地表阻曳系数对暴雨数值天气预报影响的对比试验

THE COMPARATIVE EXPERIMENT OF INFLUENCES ABOUT SURFACE DRAG COEFFICIENTS IN BOUNDARY PROCESS ON NUMERICAL WEATHER FORECASTING FOR HEAVY RAIN

为研究边界层过程中地表阻曳系数对短期数值预报（特别是降水）的影响，利用复杂地形条件下有限区域数值预报模式，根据青藏高原及其北侧部分地区已有的观测结果，改变了不同地区地面阻曳系数及其组合，设计出４种不同的数值试验方案，对１９９１年６月１１—１５日的一次典型江淮梅雨天气过程进行了２４—９６ｈ数值预报试验。结果表明：（１）地表阻曳系数对雨量中心强度的短期预报有一定影响；（２）４个方案中以修改了青藏高原及其北侧地区阻曳系数值的方案２更好些；（３）随积分时间延长。

In this paper,the limite-area numerical weather forecasting model suitable for complex topography and the observation data over Tibetan Plateau and part area of its north-side are used to study the influences of surface dray coefficients in boundary process on numerical weather forecasting ( especially precipitation forecasting ) Firstly,dray coefficients of different underlying surface are altered and combined Secondly,4 groups of different numerical experiment schemes are designed At last,24 96h numerical forecasting experiments about a typical Jianghuai Meiyu heavy rain weather process during 11 15 June,1991 have been carried out The results show: (1) Surface dray coefficients has some influences on short-range forecasting of center intensity of rainfall (2) Among 4 schemes,scheme 2,in which the drag coefficients over Tibetan Plateau and part area of its north-side are modified,has a better result (3) With integration time prolonging,the influences about boundary process on rainfall and weather situation are more notable