A simple model of the hydrologic cycle and climate: 2. Observational evidence for the parametrization of atmospheric heat and moisture divergence

Entekhabi ( Adv. Water Resour., 17 (1 & 2) (1994) 79–91) extended the simple climate model of Koster and Eagleson ( J. Climate, 3(6) (1990) 593–606) to include a closed-system hydrologic cycle. Because the screening model does not simulate three-dimensional dynamics, it uses a simple linear reservoir transfer scheme to parametrize the lateral convergence of heat and moisture from the atmospheric column overlying the ocean to the column overlying the landsurface. Observations of wind and humidity profiles in the tropical Atlantic and South America are used to estimate the dependence of the net convergence of moisture over the continent on the precipitable water over land and ocean. In this manner, comparisons may be made between the parametrization of sensible heat and moisture convergence assumed in the screening model and measured quantities. The observed results indicate a similar pattern of sensitivity between the net convergence and the linear reservoir coefficient that form the basis of the parametrization.