{"title":"AMS Publications Support for Open, Transparent, and Equitable Research","authors":"Douglas Schuster, Michael Friedman","doi":"10.1175/jpo-d-23-0188.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0188.1","url":null,"abstract":"","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"86 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135221891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The Tsushima Strait (TS) is the sole passage for volume transport from the East China Sea to the Sea of Japan. To date, the process underlying the interannual variability in volume transport remains unclear. In this study, 27-yr (1993–2019) reanalysis data from the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2M) system and in situ/satellite observations were employed to understand this process. The results suggest that TS transport was generally high in 1999, 2003/04, and 2010 and low in 1995/96, 2005/06, 2008, and 2014/15. The sea level anomaly (SLA) outside the entrance of the TS, that is, the upstream TS forcing, dominates the interannual TS transport variation. A high SLA pumps more water into the Sea of Japan via the TS, and vice versa. By synthesizing JCOPE2M reanalysis data and satellite observations, further analysis revealed that cyclonic mesoscale eddies from the subtropical countercurrent (STCC) could be responsible for this high SLA by reducing Kuroshio transport, enhancing Kuroshio intrusion across the shelf, and increasing the SLA around the upstream TS region. The reverse was true for anticyclonic STCC eddies. Variability in the Kuroshio intrusion southwest of Kyushu induces variations in the TS transport on an interannual time scale.
{"title":"Diagnostic Analysis of the Response of Volume Transport through the Tsushima Strait to the Eddy-Induced Variations in the Kuroshio Region","authors":"Junyong Zheng, Xinyu Guo, Yasumasa Miyazawa, Haiyan Yang, Min Yang, Xinyan Mao, Wensheng Jiang","doi":"10.1175/jpo-d-22-0164.1","DOIUrl":"https://doi.org/10.1175/jpo-d-22-0164.1","url":null,"abstract":"Abstract The Tsushima Strait (TS) is the sole passage for volume transport from the East China Sea to the Sea of Japan. To date, the process underlying the interannual variability in volume transport remains unclear. In this study, 27-yr (1993–2019) reanalysis data from the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2M) system and in situ/satellite observations were employed to understand this process. The results suggest that TS transport was generally high in 1999, 2003/04, and 2010 and low in 1995/96, 2005/06, 2008, and 2014/15. The sea level anomaly (SLA) outside the entrance of the TS, that is, the upstream TS forcing, dominates the interannual TS transport variation. A high SLA pumps more water into the Sea of Japan via the TS, and vice versa. By synthesizing JCOPE2M reanalysis data and satellite observations, further analysis revealed that cyclonic mesoscale eddies from the subtropical countercurrent (STCC) could be responsible for this high SLA by reducing Kuroshio transport, enhancing Kuroshio intrusion across the shelf, and increasing the SLA around the upstream TS region. The reverse was true for anticyclonic STCC eddies. Variability in the Kuroshio intrusion southwest of Kyushu induces variations in the TS transport on an interannual time scale.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"60 4","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135456001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Time-varying processes contribute to ocean heat transport and are important to understand for accurate climate modeling. While past studies have quantified time-varying contributions to advective transport, less attention has been given to diabatic processes such as surface forcing and mixing. Using a global eddy-permitting ocean model we quantify the contribution of time-variable processes to meridional and diathermal (warm-to-cold) heat transport at different timescales using a temporal eddy-mean decomposition performed in the temperature-latitude plane. Time-varying contributions to meridional heat transport occur predominantly at mesoscale eddy-dominated mid-latitudes and in the tropics, associated with the seasonal cycle and Tropical Instability Waves. The seasonal cycle is a dominant driver of surface flux- and mixing-driven diathermal heat transports. Non-seasonal (and non-diurnal) processes contribute up to about 10% of the total. We show that transient contributions to diathermal heat transport can be interpreted as sources of Eulerian temperature variance. We thus extend recent work on the drivers of temperature variability by evaluating the role of mixing. Mixing dampens seasonal and diurnal temperature variability, except near the equator where it can be a source of seasonal variability. At mesoscale timescales mixing drives variability within and near the base of the boundary layer, the mechanisms of which are explored using a column model. We suggest that climate models that don’t resolve the mesoscale may be missing the rectified heat transport associated with high-frequency diabatic processes, in addition to the adiabatic eddy fluxes that are commonly parameterized.
