Statistical comparison of observed and CMAQ modeled daily sulfate levels

New statistical procedures to evaluate the Models-3/Community Multiscale Air Quality (CMAQ) using observed data are introduced. Certain space-time correlations are used to assess dynamic aspects of CMAQ and to compare the space-time structure of CMAQ to that of observations. Our analyses show that, overall, CMAQ matches the space-time correlation structure of observed sulfate concentrations well. Analyses on the space-time correlation of the difference of observations and CMAQ output show that CMAQ partially captures time lagged spatial variation of sulfate concentrations. Separable covariance functions are shown to provide a poor description of the observations. (C) 2004 Elsevier Ltd. All rights reserved.