丽江近51年暴雨异常气候特征

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

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.

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.