Search Results
motions is important to understanding how the energy of ocean circulation is eventually dissipated, a process yet to be fully understood. The distribution of the kinetic energy in the ocean over a range of spatial scales, as expressed by its wavenumber spectrum, provides information on the underlying processes of oceanic mesoscale turbulence. In the wavenumber spectrum, mesoscale turbulence corresponds to the wavenumber band in which the spectral slope is steepest and nearly constant, exhibiting an
motions is important to understanding how the energy of ocean circulation is eventually dissipated, a process yet to be fully understood. The distribution of the kinetic energy in the ocean over a range of spatial scales, as expressed by its wavenumber spectrum, provides information on the underlying processes of oceanic mesoscale turbulence. In the wavenumber spectrum, mesoscale turbulence corresponds to the wavenumber band in which the spectral slope is steepest and nearly constant, exhibiting an
the mechanism of gas exchange at the air–sea interface. Tellus , 42B , 250 – 253 . Hristov , T. , C. A. Friehe , and S. Miller , 1998 : Wave-coherent fields in the air flow over ocean waves: Identification of cooperative behavior buried in turbulence. Phys. Rev. Lett. , 81 , 5245 – 5248 . Isobe , M. , K. Kondo , and K. Horikawa , 1984 : Extension of MLM for estimating directional wave spectrum. Proc. Symp. on Description and Modelling of Directional Seas, Copenhagen
the mechanism of gas exchange at the air–sea interface. Tellus , 42B , 250 – 253 . Hristov , T. , C. A. Friehe , and S. Miller , 1998 : Wave-coherent fields in the air flow over ocean waves: Identification of cooperative behavior buried in turbulence. Phys. Rev. Lett. , 81 , 5245 – 5248 . Isobe , M. , K. Kondo , and K. Horikawa , 1984 : Extension of MLM for estimating directional wave spectrum. Proc. Symp. on Description and Modelling of Directional Seas, Copenhagen
-eddy simulation (LES) studies (e.g., Noh et al. 2004 ; Polton and Belcher 2007 ; Kukulka et al. 2009 ). Because the intensity of the Langmuir turbulence depends on the relative importance of the wind forcing and the wave forcing, it strongly depends on the sea state through its surface wave field. Therefore, existing upper-ocean mixing parameterizations without explicit sea-state dependence may introduce significant errors in conditions where the surface wave field is not in equilibrium with local wind
-eddy simulation (LES) studies (e.g., Noh et al. 2004 ; Polton and Belcher 2007 ; Kukulka et al. 2009 ). Because the intensity of the Langmuir turbulence depends on the relative importance of the wind forcing and the wave forcing, it strongly depends on the sea state through its surface wave field. Therefore, existing upper-ocean mixing parameterizations without explicit sea-state dependence may introduce significant errors in conditions where the surface wave field is not in equilibrium with local wind
turbulence theory argues for a direct (i.e., downscale) cascade for the total baroclinic energy ( Rhines 1977 ; Salmon 1980 ; Fu and Flierl 1980 ; Hua and Haidvogel 1986 ). This is in the opposite sense to the barotropic KE cascade. Concurrent with the horizontal cascade, the geostrophic turbulence theory of Charney (1971) predicts a vertical transfer of energy from the baroclinic modes into the barotropic mode. For a fluid with strongly surface-intensified stratification, such as the ocean, the
turbulence theory argues for a direct (i.e., downscale) cascade for the total baroclinic energy ( Rhines 1977 ; Salmon 1980 ; Fu and Flierl 1980 ; Hua and Haidvogel 1986 ). This is in the opposite sense to the barotropic KE cascade. Concurrent with the horizontal cascade, the geostrophic turbulence theory of Charney (1971) predicts a vertical transfer of energy from the baroclinic modes into the barotropic mode. For a fluid with strongly surface-intensified stratification, such as the ocean, the
1. Introduction Wave propagation through random media has been studied extensively ( Chernov 1960 ; Rytov et al. 1989 ; Ishimaru 1999 ; Sato et al. 2012 ). Specifically, the scattering of sound in a fully developed turbulent flow (thought of as a random medium) has been given attention in a number of theoretical and experimental studies ( Tatarskii 1961 ; Monin and Yaglom 1971 ). Understanding of the ocean turbulence phenomenon and its role in the energy balance is one of the essential
1. Introduction Wave propagation through random media has been studied extensively ( Chernov 1960 ; Rytov et al. 1989 ; Ishimaru 1999 ; Sato et al. 2012 ). Specifically, the scattering of sound in a fully developed turbulent flow (thought of as a random medium) has been given attention in a number of theoretical and experimental studies ( Tatarskii 1961 ; Monin and Yaglom 1971 ). Understanding of the ocean turbulence phenomenon and its role in the energy balance is one of the essential
