The amplification of UV irradiance at the Earth’s surface that is due to successive reflections between the snow-covered ground and the scattering atmosphere is analyzed by a method based on decoupling the atmosphere and the surface functions. For a uniform Lambertian surface the amplification factor for the global irradiance depends only on the product of the surface reflectance and the atmospheric backscatter. It varies with wavelength, reaching a maximum near 320 nm; this maximum is close to 50% for clean snow. In UV-B the amplification depends strongly on tropospheric ozone. For non-Lambertian, nonuniform surfaces it is possible, by the same method, to define effective or average reflectances.
© 1998 Optical Society of America
(030.5620) Coherence and statistical optics : Radiative transfer
(120.5700) Instrumentation, measurement, and metrology : Reflection
(260.0260) Physical optics : Physical optics
(260.7190) Physical optics : Ultraviolet
Jacqueline Lenoble, "Modeling of the Influence of Snow Reflectance on Ultraviolet Irradiance for Cloudless Sky," Appl. Opt. 37, 2441-2447 (1998)