THE INFLUENCE OF SOLAR RADIATION ATTENUATION IN SNOW ON NEAR SURFACE ENERGY BALANCE IN COMPLEX TOPOGRAPHY

ABSTRACT: Snow transmits, absorbs, and reflects solar radiation but is nearly a black body in the longwave spectrum. On clear days, longwave radiation is emitted to the cold sky, thus cooling the snow surface. Simultaneously, solar radiation attenuates as it is absorbed, adding thermal energy with depth. Radiation recrystallization occurs as a result of a temperature gradient caused by the interaction between outgoing longwave radiation and incoming shortwave (solar) radiation. Most shortwave radiation is absorbed in the top three to five centimeters. However, the absorption is also spectrally dependent and short solar wavelengths show deeper penetration. The re-sulting, subsurface heating and corresponding temperature gradient, is consistent with observed devel-opment of radiation recrystallized snow. Surface temperature and temperature gradients through snow pack can be spatially modeled with a computer model RadThermRT and an empirically altered Beer-Lambert-Bouguer for shortwave radiation attenuation