{"title":"On the contribution of transient diabatic processes to ocean heat transport and temperature variability","authors":"Claire K. Yung, Ryan M. Holmes","doi":"10.1175/jpo-d-23-0046.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0046.1","url":null,"abstract":"Abstract Time-varying processes contribute to ocean heat transport and are important to understand for accurate climate modeling. While past studies have quantified time-varying contributions to advective transport, less attention has been given to diabatic processes such as surface forcing and mixing. Using a global eddy-permitting ocean model we quantify the contribution of time-variable processes to meridional and diathermal (warm-to-cold) heat transport at different timescales using a temporal eddy-mean decomposition performed in the temperature-latitude plane. Time-varying contributions to meridional heat transport occur predominantly at mesoscale eddy-dominated mid-latitudes and in the tropics, associated with the seasonal cycle and Tropical Instability Waves. The seasonal cycle is a dominant driver of surface flux- and mixing-driven diathermal heat transports. Non-seasonal (and non-diurnal) processes contribute up to about 10% of the total. We show that transient contributions to diathermal heat transport can be interpreted as sources of Eulerian temperature variance. We thus extend recent work on the drivers of temperature variability by evaluating the role of mixing. Mixing dampens seasonal and diurnal temperature variability, except near the equator where it can be a source of seasonal variability. At mesoscale timescales mixing drives variability within and near the base of the boundary layer, the mechanisms of which are explored using a column model. We suggest that climate models that don’t resolve the mesoscale may be missing the rectified heat transport associated with high-frequency diabatic processes, in addition to the adiabatic eddy fluxes that are commonly parameterized.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":" 41","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135863120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olavo B. Marques, Matthew H. Alford, Robert Pinkel, Jennifer A. MacKinnon, Gunnar Voet, Jody M. Klymak, Jonathan D. Nash
Abstract Enhanced diapycnal mixing induced by the near-bottom breaking of internal waves is an essential component of the lower meridional overturning circulation. Despite its crucial role in the ocean circulation, tidally driven internal wave breaking is challenging to observe due to its inherently short spatial and temporal scales. We present detailed moored and shipboard observations that resolve the spatio-temporal variability of the tidal response over a small-scale bump embedded in the continental slope of Tasmania. Cross-shore tidal currents drive a nonlinear trapped response over the steep bottom around the bump. The observations are roughly consistent with two-dimensional high-mode tidal lee-wave theory. However, the alongshore tidal velocities are large, suggesting that the alongshore bathymetric variability modulates the tidal response driven by the cross-shore tidal flow. The semidiurnal tide and energy dissipation rate are correlated at subtidal timescales, but with complex temporal variability. Energy dissipation from a simple scattering model shows that the elevated near-bottom turbulence can be sustained by the impinging mode-1 internal tide, where the dissipation over the bump is O (1%) of the incident depth-integrated energy flux. Despite this small fraction, tidal dissipation is enhanced over the bump due to steep topography at O (1) km horizontal scale and may locally drive significant diapycnal mixing.
