短时强降水的高分辨率时空分布特征

为更深入了解短时强降水的气候背景，提高对短时强降水的预报水平及城市的防灾减灾能力，利用安徽79 个气象台站1995—2010 年逐小时降水量数据，基于统计方法对3 个强度等级的短时强降水(≥30 mm/h、≥40 mm/h、≥50 mm/h)的空间、时间分布特征进行分析。结果表明：空间上，安徽省短时强降水主要分布在淮北平原、大别山区和皖南山区。山区的强降雨位于山脉的迎风坡和河谷地带，呈西北—东南带状，与西南急流的方向垂直。相比于山区，淮北平原更易出现极端强降水(≥50 mm/h)。短时强降雨带在6—7 月有1 次明显的北跳，幅度约4 个纬度，与副高的北跳关系密切。时间上，短时强降水月分布呈单峰结构，7 月为最频发的月份。日分布则呈明显的双峰结构，凌晨、午后到傍晚是易发时间段，并且降水强度越强、双峰结构越趋明显。该研究为短时强降水的短时预报及临近预警提供了重要参考。

High Resolution Spatial-Temporal Distribution Characteristics of Short-time Heavy Rainfall

The paper aims to better understand climatic background of short-time heavy rainfall and improve the forecast level as well as disaster prevention and mitigation capacity. Based on hourly precipitation data of 79 meteorological observation stations in Anhui Province during 1995 and 2010, with the help of statistical method, the spatial-temporal distribution characteristics of short-time heavy rainfall with three intensity levels (≥30 mm/h, ≥40 mm/h, ≥50 mm/h) were analyzed. The results showed that, in terms of spatial distribution, high incidence of short-time heavy rainfall in Anhui was basically in Huaibei Plain, Dabie Mountainous Area and Southern Mountainous Area. The heavy rainfall zone of mountainous areas was located in the windward side of mountain and river valley, with northwest- southeast direction perpendicularly to the direction of southwest jet flow. Compared with the mountainous areas, the Huaibei Plain was more prone to observe extreme precipitation of more than 50 mm/h. There was an apparent jump to the north of short-time heavy rainfall zone from June to July, about four latitudes, which was closely related to subtropical high of northern jump. In terms of time distribution, month distribution of short-time heavy rainfall was unimodal structure, with the highest frequency in July. The diurnal variation had a clear characteristic of bimodal structure, with prone periods in the morning and from afternoon to the evening. And the stronger the precipitation intensity, the more obvious the bimodal structure was. This study provided an important reference for the short time forecasting and early warning of short-time heavy rainfall.