Abstract
Human activities such as water withdrawal from rivers and groundwater for irrigation affect not only the global water cycle but also the atmospheric circulation. Previous studies have investigated the impacts of human activities on the terrestrial water cycle by using hydrological models or offline land surface models (LSMs). However, less attention is paid on the impacts of human water management on land-atmosphere interactions. In this study, we coupled an atmospheric general circulation model (AGCM) with the LSM of Pokhrel et al. (2015) that is integrated with irrigation and groundwater pumping schemes. The main objective of this study is to quantify the influence of human activities on the global water cycle. Model indicates declining water table depth in the Ogallala aquifer where the withdrawal from groundwater for irrigation the irrigation is large. Results also show that the evapotranspiration over Pakistan and India where the irrigation water demand is higher than in other the regions tends to increase, and the precipitation over the eastern parts of those regions also tends to increase.
