摘要
基于1991—2013年5—9月内蒙古自治区117个气象站逐小时降水量资料,分别定义各站点小时降水量的强降水阈值,揭示强降水事件时空变化特征,同时利用经验正交函数(EOF)分析方法研究小时强降水变化特征。结果表明:第99个百分位阈值、强降水事件发生频率和1h降水量最大值空间分布基本一致,表现为自内蒙古西部向东部递增,高值区位于阴山山脉南部和大兴安岭山脉东南部的迎风坡,低值区位于内蒙古西部。21世纪以来,内蒙古强降水事件发生频率和强度都呈现增加的趋势。内蒙古强降水事件集中出现在7月中旬到8月上旬,而且午后至傍晚时段最为活跃,内蒙古东部区域的强降水事件有夜发性特点。内蒙古强降水事件持续时间在1~5h,其中持续时间为2h所占比例最大,说明强降水事件是由中小尺度天气系统造成的,而且同西太平洋副热带高压关系密切。
Based on the hourly precipitation data collected at 117 meteorological observation stations from May to September during 1991-2013 in Inner Mongolia,characteristics of spatial-temporal variations of hourly strong precipitation were studied with threshold values of hourly strong precipitation for each station and by Empirical Orthogonal Function(EOF)analysis method.The results showed that spatial distribution of 99%threshold value,strong precipitation frequencies and the maximum values of hourly strong precipitation occurred the same basically.There appeared increasing from the west to the east in Inner Mongolia.The high value areas were located on the windward slopes of the Yinshan Mountains and the Da Hinggan Mountains.The low value areas were located on the west of Inner Mongolia.It is founded that the frequency and intensity of hourly strong precipitation obviously increased in 21 th century.Hourly strong precipitation events appeared mainly from the mid July to the early August.Furthermore,the most active period emerged from the afternoon to the evening.The strong precipitation events appeared in the midnight on the east of Inner Mongolia.The strong precipitation events sustained 1-5hours,and the duration of 2hours was the largest proportion.The strong precipitation events were usually caused by the mesoscale and microscale weather system and had a close relationship with the West Pacific Subtropical High.
出处
《中国沙漠》
CSCD
北大核心
2015年第3期735-743,共9页
Journal of Desert Research
基金
中国气象局预报员专项项目(CMAYBY2014-009)
内蒙古山洪地质灾害防治气象保障工程预报预警业务子系统建设项目"强对流天气历史个例库建设研究"
内蒙古气象局专家型预报员暴雨团队
关键词
小时强降水阈值
时空变化
中小尺度天气系统
threshold value of hourly strong precipitation
spatial-temporal variations
mesoscale and microscale weather system
