For several years the CERSAT has been providing sea ice maps derived from various scatterometers (microwave radar) on board earth observation satellites (ERS-1, ERS-2, ADEOS-1 or QuikSCAT). This instruments initially designed for measuring winds at the ocean surface allow to detect both the edge of the ice pack and the nature of the ice which it is made of (first-year, old ice, ...). A correlation analysis technique between successive maps is used to determine the movements animating this sea ice, mainly under the effect of the winds.
The full package gathering all data collected along the WOCE experiment (in-situ, satellite, models,...) is now available on a double DVD. The data are stored as homogeneous netCDF files. Search and visualization tools are also included within the DVDs. As a contribution to this dataset, CERSAT provides global satellite mean wind fields, weekly and monthly averaged, covering the 1991-2002 period and using measurements by ERS-1, ERS-2, ADEOS/NSCAT and QuikSCAT.
The DVD was first distributed at WOCE final conference, hold in San Antonio (Texas) from 18th to 22nd November. It will be soon available at CERSAT.
Nevertheless, the satellite mean wind fields featured within the DVD are already available on CERSAT anonymous ftp server (ftp.ifremer.fr, folder : ifremer/cersat/products/gridded/mwf-*) or on our web site ("data" topic).
In the frame of the PNEC (Programme National d'Environnement Côtier) and the Défi IFREMER Golfe de Gascogne, a new browser of images has been developed and is now available at the CERSAT site. It features day by day images of remote-sensed parameters over the Bay of Biscay (sea surface temperature, chlorophyll, solar irradiance,...). The browser makes possible monitoring and understanding of typical phenomena like algua blooms. It is also intended to feed and to validate biogeochemical models.
Extending the dataset set up with ERS-1, ERS-2 and NSCAT series, CERSAT provides the scientific community with easy-to-use synoptic gridded fields of wind-related parameters (speed and stress vectors), estimated from observations by NASA scatterometer SeaWinds onboard QuikSCAT. They are provided with three time resolutions - daily, weekly and monthly averages - on a global 0.5°x0.5° resolution grid, since July 1999. The data are available in netCDF format and quicklook pictures are also provided.
Waves are being measured over the whole surface of the ocean by ESA satellite ENVISAT. Before being assimilated operationaly in forecasting models, the ENVISAT/ASAR wave data have to be fully calibrated and validated. In order to make this task easier, CERSAT is providing users with colocated datasets of ASAR (onboard ENVISAT) cross-spectra and wave spectra with in-situ measurements (wind, waves, sst) from various buoy networks. Envisat ASAR Wave mode products are also colocated with WAM data from the ECMWF model.
JASON-1 is a new franco-american altimeter launched in December 2001. Using the colocated datasets distributed at CERSAT, here is a first estimation by Pierre Queffeulou (IFREMER/CERSAT) of Jason data quality from comparisons with other altimeters as well as in-situ (buoys) measurements. This study focus on wind and significant wave height measurements provided by this instrument. They are inter-compared with similar observations by ERS-2 and GFO altimeters.