Search Results
evidence the ubiquity of cyclonic eddies often coupled with meddies ( Richardson et al. 2000 ; Carton et al. 2002 ; L’Hégaret et al. 2014 ). These cyclones are regularly formed off the southern coast of Portugal in the MW layers ( Serra et al. 2005 ; Barbosa Aguiar et al. 2013 ). In situ studies of cyclone–meddy dipoles near the Portimão Canyon revealed that the cyclonic part also bears anomalies in temperature T and salinity S , albeit weaker than its companion meddy. In the example surveyed by
evidence the ubiquity of cyclonic eddies often coupled with meddies ( Richardson et al. 2000 ; Carton et al. 2002 ; L’Hégaret et al. 2014 ). These cyclones are regularly formed off the southern coast of Portugal in the MW layers ( Serra et al. 2005 ; Barbosa Aguiar et al. 2013 ). In situ studies of cyclone–meddy dipoles near the Portimão Canyon revealed that the cyclonic part also bears anomalies in temperature T and salinity S , albeit weaker than its companion meddy. In the example surveyed by
1. Introduction Mediterranean water eddies (meddies) are coherent mesoscale features commonly observed in the North Atlantic. They are vortex lenses characterized by the contrast of hydrographic properties of the warm and salty Mediterranean water trapped within their core and the fresher and cooler surrounding water. This core, usually 650 to 750 m thick and centered near 1200 m, has well-mixed water properties with typical temperature and salinity values ranging from respectively 11.5° to 13
1. Introduction Mediterranean water eddies (meddies) are coherent mesoscale features commonly observed in the North Atlantic. They are vortex lenses characterized by the contrast of hydrographic properties of the warm and salty Mediterranean water trapped within their core and the fresher and cooler surrounding water. This core, usually 650 to 750 m thick and centered near 1200 m, has well-mixed water properties with typical temperature and salinity values ranging from respectively 11.5° to 13
intense erosion before they reach the eddy graveyard. LCEs drift several months across the GoM before reaching any topographic obstacle, and erosion of their salinity maximum was observed to start during this drift ( Portela et al. 2018 ). Seismic reflection images of the northern GoM ( Dickinson et al. 2017 ) showed the presence of anomalous acoustic reflectors near the edges of, and below, the northern edge of an LCE. They are organized as vertically stacked layers with large lateral extent (up to
intense erosion before they reach the eddy graveyard. LCEs drift several months across the GoM before reaching any topographic obstacle, and erosion of their salinity maximum was observed to start during this drift ( Portela et al. 2018 ). Seismic reflection images of the northern GoM ( Dickinson et al. 2017 ) showed the presence of anomalous acoustic reflectors near the edges of, and below, the northern edge of an LCE. They are organized as vertically stacked layers with large lateral extent (up to
), the construction of climatological datasets for temperature and salinity devoid of spurious water masses ( Lozier et al. 1994 ), the construction of inverse models of the ocean circulation ( Wunsch 1996 ), the tracking and analysis of water masses ( Montgomery 1938 ; Walin 1982 ), the construction of isopycnal models of the ocean based on generalized coordinate systems ( Griffies et al. 2000 ; de Szoeke 2000 ), the study of the residual circulation ( Wolfe 2014 ), and the parameterization of
), the construction of climatological datasets for temperature and salinity devoid of spurious water masses ( Lozier et al. 1994 ), the construction of inverse models of the ocean circulation ( Wunsch 1996 ), the tracking and analysis of water masses ( Montgomery 1938 ; Walin 1982 ), the construction of isopycnal models of the ocean based on generalized coordinate systems ( Griffies et al. 2000 ; de Szoeke 2000 ), the study of the residual circulation ( Wolfe 2014 ), and the parameterization of
et al. (1993) , the barotropic streamfunction is obtained by integrating along potential vorticity contours the two forcings: the Ekman pumping and the baroclinic contribution to bottom pressure torque [the so-called JEBAR effect found by Sarkisyan and Ivanov (1971) ]. (v) Quite a number of other studies used full blown OGCMs to spin up the barotropic circulation keeping the model temperature and salinity close to the observed time-mean temperature and salinity ( Sarkisyan and Keonjiyan 1975
et al. (1993) , the barotropic streamfunction is obtained by integrating along potential vorticity contours the two forcings: the Ekman pumping and the baroclinic contribution to bottom pressure torque [the so-called JEBAR effect found by Sarkisyan and Ivanov (1971) ]. (v) Quite a number of other studies used full blown OGCMs to spin up the barotropic circulation keeping the model temperature and salinity close to the observed time-mean temperature and salinity ( Sarkisyan and Keonjiyan 1975
