An assessment of impacts of orientation, non-sphericity, and size of small atmospheric ice crystals on scattering property calculations to improve in-situ aircraft measurements, satellite retrievals, and climate models
Greg McFarquhar, University of Illinois at Urbana-Champaign
We propose to calculate the single-scattering properties of small (maximum dimension less than 30 μm) atmospheric ice crystals at non-absorbing and moderate-absorbing wavelengths using a discrete dipole approximation. In order to determine the impacts of the shapes and sizes of small ice crystals on the derivation of particle properties from airborne cloud probes (i.e., forward scattering spectrometer probe) and on the bulk radiative properties of ice clouds as needed for satellite retrieval algorithms and numerical models, the scattering properties of three idealized models (i.e., budding Bucky ball, Gaussian random sphere, and droxtal) representing observed morphologies of small ice crystals will be determined. This represents the extension of a database of single-scattering properties first developed by Um and McFarquhar to include a much larger variety of shapes and sizes of ice crystals, representing the wide variations observed in clouds.