A land-surface hydrology parameterization with subgrid variability for general circulation models

Describes a more incremental approach to generalizing the bucket representation of land-surface hydrology based on a model that represents the variation in infiltration capacity within a GCM grid cell. The variable infiltration capacity (VIC) model requires estimation of three parameters: an infiltration parameter, an evaporation parameter, and a base flow recession coefficient. The bucket model runoff has much greater variability than historic streamflows for short time scales (eg 1 day); the VIC model is much more similar to observed flows in this respect. The bucket model tends to have unrealistically high short-term variability. Sensitivity analysis showed that the base flow parameter exerted the greatest influence on both the mean and variability of most of the hydrologic variables, especially winter runoff, summer evaporation, and summer and winter soil moisture. -from Authors