Initialization Method

1. UW inverse PBL model Blend with NCEP SLP SLP (swath) QSCAT winds gradient winds BestTrack minSLP Balanced vortex (temp, ght, wind) Weighted vertical Distribution of wind 3-D Winds SLP QSACT 4DVar Prediction model (WRF, MM5, Coupled model) Initialization Method • Construct 3-D vortex using QuikSCAT winds • Generate dynamically/thermodynamically balanced initial vortex using 4DVar

2. Model Initial Conditions in Hurricane Isabel on 8 September 2003 NCEP QuikSCAT Blended QuikSCAT+NCEP QuikSCAT+4DVar

3. NCEP Vertical cross sections of potential temperature (black lines) and wind speed (color) of the three initial conditions. Warm Core Blended 4DVar

4. Control simulation without QuikSCAT data Data assimilation with QuikSCAT data + 4DVar Data assimilation with QuikSCAT data + 4DVar Observed

5. Comparison of Model Simulations W/O QuikSCAT data and Observed Rain/Reflectivity Simulation with NCEP analysis HRD P3 LF Radar Reflectivity In Hurricane Isabel (2003) Using Qscat Blended Data Using Qscat Blended Data + 4DVar