Optical and Microwave Modeling of Snow

Measuring snowpack parameters remotely utilizing data captured by sensors onboard satellite or aircraft has long been the goals of our science community. The remote sensing approaches enable mapping and characterizing snowpack parameters in a globally and timely manner. The microwave and visible sensors have wide coverage of land surfaces, have moderate to high resolution, and have short revisit cycle. Moreover, the active and passive microwave remote sensing instruments have the advantage to be operated day and night, nearly irrespective of weather conditions. The snowpack parameters that can be derived from visible to microwave observations include the snow coverage, the onset of snow melting, snow wetness, the snow depth, the snow density, the snow water equivalent (SWE), etc. The derivations of these parameters are based upon the unique signatures in the interaction of electromagnetic waves with the snowpack. Accurate forward scattering and emission models that successfully predict the observed features and connect the microwave and visible observables to snowpack parameters form the basis to a reliable interpretation of the sensor collected data. The retrieval of snowpack parameters also relies on robust and accurate forward scattering and emission models.