A Study on Distribution Characteristics of Heavy Precipitation in the Regions Supplied with Electric Power in Central and Eastern Tibet*

Abstract

Spatial and temporal distribution characteristics, precipitation concentration degree and concentration period distribution characteristics of heavy precipitation in Tibet Plateau region are analyzed with statistical methods, e.g. wavelet analysis, EOF analysis and precipitation concentration degree, etc. on the basis of daily precipitation data of 39 meteorological observation stations in Tibet region from 1980 to2012, and analysis results show that the spatial distribution of precipitation in Tibet region is seriously uneven, showing the distribution characteristics of low precipitation in the west and north and high precipitation in the east and south, and several heavy precipitation centers exist simultaneously; the frequency of heavy precipitation in Tibet shows an upward trend (up to 0.28 time /10a), and has a 11-year significant period; the precipitation concentration degree is 0.2-0.9, showing a gradual progressive increase trend from south to north; the precipitation is mainly concentrated between the 32nd Climate and the 45th Climate, that is, between early May and mid-August every year, in which the the precipitation is highly concentrated in the regions along Yarlung Zangbo River, and the precipitation concentration period in eastern Tibet region changes obviously, and Shigatse region, regions from eastern Nagchu to northern Nyingchi, and Yajiang valley are the main regions where precipitation concentration degree changes abnormally, and these regions are the key regions of power interconnection project in central and eastern Tibet, the study of which plays a science and technology support role in the operation and maintenance of power grid project.