近36年昌都市降水集中度与集中期时空变化特征

本文利用1980~2015年近36a昌都市7个台站的逐日降水资料,计算降水集中度(PCD)与集中期(PCP),采用相关分析、合成分析等统计方法研究对PCD、PCP时空特征及与年降水量关系进行分析。结果表明:昌都市PCD范围在0.53~0.76,多年平均值为0.64,PCP范围在39候(7月中旬)~45候(8月中旬),平均值为41.7侯(7月下旬);空间上,昌都市PCD由北向南,自西向东逐渐增大,PCP呈“北早南晚、西早东晚”分布;昌都市大部地方PCD与年降水量呈显著正相关,年降水越多,降水越集中,出现“先旱后涝”的可能性越大。 

Temporal and Spatial Change Characteristics of Precipitation Concentration Degree and Precipitation Concentration Period in Qamdo over the Last 36 Years

Based on the daily precipitation data from the 7 weather stations in Qamdo from 1980 to 2015,this study calculates the precipitation concentration degree (PCD) and precipitation concentration period (PCP) and analyzes the spatio-temporal characteristics of PCD and PCP and their relationship with annual precipitation,by using the statistical methods of correlation and composite analysis. The results show that the range of PCD in Qamdo is between 0.53 and 0.76,and the average PCD is 0.64; the range of PCP is between 39 (mid-July) and 45 (mid-August) pentads,and the average PCP is 41.7pentads (late July). From the spatial distribution,the PCD gradually increases from north to south and from west to east; and the PCP distributes as “early in the north and late in the south,early in the west and late in the east”. In most areas of Qamdo,there is a obvious positive relationship between the PCD and the annual precipitation,thus,the precipitation is more concentrated over the areas with more annual precipitation,in addition,and the possibility that “drought earlier and flood later”occurs is greater.