玉溪暴雨天气发生规律及成因分析

1951~2008年玉溪市暴雨发生次数最多的是澄江县,其次是华宁、元江、红塔区。进入21世纪后,随着全球气候变暖,暴雨次数比20世纪明显增多,主要集中在盛夏6~8月,占总次数的72%,其中单点暴雨和小范围暴雨占全部过程暴雨的95%,造成了玉溪市主汛期洪涝灾害频繁发生。形成玉溪暴雨时空分布差异大的天气环流系统主要有切变冷锋型、高原糟冷锋型、两高辐合型、热带天气系统北上型四大类,其次,特殊的地形地貌也是造成玉溪单点暴雨和小范围暴雨较多的原因。

OCCURRENCE REGULARITY AND CAUSE ANALYSIS OF RAINSTORM WEATHER IN YUXI

The highest number of the rainstorms occurrence times is Chengjiang County in Yuxi during 1951 - 2008, followed by Huaning, Yuanjiang and Hongta. When entering the 21st century, as global climate getting warmer, the occurrence times of rainstorms increase significantly than that of 20th century, mainly concentrating in midsummer from June to August, accounting for 72% of the total number, in which single-point rainstorms and small-scale rainstorms occupy 95 % of whole process of rainstorms, resulting in frequent occurrences of flood disasters in main flood season in Yuxi. The formation of large differences between temporal and spatial distribution of Yuxi mainly has four kinds of atmospheric circulation systems, including shear-cold-front pattern, plateautrough-cold-front pattern, two-high-convergence pattern and tropical-weather-system-northward pattern, second- ly, the special landscape also contributes to more single-point rainstorms and small-scale rainstorms in Yuxi.