Abstract
Water vapor concentrations in the upper troposphere and lower stratosphere from 7ON to 40S over North and South America were deduced from solar spectra recorded on 56 flights of a high flying jet aircraft. Ambient concentrations between 10.7 and 18.3 km declined with altitude at all latitudes to a minimum at about 2 km above the local tropopause, and remained nearly constant thereafter to 18.3 km. Although seasonal variance was pronounced in the troposphere over New Mexico, changes of only a few per cent were observed in the lower stratosphere, assuming uniform mixing from 17.7 km to the top of the atmosphere. Hemispheric latitudinal distribution of water vapor in the lower stratosphere measured during the Northern Hemispheric winter of 1967–68 showed a maximum concentration of 1.75 mg kg−1 at 65N and a progressive decline to a minimum of 1.25 mg kg−1 near 30S. Intermediate minima and maxima were also observed at 25N and 10N, respectively.
