previous findings. Additionally, the study reveals a significant association between whitecapping coverage and observed acoustic volume backscatter intensity, underscoring the role of wave breaking in bubble plume generation. The shape of the probability distribution of bubble plume depths reveals a transition towards stronger and more organised bubble entrainment events during higher wind speeds. Furthermore, we show that deeper bubble plumes are associated with turbulent Langmuir number Lat∼ 0.3, highlighting the potential role of Langmuir circulation on the transport and deepening of bubble plumes. These results contribute to a better understanding of the complex interactions between ocean waves, wind, and bubble plumes, providing valuable insights for improving predictive models and enhancing our understanding of air-sea interactions.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"331 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141686531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Major Improvement of Atmospheric Wave Boundary Layer Model for Storm Surge Modeling by Including Effect of Wave Breaking on Air-Sea Momentum Exchange 通过纳入破浪对海气动量交换的影响，对用于风暴潮建模的大气波浪边界层模型进行重大改进

Journal of Physical Oceanography Pub Date : 2024-03-20 DOI: 10.1175/jpo-d-23-0233.1

Anyifang Zhang, Xiping Yu

{"title":"A Major Improvement of Atmospheric Wave Boundary Layer Model for Storm Surge Modeling by Including Effect of Wave Breaking on Air-Sea Momentum Exchange","authors":"Anyifang Zhang, Xiping Yu","doi":"10.1175/jpo-d-23-0233.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0233.1","url":null,"abstract":"\u0000Accurate estimation of the wind stress under extreme conditions is crucial for modeling storm surges and storm waves, which is important to the development of a warning system for coastal disaster prevention. The problem, however, is highly challenging owing to the presence of complex ocean surface processes under the action of unusually strong wind. In this study, the existing atmospheric wave boundary layer model is significantly enhanced by including various effects of wave breaking. Both the effect of wave breaking on the dissipation of energy and its effect on the transfer of momentum within the atmospheric boundary layer are carefully formulated. The wind stress coefficients obtained with the enhanced model are shown to be in good agreement with the measurements in not only deep but also shallow waters. The enhanced atmospheric wave boundary layer model is coupled with ocean wave as well as circulation models to simulate typhoon-induced storm surges and storm waves in the Pearl River Delta region. The computational results show that the coupled model with improved evaluation of the wind stress is substantially advantageous when compared with existing approaches.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"11 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140227325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the release and renewal of freshwater in the Beaufort Gyre of the Arctic Ocean 北冰洋波弗特环流淡水的释放和更新

Journal of Physical Oceanography Pub Date : 2024-03-20 DOI: 10.1175/jpo-d-23-0184.1

Qiang Wang

{"title":"On the release and renewal of freshwater in the Beaufort Gyre of the Arctic Ocean","authors":"Qiang Wang","doi":"10.1175/jpo-d-23-0184.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0184.1","url":null,"abstract":"\u0000The Arctic Beaufort Gyre plays a critical role for climate and marine ecosystems. This study investigates the response of the liquid freshwater in the Beaufort Gyre to various wind perturbations using numerical simulations. A new diagnostic call ‘freshwater renewal’ is introduced, which quantifies the amount of freshwater that has entered the Beaufort Gyre since a specific point in time. The findings reveal that the process of freshwater renewal is persistently efficient in the Beaufort Gyre region, occurring irrespective of the gyre’s status. The spatial distribution of freshwater renewal varies, influenced by factors such as wind forcing and gyre circulation patterns. Cyclonic wind perturbation associated with a negative Beaufort High sea level pressure anomaly triggers freshwater release from the Beaufort Gyre, with freshwater export and renewal dependent on wind perturbation locations and timescales. While some released Beaufort Gyre freshwater exits the Arctic Ocean through Davis and Fram straits, a considerable portion could remain within the Arctic Ocean for many years under specific conditions. Wind perturbation associated with the positive Arctic Oscillation enhances Arctic export of Beaufort Gyre freshwater, mainly through Fram Strait. The Arctic export of total freshwater and the Arctic export of the portion originating from the Beaufort Gyre have different timescales and magnitudes. Hence, it is essential to collectively examine different freshwater components in order to assess the role of Arctic export in the climate system.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"28 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140225991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Brazil Basin Tracer Release Experiment: Observations 巴西盆地示踪剂释放实验：观测结果

Journal of Physical Oceanography Pub Date : 2024-03-15 DOI: 10.1175/jpo-d-22-0249.1

