Scale effect and scale correction of land-surface albedo in rugged terrain

Jianguang Wena*, Qiang Liua, Qinhuo Liua, Qing Xiaoab & Xiaowen Liac a State Key Laboratory of Remote Sensing Science , Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University , P.O. Box 9718, Beijing, 100101, China b Beijing Research Institute of Uranium Geology , Beijing, 100029, China c School of Geography and Remote Sensing Science , Beijing Normal University , Beijing, 100875, China * E-mail: horse_wjg@hotmail.com Influence of topography must be corrected when fine-scale remote sensing data are used to estimate surface albedo in rugged terrain. In the case of coarse-scale satellite remote sensing data, the topographic effect on albedo estimation is generally ignored because the influence to albedo estimation of overall slope in coarse-scale pixels is usually considered negligible; however, because of the scale effect in albedo, neglecting within-pixel topology may cause errors in albedo estimation from coarse-scale data. This paper investigates the scale effect on land-surface albedo estimations, particularly in the case of converting fine-scale albedo to coarse-scale albedo in rugged terrain. Starting from the definition of difference-scale albedo in rugged terrain, a method is presented to convert fine-scale surface albedo to coarse-scale albedo, then deriving a factor to correct coarse-scale land-surface albedo. The performance and accuracy analysis of the method are investigated by using a simulated digital elevation model (DEM) with different mean slopes, as well as real DEM and Thematic Mapper images. Results show that the method is effective for scale-effect correction of land-surface albedo in rugged terrain.