Monday, 14 January 2002: 1:44 PM
Sea Surface Pressure Fields From NASA’s Seawinds Scatterometer and their Impact on NWP
The impact of the assimilation of scatterometer-derived pressures into an atmospheric model is investigated. Already, spaceborne scatterometers have demonstrated the ability of impacting model forecasts by providing surface vector wind measurements over the ocean with excellent spatial and temporal coverage. The present NASA scatterometer, Seawinds aboard the QuikSCAT satellite provides near-realtime data which is suitable for forecasts and assimilation into numerical models in a timely operational sense. The focus here is the assimilation of surface pressure fields calculated from the near-realtime QuikSCAT wind data through a variational method. Validation of the scatterometer-derived pressures is demonstrated with co-located in situ observations taken by research vessels and buoys. For the purposes of forecast impact assessment, the QuikSCAT pressures are assimilated at the NASA Data Assimilation Office using the GEOS model scheme. Separate model runs are compared using assimilated QuikSCAT pressures and assimilated QuikSCAT winds. Objective analysis of these forecasts will be presented and the impact of the scatterometer-derived pressures upon the model forecasts will be evaluated.