大渡河流域降水时空变化特征

Temporal and Spatial Variation of Precipitation in Dadu River Basin

大渡河流域作为岷江正源,该流域的降水不仅对大渡河水循环以及山洪灾害的防治有着重要影响,而且对岷江也有着极其重要的影响。通过arcgis水文分析,将大渡河流域分为13个支流区域。基于1979-2018年降水数据,综合分析大渡河流域及13个支流的年、季节、月降水量以及日尺度极端降水的时空变化特征。结果表明:(1)1979-2018年间,在流域尺度上,不同时间维度的降水量变化趋势虽然不一致,但均不显著。其中,年降水量呈上升趋势,为0.11 mm.a^(-1);春、冬季降水呈上升趋势,夏、秋季降水呈下降趋势。在水资源分区上,各分区不同时间尺度降水的变化趋势呈明显的非一致性,其中大渡河各分区中上游降水为上升趋势,下游为下降趋势。(2)大渡河流域降水存在明显的空间分异性,且随着降水指标时间尺度的缩短而增强;不同时间维度降水整体上呈自东南部向西北部减少的趋势,流域的东南部始终为高值中心。

Dadu River Basin is the source of Minjiang River,the precipitation in the region has great influence not only on the water cycle of Dadu River,as well as the prevention and control of disasters of torrential flood,but also on the condition of Minjiang River.Dadu River Basin is divided into 13 tributary regions through ArcGIS hydrological analysis.The temporal and spatial variations of annual,seasonal,monthly precipitation and daily scale extreme precipitation in the Dadu River Basin and 13 tributaries were comprehensively analyzed based on the precipitation data from 1979 to 2018 in the paper.The results showed that(1)from 1979 to 2018,the variation trends of precipitation of the basin were inconsistent in different season,but the differences were not significant,and the annual precipitation presented an upward trend in these years,which was 0.11 mm.a^(-1)on average,and it presented upward trend in spring and winter,downward trend in summer and autumn,in different water resource partition of the basin,the variation trend of precipitation at different season showed obvious inconsistency,it presented upward trend in the middle and upper reaches and downward trend in the lower reaches;that(2)the spatial differentiation in precipitation of Dadu River basin was obvious,and the differentiation increased with the shortening of the time scale of the precipitation index,the precipitation presented decreased trend from southeast to northwest in different season,and the southeast of the basin was the center of high precipitation all the time.