Preliminary Verification of the NCAR-AirDat Operational RTFDDA-WRF System

AirDat began operationally running an explicit, CONUS-Scale version of the Advanced Research WRF (ARW) known as the NCAR-AirDat RTFDDA-WRF during the summer of 2009. The system is built upon the WRF model framework, but uses a Newtonian relaxation observational nudging data assimilation engine, which allows the model to more effectively assimilate asynoptic measurements such as those collected by the Tropospheric Airborne Meteorological Data Reporting (TAMDAR) sensor. The TAMDAR sensor measures humidity, pressure, temperature, winds aloft, icing, and turbulence, along with the corresponding location, time, and altitude from built-in GPS. These observations are transmitted in real time to a ground-based network operations center via a global satellite network.

Verification of the NCAR-AirDat RTFDDA-WRF operational forecasts was conducted by interpolating the model output to WMO/GTS standard radiosonde and METAR station points and computing statistical error metrics including BIAS, MAE and RMSE. The objectives of this study are to (i) Identify the impacts that TAMDAR data may have on the WRF-ARW forecast system, (ii) quantify any gains in forecast skills provided by more adequately assimilating asynpotic observations, and (iii) monitor the accuracy, contribution, and health of the TAMDAR QA system. Preliminary verification results suggest that the proper assimilation of the TAMDAR data improves the analyses and forecasts of the NCAR-AirDat operational 4 km CONUS RTFDDA-WRF system. These findings will be presented for the second half of 2009.