Estimation of Errors in Objectively Analyzed Fields and Sensitivity to Number and Spacing of Stations

Single-column models (SCMs) are designed to test parameterizations for radiative fluxes, cloud processes, and surface exchange that are used in general circulation models (GCMs). The SCM is a vertical column of GCM grid cells exercised in isolation from the GCM. The lateral information normally supplied to the column by neighboring columns in a GCM must be supplied externally by estimates of the temperature and moisture advection and the horizontal wind divergence to force the physical processes within the isolated column. In the Atmospheric Radiation Measurement (ARM) Program, these required forcing terms are derived from observations using objective analysis. We seek to quantify the errors in the objectively analyzed fields and to investigate the sensitivity of these errors to the number and spacing of observation stations.