Quantifying the effect of irrigation on regional climate in China using regional climate modeling

Abstract:

Irrigation is considered as one of the major anthropogenic factors strongly modulating regional hydroclimate. While the first-order local effects induced by additional moisture in irrigated region appear to be surface cooling and increased evapotranspiration, their interactions with the background climate are highly nonlinear and complex, introducing unexpected feedback. China has rapidly expanded the irrigation areas, particularly over the North China Plain (NCP). The low level of rainfall in northern China gives rise to the need for irrigation to supplement the soil water when rainfall does not meet water demand. In this study, we quantify the effect of irrigation on regional climate in China. We design the experiment to mimic the large-scale irrigation practiced in NCP using the Weather Research and Forecasting (WRF) modeling system. Two long-term simulations with and without irrigation modules are performed and compared to discern the effects of irrigation on the local and remote responses of rainfall distribution. Our analysis focuses on the characteristics of the changes in rainfall and underlying mechanism.

Acknowledgments

This research was supported by project GRF16309719, which was funded by the Research Grants Council (RGC) of Hong Kong.