The reflectance of rough snow surfaces in Antarctica from POLDER/ADEOS remote sensing data

The POLDER (POLarisation and Directionality of the Earth's Reflectances) se nsor was launched onboard the Japanese ADEOS satellite in August 1996. It m easured the energy reflected by the Earth in the solar spectrum at 8 wavele ngths. From this sensor, an Earth target could be seen up to 14 times along a single path providing a good characterization of the BRDF (Bidirectional Reflectance Distribution Function) from space. A set of one month of POLDE R data over east Antarctica was analyzed. After cloud masking and atmospher ic corrections, mean BRDFs were derived for different areas. In some parts of the ice sheet the BRDF is assymetric with a strong reflectance peak in t he half space oriented towards the sun (backscatter). This peak is due to t he anisotropic roughness of the surface (sastrugi) and its position depends on the sastrugi direction.