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conditions. In Brink's model the response istherefore dependent on location; in MF's model it isnot. Also, Brink's boundary conditions limit the zonalfetch, whereas MF's model has unlimited fetch. Brinksucceeds in reproducing characteristic features of hisobserved coherence maps. In this paper we show thatMF's model also reproduces the characteristic featuresof observed coherence maps. One reason why we recalculate coherence maps using MF's model is that itis algebraically simpler because it assumes
conditions. In Brink's model the response istherefore dependent on location; in MF's model it isnot. Also, Brink's boundary conditions limit the zonalfetch, whereas MF's model has unlimited fetch. Brinksucceeds in reproducing characteristic features of hisobserved coherence maps. In this paper we show thatMF's model also reproduces the characteristic featuresof observed coherence maps. One reason why we recalculate coherence maps using MF's model is that itis algebraically simpler because it assumes
. Brink (1989) , Samelson (1990) , and later Lippert and Müller (1995) all calculated coherence maps from a simple linear quasigeostrophic model with stochastic wind forcing, for comparison with the observed maps. The model has a flat bottom and no mean currents. The forcing is assumed to be statistically homogeneous and described either by its autocovariance function in separation space or by its spectrum in wavenumber space. Choosing certain idealized but reasonable spectra or autocovariance
. Brink (1989) , Samelson (1990) , and later Lippert and Müller (1995) all calculated coherence maps from a simple linear quasigeostrophic model with stochastic wind forcing, for comparison with the observed maps. The model has a flat bottom and no mean currents. The forcing is assumed to be statistically homogeneous and described either by its autocovariance function in separation space or by its spectrum in wavenumber space. Choosing certain idealized but reasonable spectra or autocovariance
sample globally, obtaining mean temperatures and velocities over 9–25-day intervals and therefore are averaging over several full tidal and internal wave cycles. One of the design objectives in deploying ALACE floats was to measure absolute reference velocities for use in refining hydrographic transport estimates. The first goal of this study is to make use of ALACE measurements to map mean temperature and dynamic topography in the Southern Ocean. ALACE temperatures are then compared with
sample globally, obtaining mean temperatures and velocities over 9–25-day intervals and therefore are averaging over several full tidal and internal wave cycles. One of the design objectives in deploying ALACE floats was to measure absolute reference velocities for use in refining hydrographic transport estimates. The first goal of this study is to make use of ALACE measurements to map mean temperature and dynamic topography in the Southern Ocean. ALACE temperatures are then compared with
–Weiss parameter. The comparison of trajectories obtained with these two methods showed that both sets of trajectories presented similar patterns (not shown). Last, the complete set of the 213 maps of the Okubo–Weiss parameter for the whole basin, with vortices labeled automatically as described before, has been visually inspected, showing that there were few errors in the trajectories obtained with the automatic method. 5. Discussion The application of the Okubo–Weiss criterion has shown a basin full of
–Weiss parameter. The comparison of trajectories obtained with these two methods showed that both sets of trajectories presented similar patterns (not shown). Last, the complete set of the 213 maps of the Okubo–Weiss parameter for the whole basin, with vortices labeled automatically as described before, has been visually inspected, showing that there were few errors in the trajectories obtained with the automatic method. 5. Discussion The application of the Okubo–Weiss criterion has shown a basin full of
PDFs are due to coherent vortices in a semienclosed basin such as the Mediterranean basin. The Mediterranean Sea is dominated by the entrance of freshwater incoming from the Atlantic Ocean through the Strait of Gibraltar. The instability of this inflow and local wind action often generate coherent vortices in several parts of the basin that enhance the mixing of these incoming light waters with the saltier resident waters (e.g., Millot 1999 , 2005 ). Analysis of altimetric maps shows that PDFs of
PDFs are due to coherent vortices in a semienclosed basin such as the Mediterranean basin. The Mediterranean Sea is dominated by the entrance of freshwater incoming from the Atlantic Ocean through the Strait of Gibraltar. The instability of this inflow and local wind action often generate coherent vortices in several parts of the basin that enhance the mixing of these incoming light waters with the saltier resident waters (e.g., Millot 1999 , 2005 ). Analysis of altimetric maps shows that PDFs of
