Comparison of Ocean Dynamics with a Regional Circulation Model and Improved Altimetry in the North-Western Mediterranean

Abstract

The spatial and temporal resolution of satellite altimetry is usually sufficient for monitoring the changes of sea surface topography in the open ocean. However, coastal ocean dynamics are much more complex, being characterized by smaller spatial and temporal scales of variability. The quality and availability of satellite-derived products along the coasts have to be improved, with a strategy optimized for coastal targets. Therefore a coastal multi-satellite altimetry dataset (TOPEX/Poseidon, Jason-1; Envisat; GFO) at a 10 -20 Hz sampling rate has been derived from routine geophysical data products using a new processing software dedicated to coastal zone applications. Improved along-track sea level variations with fine space scales are available in the North-western Mediterranean Sea from 2001 to 2003, and are compared with high-resolution numerical model elevations from the eddy-resolving model SYMPHONIE. This preparatory work emphasizes the potential of improved multi-satellite altimetry for validating coastal hydro-dynamical models and could contribute in the future to a better tuning of the boundary conditions of the simulations.

Modeling the spawning strategies and larval survival of the Brazilian sardine (Sardinella brasiliensis)

“…For SSH, the main differences are related to the underestimation of SSH values by the model. This bias is probably related to the thermal expansion of the water column (steric effect), present in SSH altimeter observations, but absent from ROMS because of the Boussinesq approximation, that captures only its spatial structure (Bouffard et al, 2008). Despite these limitations, the model results reproduced quite well the physical characteristics of SBB, as already detailed.…”

Recent improvements in mesoscale characterization of the western Mediterranean Sea: synergy between satellite altimetry and other observational approaches

“…In the Corsica Channel, the combination of several long-time-series tide gauges operated by national hydrographical services, three absolute calibration sites exploited by CNES, current-meter moorings maintained by CNR, and an XCTD transect in conjunction with along-track altimetry and multi-satellite cross-over points, has enabled the quantification of the geostrophic signal associated with the seasonal and sub-seasonal currents crossing the channel (Vignudelli et al 2005, Bouffard et al 2008b). This combination of data sources has also made it possible to estimate the error budget in monitoring the transport through the Corsica Channel with the X-TRACK coastal-oriented data by comparing the estimates deduced with in situ measurements.…”

Using a Lagrangian model to estimate source regions of particles in sediment traps

“…In this situation, the particle source regions or the "vertical flux" should be estimated very carefully. Recently, studies have proven that a three-dimensional (3D) flow field can be rebuilt by a well-rounded 3D hydrodynamic ocean model (e.g., Bouffard et al, 2008;Marsaleix et al, 2008); therefore, we use this method for our analysis.…”