James R. Ledwell (deceased)

{"title":"The Brazil Basin Tracer Release Experiment: Observations","authors":"James R. Ledwell (deceased)","doi":"10.1175/jpo-d-22-0249.1","DOIUrl":"https://doi.org/10.1175/jpo-d-22-0249.1","url":null,"abstract":"\u0000Lightening of bottom water is required to close the abyssal overturning circulation, believed to play an important role in the climate system. A tracer release experiment and turbulence measurement programs have revealed how bottom water is lightened, and illuminated the associated circulation in the deep Brazil Basin, a representative region of the global ocean. Tracer was released on an isopycnal surface about 4000 m deep, over one of the fracture zones emanating from the Mid-Atlantic Ridge (MAR). Tracer that mixed toward the bottom moved toward the MAR across isopycnal surfaces that bend down to intersect the bottom at a rate implying a near-bottom buoyancy flux of 1.5 × 10−9 m2/s3, somewhat larger than inferred from dissipation measurements. The diffusivity at the level of the tracer release is estimated at 4.4 ± 1 × 10−4 m2/s, again larger than inferred from dissipation rates.\u0000The main patch moved southwest at about 2 cm/s while sinking due to the divergence of buoyancy flux above the bottom layer. The isopycnal eddy diffusivity was about 100 m2/s. Westward flow away from the MAR is the return flow balancing the eastward near-bottom upslope flow. The southward component of the flow is roughly consistent with conservation of potential vorticity. The circulation as well as the pattern of diapycnal flux are qualitatively the same as in St. Laurent et al (2001) but are more robust. The results indicate that diapycnal diffusivity is about twice that invoked by Morris et al. (2001) in calculating the basin-wide buoyancy budget.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"122 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140238013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Assessing modelled mesoscale stirring using microscale observations 利用微观观测评估中尺度搅拌模型

Journal of Physical Oceanography Pub Date : 2024-03-13 DOI: 10.1175/jpo-d-23-0135.1

D. A. Cherian, Y. Guo, F. O. Bryan

{"title":"Assessing modelled mesoscale stirring using microscale observations","authors":"D. A. Cherian, Y. Guo, F. O. Bryan","doi":"10.1175/jpo-d-23-0135.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0135.1","url":null,"abstract":"\u0000We assess the representation of mesoscale stirring in a suite of models against an estimate derived from microstructure data collected during the North Atlantic Tracer Release Experiment (NATRE). We draw heavily from the approximate temperature variance budget framework of Ferrari and Polzin (2005, Journal of Physical Oceanography). This framework assumes two sources of temperature variance away from boundaries: first, the vertical stirring of the large-scale mean vertical gradient by small-scale turbulence; and second, the lateral stirring of large-scale mean along-isopycnal gradients by mesoscale eddies. Temperature variance so produced is transformed and on average transferred down scales for ultimate dissipation at the microscale at a rate χ estimated using microstructure observations. Ocean models represent these pathways by a vertical mixing parameterization, and an along-isopycnal lateral mixing parameterization (if needed). We assess the rate of variance production by the latter as a residual from the NATRE dataset, and compare against the parameterized representations in a suite of model simulations. We find that variance production due to lateral stirring in a POP2 1/10° simulation agrees well, to within the estimated error bars, with that inferred from the NATRE estimate. A POP2 1° simulation and the ECCOV4r4 simulation appear to dissipate an order of magnitude too much variance by applying a lateral diffusivity, when compared to the NATRE estimate, particularly below 1250 m. The ECCOV4r4 adjusted lateral diffusivities are elevated where the microstructure suggests elevated χ sourced from mesoscale stirring. Such elevated values are absent in other diffusivity estimates suggesting the possibility of compensating errors and caution in interpreting ECCOV4r4’s adjusted lateral diffusivities.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"7 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140244983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Eddy - Internal Wave Interactions: Stimulated Cascades in Cross-scale Kinetic Energy and Enstrophy Fluxes 涡-内波相互作用：跨尺度动能和营养通量的受激级联

Journal of Physical Oceanography Pub Date : 2024-03-12 DOI: 10.1175/jpo-d-23-0191.1

