Measurements of cirrus cloud parameters using AIRS

摘要

The Atmospheric Infrared Sounder (AIRS), launched in May 2002, is the first of a new generation of high-spectral resolution temperature and humidity sounders for numerical weather prediction and climate change studies. The accuracy of the AIRS radiances, and the validity of the clear sky AIRS Forward Model, have already been demonstrated. With daily global coverage by the instrument, the almost continuous wavelength coverage in the 10-12 micron and 3.7 micron atmospheric windows enables AIRS to excel at detecting cirrus clouds. This paper presents global retrievals of cloud top pressure, ice particle size and amount, using the AIRS radiances. Cloud optical depths lower than 0.1 (at 10 μm) have been detected. We also present comparisons between retrievals done using spherical particles to those done using nonspher-ical particles.