Evaluation of TAMDAR Data Impact on 4-km CONUS WRF-based RTFDDA Simulations and Warm-season Convection Prediction

Upper-air observations are disproportionately sparse, both temporally and spatially, when compared to surface observations. Tropospheric Airborne Meteorological Data Reporting (TAMDAR) network, operated by AirDat LLC., dramatically enhances upper-air observations, especially in the lower troposphere. TAMDAR measures humidity, pressure, temperature, and winds by commercial airlines along the flight routes. The measurements have been assimilated into the WRF-based RTFDDA (Real-Time Four-Dimensional Data Assimilation) system that has been running operationally for the CONUS domain at 12-km and 4-km resolution since July 2009. In this work, the impact of TAMDAR data on RTFDDA simulations will be examined based on parallel runs with and without using the TAMDAR measurements. The simulations will be verified against radiosondes and surface observations. The TAMDAR data impact in association with increased horizontal resolution on RTFDDA simulations will also be investigated. Furthermore, based on case studies, we will examine how the WRF-based RTFDDA system, which incorporates all the available observations including the TAMDAR data, represents the coherently propagating “epidodes” of warm season rainfall over the CONUS. Comparisons of the model results of the 12-km and 4-km RTFDDA simulations will expose the strength and weakness of implicit versus explicit moist parameterization for summer convection predictions.