Physics-based modelling for remote sensing of snow

Sandells, M., Flerchinger, G., Gurney, R. and Marks, D. (2010) Physics-based modelling for remote sensing of snow. In: British Hydrological Society Third International Symposium: Role of Hydrology in Managing Consequences of a Changing Global Environment, 19-23 July 2010, Newcastle University, UK.

Abstract/Summary

Remote sensing is the only practicable means to observe snow at large scales. Measurements from passive microwave instruments have been used to derive snow climatology since the late 1970’s, but the algorithms used were limited by the computational power of the era. Simplifications such as the assumption of constant snow properties enabled snow mass to be retrieved from the microwave measurements, but large errors arise from those assumptions, which are still used today. A better approach is to perform retrievals within a data assimilation framework, where a physically-based model of the snow properties can be used to produce the best estimate of the snow cover, in conjunction with multi-sensor observations such as the grain size, surface temperature, and microwave radiation. We have developed an existing snow model, SNOBAL, to incorporate mass and energy transfer of the soil, and to simulate the growth of the snow grains. An evaluation of this model is presented and techniques for the development of new retrieval systems are discussed.