2001), Gain of the AVHRR visible channel as tracked using bidirectional reflectance of Antarctic and

• Main Authors: S. J. Masonis, S. G. Warren
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Antarctic; Greenland; Antarc*; Antarctica; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.517.1073; http://www.atmos.washington.edu/~sgw/PAPERS/2001_Sarah_IJRS.pdf

Abstract. The snow surfaces of the high plateaus of the East Antarctic and Greenland ice sheets are used to determine multi-year drift in the sensitivity of the visible channel of the Advanced Very High Resolution Radiometer (AVHRR) on the polar-orbiting satellites NOAA-9, 10, and 11. Bidirectional re ectance distribution functions are empirically derived for the months ofOctober–February (Antarctica) and April–August (Greenland) using a simpli ed atmospheric model. The bidirectional re ectance of the snow surface should not change from year to year for near-nadir satellite views. Therefore, drift in the derived bidirectional re ectance distribution function is interpreted as drift in channel sensitivity. Several factors make the snow surface of an ice sheet suitable as a calibration target for visible and near-UV channels. (1) In this spectral region, snow has a very high albedo (>97 % ) that is invariant with grain size and incidence angle. (2) On the high plateaus the temperatures are always far below freezing so the surface consists of cold ne-grained snow, and there is negligible contamination. (3) The ice sheet surfaces are uniform and at across large areas. (4) Ozone is