A scattering phase function for ice cloud: Tests of applicability using aircraft and satellite multi-angle multi-wavelength radiance measurements of cirrus

A parametrization of the Henyey-Greenstein scattering phase function is pre sented for application to aircraft and satellite remote sensing of cirrus-c loud bulk and microphysical properties at non-absorbing and absorbing wavel engths. The phase function is based initially around a non-absorbing labora tory-measured phase function between scattering angles of 30 degrees and 18 0 degrees, although at scattering angles greater than 95 degrees the phase function is made constant with scattering angle. This 'analytic' phase func tion has an asymmetry parameter value of 0.80 at non-absorbing wavelengths. This analytic phase function is tested using aircraft-based transmission r adiance measurements at the wavelengths of 0.55 mum, 0.87 mum, 1.6 mum and 3.7 mum between scattering angles of 10 degrees and 120 degrees, and satell ite retrievals of cirrus-cloud spherical albedo at the wavelength of 0.67 m um between scattering angles of 60 degrees and 180 degrees. The analytic ph ase function reproduces both aircraft and satellite measurements well, and is shown to be a distinct improvement over single-crystal model phase funct ions representing both small and large crystals in terms of angular scatter ing pattern and retrieved optical thickness.