{"title":"Observations of tidally driven turbulence over steep, small-scale topography embedded in the Tasman slope","authors":"Olavo B. Marques, Matthew H. Alford, Robert Pinkel, Jennifer A. MacKinnon, Gunnar Voet, Jody M. Klymak, Jonathan D. Nash","doi":"10.1175/jpo-d-23-0038.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0038.1","url":null,"abstract":"Abstract Enhanced diapycnal mixing induced by the near-bottom breaking of internal waves is an essential component of the lower meridional overturning circulation. Despite its crucial role in the ocean circulation, tidally driven internal wave breaking is challenging to observe due to its inherently short spatial and temporal scales. We present detailed moored and shipboard observations that resolve the spatio-temporal variability of the tidal response over a small-scale bump embedded in the continental slope of Tasmania. Cross-shore tidal currents drive a nonlinear trapped response over the steep bottom around the bump. The observations are roughly consistent with two-dimensional high-mode tidal lee-wave theory. However, the alongshore tidal velocities are large, suggesting that the alongshore bathymetric variability modulates the tidal response driven by the cross-shore tidal flow. The semidiurnal tide and energy dissipation rate are correlated at subtidal timescales, but with complex temporal variability. Energy dissipation from a simple scattering model shows that the elevated near-bottom turbulence can be sustained by the impinging mode-1 internal tide, where the dissipation over the bump is O (1%) of the incident depth-integrated energy flux. Despite this small fraction, tidal dissipation is enhanced over the bump due to steep topography at O (1) km horizontal scale and may locally drive significant diapycnal mixing.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"237 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136262330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The subpolar North Atlantic is known to have rich mesoscale and submesoscale variations, however, their spectral characteristics have not been documented in observations. This study documents the Kinetic Energy (KE) spectra using Acoustic Doppler Current Profiler measurements that cover both the Iceland Basin and the Irminger Sea. The KE spectrum is partitioned into geostrophically balanced motions and unbalanced motions. The results reveal that balanced motions dominate the KE spectra. The unbalanced motions enhance in spring and fall to flatten the spectra and dominate small scale (<50km) energy, though uncertainty is high due to measurement noise and method assumptions. In addition, the dynamical framework that drives the balanced motions undergoes distinct seasonal shifts. In the spring and summer seasons of the Iceland Basin, as well as the summer season of the Irminger Sea, the wavenumber spectra of balanced motions exhibit a slope of approximately −3, consistent with the internal quasi-geostrophic turbulence theory. Conversely, in the fall season of the Iceland Basin and the spring and fall seasons of the Irminger Sea, the wavenumber spectra of geostrophic balanced motions have a slope close to −2, consistent with surface quasi-geostrophic turbulence theory. Additionally, we have found that the intensity of mesoscale eddies in the spring season can modulate both the slope and intensity of the wavenumber spectra of geostrophic balanced flows.
{"title":"Characteristics of the Kinetic Energy Spectra in the Subpolar North Atlantic","authors":"Junwei Chai, Jian Zhao","doi":"10.1175/jpo-d-22-0247.1","DOIUrl":"https://doi.org/10.1175/jpo-d-22-0247.1","url":null,"abstract":"Abstract The subpolar North Atlantic is known to have rich mesoscale and submesoscale variations, however, their spectral characteristics have not been documented in observations. This study documents the Kinetic Energy (KE) spectra using Acoustic Doppler Current Profiler measurements that cover both the Iceland Basin and the Irminger Sea. The KE spectrum is partitioned into geostrophically balanced motions and unbalanced motions. The results reveal that balanced motions dominate the KE spectra. The unbalanced motions enhance in spring and fall to flatten the spectra and dominate small scale (<50km) energy, though uncertainty is high due to measurement noise and method assumptions. In addition, the dynamical framework that drives the balanced motions undergoes distinct seasonal shifts. In the spring and summer seasons of the Iceland Basin, as well as the summer season of the Irminger Sea, the wavenumber spectra of balanced motions exhibit a slope of approximately −3, consistent with the internal quasi-geostrophic turbulence theory. Conversely, in the fall season of the Iceland Basin and the spring and fall seasons of the Irminger Sea, the wavenumber spectra of geostrophic balanced motions have a slope close to −2, consistent with surface quasi-geostrophic turbulence theory. Additionally, we have found that the intensity of mesoscale eddies in the spring season can modulate both the slope and intensity of the wavenumber spectra of geostrophic balanced flows.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"161 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136262013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A variety of submesoscale coherent vortices (SCVs) in the Kuroshio Extension region have been reported by recent observational studies, and the preliminary understanding of their properties, spatial distribution and possible origins has progressively improved. However, due to relatively sparse in situ observations, the generation mechanisms of these SCVs and associated dynamic processes remain unclear. In this study, we use high-resolution model simulations to fill the gaps of the in situ observations in terms of the three-dimensional structures and life cycles of SCVs. Vortex detection and tracking algorithms are adopted and the characteristics of warm-core and cold-core SCVs are revealed. These vortices have finite Rossby numbers (0.25-0.4) and their horizontal structures can be well described by the Tayler vortex model in terms of the gradient wind balance. The vertical velocity field is characterized by a distinct dipole pattern with upwelling and downwelling cells at the vortex edge. It is very likely that both types of SCVs are generated along the eastern Japan coast through flow–topography interactions, and the Izu–Ogasawara Ridge and Hokkaido slope are found to be two important generation sites where topography friction produces extremely low potential vorticity. After leaving the boundary, SCVs can propagate over long distances and trap a water volume of ~10 11 m 3 .