R. Barkan, K. Srinivasan, J. McWilliams

{"title":"Eddy - Internal Wave Interactions: Stimulated Cascades in Cross-scale Kinetic Energy and Enstrophy Fluxes","authors":"R. Barkan, K. Srinivasan, J. McWilliams","doi":"10.1175/jpo-d-23-0191.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0191.1","url":null,"abstract":"\u0000The interactions between oceanic mesoscale eddies, submesoscale currents, and internal gravity waves (IWs) are investigated in submesoscale resolving realistic simulations in the North Atlantic Ocean. Using a novel analysis framework that couples the coarse-graining method in space with temporal filtering and a Helmholtz decomposition, we quantify the effects of the interactions on the cross-scale kinetic energy (KE) and enstrophy fluxes. By systematically comparing solutions with and without IW forcing we show that externally-forced IWs stimulate a reduction in the KE inverse cascade associated with mesoscale rotational motions and an enhancement in the KE forward cascade associated with divergent submesoscale currents – i.e., a stimulated cascade process. The corresponding IW effects on the enstrophy fluxes are seasonally dependent, with a stimulated reduction (enhancement) in the forward enstrophy cascade during summer (winter). Direct KE and enstrophy transfers from currents to IWs are also found, albeit with weaker magnitudes compared with the stimulated cascades. We further find that the forward KE and enstrophy fluxes associated with IW motions are almost entirely driven by scattering of the waves by the rotational eddy field, rather than by wave-wave interactions. This process is investigated in detail in a companion manuscript. Finally, we demonstrate that the stimulated cascades are spatially localized in coherent structures. Specifically, the magnitude and direction of the bi-directional KE fluxes at submesoscales are highly correlated with, and inversely proportional to, divergence-dominated circulations, and the inverse KE fluxes at mesoscales are highly correlated with strain dominated circulations. The predominantly forward enstrophy fluxes in both seasons are also correlated with strain dominated flow structures.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"12 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140249037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The role of surface potential vorticity in the vertical structure of mesoscale eddies in wind-driven ocean circulations 表层势涡度在风驱动海洋环流中尺度涡旋垂直结构中的作用

Journal of Physical Oceanography Pub Date : 2024-03-11 DOI: 10.1175/jpo-d-23-0203.1

Wenda Zhang, S. Griffies, R. Hallberg, Yi-Hung Kuo, C. L. Wolfe

{"title":"The role of surface potential vorticity in the vertical structure of mesoscale eddies in wind-driven ocean circulations","authors":"Wenda Zhang, S. Griffies, R. Hallberg, Yi-Hung Kuo, C. L. Wolfe","doi":"10.1175/jpo-d-23-0203.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0203.1","url":null,"abstract":"\u0000The vertical structure of ocean eddies is generally surface-intensified, commonly attributed to the dominant baroclinic modes arising from the boundary conditions (BCs). Conventional BC considerations mostly focus on either flat- or rough-bottom conditions. The impact of surface buoyancy anomalies—often represented by surface potential vorticity (PV) anomalies—has not been fully explored. Here, we study the role of the surface PV in setting the vertical distribution of eddy kinetic energy (EKE) in an idealized adiabatic ocean model driven by wind stress. The simulated EKE profile in the extra-tropical ocean tends to peak at the surface and have an e-folding depth typically smaller than half of the ocean depth. This vertical structure can be reasonably represented by a single surface quasi-geostrophic (SQG) mode at the energy-containing scale resulting from the large-scale PV structure. Due to isopycnal outcropping and interior PV homogenization, the surface meridional PV gradient is substantially stronger than the interior PV gradient, yielding surface-trapped baroclinically unstable modes with horizontal scales comparable to or smaller than the deformation radius. These surface-trapped eddies then grow in size both horizontally and vertically through an inverse energy cascade up to the energy-containing scale, which dominates the vertical distribution of EKE. As for smaller horizontal scales, the EKE distribution decays faster with depth. Guided by this interpretation, an SQG-based scale-aware parameterization of the EKE profile is proposed. Preliminary offline diagnosis of a high-resolution simulation shows the proposed scheme successfully reproducing the dependence of the vertical structure of EKE on the horizontal grid resolution.","PeriodicalId":506940,"journal":{"name":"Journal of Physical Oceanography","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140253969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A Scale-aware Parameterization of Restratification Effect of Turbulent Thermal Wind Balance 湍动热风平衡的再卷积效应的尺度感知参数化

Journal of Physical Oceanography Pub Date : 2024-03-11 DOI: 10.1175/jpo-d-23-0169.1

P. Yang, Z. Jing, Haiyuan Yang, Lixin Wu

引用次数: 0