基于精细化降水分布的山洪气象条件分析

Analyses of Meteorological Conditions Affecting Flash Floods Based on Elaborate Distribution of Precipitation

提出了天气雷达联合地面雨量计估测降水的局地分级平均校准方法。以该方法得到的精细化降水分布(0.01°×0.01°)为基础,对重庆綦江石角流域(面积707 km^2)2008年5月28日、2009年8月5日和2010年6月23日的3次洪峰过程进行了山洪气象条件分析。结合由数字高程模型(Digital Elevation Model,DEM)资料计算的流域河道出口距离分布,提出了流域出口无损径流序列(假设降水全部转换为径流)的预报方法。结果表明:与局地平均校准法相比,局地分级平均校准法对强降水的估计效果更好。无损径流预报对预测山洪发生的可能性具有参考意义。

A raingauge-based local classified average bias-adjusted algorithm for radar quantitative precipita- tion estimate is presented. Based on the elaborate distribution of precipitation with a resolution of 0.01°× 0.01° from the proposed algorithm, the meteorological conditions are examined for three flood peak events of Shijiao Catchment （707 km2） in Qijiang, Chongqing Municipality occurring on 28 May 2008, 5 August 2009 and 23 June 2010, respectively. A method of extrapolating lossless runoff series （given all precipitati- on transforming into runoff） is developed by combining the elaborate distribution of precipitation and the distribution of distance from catchment outlet calculated from DEM （digital elevation model）. The results show that： the local classified average bias-adjusted algorithm is a better way in the intense rainfall esti- mate than the local average bias-adjusted algorithm. The lossless runoff forecast gives support to alert forecasters to the potential for flash flood.