2010年7～8月四川三次大暴雨过程区域数值模式能力评估

本文对2010年7月14~19日、7月22~24日、8月17~19日四川出现的3次区域性大暴雨过程,比较分析了成都区域中心及国家气象中心运行的GRAPES模式降水预报情况以及中、高层环流形势,通过天气学检验得出以下结论:(1) G-SC模式预报降水范围偏小、强度偏弱,强降水中心存在较大偏差;G-BJ模式能预报出降水的主要落区,但降水强度偏弱,虚假强水中心偏多;(2) GRAPES模式对青藏高原东侧天气系统的预报能力偏弱,G-BJ对大尺度环流系统的预报能力优于G-SC模式;(3)九龙站和名山站单站探空廓线图显示G-SC模式在对流层高层温度和风速不随高度变化,对流层底层比湿较实况偏小,因此,温度场、风场以及湿度场强度及分布都有待改善;(4)成都区域中心运行的GRAPES模式在初值、高度场强度、近地面温度等方面都具有很大的改进空间,这需要在资料同化、边界层方案、地形处理等方面做工作。 

Capability Assessment of Regional Numerical Model on Thrice Heavy Rainstorm in Sichuan from July to August,2010

According to three regional heavy rain process appeared in Sichuan, during 14~19 July, 22~24 July, 17~19 August, 2010.It comparative analysed the precipitation forecast and in middle and high-level circulation of GRAPES mode from Chengdu Regional Center and National Meteorological Center, the results got by synoptic examination as follows:(1) the G-SC model forecast precipitation range slants are of small, weak intensity, rainfall center existences big deviation, The G-BJ model can forecast the main area of precipitation falling, but precipitation intensity is weak, the false strong water center slants more, (2) predict weather system of GRAPES mode on the east to Tibetan Plateau is weakly, the G-BJ on the prediction of large scale circulation system is better than the G-SC mode; (3) the sounding profile figures from Jiulong station and Mingshan station show that the temperature and wind speed in the upper troposphere from G-SC mode does not vary with height change, specific humidity in troposphere low-level smaller than observation, therefore, the intensity and distribution of temperature and wind and humidity field are expected to be improved, (4) There is a great room to improve the GRAPES mode from Chengdu regional center in the initial value, height intension, surface temperature and so on, which need to do some work on data assimilation, boundary layer scheme, terrain processing.