1961-2020年西北地区夏季降水趋势变化特征OACSTPCD

Based on the daily precipitation observation data of 364 stations in northwest China in recent 60 years,the spatial and temporal variation characteristics of summer precipitation trend in northwest China were compared and studied from the perspective of precipitation and precipitation days.The results show that,on average,the summer precipitation in northwest China accounts for more than 50%of the total annual precipitation in the region.On the whole,the precipitation in northwest China shows a linear trend of significant increase,but it is not consistent with the increase in the whole region.The number of stations with increased(decreased)precipitation accounts for about 57%(43%)of the total stations in the region,and the number of stations with increased(decreased)precipitation days accounts for about 43%(57%)of the total stations.The stations increased at the same time are mainly located in southern Xinjiang basin,the western northern Xinjiang,central and northern Qinghai,while the stations decreased at the same time are mainly located in southeast Gansu,Ningxia,eastern central Shaanxi and other places,while the stations with reversed changes are mainly located in northern Xinjiang,the southwestern edge of Qinghai province,and southern Shaanxi.In the past 60 years,the extreme precipitation and precipitation days in northwest China also show a linear increase trend.In addition to the interannual variation,there are also interdecadal variation characteristics of precipitation and precipitation days in various regions of northwest China,but there are certain differences in the change phases of different regions.