Abstract: Based on the observation data of solar global radiation at 7 stations and relative sunshine at 113 stations of Yunnan Province, the time series of solar global radiation over the whole province during 1961-2007 were calculated. The characteristics of the spatial-temporal distribution and variation of solar global radiation were studied in the province as well as in the 4 climate subareas, which were determined by using the rotated principal component method. The main results are as follows: annual mean solar global radiation was more in the central part (I), next in the southwest part (IV), and least in the east part (II) and the northwest part (III) of Yunnan Province. The annual solar global radiation fluctuatedly declined at a mean rate of -0.64%/10a in 1961-2007; it remarkably decreased in the central part and the east part, but slightly increased in the southwest part. Two abrupt climate changes of solar global radiation took place in the period of 1961-2007; the first abrupt decrease occurred in about 1986, and the second abrupt rise occurred in about 1993. The analysis results show that relative humidity and total cloud cover are the two important factors influencing the variations of solar global radiation.

Key words: Yunnan Province, solar global radiation, climate trend, abrupt change