多普勒雷达资料对暴雨定量预报的同化对比试验

Comparison experiment of quantitative rainfall prediction for rainstorm with assimilated Doppler radar data

基于NCEP/NCAR再分析资料和连云港雷达探测资料,利用WRF模式及其三维变分同化V2.1系统,对发生在2008年4月19日连云港地区一次区域性暴雨过程进行了三维变分同化数值模拟对比研究。结果表明,同化了雷达资料后,模式预报效果比单独使用NCEP做初始场效果明显改善,暴雨落区和量值更接近实况。同化了雷达资料后,模式预报的垂直运动区、最大上升区、水汽输送通道和高空涡度分布等更接近强降水区,结构也更精细,说明初始场增加雷达资料后,对初始风场的结构、强度和初始云水分布有实质性的改进,从而提高了对暴雨定量预报的效果。

Based on NCEP/NCAR reanalysis data and Doppler radar data of Lianyungang, a local rainstorm process during April 19--20, 2008 over Lianyungang region was compared with Weather Research and Forecasting （WRF） Model and 3DVAR assimilation system of V2.1. The results showed that： the forecast efficiency with Doppler radar data had more significant improvement than that signal NCEP data. Rainstorm falling area and precipitation using WRF model with Doppler radar data were close to real data. The positions of the vertical movement region, the largest ascending region, the vapor transfer channel and the distribution of vorticity in altitude were close to heavy rain region after Doppler radar data was assimilated, the structure of them had also a more precise. So the wind structure with intensity and the cloud with moisture in initial fields had substantive improvement after Doppler radar data added into initial fields. The efficiency of quantitative rainfall prediction was improved.