Variations of Annual Mean Temperature and Durative Extreme Temperature Frequency at Mohe During 1961-2004

Annual mean temperature, frequency of annual durative warm days and cold nights, and frequency of seasonal durative warm days and cold nights were calculated based on the daily mean, maximum and minimum temperature at Mohe during 1961-2004. Linear trends, increments, significance tests and stationarity test were analyzed. Annual mean temperature increased by 1.61 ℃ and the frequency of annual durative warm days rose by four times. There were significant increasing trends in both frequency of winter durative warm days and summer durative cold nights. Significance tests were made on linear regression relationship between annual mean temperature and frequency of annual durative series, and frequency of seasonal durative series. As the linear regression relationship was statistically significant, significance tests were made on every frequency series to the annual mean temperature individually, to indicate the correlation among them. The results were as follows: From annual aspect, the increase in the annual mean temperature was significantly influenced by the increase of annual durative warm day frequency and the decrease of annual durative cold night frequency; from seasonal aspect, the increase in annual mean temperature was significantly influenced by the increase of spring and summer durative warm day frequency, together with the decrease of spring and autumn durative cold night frequency.