Assimilation of TRMM lightning data in the WRF-ARW Model

• 1、Atmospheric Science School，Lanzhou University，Lanzhou 730000

Abstract：Non-induced electrification theory and related observation show that there is a strong relationship between the occurrence of lightning flash and the content of precipitation-sized ice mass in the mixed phase region. The relationships between total lightning flash rate and ice-phase particles (i.e. graupel, ice and snow) on the scale of 10 km are constructed based on the TRMM observations of lightning flash, radar and microwave, then the assimilation of lightning data for the numerical weather prediction of a hail storm with three TRMM overpasses that occurred over the Huang-Huai Valleys on May 9, 1999 observations are conducted using the previous relationships between total lightning flash and ice-phase particle. The constructed relationships were added into the WSM6 microphysical scheme of Weather Research and Forecasting (WRF) to adjust the mixing ratio of ice-phase particles within the mixed phase region between ?10 C to ?40 C in order to improve the forecast skill of strong convections. The result shows that the magnitude and spatial distribution of water vapor, wind field and potential temperature in the initial field have been effectively adjusted in the assimilation experiment of flash data, which are favorable to the development of convection. In addition, both the short-term maximum radar reflectivity and precipitation forecasting are also improved, and closer to the TRMM observation.

Keywords： lightning ice-phase particle data assimilation WRF Model the TRMM satellite