Implications of the stratospheric water vapor distribution as determined from the Nimbus-7 LIMS experiment.

Abstract

The LIMS experiment on Nimbus-7 has provided new results on the stratospheric water vapor distribution. The data show: 1) a latitudinal gradient with mixing ratios that increase by a factor of two from equator to +- 60o at 50 mb, 2) most of the time there is a fairly uniform mixing ratio of 5 ppmv at high latitudes, but more variation exists during winter, 3) a well-developed hygropause at low- to mid-latitudes of the lower stratosphere, 4) a source region of water vapor in the upper stratosphere to lower mesosphere that is consistent with methane oxidation chemistry, at least within the uncertainties of the data, 5) an apparent zonal mean H2O distribution that is consistent with the circulation proposed by Brewer in 1949, and 6) a zonal mean distribution in the lower stratosphere that is consistent with the idea of quasi-isentropic transport by eddies in the meridional direction. -from Authors