Scale dependence of solar heating rates in tropical convective cloud systems with implications to general circulation models -- 3-D reconstructions using satellite data

Abstract

We examine the scale dependence of solar radiative heating rates within tropical convective-cirrus systems to identify which scales contribute significantly to a model's grid-mean heating rate (i.e., spatial average over a climate model's grid cell), and determine their relationship to the cloud field properties (e.g., cloud top height variation). These results are used to understand the spatial resolution and subgrid-scale cloud property information needed in climate models to accurately simulate the grid-mean solar heating of these systems. Three-dimensional cloud heating rates are computed by a broadband Monte Carlo model for regional-scale cloud fields whose properties are retrieved from satellite data over the Tropical Western Pacific. One key result is that the grid-mean heating rates are largely governed by hotspots - regions of intense local heating that occupy only a small fraction of the grid area. The relationship of these hotspots to the subgrid-scale cloud field properties, as well as other climate modeling implications will be presented.