Climate Sensitivity to Sub-grid Scale Disaggregation of Precipitation

Significant land processes occur on spatial scales too fine to be resolved by most current general circulation models. To better address these sub-grid scale processes, a model is introduced that represents them by a sub-mesh imposed on each atmospheric model grid. This fine-mesh land model easily incorporates explicit sub-grid parameterizations, including spatial rainfall disaggregation.

A fine-mesh model simulation that includes the precipitation disaggregation scheme is compared to the control fine-mesh climate, with particular attention to the diurnal and seasonal time-scales. Results from this analysis suggest that there is a close relationship between the diurnal cycle of rainfall at a particular point and the spatial distribution of convective rainfall around it. The surface-atmosphere transfer mechanisms behind this relationship are explored.