{"title":"Topography-Generated Submesoscale Coherent Vortices in the Kuroshio-Oyashio Extension Region from High-Resolution Simulations","authors":"Ruichen Zhu, Haiyuan Yang, Zhaohui Chen, Zhiyou Jing, Zhiwei Zhang, Bingrong Sun, Lixin Wu","doi":"10.1175/jpo-d-23-0072.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0072.1","url":null,"abstract":"Abstract A variety of submesoscale coherent vortices (SCVs) in the Kuroshio Extension region have been reported by recent observational studies, and the preliminary understanding of their properties, spatial distribution and possible origins has progressively improved. However, due to relatively sparse in situ observations, the generation mechanisms of these SCVs and associated dynamic processes remain unclear. In this study, we use high-resolution model simulations to fill the gaps of the in situ observations in terms of the three-dimensional structures and life cycles of SCVs. Vortex detection and tracking algorithms are adopted and the characteristics of warm-core and cold-core SCVs are revealed. These vortices have finite Rossby numbers (0.25-0.4) and their horizontal structures can be well described by the Tayler vortex model in terms of the gradient wind balance. The vertical velocity field is characterized by a distinct dipole pattern with upwelling and downwelling cells at the vortex edge. It is very likely that both types of SCVs are generated along the eastern Japan coast through flow–topography interactions, and the Izu–Ogasawara Ridge and Hokkaido slope are found to be two important generation sites where topography friction produces extremely low potential vorticity. After leaving the boundary, SCVs can propagate over long distances and trap a water volume of ~10 11 m 3 .","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"45 7-8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134908580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Through an expansive series of simulations, we investigate the effects of spatially uniform shear on the transport, structure, and dynamics of salt fingers. The simulations reveal that shear adversely affects the heat and salt fluxes of the system, reducing them by up to an order of magnitude. We characterize this in detail across a broad range of Richardson numbers and density ratios. We demonstrate that the density ratio is strongly related to the amount of shear required to disrupt fingers with larger density ratio systems being more susceptible to disruption. An empirical relationship is proposed that captures this behavior that could be implemented into global ocean models. The results of these simulations accurately reproduce the microstructure measurements from NATRE observations. This work suggests that typical salt finger fluxes in the ocean will likely be a factor of 2–3 less than predicted by models not taking the effects of shear on double-diffusive systems into account.
