Autocorrelations of Moisture Parameters on Isentropic Surfaces

Abstract

Arguments are put forth supporting the contention that the analysis of specific humidity on isentropic surfaces should be considered as the optimum method for the analysis of atmospheric moisture. Autocorrelation curves of relative humidity and specific humidity on isentropic surfaces are presented. These curves indicate that for the case considered: 1) the values of the autocorrelation for specific humidity were greater than that of relative humidity for all separation distances considered; and 2) for distances >300 km the autocorrelation of specific humidity displayed a more gradual decrease with separation distance than did that of relative humidity. From these results it is deduced that an objective analysis scheme can make more effective use of the available moisture information if the analysis is of specific humidity on isentropic surfaces rather than relative humidity on pressure or isentropic surfaces.