-resolution, eddy-rich ocean global circulation model simulation, we ask, to what extent is the steady-state eddy field at a particular location consistent with a homogeneous model of mesoscale turbulence? To address this question, we analyze the output from the 1/6° run of the Modeling Eddies in the Southern Ocean (MESO) project ( Hallberg and Gnanadesikan 2006 ), a series of simulations using an isopycnal primitive equation (PE) model. We consider first the statistical and structural properties of the eddy
-resolution, eddy-rich ocean global circulation model simulation, we ask, to what extent is the steady-state eddy field at a particular location consistent with a homogeneous model of mesoscale turbulence? To address this question, we analyze the output from the 1/6° run of the Modeling Eddies in the Southern Ocean (MESO) project ( Hallberg and Gnanadesikan 2006 ), a series of simulations using an isopycnal primitive equation (PE) model. We consider first the statistical and structural properties of the eddy
1. Introduction Wave breaking at the ocean surface limits wave growth ( Melville 1994 ), enhances gas exchange ( Zappa et al. 2007 ), and generates turbulence that mixes the ocean surface layer ( Burchard et al. 2008 ; Kukulka and Brunner 2015 ). Previous observations of wave-breaking turbulence have shown strong enhancement near the surface, at values that far exceed those predicted by simple “law of the wall” boundary layer scaling ( Agrawal et al. 1992 ; Terray et al. 1996 ; Gemmrich and
1. Introduction Wave breaking at the ocean surface limits wave growth ( Melville 1994 ), enhances gas exchange ( Zappa et al. 2007 ), and generates turbulence that mixes the ocean surface layer ( Burchard et al. 2008 ; Kukulka and Brunner 2015 ). Previous observations of wave-breaking turbulence have shown strong enhancement near the surface, at values that far exceed those predicted by simple “law of the wall” boundary layer scaling ( Agrawal et al. 1992 ; Terray et al. 1996 ; Gemmrich and
project onto spatial scales. This is a serious limitation to our understanding of submesoscale turbulence because the interaction of modes across spatial scales is at the core of turbulence theories. Fig . 1. Frequency spectrum of kinetic energy from mooring WHOI 794 at 35°N, 152°W (October 1983–September 1985). Marked are f and M 2 . Shading shows 95% confidence intervals. It is generally believed that the kinetic energy in the midlatitude upper ocean is dominated by geostrophic eddies at scales
project onto spatial scales. This is a serious limitation to our understanding of submesoscale turbulence because the interaction of modes across spatial scales is at the core of turbulence theories. Fig . 1. Frequency spectrum of kinetic energy from mooring WHOI 794 at 35°N, 152°W (October 1983–September 1985). Marked are f and M 2 . Shading shows 95% confidence intervals. It is generally believed that the kinetic energy in the midlatitude upper ocean is dominated by geostrophic eddies at scales
of the unresolved scales has to be implemented to correctly reproduce the flux of energy between scales ( Pearson et al. 2017 ; Dubrulle 2019 ). But, although in three-dimensional turbulence energy is known to cascade from scales at which it is injected toward smaller scales where it is utterly converted to heat, the details of such cascade in the ocean are rather complex and still poorly understood ( Müller et al. 2005 ; McWilliams 2016 ; Renault et al. 2019 ). This hinders its correct
of the unresolved scales has to be implemented to correctly reproduce the flux of energy between scales ( Pearson et al. 2017 ; Dubrulle 2019 ). But, although in three-dimensional turbulence energy is known to cascade from scales at which it is injected toward smaller scales where it is utterly converted to heat, the details of such cascade in the ocean are rather complex and still poorly understood ( Müller et al. 2005 ; McWilliams 2016 ; Renault et al. 2019 ). This hinders its correct
1. Introduction Although shear-driven turbulence in the ocean occurs over small scales, there are regions where the influence of this mixing can have a large-scale impact. In particular, the shear-driven mixing in both the Equatorial Undercurrent (EUC) and in overflows is climatically significant. In the former case, it is clear that mixing in the EUC affects the sea surface properties and hence has a direct influence on the climate. Mixing in overflows, despite the fact that it occurs well
1. Introduction Although shear-driven turbulence in the ocean occurs over small scales, there are regions where the influence of this mixing can have a large-scale impact. In particular, the shear-driven mixing in both the Equatorial Undercurrent (EUC) and in overflows is climatically significant. In the former case, it is clear that mixing in the EUC affects the sea surface properties and hence has a direct influence on the climate. Mixing in overflows, despite the fact that it occurs well