{"title":"Patterns, Transport, and Anisotropy of Salt Fingers in Shear","authors":"Justin M Brown, Timour Radko","doi":"10.1175/jpo-d-23-0049.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0049.1","url":null,"abstract":"Abstract Through an expansive series of simulations, we investigate the effects of spatially uniform shear on the transport, structure, and dynamics of salt fingers. The simulations reveal that shear adversely affects the heat and salt fluxes of the system, reducing them by up to an order of magnitude. We characterize this in detail across a broad range of Richardson numbers and density ratios. We demonstrate that the density ratio is strongly related to the amount of shear required to disrupt fingers with larger density ratio systems being more susceptible to disruption. An empirical relationship is proposed that captures this behavior that could be implemented into global ocean models. The results of these simulations accurately reproduce the microstructure measurements from NATRE observations. This work suggests that typical salt finger fluxes in the ocean will likely be a factor of 2–3 less than predicted by models not taking the effects of shear on double-diffusive systems into account.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"143 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135113709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
John M. Toole, Ruth C. Musgrave, Elizabeth C. Fine, Jacob M. Steinberg, Richard A. Krishfield
Abstract The vertical structure of subinertial variability is examined using full-depth horizontal velocity and vertical isopycnal displacement observations derived from the Ocean Observatory Initiative (OOI). Vertical profiles on time scales between 100 hours and 1 year or longer are characterized through Empirical Orthogonal Function decomposition and qualitatively compared to theoretical modal predictions for the cases of flat, sloping and rough bathymetry. OOI observations were obtained from mooring clusters at four deep-ocean sites: Argentine Basin, Southern Ocean, Station Papa, and Irminger Sea. As no single OOI mooring in these arrays provides temperature, salinity and horizontal velocity information over the full water column, sensor observations from two or more moorings are combined. Depths greater than ~150-300 m were sampled by McLane Moored Profilers; in three of the four cases, two Profilers were utilized on the moorings. Owing to instrument failures on the deployments examined here, only about two years of full-ocean-depth observations are available from three of the four sites and some three+ years from the other. Results from the OOI Global sites are contrasted with a parallel analysis of three and one half years of observations about the axis of the Gulf Stream where much of the subinertial variability is associated with Stream meandering past the moorings. Looking across the observations, no universal vertical structure is found that characterizes the subinertial variability at the five sites examined; regional bathymetry, stratification, baroclinicity, nonlinearity and the forcing (both local and remote) likely all play a role in shaping the vertical structure of the subinertial variability in individual ocean regions.
{"title":"On The Vertical Structure Of Deep Ocean Subinertial Variability","authors":"John M. Toole, Ruth C. Musgrave, Elizabeth C. Fine, Jacob M. Steinberg, Richard A. Krishfield","doi":"10.1175/jpo-d-23-0011.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0011.1","url":null,"abstract":"Abstract The vertical structure of subinertial variability is examined using full-depth horizontal velocity and vertical isopycnal displacement observations derived from the Ocean Observatory Initiative (OOI). Vertical profiles on time scales between 100 hours and 1 year or longer are characterized through Empirical Orthogonal Function decomposition and qualitatively compared to theoretical modal predictions for the cases of flat, sloping and rough bathymetry. OOI observations were obtained from mooring clusters at four deep-ocean sites: Argentine Basin, Southern Ocean, Station Papa, and Irminger Sea. As no single OOI mooring in these arrays provides temperature, salinity and horizontal velocity information over the full water column, sensor observations from two or more moorings are combined. Depths greater than ~150-300 m were sampled by McLane Moored Profilers; in three of the four cases, two Profilers were utilized on the moorings. Owing to instrument failures on the