The flux of water‐vapour due to the mean winds and the convergence of this flux over the Northern Hemisphere in January and July

Charts are presented showing the flux of water vapour due to the mean winds, based on the mean distribution of water vapour and the mean geostrophic winds, in January and July, over an area comprising most of the Northern Hemisphere. There is evidence that this flux approximates fairly well to the total flux of water vapour, but the divergence of this flux does not always approximate so well to the divergence of the total flux. Nevertheless, comparison with independent estimates of evaporation minus precipitation over the oceans suggests that the two divergences are at least of the same order of magnitude, and further comparison with published charts of the divergence of the total annual flux of water vapour suggests some degree of detailed correspondence.