Experimental and theoretical spectral reflection properties of ice clouds generated in a laboratory chamber

In a preliminary experimental program, the measured bidirectional reflection properties between 1.0 and 3.5 mu m from a grating spectrometer with a resolution of approximately 0.1 mu m for ice crystal clouds generated in a cold chamber are compared with theoretical results computed from a Line-by-line equivalent solar radiative transfer model. The theoretical calculations are based on the measured habits, concentrations, and sizes of the ice particles from replicas of the ice crystals that show a mean maximum size of approximately 7 mu m. The experimental design was first tested with transmission measurements in a pure water-vapor environment that compare closely with theoretical expectations. Within the uncertainties and in consideration of the assumptions necessitated by the preliminary nature of this program, there is a close comparison between the experimental and theoretical results. (C) 2000 Optical Society of America OCIS codes: 010.2940, 010.1310, 010.1290.