OSI SAF scatterometer wind products

In Europe, scatterometer product development is organised through the EUMETSAT Satellite Application Facilities. SeaWinds developments are focussed on using the data for Numerical Weather Prediction and short-range weather forecasting. The former is well suited by the products as currently produced at KNMI at 100-km resolution (see http://www.knmi.nl/scatterometer/qscat_prod). For short-range forecasting or in semi-enclosed sea areas such as the Mediteranean, however, higher resolution is desirable. KNMI attempts to improve the spatial filtering properties of the wind retrieval by using prior information on the expected meteorological balance, e.g., favouring rotational structures in high-latitude regions. Moreover, we use solutions in all wind directions, but weighted by their inherent probability. Our 2D Variational Ambiguity Removal, 2D-VAR, is capable of exploiting such probability information.

We anticipate that the 2D-VAR method has the advanced filtering properties for maintaining small-scale meteorological information in SeaWinds, while reducing noise. This is tested by comparing the spatial covariance structures of the KNMI products, with those of the NOAA SeaWinds product, and, for reference, those of the ECMWF model. The methodology leads towards a high-resolution scatterometer wind product for SeaWinds, but is also envisaged for ASCAT on METOP.