Assimilation Test and Analysis of the GPS Data from the Eastern Margin of Tibetan Plateau in the Rainstorm Simulation

An assimilation test was conducted by selecting the intensive precipitation that occurred on June 30th, 2009 in south Yunnan and north Hunan as well as by using WRF model and the precipitable water vapor (PWV) data observed at 18 ground- based GPS stations established in the eastern margin of Tibetan Plateau. The experiment shows that the assimilation with the GPS / PWV data from all the 18 stations including 8 stations in Yunnan Province found out that the precipitation intensity varied greatly in north Hunan in the intensive precipitation region of the downstream area and that the assimilation with the GPS / PWV data from 6 stations in the vicinity of 100°E found out that the precipitation intensity varied little in north Hunan in the intensive precipitation region of the downstream area. Using the GPS / PWV data from all the stations, the humidity in most part of the area of model initial increased, the corresponding downstream precipitation central intensity increased, the humidity in small part of the area decreased and the corresponding precipitation area shifted southward. The assimilation of the GPS / PWV data had a greater effect on the model initial temperature field and height field, but a smaller effect on temperature and wind field.