Characteristics of Climate Changes in Xinjiang from 1960 to 2005

A data set of precipitation, mean temperature and other climate variables at 94 stations of Xinjiang Uygur Autonomous Region is firstly used to analyze climate changes in Xinjiang Uygur Autonomous Region. The widely accepted procedures for creating regional averaged climatic time series and calculating linear trend and cumulative anomaly have been used. Analyses and discussion have been made for annual precipitation, mean temperature, wind speed, low cloud cover, total cloud cover, specific humidity, pan evaporation, and diurnal temperature range, and the seasonal analysis only includes precipitation and mean temperature. Solar radiation from a limited number of stations was available to evaluate the relationship between solar radiation and sunshine duration, total cloud cover, low cloud cover, and pan evaporation. The analyses show that the increasing rate of annual precipitation in Xinjiang as a whole was about 8.5 mm·(10 a)-1, and time series of annual precipitation turned from dry to wet in 1987. It is consistent with some earlier studies. Furthermore, the seasonal analyses demonstrate that precipitation began to transfer in the winter of 1986 actually. Except the Turpan basin, precipitation is increasing all over Xinjiang. Mean temperature is warming throughout Xinjiang. The regional mean temperature has a significant increasing trend, and the rate of warming in winter is larger than that in the other seasons. The authors also find that pan evaporation decreased in Xinjiang from 1960 to 2005, and the decrease is statistically significant. The changing rate is -26.5 mm·(10 a)-1, which is smaller than the average values in the whole China. There were not significant longterm changes of annual sunshine duration, total cloud cover. Longterm changes in regional averaged specific humidity and low cloud cover have a significant increasing trend, and they also have the similar pattern to decadal or annual change of precipitation. The increasing changes of them perhaps lead to the increasing of precipitation. It is worth to study further. The authors also tentatively analyzed the possible causes for the observed change. However, it may be premature to give a definite conclusion at this moment.