Correction of sub-pixel topographical effects on land surface albedo retrieved from geostationary satellite (FengYun-2D) observations

35th International Symposium on Remote Sensing of Environment

地球科学;生态环境科学

Roupioz, L.^1,2,3 ; Jia, L.^2 ; Nerry, F.^1 ; Menenti, M.^3

ICube Lab., UMR 7357 CNRS-Unistra, 300 bvd S. Brant, 67400 Illkirch, France^1

Alterra, Wageningen UR, PB 47, 6700AA Wageningen, Netherlands^2

Faculty of Aerospace Engineering, TU Delft, Stevinweg 1, 2628CN Delft, Netherlands^3

关键词: BRDF (bidirectional reflectance distribution function);    Digital elevation model;    High spatial resolution;    Land surface albedo;    Qinghai-Tibetan plateau;    Surface reflectance;    Topographic correction;    Topographical effects;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/17/1/012270/pdf
DOI  :  10.1088/1755-1315/17/1/012270

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

The Qinghai-Tibetan Plateau is characterised by a very strong relief which affects albedo retrieval from satellite data. The objective of this study is to highlight the effects of sub-pixel topography and to account for those effects when retrieving land surface albedo from geostationary satellite FengYun-2D (FY-2D) data with 1.25km spatial resolution using the high spatial resolution (30 m) data of the Digital Elevation Model (DEM) from ASTER. The methodology integrates the effects of sub-pixel topography on the estimation of the total irradiance received at the surface, allowing the computation of the topographically corrected surface reflectance. Furthermore, surface albedo is estimated by applying the parametric BRDF (Bidirectional Reflectance Distribution Function) model called RPV (Rahman-Pinty-Verstraete) to the terrain corrected surface reflectance. The results, evaluated against ground measurements collected over several experimental sites on the Qinghai-Tibetan Plateau, document the advantage of integrating the sub-pixel topography effects in the land surface reflectance at 1km resolution to estimate the land surface albedo. The results obtained after using sub-pixel topographic correction are compared with the ones obtained after using pixel level topographic correction. The preliminary results imply that, in highly rugged terrain, the sub-pixel topography correction method gives more accurate results. The pixel level correction tends to overestimate surface albedo.