| The longitudinal Ridge Gorge in southwest China,the precipitation is affected by the southwest monsoon and the East Asian monsoon,plus the“channel-barrier”effect of the north-south trend to Hengduan mountain terrain,so it has a strong space-time division.However,due to the constraints of economy,climate,traffic and other conditions,the rainfall sites in the mountainous watershed of the Southwest plateau are scarce,which is difficult to reflect the temporal and spatial characteristics of precipitation in the basin.With the progress of remote sensing rain measuring technology,the research on precipitation characteristic analysis based on remote sensing precipitation data has become an effective means to carry out the research in the scarce area of measured data.This study aims to reveal the characteristics of precipitation in Nujiang River basin.Firstly,using the measured data of 12 meteorological stations in the basin,the correlation analysis and the scatter slope method are used to analyze the applicability of TRMM 3B43 Version7 precipitation data in this area.Then,using the relevant theories and methods of statistics and spatial analysis,based on TRMM 3B43 data from year,quarter.The precipitation characteristics in the basin were analyzed at the monthly scale,and the factors affecting the precipitation in the watershed were analyzed,and the following conclusions were obtained:1、TRMM 3B43 Version7 Monthly precipitation data have good applicability and high accuracy level in Nujiang River basin,which can be used to study the spatial and temporal distribution of precipitation in Nujiang River basin.2、Based on TRMM data,the precipitation characteristics of Nujiang river basin are discussed,and the following conclusions are obtained:(1)The spatial variability of precipitation in the watershed is strong,and the average annual precipitation is different in different regions.On the whole,the spatial distribution of the years mean precipitation in Nu River valley follows the increase from upstream to downstream,and the distribution rule of less rain area in the middle reaches.In the downstream of Yunnan Province(23.38°N~25.98°N),the annual precipitation is the most,the precipitation is over 1000 mm,and the upper reaches of Tibet(30.52°N~32.63°N)have the lowest annual rainfall and less than 550 mm precipitation.(2)The seasonal characteristics of precipitation in the basin are very obvious,the precipitation is mainly in summer,the precipitation in spring and autumn is the second,the winter precipitation is the least.The spatial distributions of precipitation and precipitation in flood season,non flood season and four seasons are different.Generally speaking,summer precipitation is between 240~900mm,spring and autumn precipitation is between 45~600mm and 75~420mm,winter rainfall is between 3~240mm,rainfall in flood season is in 363.5~1225.0mm,the area with the most precipitation is in the downstream of river basin,Non-flood season rainfall is between 47.6~609.0mm and the most precipitation area is located in the middle reaches of the river.(3)The characteristics of monthly precipitation,monthly precipitation and spatial distribution of precipitation in the upper,middle and lower reaches of the basin are different.Generally speaking,the downstream precipitation is the most,the precipitation is between 0~260mm,the second is the precipitation in the middle reaches of the river basin,the precipitation is between 0~225mm,the upper reaches of the basin is the least,the precipitation is between 0~150mm.Among them,the upper reaches of the basin is characterized by“single peak”,and the peak of precipitation occurs in June and July;Middle reaches have“single peak type”,“Shuangfeng type”and“three peak type”.The precipitation characteristic,the precipitation peak appears in March,May and July;the downstream precipitation features“single peak type”and “Shuangfeng type”,the peak value of precipitation appears in May,July and mid-August.3、The rainfall in the watershed has a strong correlation with the elevation of the topography,but the correlation with the slope and slope direction of the mountain is poor. |
PDF Full Text Request