青藏高原东缘GPS水汽资料对暴雨模拟的影响分析

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

选取2009年6月30日发生在云南南部和湖南北部的强降水过程,利用WRF模式和建立在青藏高原东缘地区18个地基GPS站点观测的可降水量资料(GPS/PWV)进行同化试验。试验表明:选取全部18个站和云南省8个站GPS/PWV资料进行同化,发现下游地区的强降水区湖南北部降水强度发生较大变化。选取100°E附近的6个站GPS/PWV资料进行同化,发现下游地区的强降水区湖南北部降水强度变化不大。利用全部站点GPS/PWV资料,模式初始场大部分地区湿度增加,对应下游降水中心强度增加,少部分地区湿度减少,对应降水区域南移。GPS/PWV资料同化对模式初始场湿度场和高度场影响较大,而对温度和风场影响较小。

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 preeipitable 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 th, e GPS/PWV data from all the 18 stations including 8 stations in Yunnan Province found out that the precipitation intensi- ty 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.