Variational Ambiguity Removal for the Scatterometer on-line Processing

IFREMER's Department of Oceanography from Space has developed specific softwares for on-line and off-line processing of the scatterometer data. It was done by CERSAT under European Space Agency contract. The algorithms resolve well the directional ambiguity problem in nearly 90% of the cases but provide unrealistic wind structures in the 10% left. These later cases are often linked to energetic mesoscale events that are of great interest for operational meteorology. Taking into account the experience acquired during the ERS experiment and previous studies performed at the French Meteorological Office (METEO-FRANCE), it is proposed to study an algorithm using variational techniques to resolve such cases with a reasonable percentage of success. Variational techniques are used operationally in the meteorological centers to estimate the best fit between the forecast wind field and the available observations. Thus a strong background exists in this field and can be used for scatterometer data processing.