) conservative property, (or ) is used as the thermodynamic state variable in addition to salinity and Boussinesq reference pressure in current ocean models ( McDougall 2003 ). It is the aim of this note to provide closed and explicit conservation equations for all previously discussed forms of energy based on molecular fluxes of enthalpy and salt and kinetic energy dissipation and to provide a simple but consistent description of the energetics of the ocean in Boussinesq approximation. 2. Energetics of
) conservative property, (or ) is used as the thermodynamic state variable in addition to salinity and Boussinesq reference pressure in current ocean models ( McDougall 2003 ). It is the aim of this note to provide closed and explicit conservation equations for all previously discussed forms of energy based on molecular fluxes of enthalpy and salt and kinetic energy dissipation and to provide a simple but consistent description of the energetics of the ocean in Boussinesq approximation. 2. Energetics of
gradient of Q changes sign over the domain, confirming the conditions for baroclinic and barotropic instabilities. Fig . 1. Meddy initialization. (top) Vertical sections across the vortex axis showing (left) ( Q / f − 1) and (right) (PV E / f − 1) for the QG and PE simulations; (bottom) same sections in the PE simulation, for initial fields of (left) salinity and (right) temperature
gradient of Q changes sign over the domain, confirming the conditions for baroclinic and barotropic instabilities. Fig . 1. Meddy initialization. (top) Vertical sections across the vortex axis showing (left) ( Q / f − 1) and (right) (PV E / f − 1) for the QG and PE simulations; (bottom) same sections in the PE simulation, for initial fields of (left) salinity and (right) temperature
simulations used a simple relaxation with a time scale of 3 h to the interpolated SST and sea surface salinity fields computed as part of the M15 solutions. Vertical diffusivities and viscosities were set to 10 −4 m 2 s −1 and horizontal values to 1.5 m 2 s −1 . Model time steps were 15 s, and the model was run for 17 days, corresponding to roughly 22 inertial periods. Output of all dynamical variables was archived at intervals of 30 min for the first 6.25 days and at intervals of 90 min thereafter
simulations used a simple relaxation with a time scale of 3 h to the interpolated SST and sea surface salinity fields computed as part of the M15 solutions. Vertical diffusivities and viscosities were set to 10 −4 m 2 s −1 and horizontal values to 1.5 m 2 s −1 . Model time steps were 15 s, and the model was run for 17 days, corresponding to roughly 22 inertial periods. Output of all dynamical variables was archived at intervals of 30 min for the first 6.25 days and at intervals of 90 min thereafter
1. Introduction Wang et al. (2013 , hereinafter W13) proposed a method for projecting surface density and height downward in the water column. The method requires simultaneous observations of surface density (or temperature, in the absence of salinity) and height. The density projection is made using the surface quasigeostrophic (SQG) approximation ( Blumen 1978 ; Held et al. 1995 ; Lapeyre and Klein 2006 ; LaCasce and Mahadevan 2006 ; Tulloch and Smith 2006 ; Isern-Fontanet et al. 2008
1. Introduction Wang et al. (2013 , hereinafter W13) proposed a method for projecting surface density and height downward in the water column. The method requires simultaneous observations of surface density (or temperature, in the absence of salinity) and height. The density projection is made using the surface quasigeostrophic (SQG) approximation ( Blumen 1978 ; Held et al. 1995 ; Lapeyre and Klein 2006 ; LaCasce and Mahadevan 2006 ; Tulloch and Smith 2006 ; Isern-Fontanet et al. 2008
anticyclonic shear. Fig . 4. Jet initial condition in (top) υ and (middle) T . The maximum downstream speed is 0.35 m s −1 , and the inshore edge is characterized by a minimum relative vorticity of −1.8 f . Salinity is neglected, and the density is computed according to geostrophy. (bottom) The potential vorticity field of this initial condition. A region of negative potential vorticity appears at middepth between 8 and 10 km. Away from the jet, potential vorticity is constant. Figure 4 (bottom) shows
anticyclonic shear. Fig . 4. Jet initial condition in (top) υ and (middle) T . The maximum downstream speed is 0.35 m s −1 , and the inshore edge is characterized by a minimum relative vorticity of −1.8 f . Salinity is neglected, and the density is computed according to geostrophy. (bottom) The potential vorticity field of this initial condition. A region of negative potential vorticity appears at middepth between 8 and 10 km. Away from the jet, potential vorticity is constant. Figure 4 (bottom) shows
