Investigation of the effect of variable viewing angle with airborne multiangular measurements

This study examines and discusses the usability of airborne spectrometer in investigation of the effect of variable viewing angle in snow cover monitoring. The focus is on the effect of the observation angle to the detected snow spectra and forest transmissivity. Reflectance determination is sensitive to snow anisotropical reflectance properties and, in forested areas, spectra can be very different, observed from variable sensor view angles. The results of this study are used to investigate the anisotropical scattering of snow-covered areas and they are also compared with Envisat MERIS and Terra MODIS observations. With the airborne spectrometer - derived land cover multiangular spectral features the data obtained at wide viewing angles can be corrected. The results suggest that the airborne data are feasible for the modelling and accuracy assessment of satellite data-based snow cover area (SCA) estimation algorithms.