Properties of overlapping cirrus clouds as deduced from the GOES-12 imagery data

Cirrus clouds modify both solar reflected and terrestrial emitted radiances. Due to their ubiquitous presence, many research efforts have been devoted to retrieve cirrus properties using satellite observations. Detection and retrieval of cirrus clouds from satellite observations face two major challenges: They are often semitransparent from visible to infrared wavelengths and they often occur above a lower cloud system. The Twelfth Geostationary Operational Environmental Satellite (GOES-12) is the first in a series of new geostationary satellites, which provides a new suite of imager bands. The new GOES-12 imager has replaced the 12-micron channel with a 13.3-micron CO2 absorption channel that allows for the application of a CO2-slicing retrieval technique. Using the CO2-slicing method detects thin cirrus clouds more effectively than using conventional infrared-window method. Using the conventional infrared-window method also has difficulty in determining an accurate cirrus cloud top height. Furthermore, operational satellite cloud retrieval techniques are wholly based on the single cloud layer assumption. This study attempts to use the GOES-12 imagery data to discriminate between overlapping and single-layer cirrus clouds. Properties of the overlapping and single-layer cirrus cloud amounts, cloud top heights, cloud emissivities, and cloud optical depths as well as initial validation comparisons are reported.