宁夏六盘山和周边地区1980—2017年降水变化特征

Characteristics of Rainfall Changes in Liupanshan and Its Surrounding Areas During 1980 to 2017

基于1980—2017年宁夏六盘山、固原、西吉、隆德、泾源4站的逐日降水资料,研究近38 a宁夏六盘山和周边地区降水量和降水日的变化特征.结果表明,在六盘山及其周边地区,小雨对年降水量和年降水日贡献最大,中雨和大雨其次,暴雨最小.周边地区的年代平均降水量呈明显的增加趋势,以152.1 mm/10 a的速度递增,六盘山地区的变化趋势不明显.六盘山地区的年代降水日明显减少,周边地区呈现微弱的增加趋势.六盘山地区不同强度降水量均呈减少趋势,周边地区除大雨外不同强度降水量均呈增加趋势.六盘山地区年平均总降水日、小雨日、中雨日呈减少趋势,大雨日和暴雨日呈增加趋势,而周边地区除大雨日外不同强度降水量均呈微弱的增加趋势.小雨日的减少是六盘山地区年降水量减少的主要原因,并在1988年发生突变后持续减少,且通过0.01的显著性检验;中雨量的增加是周边地区年降水量增加的主要原因.

Based on the daily rainfall data of four stations in Liupanshan,Guyuan,Xiji,Longde,and Jingyuan of Ningxia from 1980 to 2017,the variation characteristics of rainfall amount and rainy days in Liupanshan Mountain and its surrounding areas in the last 38 years were studied.The results show that in Liupanshan and surrounding areas,light rainfall contributes most to annual rainfall and annual rainfall days,followed by moderate and heavy rainfall,and least heavy rainfall.The mean annual rainfall in the surrounding areas shows a clear increasing trend with 152.1 mm per 10 years increments,while the trend in Liupanshan area is not obvious.The annual rainfall time in Liupanshan station decreases significantly,and the surrounding areas show a weak increasing trend.The rainfall at Liupanshan station shows a decreasing trend for all magnitudes,while the surrounding areas show an increasing trend except for heavy rainfall.The annual average total rainfall days,light rainfall days and medium rainfall days at Liupanshan station show a decreasing trend,and heavy rainfall days and heavy rainfall days show an increasing trend;while the surrounding areas show a weak increasing trend except for heavy rainfall days.The decrease of light rainfall days is the main reason for the decrease of annual rainfall at Liupanshan station and continues to decrease after the abrupt change in 1988,which passed the significance test of 0.01;and the increase of medium rainfall is the main reason for the increase of annual precipitation in the surrounding areas.