Imaging Spectrometry in High-Alpine Topography: The Derivation of Accurate Broadband Albedo

Three flight lines over high-alpine terrain have been recorded with the imaging spectrometer DAIS7915 in August 2002. The aim of this campaign was the derivation of broadband albedo to support distributed energy-balance modelling. The data was successfully ortho-rectified and a vicarious calibration as well as topographic-atmospheric correction were performed. To enable the derivation and investigation of black-sky and white-sky albedo, twoparameter kernel-based BRDF models were fitted to subsets. Coupling of these BRDF-models with the energybalance code PERMEBAL suggests a significant influence of angular anisotropy on net radiation in complex topography. Comparison of modeled and measured time series of albedo show a good representation of its temporal evolution, but a large offset between the ground measurements and the BRDF model inversions is present.