Climate Change and Its Effect on Annual Runoff in Lijiang Basin-Mt. Yulong Region,China

Based on the meteorological and hydrologic data in the Lijang(丽江) basin from 1979 to 2006,variational trend and characteristics of climate change and its effect on runoff in Yanggong(漾弓) River were examined in the study.The results show that the temperature have significantly increased in the drainage basin during the past 28 years.The average temperature increased markedly from 1979 to 2006,and the increase of temperature in winter was higher than those in other seasons.The annual precipitation varied with a slightly upward trend in the same period,suggesting that the increase mainly occurred in spring and summer while the decrease occurred in autumn and winter.The streamflow at Yanggong River showed a significant increasing trend.During the four seasons,spring experienced the most significant increase,and autumn experienced the smallest.On the basis of the above study,we found that the increasing trend in runoff was more significant than the increase in precipitation in the study area.That was the synactic results of variation of groundwater,ice-snow meltwater and precipitation caused by global climate change.