Impacts of climate change on water resources in source regions of Yangtze River and Yellow River

The characteristics of the climate in the source regions of the Yangtze River and Yellow River were analyzed based on the monthly precipitation and monthly mean temperature at 22 meteorological stations from 1961 to 2010.The difference in the value between precipitation and evaporation was used to represent the water resources,in order to analyze the impacts of climate change on the water resources.The results show that the precipitation,temperature,and evaporation in the source regions of the Yangtze River and Yellow River have changed significantly,especially in the last 20 years,when there were significant increasing trends in these properties.The water resources presented a fluctuating variation in the source region of the Yellow River and increased significantly in the last 10 years in the source region of the Yangtze River.The increase of precipitation can directly lead to the increase of water resources;however,the increasing temperature can lead to high evaporation that would consume more water resources.Therefore,the influences on water resources can be balanced out by the changes of precipitation and temperature,which explains why there is no significant change in the water resources in the source region of the Yellow River.The temperature increased significantly in the last 10 years in the source region of the Yangtze River,causing more glaciers to melt and water resources to increase in the region.