Séminaire

Coastal regions provide a wide range of resources and services, and thus represent an essential environment for human activities. Hori- zontal transport and cross-shelf exchanges play an important role in regulating the ecological and biogeochemical conditions of coastal en- vironments. Therefore, understanding the mechanisms which regulate and control these processes is crucial for the sustainable management of coastal resources. In recent years, the identification of Lagrangian Coherent Struc- tures (LCSs) has become increasingly important for the analysis of horizontal mixing and transport in the oceans. Altimetry-based LCSs provide accurate information on transport and mixing patterns in the open ocean. However, results from the Latex10 campaign (1-24 September, 2010) showed that they are unreliable close to the coast. In order to accurately characterize transport patterns and their impact in coastal regions, we present a multidisciplinary approach which integrates novel analytical techniques based on in-situ, satel- lite and numerical data. Such approach will be initially tested in the Gulf of Lion (GoL, Northwestern Mediterranean), although its gen- eral design is valid for any coastal region. LCSs will be identified from both realistic numerical model simulations and altimetry derived ve- locity fields. A region-specific processing procedure for along-track altimetry measurements will be applied in order to obtain more ac- curate altimetry derived velocity fields in the GoL. LCS maps will be analyzed with the Self Organizing Map technique (SOM) to identify the dominant transport patterns and their temporal variability. Re- sults from the numerical model, as well as in-situ observations, will be used to evaluate the corrections on the altimetry velocity fields. The PHYSAT algorithm will be used to characterize the spatial and temporal variability of the ecological community from remote sensed optical measurements. Comparing the detected transport patterns with the corresponding phytoplankton assemblages will allow to as- sess their ecological impact and to investigate the underlying physical- biogeochemical interactions. Such results are expected to provide a significant contribution for the development of a sustainable manage- ment of the ecological resources of the GoL.