Energy entering the snow cover in form of solar shortwave radiation is an important parameter in many fields of snow research such as snow cover modelling (metamorphism), snow ecology, snow photochemistry and also climate studies. Radiation entering the snow cover is transmitted to deeper layers in snow depending on the snow characteristics and on the wavelength of light. For each of the mentioned fields of research a different spectral region and also spectral resolution is of importance. Investigations on snow ecology for example rely on information of a spectrally detailed radiation transfer whereas for snow metamorphism studies it is sufficient to account only for broad spectral bands.

A variety of different approaches are available to model the radiation transfer through snow. The simplest emloy an exponential decrease of flux together with an extinction coefficient which is dependend on snow density, gain size and wavelength. More sophisticated models calculate the optical properties of snow and use these to solve the radiation transfer equation by approximative methods. Until now, no snow radiation transfer model is available which accounts for the complex stratigraphy of a snow cover especially on the grain shape. Moreover, thorough evaluations of models present are not available. This study aims to evaluate simple and complex models of radiation transfer and to present a new snow-radiation model. Furthermore, an application of this new snow-radiation model on a snow ecological topic is given.

Comparisons between broad band measurements of the radiative fluxes in snow with simple models show the necessity for improvements of such models in reproducing the grain size and density dependence of radiation fluxes in snow. However, wavelength dependence can be modelled. Spectrally de