Remote sensing of midlatitude cirrus radiative properties: A seven-year climatology

A retrieval algorithm has been developed using the combined lidar and infrared radiometer (LIRAD) method, which estimates the cloud height, thickness, temperature, emittance, and visible optical depth of cirrus clouds. Improvements made to the original LIRAD method include a variable backscatter-to-extinction ratio in time, a new technique for estimating the upwelling radiance reflected off the cloud into the beam of the radiometer, and a detailed radiative transfer model that estimates clear sky radiance, including contributions from ozone. Also discussed is the potential for using microwave radiometer measurements to improve estimates of clear sky radiance.; The retrieval algorithm is utilized to derive the macrophysical and radiative properties using a 7-year dataset of lidar and radiometric measurements obtained at the University of Utah, Facility for Atmospheric Remote Sensing in Salt Lake City, UT. In addition, the observations have been divided into subcategories based on cirrus cloud generating mechanism. A radiative climatology has been developed and used to relate the macrophysical and radiative properties of high clouds in the form of a radiative parameterization of cirrus clouds for use in general circulation models.