P59  Inter-Comparison of the WRFv3.3.1 AFWA Operational and RRTMG-Replacement Configurations

Harrold, Michelle, Jamie Wolff, John Halley Gotway, Paul Oldenburg, and Zachary Trabold, National Center for Atmospheric Research/RAL and DTC

The Weather Research and Forecasting (WRF) model is a state-of-the-art numerical weather prediction system used in both research and operational forecasting applications. The model is highly configurable to the usersÕ requirements and suitable for a broad spectrum of weather regimes.  Rigorously testing select configurations and evaluating the performance for specific applications is necessary due to the flexibility offered by the model. The Developmental Testbed Center (DTC) performed extensive testing and evaluation with the Advanced Research WRF (ARW) dynamic core for two physics suite configurations, with a goal of assessing the forecast and computational performance of the updated Rapid Radiative Transfer Model (RRTMG) long- and short-wave radiation schemes. One configuration was based on the Air Force Weather AgencyÕs (AFWA) Operational Configuration, while the second configuration substituted AFWAÕs current operational long- and short-wave radiation schemes (RRTM/Dudhia) with the RRTMG radiation schemes. This presentation will focus on assessing the forecast performance of these two configurations; both configurations were run over the same set of cases, allowing for a direct comparison of performance between the two. The evaluation includes a forecast period from 2 June 2008 to 31 May 2009, with forecasts being initialized every 36 hours; this extensive testing period allows for robust results as well as the ability to investigate seasonal performance of the configurations. Results will focus on the evaluation of traditional verification metrics for surface and upper air variables, along with an assessment of statistical and practical significance. A brief analysis of computational resources required to run each configuration will also be discussed.