Determination of Temperature and Moisture Profiles in a Cloudy Atmosphere Using AIRS/AMSU

Abstract

High spectral resolution infrared satellite data can be used to retrieve accurate atmospheric temperature and water vapor profiles. In order to achieve the greatest retrieval accuracy, all the factors affecting the radiances, especially clouds, must be accurately accounted for. We have developed a methodology for retrieving atmospheric and surface parameters under cloudy conditions using the AIRS/AMSU instruments. Since all fields-of-view are contaminated to some degree by clouds, the task of eliminating clouds must be analytical, objective, and accurate. This is accomplished with great success by making use of observations in adjacent fields-of-view utilizing both the microwave and infrared bands. The treatment of clouds is carried out systematically and does not require any field-of-view to be necessarily clear. The only assumption about cloudiness is that clouds have identical spectral properties in both fields-of-view. The algorithm permits the determination of atmospheric temperature and water vapor profiles accurately under cloudy conditions and shows little degredation in their accuracy as a function of increased cloudiness.