Detection and Attribution of the Inflence of Climate Change and Human Activity on Hydrological Cycle in China's Eastern Monsoon Area

The hydrological cycle is affected by both climate change and human activity, and separation of the effects of internal variability and human activity is important to a better understanding of climate change. The current study uses an atmosphere-land interaction model that considers the effect of anthropogenic ground water exploitation and consumption to simulate the climate response to various factors. On the basis of the Optimal Fingerprint Detection and Attribution method, this study analyzes the hydrological change (presented by the annual change in surface temperature, precipitation, water resource, and evapotranspiration) in China's six major river basins within the eastern monsoon area-those of the Yellow River, Huaihe River, Haihe River, Zhujiang River, Yangtze River, and Songhuajiang River. The results are as follows:The forcing effects of greenhouse gases, anthropogenic aerosol projection, ozone change, and land-use change are detected in the surface temperature in most basins for the period 1965-2005, indicating a major influence of these forcings in long-term surface temperature change. In the annual precipitation change over the same period, these forcing effects are only detectable in the Huaihe and lower Yangtze River basins, and are a major factor in the latter of the two. During the period 1965-1984, a forcing effect of anthropogenic groundwater exploitation and consumption is detectable, being a major factor in these areas. In the water resource series of 1982-2005, the forcing effects of greenhouse gases, anthropogenic aerosol projection, ozone change, and land-use change are detectable for the Huaihe, lower Yangtze, and lower Yellow River basins, but may not be the major factor. In the evapotranspiration series for the same period, the above forcing effects are only detectable in the Zhujiang and lower Yangtze river basins, but are major effects in the latter of these two basins only.