A direct linear relationship between water vapour content of lower, middle and upper-middle troposphere respectively with the radiances for 8.3, 7.3 and 6.7 μm spectral observations has been attempted. From the atmospheric simulations such a relationship is found to exist with a good degree of correlation and is seen to be quite insensitive to temperature changes. Such an approach is used to interpret the water vapour imageries obtained from TIROS-N sounder through construction of detailed water vapour distribution maps.
