2.1.1 Human water use (HWR)
The scheme of HWR was incorporated into CAS-LSM as a sub-model (Zou et al. 2015; Zeng, Xie and Liu 2017). The HWR mainly considered withdrawal due to groundwater pumping, in which the estimated groundwater pumping rate from aquifers was apportioned among agricultural, industrial and domestic use. The industrial and domestic consumptions had two components, where the wastewater produced by industry and human daily life was treated as a discharge into local rivers and the net water consumption was treated as evaporation to the atmosphere. The aquifer recharge rate was updated by subtracting the GW extraction rate from the original aquifer recharge rate; for irrigation consumption, the net water input rate was timed as the ratio of the agricultural consumption rate and added to the top of the soil’s surface. The pumping rate and the other ratios were determined by forcing data combined from three data sources, including the Food and Agriculture Organization of the United Nations (FAO) global water information system (http://www.fao.org/nr/water/aquastat/main/index.stm), the Global Map of Irrigation Areas, version 5.0 (Siebert et al. 2005, 2013), and the historical monthly soil moisture and saturated soil moisture simulated by CLM4.5 offline using the atmospheric forcing data set described by Qian et al. (2006) for the years 1965–2000.