Spectral albedo of 83 vegetation assemblages on Bylot Island, Canadian high-Arctic

The main study site is Qarlikturvik valley on Bylot Island, centered around (73.15°W, 80.00°N). Some spectra were also obtained in Mala River valley (73.006°N, 80.685°W), on Baffin Island across Navy Board inlet. Most of the vegetation is herbaceous tundra and includes prostrate shrubs such as Salix arctica, Dryas integrifolia and Cassiope tetragona. The only erect species is Salix richardsonii, which grows up to 50 cm tall. The purpose of this work was to compare the albedo of prostrate vegetation to that of Salix richardsonii. 44 spectra of prostrate vegetation were recorded. The dominant vegetation types were moss, graminoids, Salix arctica, soil, and Salix richardsonii. In most cases, moss, Salix arctica and graminoids were present at the same spot in variable proportions. Spectra were classified according to the dominant vegetation type. Spectra classified as soil were in fact mudboils surrounded by vegetation, so that it was never just soil. 39 spectra of Salix richardsonii were recorded at 3 locations called SALIX-D1, SALIX-G2 and SALIX-M, the latter being on Baffin Island. Shrubs were more developed and had more leaves at SALIX-G2. SALIX-M was the driest site with shrubs having few leaves and being shorter, about 35 cm high. Spectral albedo was measured over the range 346.5 to 2400 nm with a field portable spectroradiometer (HR-1024 model, Spectra Vista Corporation, SVC) between 10 and 18 July 2015, between about 10:30 and 16:30 local time each day so that the solar zenith angle (SZA) varied between 50.1 and 60.3°. The light collector connected to the spectrometer was an SVC full sky irradiance integrating sphere 7.5 cm in inner diameter with a nadir to 85° field of view, making it a nearly perfect cosine receptor. It was located at the end of a 2-m metal rod resting on a tripod, at a height of about 1.2 m. The spectral resolution varies between 1 and 1.5 nm for the Si detector (346.5-982 nm), 3.5 to 4 nm for the first InGaAs detector (982-1883 nm) and 2.5 nm for the second InGaAs detector (1883-2514 nm). For each spectrum, a running mean average was used to improve the signal to noise ratio. Averaging was over a 12 nm range from 346.5 to 1800 nm, and 80 nm beyond that. Most spectra were recorded under mostly clear sky conditions. Only 5 spectra were recorded under overcast conditions, on 16 July 2015. These were all at SALIX-D1 and are classified as SALIX D1 overcast in the data files. Two files have been uploaded: one for prostrate vegetation, one for Salix richardsonii. The format is tab-delimited text files. Relative spectral irradiance under clear sky and overcast conditions are available at https://doi.org/10.5281/zenodo.10222606. Photographs of 81 out of the 83 spots where spectral albedo were measured are available at 15277241 https://doi.org/10.5281/zenodo.15277241 These data are discussed in Domine et al. (2025) Journal of Geophysical Research-Biogeosciences, 130, e2024JG008593, https://doi.org/10.1029/2024JG008593