Remote Sensing of Seasonal Distribution of Precipitable Water Vapor over the Oceans and the Inference of Boundary-Layer Structure

Abstract

From the depth of the water vapor spectral lines in the 8–9 μm window region, measured by the Nimbus 4 Infrared Interferometer Spectrometer (IRIS) with a resolution of about 3 cm⁻¹, the precipitable water vapor w over the oceans is remotely sensed. In addition the IRIS spectral data in the 11–13 μm window region have been used to derive the sea surface temperature (SST). Seasonal maps of w on the oceans deduced from the spectral data reveal the dynamical influence of the large-scale atmospheric circulation. With the help of a model for the vertical distribution of water vapor, the configuration of the atmospheric boundary layer over the oceans can be inferred from these remotely sensed w and SST. The gross seasonal mean structure of the boundary layer inferred in this fashion reveals the broad areas of trade wind inversion and the convectively active areas such as the ITCZ. The derived information is in reasonable agreement with some observed climatological patterns over the oceans.