丽江近51年暴雨异常气候特征

利用丽江地区常规观测资料,对丽江地区近51年来暴雨事件发生的频次及强度进行分析,研究结果表明：（1）丽江地区暴雨事件全部发生在汛期内（5～10月）,呈单峰型分布,7月、8月为暴雨集中发生时期,连续性暴雨事件在丽江地区属于极小概率事件.（2）暴雨事件发生频次与降水量均呈现一致上升趋势,在年际尺度上具有3～5年的周期性.（3）丽江地区小雨发生频次最多,占总降水频次比率超过63％.暴雨频次所占比率较小,最高发生在7月,仅为2.69％.大雨与暴雨的频次占总降水频次不足9％,但由极端降水事件产生的降水量却占总降水量超过35％.（4）小雨、中雨的降水量年际变化稍小,呈下降的趋势;大雨、暴雨的降水量年际变化明显,有明显的上升趋势.

CLIMATE CHARACTERISTICS OF TORRENTIAL RAINFALL ANOMALY IN LIJIANG IN RECENT 50 YEARS

To analysis the frequency and intensity of torrential sing conventional observation data. The results show that： （1） in flood season （May -October）, presenting unimodal type. trated period. Continuity of the torrential rain events in Lijiang rain events in Lijiang area in nearly 51 years by u- Torrential rain events in Lijiang area all occurred July and August are torrential rain events concen- area belongs to small probability events. （2） Occurrence frequency of torrential rain events consistent with precipitation were showing rising trend. And they have cyclical of 3 o 5 years on the interannual scale. （3） Light rain occurrence frequency is most in lijiang area. The ratio of frequency is more than 63 %. And the torrential rain events is least, the ratio in July is the highest is only 2.69%. The frequency of heavy rain and torrential rain events of total precipitation frequency is less than 9%, but precipitation produced by extreme precipitation events to total rainfall of more than 35%. （4） The light rain and moderate rain precipitation interannual change is small, showing downward trend. The heavy rain and torrential rain precipitation has an obvious interannual variability, showing significant increased trend.