The influence of layering and grain size on microwave emission from polar firn

This paper studies the relative influence of scattering by ice grains and by density stratification on microwave emission at 37 GHz and 6.6 GHz. Polar firn exhibits density stratification on centimeter depth scales, and variable particle sizes on sub-millimeter length scales. At 37 GHz, the dominant scattering mechanism is particle scattering from the ice grains. Good agreement between theory and satellite observations can be obtained with particle scattering effects alone. At 6.6 GHz, the dominant scattering mechanism is levered scattering from the abrupt interfaces between layers with different densities. Including lever scattering gives improved agreement between theory and satellite observations compared to results obtained with particle scattering alone