Study on Climate Change Facts and Their Characteristics in the Qinghai Plateau in Recent 44 Years

Based on the data of monthly air temperature and precipitation at 26 representative meteorological stations in the Qinghai Plateau during the period of 1961-2004,in this paper the standardized series of weighted average air temperature and precipitation are carried out,and the change characteristics of air temperature and precipitation in the Qinghai Plateau in recent 44 years are analyzed.The results show that the change trend of air temperature in the Qinghai Plateau accords basically with that all over the country,the decade temperature increase in the Qinghai Plateau is 0.36 ℃,the temperature increase is the most significant in winter,then in autumn,and it is not so significant in spring and summer.The temperature increase in autumn and winter has become assuasive since the 1980s,but that in spring and autumn has become more significant since the 1990s. Therefore,the general warming trend is significant,especially in the west Qinghai Plateau.The climatic warming is mainly caused by the temperature increase at night and in winter.The period of air temperature change in the Qinghai Plateau is earlier than that all over the country.There is no significant change in precipitation in the Qinghai Plateau.The spatial distribution of precipitation change in the Qinghai Plateau is inconsistent,that is the days of occurring precipitation decreases,but the precipitation intensity increases.