Overview

One goal of the Atmospheric Radiation Measurement (ARM) Program is to improve general circulation models (GCMs) by obtaining detailed meteorological information in limited areas of order 200 km square and comparing GCM parameterizations with the mean radiative and convective properties in such areas. Typical GCM grid boxes are 100 km to 200 km square, but there is in reality much structure at smaller scales that is represented by their parameterizations. Meteorological observations alone cannot represent this structure, so we use a full-physics mesoscale model forced by large-scale tendencies to give as complete a picture of the sub-200-km-scale structures as possible. This allows us to produce a full four-dimensional characterization of the atmosphere that, given sufficiently complete physics in the model and sufficiently good data, will provide a representation of the actual state of the atmosphere