BOUNDARY-LAYER STRATUS CLOUDS - INFERRED FROM SATELLITE INFRARED SPECTRAL MEASUREMENTS OVER OCEANS

A method to remotely sense marine stratus clouds, that are underneath the boundary layer inversion produced by strong subsidence, is develop ed with the help of the measurements made by the Infrared Interferomet er Spectrometer (IRIS) on board the Nimbus 4 satellite. These measurem ents, which had a spectral resolution of 2.8 cm-1 and a field view of approximately 100 km in the region 870-980 cm-1, allow one to compare the weak absorption due to water vapor lines with that of the weak nu3 -nu1 band of CO2. From such a comparison it is possible to sense the p resence of these boundary layer stratus clouds. Maps of these clouds o ver subsidence regions of the tropical and subtropical oceans deduced from IRIS data show the usefulness of the technique to climatological studies.