南疆暴雨是小概率事件,其预报预警的难度较大。南疆一些暴雨过程的历时短,降水强度大,并伴有短时强降水事件（即“短时强降水暴雨”）;而另一些暴雨过程的降水时间相对较长,未伴有短时强降水事件（即“非短时强降水暴雨”）。为探究南疆上述两类暴雨的差异,利用2013—2019年426个自动气象站逐小时降水资料,对比分析了南疆夏季短时强降水暴雨和非短时强降水暴雨的差异,结果表明:（1） 南疆夏季以短时强降水暴雨为主,超过70%的站点在暴雨日中出现过短时强降水事件;短时强降水暴雨主要发生在7月,该月约95%的暴雨日中都出现过短时强降水事件。（2） 南疆海拔在2000~2500 m的站点出现暴雨的比例最高,海拔低于1000 m的站点最低。南疆短时强降水暴雨主要发生在海拔低于2000 m的区域,非短时强降水暴雨则主要发生在海拔高于2000 m的区域,上述两类暴雨均具有明显的夜雨特征。（3） 南疆总暴雨与短时强降水暴雨的累计降水量、降水频次和平均降水强度的日变化特征相似,二者与非短时强降水暴雨的差异较大。非短时强降水暴雨的累计降水量、降水频次和平均降水强度的峰值时段均出现在上午;短时强降水暴雨的累计降水量和平均降水强度的峰值时段出现在傍晚前后和前半夜,累计降水频次的峰值时段则主要出现在后半夜至清晨,短时强降水暴雨的降水强度与累计降水量的关系比降水频次更密切。南疆短时强降水暴雨和非短时强降水暴雨的观测特征存在显著差异,二者的降水形成机制也不相同。

The probability of a rainstorm in southern Xinjiang is small, and it is challenging to forecast and give an early warning of such events. Rainstorms in southern Xinjiang have a short duration and heavy intensity, accompanied by short-term heavy rainfall events. Other heavy rainfall events are relatively long, without short-term heavy rainfall events. To explore the differences between the two rainstorm types in southern Xinjiang, hourly precipitation data from 2013 to 2019 of 426 automatic weather stations were used to compare and analyze the fine observation differences in short-term heavy rainstorms and those without short-term heavy rainfall events. Results showed that heavy short-term rainfall occurred majorly during summer in southern Xinjiang, and more than 70% of the stations experienced heavy short-term rainfall during rainstorms. Heavy short-term rainfall occurred majorly in July, which accounted for approximately 95% of heavy rain days. Rainstorms with heavy short-term rainfall in southern Xinjiang are mainly distributed in areas with an altitude lower than 2000 m. Those without heavy short-term rainfall events are mainly distributed in areas with an altitude higher than 2000 m. The rainfall characteristics at night of the two types of rainstorms are evident in southern Xinjiang. The diurnal variation characteristics of cumulative precipitation, precipitation frequency, and average precipitation intensity are similar between the entire rainstorm days and the rainstorm days with heavy short-term rainfall events in southern Xinjiang. However, they are different from the rainstorm days without heavy short-term rainfall events. The peak periods of accumulated precipitation, precipitation frequency, and average precipitation intensity for rainstorm days without heavy short-term rainfall events appear in the morning. The peak periods of accumulated precipitation and average precipitation intensity for rainstorm days with heavy short-term rainfall events appear in the evening and the first half of the night. Also, the peak periods of accumulated precipitation frequency mainly appear from the second half of the night to the morning. The relationship between precipitation intensity and accumulated precipitation during rainstorm days with heavy short-term rainfall events is closer than precipitation frequency. The highest proportion of rainstorms occurred at stations with an altitude of 2000-2500 m in southern Xinjiang, and the lowest occurred at stations with an altitude of less than 1000 m. There were significant differences in the observable characteristics of rainstorms with heavy short-term rainfall events and those without heavy short-term rainfall events in southern Xinjiang. The precipitation formation mechanism of the two is not the same and requires further research.