Variation and Trend Analysis of Precipitation in Datong Region

Using daily temperature and precipitation data of 8 cities in Datong from 1972 to 2009,we presented the spatio-temporal changes of Datong region by method of the trend analysis,MannKendall mutation testing and R/S analysis.The result showed showed as follows.The annual and flood seasonal precipitation slowly abated.Around 2001,the precipitation of Datong region changed greatly and the precipitation of most cities increased.From 1972 to 2009,there was a high frequent oscillation period of 3a in flood seasonal precipitation at Datong region,and also a low frequent oscillation period of 15a.It obviously showed that the more precipitation period was in 1973-1978,1990-1997 and 2004-2009,and the less precipitation period was in 1982-1986,1997-2001.The precipitation at Datong region existed the Hurst phenomenon,precipitation trend at most cities in future will keep decreasing trend just as those at present while those at few cities will be not obvious.