摘要：We publish and describe a surface spectral reflectance data recordof seasonal snow (dry, wet, shadowed), forest ground (lichen, moss) andforest canopy (spruce and pine, branches) constituting the main elements ofthe boreal landscape. The reflectances are measured withspectro(radio)meters covering the wavelengths from visible (VIS) toshort-wave infrared (SWIR) (350 to 2500 nm). In this paper, we describe theinstruments used and how the spectral observations at different scales alongwith the concurrent in situ reference data have been collected, processedand archived. Information on the quality of the data and factors causinguncertainty are discussed. The main experimental site is located inthe Sodankylä Arctic Space Centre in northern Finland (67.37∘ N,26.63∘ E; 179 m a.s.l) and the surrounding region. The collectionincludes highly controlled snow and conifer branch laboratory spectralmeasurements, portable field spectroradiometer observations of snow andsnow-free ground at different locations, and continuous mast-bornereflectance time series data of a pine forest and forest opening. Inaddition to the surface level spectral reflectance, data from airborneimaging spectrometer campaigns over the Sodankylä boreal forest andSaariselkä fell region at selected spectral bands are included in thecollection. All measurements of the data record correspond to a typicalpolar-orbiting satellite observation event in the high-latitude spring seasonregarding their Sun or illumination source (calibrated lamp) zenith angleand close-to-nadir instrument viewing angle. For all measurement geometries,observations are given in surface reflectance quantity corresponding to thetypical representation of a satellite observation quantity to facilitatetheir comparison with other data sources. The openly accessible spectralreflectance data at multiple scales are suitable to climate andhydrological research and remote sensing model validation and development.To facilitate easy access to the data record the four datasets describedhere are deposited in a permanent data repository(http://www.zenodo.org/communities/boreal_reflectances/)(Hannula et al., 2019). Each dataset of a distinct scale has its own uniqueDOI – laboratory: https://doi.org/10.5281/zenodo.3580078 (Hannula and Heinilä, 2018a);field: https://doi.org/10.5281/zenodo.3580825 (Heinilä et al., 2019a); mast-borne:https://doi.org/10.5281/zenodo.3580096 (Hannula and Heinilä, 2018b); and airborne:https://doi.org/10.5281/zenodo.3580451 (Heinilä, 2019a) and https://doi.org/10.5281/zenodo.3580419(Heinilä, 2019b).
