Assimilation of GPM GMI rainrate product with community GSI and case study result

The Global Precipitation Measurement (GPM) is a multi-satellite constellation that provides real time or near real time global observations of rain and snow since being launched on February 2014. With the dual-frequency precipitation radar and the 13-channel Microwave Imager (GMI), the GPM can provide observations for light to heavy precipitation from tropics to high latitudes. This research is to investigate the assimilation of the GMI level-2 retrieved rainrate product and to assess its impact on precipitation forecast of severe weather. The community Gridpoint Statistical Interpolation (GSI) v3.4 developed by the Development Testbed Center (DTC) is used to conduct the data assimilation experiments. With collaboration with the NASA Short-term Prediction Research and Transition (SPoRT) Center, this research explores regional assimilation of the GPM GMI rainrate product with case studies for convective storms.

Our presentation will highlight recent progress on development of the methodology to assimilate the GPM product 2AGPROFGMI. Case studies with assimilation of the retrieved GMI rainfall rate data for initializing real convective storms will be discussed. Data assimilation experiments and fine resolution simulations of the convective storms conducted using the Weather Research and Forecasting (WRF) model will be compared and assessed for the impact of the GMI rainfall rate data. Details on the methodology of data assimilation, preliminary result from numerical experiments and the impact of GMI data on precipitation forecast will be presented at the conference.