GPS折射率资料在梅雨锋暴雨数值模拟中的应用

The Application of GPS Refractive Index Data to Numerical Simulation of Meiyu Front

运用WRF三维变分同化系统同化GPS掩星折射率资料,并应用到2007年7月4—6日梅雨锋暴雨个例中进行数值模拟试验,以此考察GPS掩星折射率资料在梅雨锋暴雨数值模拟中的应用。同化结果表明:GPS掩星折射率资料对初始资料的调整主要是中低层湿度场,对于温度场和高度场的调整都是从底层到高层逐渐增大;加入GPS掩星折射率资料对降水预报有所改进,这与中低层湿度场的初始调整有关系;从对模拟结果进行诊断和结构分析中可以发现负散度增量和正涡度增量与降水中心和区域有很好的对应,同化资料之后对于各降水中心地区增强了产生降水的动力条件。

In this paper,GPS occultation refractive index data are assimilated by three-dimensional variation assimilation system of WRF model which is used to explore the improvement of its initial value through the numerical simulation of 4-6 July 2007 Meiyu.GPS occultation data adjustments to the initial data are mainly at low-level moisture field;For the temperature and height fields,adjustments are gradually increasing from bottom to top.The horizontal and vertical incremental analysis is able to explore the effects of assimilation on improving the forecast,as well as learn more about the spatial structure of the system as a way to explore the dynamic mechanism of its occurrence and development.Assimilated results show that adding GPS occultation data to precipitation forecasting is the most obvious because of the initial low-level moisture field adjustment.The negative divergence and positive vorticity increments are well corresponding to precipitation zones.And it enhances the dynamic conditions of precipitation.