Abstract:

his paper explored the temperature variation in the region of middle reaches of the Yarlung Zangbo river valley of Tibet in China in past 51 years.The observed meteorological data during 1957 to 2007,including average mean temperature in annual,seasonal and daily times series,had been used to study the characteristics of temperature change trend using the linear statistical method and wavelet analysis method.It was showed that the annual temperature presented a significant increasing trend and the change rate was 027℃/10 a in recent 51 a.It was more significant than the lower altitudes in other parts of Tibet.The warming trend was more obvious in autumn and winter than in summer.There were obvious periodic oscillation of 15~20 a for the seasonal and annual mean temperature variations.The abrupt climate change point was about in 1987,and the temperature belonged to the lower period before that time,and higher period after that time.There were an increasing trend in spring,autumn and winter in 1975,but this trend wasn’t appeared until summer in 1983.