Assimilation of space imagery for retrieving of marine surface currents

Autor: Korotaev, Gennady K., Huot, Etienne, Le Dimet, François-Xavier, Herlin, Isabelle, Stanichny, S.V., Solovyev, D.M.
Přispěvatelé: Marine Hydrophysical Institute (MHI), National Academy of Sciences of Ukraine (NASU), Coupling environmental data and simulation models for software integration (Clime), Inria Paris-Rocquencourt, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Modelling, Observations, Identification for Environmental Sciences (MOISE), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Laboratoire Jean Kuntzmann (LJK), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Pierre Mendès France - Grenoble 2 (UPMF)-Inria Grenoble - Rhône-Alpes
Jazyk: angličtina
Rok vydání: 2007
Předmět:
Zdroj: European Geosciences Union General Assembly 2007
European Geosciences Union General Assembly 2007, Apr 2007, Vienne, Austria
Popis: International audience; Variational assimilation method is applied to retrieve the sea surface velocity from the set of NOAA-AVHRR images with the spatial resolution 1 km. The method is based on the assumptions that the evolution of image contrasts is described by the transport -diffusion model and that the surface velocity field varies much slower than the temperature field observed by space imagery. The set of images of the Black and Caspian Sea surface is processed to analyze surface current scales and intensity. Space observations of fine scale meandering of the Rim Current Jet, fine structure of mesoscale eddy currents and detachment of the wind-induced coastal upwelling are the base of the analysis. Presented examples show that surface currents induced by mesoscale features with typical spatial scale up to few kilometers are very intense. The current speed obtained by the processing of imagery sometimes exceeds twice that retrieved from altimetry measurements, which assumes at least ten km spatial averaging. Maximal of velocity achieves 0.524m/s whereas altimetry assimilation shows broad jet with the current speed about 0.1-0.15 m/s. The current speed in mesoscale eddies in average is about 0.35 m/s while its maximum value achieves 0.444 m/s. The Black Sea Rim Current jet is rather narrow and subjected to the strong meandering. The most intense meanders induce the formation of cyclonic and anticyclonic eddies to the left and to the right of the jet. The current speed of the jet achieves 0.45 m/s which correspond to the restricted direct measurements which were fulfilled at the Black Sea. The comparison with independent measurements of sea surface currents by drifters show good quality of the estimated velocity field.
Databáze: OpenAIRE
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