deployments examined here, only about two years of full-ocean-depth observations are available from three of the four sites and some three+ years from the other. Results from the OOI Global sites are contrasted with a parallel analysis of three and one half years of observations about the axis of the Gulf Stream where much of the subinertial variability is associated with Stream meandering past the moorings. Looking across the observations, no universal vertical structure is found that characterizes the subinertial variability at the five sites examined; regional bathymetry, stratification, baroclinicity, nonlinearity and the forcing (both local and remote) likely all play a role in shaping the vertical structure of the subinertial variability in individual ocean regions.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135778842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yunwei Yan, Xiangzhou Song, Guihua Wang, Xiaojing Li
Abstract Cool-skin and warm-layer effects are important phenomena in the ocean-atmosphere system. Here, we study tropical cool-skin and warm-layer effects and their impact on surface heat fluxes using the methods proposed by Fairall et al. in 1996, i.e., the F96 cool-skin scheme and the combined warm-layer method. The results reveal strong cool-skin effects (~−0.3 K) in the Indo-Pacific warm pool, but weak effects in the equatorial Pacific and Atlantic cold tongues. The spatial pattern of the cool-skin effect is determined by the difference in the specific humidity between the sea and air. The warm-layer effect is strong (~0.25 K) in both the warm pool and cold tongues but weak in the trade wind regions and exhibits a spatial pattern that is inversely related to the surface wind speed. In the tropics, the cool-skin effect causes an average reduction of 11.0 W m −2 in the heat loss from the ocean to the atmosphere, while the warm-layer effect causes an increase of 6.0 W m −2 . With respect to the F96 cool-skin scheme, four common wind speed-dependent empirical models could not fully capture the spatial distribution of the cool-skin effect. A new empirical model that depends on the sea-air humidity difference is proposed to overcome this problem. Compared to the combined warm-layer method, when only the F96 warm-layer scheme is applied, the effect is underestimated at both low and high wind speeds. These new findings improve our understanding of the cool-skin and warm-layer effects and provide insights into their parameterization schemes.
冷皮效应和暖层效应是海洋-大气系统中的重要现象。本文采用Fairall et al.(1996)提出的F96冷皮方案和暖层组合方法，研究热带冷皮和暖层效应及其对地表热通量的影响。结果表明，印度洋-太平洋暖池的冷皮效应较强(~−0.3 K)，而赤道太平洋和大西洋冷舌的冷皮效应较弱。冷皮效应的空间格局是由海洋和空气的比湿度差异决定的。暖层效应在暖池和冷舌区均较强(~0.25 K)，而在信风区较弱，且与地面风速呈负相关。在热带地区，冷皮效应使海洋向大气的热量损失平均减少11.0 W m−2，而暖层效应使海洋向大气的热量损失增加6.0 W m−2。对于F96冷表皮方案，4种常见的风速依赖经验模型不能完全反映冷表皮效应的空间分布。为了克服这一问题，提出了一种新的基于海气湿度差的经验模型。与复合暖层方法相比，仅应用F96暖层方案时，无论在低风速还是高风速下，效果都被低估。这些新发现提高了我们对冷层和暖层效应的理解，并为它们的参数化方案提供了见解。
{"title":"Tropical Cool-skin and Warm-layer Effects and their Impact on Surface Heat Fluxes","authors":"Yunwei Yan, Xiangzhou Song, Guihua Wang, Xiaojing Li","doi":"10.1175/jpo-d-23-0103.1","DOIUrl":"https://doi.org/10.1175/jpo-d-23-0103.1","url":null,"abstract":"Abstract Cool-skin and warm-layer effects are important phenomena in the ocean-atmosphere system. Here, we study tropical cool-skin and warm-layer effects and their impact on surface heat fluxes using the methods proposed by Fairall et al. in 1996, i.e., the F96 cool-skin scheme and the combined warm-layer method. The results reveal strong cool-skin effects (~−0.3 K) in the Indo-Pacific warm pool, but weak effects in the equatorial Pacific and Atlantic cold tongues. The spatial pattern of the cool-skin effect is determined by the difference in the specific humidity between the sea and air. The warm-layer effect is strong (~0.25 K) in both the warm pool and cold tongues but weak in the trade wind regions and exhibits a spatial pattern that is inversely related to the surface wind speed. In the tropics, the cool-skin effect causes an average reduction of 11.0 W m −2 in the heat loss from the ocean to the atmosphere, while the warm-layer effect causes an increase of 6.0 W m −2 . With respect to the F96 cool-skin scheme, four common wind speed-dependent empirical models could not fully capture the spatial distribution of the cool-skin effect. A new empirical model that depends on the sea-air humidity difference is proposed to overcome this problem. Compared to the combined warm-layer method, when only the F96 warm-layer scheme is applied, the effect is underestimated at both low and high wind speeds. These new findings improve our understanding of the cool-skin and warm-layer effects and provide insights into their parameterization schemes.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136112609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joseph Skitka, Brian K. Arbic, Ritabrata Thakur, Dimitris Menemenlis, William R. Peltier, Yulin Pan, Kayhan Momeni, Yuchen Ma
