The Effect of Soil Moisture on the Short-Term Climate and Hydrology Change—A Numerical Experiment

Abstract This paper describes a series of numerical experiments simulating the effect of large-scale irrigation on short-term changes of hydrology and climate. This is done through the use of a simple general circulation model, with a limited computational domain and idealized geography. The soil at three latitude bands, namely 30°N–60°N, 0–30°N, and 15°S–15°N is initially saturated with moisture. The results from these experiments indicate that irrigation affects not only the distribution of evaporation but also that of large-scale precipitation. It is found that the anomalies of soil moisture created by irrigation of these respective latitude zones can persist for at least several months due to increased evaporation and precipitation. Furthermore, it the irrigated region is located under a rainbelt, precipitation in that rainbelt is enhanced. Conversely, if the irrigated region is not located under a rainbelt, much of the additional moisture is transported to a rainbelt outside this area. Thus the moist...