中国西北地区东部短时强降水时空特征

基于中国西北地区东部136个气象站2001-2011年每6 h地面降水常规观测资料、1 674个自动站2009-2011年逐时降水资料，运用气候统计、线性趋势、归一化、分区域统计以及降水集中度（PCD）和集中期（PCP）分析等方法，研究了西北地区东部短时强降水的时空分布和气候特征。结果表明：该地区短时强降水日数年际变化不大，但区域性的短时强降水过程呈明显增加趋势；短时强降水主要发生在7月上旬至8月下旬，且具有明显的日变化特征；短时强降水总频次的空间分布与地势分布比较一致，高频高值区多位于夏半年环流盛行西南气流的迎风坡附近；在空间上PCD由东南向西北越来越集中，PCP自东向西逐步推迟。

Spatio-temporal Characteristics of the Short-time Heavy Rainfall in the East of Northwest China

In this paper, the spatio-temporal distribution and climate characteristics of short-time heavy rainfall in the east of Northwest China is studied based on every 6h rainfall observation data of 136 meteorological stations in the east of Northwest China from 2001 to 2011 and hourly precipitation data from 2009 to 2011 of 1674 automatic meteorological stations, by using climate statistical analysis, linear trend analysis, normalized analysis, subregional of statistics analysis, precipitation concentration degree (PCD) and precipitation concentration period (PCP) analysis. Results showed that the short-time heavy rainfall days interannual change is unobvious, but the regional short-time heavy rainfall process has increased significantly; the short-time heavy rainfall is mainly happened from early July to late August, and it has obvious diurnal variation; the spatial distribution of the short-time heavy rainfall frequency is accordant with the topography distribution, and high frequency area is located near the windward side of summer half year circulation prevailing southwest airflow; the PCD is more and more concentrated from southeast to northwest, and the PCP gradually postponed from east to west in the space.