Abstract The internal-wave (IW) continuum of a regional ocean model is studied in terms of the vertical spectral kinetic-energy (KE) fluxes and transfers at high vertical wavenumbers. Previous work has shown that this model permits a partial representation of the IW cascade. In this work, vertical spectral KE flux is decomposed into catalyst, source, and destination vertical modes and frequency bands of nonlinear scattering, a framework that allows for the discernment of different types of nonlinear interactions involving both waves and eddies. Energy transfer within the supertidal IW continuum is found to be strongly dependent on resolution. Specifically, at a horizontal grid spacing of 1/48°, most KE in the supertidal continuum arrives there from lower frequency modes through a single nonlinear interaction, while at 1/384° and with sufficient vertical resolution KE transfers within the supertidal IW continuum are comparable in size to KE transfer from lower-frequency modes. Additionally, comparisons are made with existing theoretical and observational work on energy pathways in the IW continuum. Induced diffusion (ID) is found to be associated with a weak forward frequency transfer within the supertidal IW continuum. ID is also limited to the highest vertical wavenumbers and is more sensitive to resolution relative to spectrally local interactions (LI). At the same time, ID-like processes involving high vertical-wavenumber near-inertial and tidal waves as well as low-vertical-wavenumber eddy fields are substantial, suggesting that the processes giving rise to a Garrett-Munk-like spectra in the present numerical simulation and perhaps the real ocean may be more varied than in idealized or wave-only frameworks.
{"title":"Probing the Nonlinear Interactions of Supertidal Internal Waves using a High-Resolution Regional Ocean Model","authors":"Joseph Skitka, Brian K. Arbic, Ritabrata Thakur, Dimitris Menemenlis, William R. Peltier, Yulin Pan, Kayhan Momeni, Yuchen Ma","doi":"10.1175/jpo-d-22-0236.1","DOIUrl":"https://doi.org/10.1175/jpo-d-22-0236.1","url":null,"abstract":"Abstract The internal-wave (IW) continuum of a regional ocean model is studied in terms of the vertical spectral kinetic-energy (KE) fluxes and transfers at high vertical wavenumbers. Previous work has shown that this model permits a partial representation of the IW cascade. In this work, vertical spectral KE flux is decomposed into catalyst, source, and destination vertical modes and frequency bands of nonlinear scattering, a framework that allows for the discernment of different types of nonlinear interactions involving both waves and eddies. Energy transfer within the supertidal IW continuum is found to be strongly dependent on resolution. Specifically, at a horizontal grid spacing of 1/48°, most KE in the supertidal continuum arrives there from lower frequency modes through a single nonlinear interaction, while at 1/384° and with sufficient vertical resolution KE transfers within the supertidal IW continuum are comparable in size to KE transfer from lower-frequency modes. Additionally, comparisons are made with existing theoretical and observational work on energy pathways in the IW continuum. Induced diffusion (ID) is found to be associated with a weak forward frequency transfer within the supertidal IW continuum. ID is also limited to the highest vertical wavenumbers and is more sensitive to resolution relative to spectrally local interactions (LI). At the same time, ID-like processes involving high vertical-wavenumber near-inertial and tidal waves as well as low-vertical-wavenumber eddy fields are substantial, suggesting that the processes giving rise to a Garrett-Munk-like spectra in the present numerical simulation and perhaps the real ocean may be more varied than in idealized or wave-only frameworks.","PeriodicalId":56115,"journal":{"name":"Journal of Physical Oceanography","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136113880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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