Reconstruction of Monthly Mean 700-mb Heights from Surface Data by Reverse Specification

Abstract

This paper demonstrates an objective method of computing monthly mean 700-mb height anomalies (H) at 108 grid points in the Western Hemisphere for a 40-yr period as a function of concurrent anomalies of monthly mean sea level pressure (P), at the same 108 points used for H, and monthly mean surface air temperature (T) averaged over 112 areas in North America. The authors applied a forward stepwise program to derive linear multiple regression equations that explained 81% of the variance of H by means of only 3.5 variables, averaged over all months and grid points. The stability of these equations held up well on 6 yr of independent data in terms of explained variance, root-mean-square error, and the spatial anomaly correlation coefficient. Therefore, it seems feasible to reconstruct maps of H for the first half of the twentieth century as a function of data on P and T only.