Bulk Scattering Properties of Ice Clouds at Visible Through Far-Infrared Wavelengths

This study reports on the development of ice cloud bulk scattering properties for use in remote sensing applications and numerical models. While the primary focus is to develop band-averaged models appropriate for use by various satellite imagers such as the Moderate Resolution Imaging Spectroradiometer (MODIS), the work has been extended to provide high-resolution spectral models from 100 to 3250 cm^-1 that are appropriate for use by infrared spectrometers such as the Atmospheric Infrared Sounder (AIRS). Additionally, models have been developed at 144 individual wavelengths (i.e., not averaged over a spectral response function) between 0.4 and 2.2 μm. The microphysical data consist of a set of 1117 particle size distributions collected in five different field campaigns and includes sampling of both midlatitude and tropical cirrus. Libraries of scattering properties have been derived for ice particles with maximum dimensions ranging from 2 to 9500 μm and at wavelengths from 0.4 to 100 μm. Ice particle habits include droxtals, hexagonal plates, solid columns, hollow columns, aggregates, and 3-D bullet rosettes. The scattering properties include single scattering albedo, asymmetry factor, absorption and extinction cross sections, extinction efficiency, and scattering phase function. One advantage of these models is that analyses involving multiple instruments can be performed using scattering models that have been developed using consistent methodology. We report on the derivation of the scattering models and some of their applications in remote sensing studies of ice clouds.