Snow Microwave Emission Modeling of Ice Lenses within the Snowpack Using the Microwave Emission Model for Layered Snowpacks (MEMLS)

Ice lens formation, which follows rain on snow events or melt-refreeze cycles in winter and spring, is likely to become more frequent as a result of increasing mean winter temperatures at high latitudes. These ice lenses significantly affect the microwave scattering and emission properties and, hence, snow brightness temperatures that are widely used to monitor snow cover properties from space. To understand and interpret the spaceborne microwave signal, the modeling of these phenomena needs improvement. This paper shows the effects and sensitivity of ice lenses on simulated brightness temperatures using the Microwave Emission Model of Layered Snowpacks (MEMLS) coupled to a soil emission model at 19 and 37 GHz in both horizontal and vertical polarizations. Results when considering pure ice lenses show an improvement of 20.5 K of the root mean square error (RMSE) between the simulated and measured Tb using several in situ datasets acquired during field campaigns across Canada. The modeled brightness temperatures were found to be highly sensitive to the vertical location of ice lenses within the snowpack.