P69  Using the NASA-Unified WRF to Assess the Impacts of Real-         Time Vegetation on Simulations of Severe Weather

Case, Jonathan L., ENSCO Inc./National Aeronautics and Space Administration SPoRT, Frank J. LaFontaine, Raytheon/NASA SPoRT Center, Sujay V. Kumar, SAIC/NASA GSFC, Christa D. Peters-Lidard, NASA GSFC

The NASA Short-term Prediction Research and Transition (SPoRT) Center has developed a real-time Greenness Vegetation Fraction (GVF) dataset, updated daily using swaths of Normalized Difference Vegetation Index data from the Moderate Resolution Imaging Spectroradiometer (MODIS) data aboard the NASA-EOS Aqua and Terra satellites.  SPoRT began generating real-time GVF composites at 1-km resolution over the Continental United States beginning 1 June 2010 for incorporation into the Land Information System (LIS) within the NASA-Unified WRF (NU-WRF) modeling system.  This paper will focus on individual case studies of severe weather events at a convection-allowing resolution to determine the impacts of incorporating real-time, high-resolution MODIS GVF in place of the Advanced Very High Resolution Radiometer (AVHRR)-based climatology GVF. 

The NU-WRF modeling system is employed to conduct sensitivity simulations of individual events.  The NU-WRF is an integrated modeling system based on the Advanced Research WRF (ARW) that is designed to represent aerosol, cloud, precipitation, and land surface processes at satellite-resolved scales in a coupled simulation environment.  For this experiment, the coupling between the LIS and the ARW model is utilized to measure the impacts of the real-time SPoRT/MODIS versus the monthly AVHRR climatology GVF.  Snapshots of LIS-Noah land surface fields from spin-up runs are used to initialize two different coupled simulations of the NU-WRF: one running with climatology AVHRR-based GVF, and the other running with the real-time MODIS-based GVF.  Results are highlighted in regions with substantial differences in GVF between the AVHRR climatology and SPoRT/MODIS product during severe weather episodes.  While many events examined had relatively minor impacts on the resulting simulations, a few severe-weather episodes experienced improved evolution of simulated precipitation by incorporating the real-time SPoRT/MODIS GVF, including the Upper Midwest severe outbreak of 17 July 2010 and the Joplin, MO tornado day of 22 May 2011.