Variability in the Annual Fields of Large-Scale Atmospheric Water Vapor Transport

Abstract

Annual mean holds of the zonal and meridional components of the vertically integrated water vapor flux in the atmosphere have been computed objectively from six years of Northern Hemispheric upper air data. Emphasis is placed on the longitudinal structure of these fields in order to identify regional contributions to the annual variations of the zonally averaged moisture fluxes. These temporal changes, particularly those associated with the meridional transport of latent heat. appear large enough to impact significantly on the maintenance of the atmospheric energy balance. While the distribution and quality of some upper air data make it difficult to estimate the degree to which the analyses precisely duplicate atmospheric behavior everywhere, this study provides documentation of a wide range of interannual variability. In this regard, the behavior of one of the years chosen for study contrasts sharply with that of the rest of the sample, as was similarly noted for other quantities evaluated by Rosen et at. (1976).