THE IMPACT OF SEASAT-A SCATTEROMETER DATA ON HIGH-RESOLUTION ANALYSES AND FORECASTS - THE DEVELOPMENT OF THE QE II STORM

In this paper the impact of Seasat scatterometer winds in numerical weather prediction (NWP) is discussed with the help of the results of some cases studied. The development of the Queen Elizabeth II (QE II) storm from 1200 UTC 9 September to 0000 UTC 11 September 1978 is analyzed and forecast with a high-resolution (60-km) limited-area model (LAM). Parallel assimilation and forecasts are performed; in the SCAT run, Seasat scatterometer winds were used, but from the parallel NOSCAT run these winds were omitted. The NOSCAT analyses catch the development of the QE II storm better than any other operational numerical weather prediction model did, to our knowledge. When Seasat surface winds were included, the wind and sea level pressure were analyzed even better. Also, the forecasts improved substantially. We expect that the impact of these winds in NWP models can be enhanced not only by further research on and development of assimilation methods, but also by an improved representation of the upper-air structure.