JP2.9 Enhancement of the Weather Research and Forecasting Model with Additional Radiosonde Data for a High-Resolution a Mesoscale Modeling System

Tuesday, 2 June 2009
Grand Ballroom Center (DoubleTree Hotel & EMC - Downtown, Omaha)
James Reynolds, US Army, Dugway, UT; and E. G. Astling

This study investigates the impact of including data from additional radiosondes in the Deterministic Four-Dimension Weather (D-4DWX) system at Dugway Proving Ground (DPG). Radiosonde measurements from DPG and the National Weather Service station in Salt Lake City (SLC) are used in this assessment. The distance between the two stations is 90 km. In the initial comparison, 1200 UTC SLC radiosonde observations were compared to DPG radiosonde observations taken between 1000-1400 UTC. Results from a sample size of more than 100 cases over a 4-year period showed differences in both temperature and wind measurements. The largest temperature difference was found at the lowest levels, with DPG colder than SLC, and the largest U and V wind component differences occurred near mountain ridge top levels at approximately 700 hPa. These results formed the basis for using analysis and forecast output fields from the D-4DWX to compare with DPG radiosonde flights that were not assimilated into D-4DWX. When local observations from one or more rawin observing systems are included in the assimilation its impact can then be measured. In this case, the model analyses or forecasts of the near surface temperature and wind field can be measured against an existing mesoscale network of Surface Atmospheric Measurement System (SAMS) stations and radiosonde flights for verification. The results of the comparisons will be based on standard statistical methods.
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