Temporal Variability of Climate in Nansi Lake Basin over 1960-2005

Climate data included the observed monthly average air temperature, precipitation as well as 20 cm pan evaporation for the period 1960-2005 from 22 meteorological stations over Nansi Lake basin were used to analyses climate change trend and its abrupt change in recent 46 years. The research results show that spring, winter and annual average air temperature has been obviously increasing, change trends of seasonal and annual precipitation were not significant. Seasonal and annual pan evaporation has been obviously decreasing, and the amplitude reduction of pan evaporation in summer and spring is larger than in autumn and winter. Annual average air temperature has presented an abrupt rising change in 1985, annual precipitation hasnpsilat presented abrupt change, and annual pan evaporation has presented two abrupt changes in 1969 and 1985. The long-term trend of pan evaporation cannot be explained by the change of single environmental factor.