Characteristics of climate change in Shiyang River Basin from 1951 to 2005

Based on meteorological data in Shiyang River Basin from 1951 to 2005,the present study analyzed the characteristics of the climate changes in this area.In the past 50 years,precipitation in the whole river basin and the lower reach decreased,but the upper and middle reaches increased.Precipitation in the upstream significantly decreased since 1962 as a turning point,and in the middle and downstream significantly increased from 1990s.There was an obvious increasing trend in atmospheric temperature which was more obvious in midstream followed by midstream and was less obvious in upstream.For the upper,middle,and lower reaches,there was significant increase since 1987,1997 and 1987,respectively,and there was significant increase especially since 2000.Wind speed of Shiyang River Basin decreased,increased,decreased,and decreased at different stages.The wind speed in the upstream significant increased in 1970’s and gradually stabilized since 1980’s.The wind speed in the midstream changed with 10 a cycle.The wind speed in the downstream increased first and decreased since 1984 as a turning point.The lowest stage appeared during 2000-2005.Humidity in Shiyang River Basin decreased which more obvious from middle 1950’s to middle of 1960’s.However,there was significant humidity reduction in the midstream in the late of 1990’s.The lowest stage appeared during 1999-2005.Currently,the drought in the downstream relieved which suggested the situation in the whole basin will be gradually improved.