Variation Characteristics of Temperature and Precipitation over the Southeast Xizang since 1960

Abstract

This study used the daily temperature and precipitation data from 27 stations in southeast Xizang during 1960-2017 to study the characteristics of climate change in China， by using the linear trend test， Mann-Kendall test， wavelet analysis， and extreme climate index methods.The results demonstrate that： （1） the annual mean， maximum and minimum temperature show obviously rising trends， with the increasing rate of 0.29~0.43 ℃·（10a）-1.The temperature increase in winter is the most obvious.The annual precipitation shows an increasing trend as a whole， with a linear trend of 6.66 mm·（10a）-1， in which it decreases in summer and autumn， and increases in winter and spring.（2） The temperature and precipitation have multi-period changes； and both have a variation period， 28 a， on a large time scale.（3） The times of the abrupt change of average temperature， maximum temperature and minimum temperature were in 1994， 2001 and 1992 respectively， and the precipitation changed from less to more in 1979.（4） The indexes of extreme high temperature， such as TXx， TNn， TNx， TXn， all increase.The frequency indexes of high temperature events， such as TX90p， TN90p， show an increasing trend， while the frequency indexes of low temperature events， such as TX10p， TN10p， show a decreasing trend.The persistence index of high temperature events （WSDI） shows an increasing trend， and the persistence index of low temperature events （CSDI） shows a decreasing trend.（5） Except that the CWD and CDD show a decreasing trend， the other extreme precipitation indexes show an increasing trend.According to the change results of mean and extreme climate， the southeastern Xizang is generally warm and humid， and it is also a sensitive area and an amplifier in Qinghai-Tibet Plateau and even China.

Keywords

• linear trend rate
• mann-kendall rest
• wavelet analysis
• extreme climate
• southeast xizang