Assimilation of GPM GMI rainfall product with GSI system

As the next generation of the Tropical Rainfall Measuring Mission (TRMM), the Global Precipitation Measurement (GPM) is providing observations of rain and snow worldwide since being launched on February 27th, 2014. The application of GPM data can have broad impact on numerical modeling of global precipitation.

This research is to examine the assimilation of the GPM Microwave Imager (GMI) retrieved product and to evaluate its impact on precipitation forecast of severe weather. We will use the community Gridpoint Statistical Interpolation (GSI) system developed by the Development Testbed Center (DTC) to conduct the data assimilation experiments. The community GSI system runs in independently environment, yet works functionally equivalent to operational centers. 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.

Our presentation will highlight our recent progress on the assimilation of the GPM product 2AGPROFGMI, the retrieved Microwave Imager (GMI) rainfall rate data for initializing a real convective storm. Data assimilation experiments and fine resolution simulations of the convective storm will be conducted using the Weather Research and Forecasting (WRF) model. The WRF model simulations and storm scale data assimilation results will be compared to evaluate the impact of the GMI rainfall rate data. Details of the methodology of data assimilation, preliminary result and test on the impact of GMI data and its influence on precipitation forecast will be presented at the conference.