. The fittedparameters are consistent with independent estimates of the errors in the wind stress analysis. The calibratederror model is used in a Kalman filtering scheme to generate monthly sea level height anomaly maps for thetropical Pacific. The filtered maps, i. e., those which result from data assimilation, exhibit fine structure that isabsent from the unfiltered model output, even in regions removed from the data insertion points. Error estimates,an important byproduct of the scheme, suggest
. The fittedparameters are consistent with independent estimates of the errors in the wind stress analysis. The calibratederror model is used in a Kalman filtering scheme to generate monthly sea level height anomaly maps for thetropical Pacific. The filtered maps, i. e., those which result from data assimilation, exhibit fine structure that isabsent from the unfiltered model output, even in regions removed from the data insertion points. Error estimates,an important byproduct of the scheme, suggest
transects of Drake Passage using underway acoustic Doppler current profiler (ADCP) data. They extracted the upper-ocean ageostrophic velocity profile from this dataset by removing an estimate of the geostrophic velocity, assumed constant with depth, taken as the ADCP velocity at 98 m. This method was based on a favorable comparison, at that depth, between the vertical shear of the ADCP cross-track velocities and independent geostrophic cross-track velocity shear estimated from expendable
transects of Drake Passage using underway acoustic Doppler current profiler (ADCP) data. They extracted the upper-ocean ageostrophic velocity profile from this dataset by removing an estimate of the geostrophic velocity, assumed constant with depth, taken as the ADCP velocity at 98 m. This method was based on a favorable comparison, at that depth, between the vertical shear of the ADCP cross-track velocities and independent geostrophic cross-track velocity shear estimated from expendable
useful to review the results of a purely linear analysis of (2.6) and (2.7) . Neglecting all nonlinear terms yields (after some algebra) The normal modes of the above are extracted by adding (2.9) and (2.10) , the latter having been multiplied by an unknown coefficient, α. The aim of a normal mode analysis is to produce an equation in one variable only. Some straightforward algebra demonstrates that α values of yield two equations of the form ( h ± ) t − β ± ( h ± ) x = − β ± ϕ x , (2
useful to review the results of a purely linear analysis of (2.6) and (2.7) . Neglecting all nonlinear terms yields (after some algebra) The normal modes of the above are extracted by adding (2.9) and (2.10) , the latter having been multiplied by an unknown coefficient, α. The aim of a normal mode analysis is to produce an equation in one variable only. Some straightforward algebra demonstrates that α values of yield two equations of the form ( h ± ) t − β ± ( h ± ) x = − β ± ϕ x , (2
low frequencies. For the data set discussed in this paper,a direct comparison has not yet been possible as theobservational period does not overlap with that ofavailable weathership records. Nevertheless, a comparison of spectral quantities is meaningful providedthat the statistical properties of the wind field donot change in time. Fig. 8 shows autospectra of the wind componentsfrom the Atlantic Weather Station "C", togetherwith those from the nearest grid point of the synoptic map. The
low frequencies. For the data set discussed in this paper,a direct comparison has not yet been possible as theobservational period does not overlap with that ofavailable weathership records. Nevertheless, a comparison of spectral quantities is meaningful providedthat the statistical properties of the wind field donot change in time. Fig. 8 shows autospectra of the wind componentsfrom the Atlantic Weather Station "C", togetherwith those from the nearest grid point of the synoptic map. The
), this leads to a system of d = 5 × N × M × L nonlinear algebraic equations. These are solved with Δ S as a control parameter using a pseudoarclength continuation method; details on this methodology are provided in Dijkstra (2005) . For each of the steady states, we now consider the evolution of infinitesimally small disturbances within the model. Linearizing (1) and (2) in the amplitude of the perturbations and separating the equations for these disturbances in time, an elliptic
), this leads to a system of d = 5 × N × M × L nonlinear algebraic equations. These are solved with Δ S as a control parameter using a pseudoarclength continuation method; details on this methodology are provided in Dijkstra (2005) . For each of the steady states, we now consider the evolution of infinitesimally small disturbances within the model. Linearizing (1) and (2) in the amplitude of the perturbations and separating the equations for these disturbances in time, an elliptic
