P-45

Progress of assimilating space-borne precipitation radars

Kozo Okamoto, Kazumasa Aonashi, Seiji Origuchi (Meteorological Research Institute MRI), Takuji Kubota (Japan Aerospace Exploration Agency) and Tomoko Tashima (Remote Sensing Technology Center of Japan)

Assimilating space-borne precipitation radars, including DPR on GPM-core and PR on TRMM, provides valuable information on vertical precipitation profile over the both land and sea that are not available with other instruments. They, however, have been underused due to the high nonlinearity of precipitation-related variables and difficult precipitation reproductivity of NWP models.

An ensemble-based variational assimilation (EnVA) scheme has been developed at MRI of JMA to address the nonlinearity issue and effectively utilize precipitation-affected satellite data. The EnVA scheme employs a cloud-resolving model of the non-hydrostatic model of JMA (JMA-NHM) to explicitly treat with precipitation variables. As the first step of assimilating precipitation radars, we investigated how well JMA-NHM simulated PR and DPR in the radar reflectivity space. It was found that JMA-NHM overestimated the reflectivity from ice particles and was not able to simulate bright bands. Based on these findings, conservative quality control procedures have been developed. Initial check of assimilating reflectivity is being conducted: reasonable increase in the precipitation was found where observed reflectivity was higher than model counterpart.