Implementation of ICE-RF optical properties in cosp_optics

[mo-abodas]

This issue documents the implementation of two new parametrizations of lidar backscatter at the wavelength of 0.532 nm developet by Dr. A. Baran (Met Office). The backscatter cross-sections (provided by Dr. Evelyn Hesse, University of Hertfordshire as part of the NERC-funded ICE-RF project - PI Prof. Anne Webb, Manchester University) have been parametrised as functions of the mass-equivalent spherical radius, consistent with the definitions used in the SOCRATES radiation package. The same form of rational polynomial Padé approximant used in the SOCRATES radiation package for water and ice clouds has also been applied here. This approach has been used most recently in the consistent parametrisation of the coupling between the CASIM two-moment microphysics and the ice crystal bulk integral optical properties.