Influence of soil moisture and surface roughness heterogeneity on modeled climate

Abstract

Our investigation focuses on changes in the coverage and geographic pattern of irrigated maize (corn) and non-irrigated bare soil. Maize and bare soil are among the most disparate land covers that occur together in the present-day landscape and they exemplify highly heterogeneous spatial mosaics. Our simulations indicate that increasing the area of bare soil downwind of irrigated maize produces a nearly linear increase in daily average surface temperatures, along with a linear decrease in the average latent heat flux. Bare soil upwind of irrigated maize, however, forces a more nonlinear response. The largest effects occur when small areas of bare soil are introduced into the domain. Simulations with several mosaics containing 50% irrigated maize and 50% bare soil also suggest that changes in the spatial arrangement of the land surface alone can result in differences in area-averaged surface temperatures and near-surface air temperatures of up to 1°C. -from Authors