GLOBAL RIVER RUNOFF CALCULATED FROM A GLOBAL ATMOSPHERIC GENERAL-CIRCULATION MODEL

The purpose of this paper is to show that an atmospheric general circulation model (GCM) can be used to calculate runoff for the world's major rivers, that river runoff provides an important diagnostic for climate modelers, and that the model runoff provides useful information for hydrologists. The global atmospheric model of Hansen et al. has been used to calculate the annual river runoff for the world's major rivers. The model has a horizontal resolution of 4° × 5°, but the runoff from each grid box within a particular river's drainage basin is summed on a resolution of 2° × 2.5° to obtain the runoff at the river mouth. The mean annual runoff is calculated and compared with observations for 33 of the world's largest rivers. The runoff depends on the model's precipitation and parameterizations of groundwater storage and evapotranspiration, which are affected by soil type and vegetation. © 1990.