Mapping of Arctic shrubland using the Net Anthocyanin Reflectance Index
Date
2026
Authors
Sundby, Anthony
Boulanger-Lapointe, NoƩmie
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Journal ISSN
Volume Title
Publisher
University of Victoria
Abstract
Arctic erect shrubs are expanding their range North and up mountains, a trend linked to increases in vegetation productivity associated with recent climate change. Shrubification impacts the movement of human and wildlife on the land as well as ecosystem heat exchanges. In the Arctic, harsh tundra conditions and short snow-free seasons make repetitive in-situ observations across large areas difficult to obtain. Synoptic approaches in the French Alps have demonstrated the feasibility of using satellite imagery to distinguish and map shrubland using the Net Anthocyanin Reflectance Index (NARI). In this study we utilized green and red-edge bands onboard the Sentinel-2 satellites to assess the effectiveness of this index in the Arctic. In the region, anthocyanin has a primary peak in late May or early June, a secondary peak in September, and a seasonal low in July. We used seven images to compare peaks and lows, and validated results using in-situ shrub cover data collected in Arviat, Nunavut. Results were mixed, with September images generally producing more accurate predictions, likely due to the difficulty of obtaining cloud- and snow-free images during the shorter primary peak. The current results suggest that NARI may be used for mapping shrubland in the Arctic although the accuracy is heavily dependent on the availability of cloud-free images during the short peaks.
Description
Keywords
Canadian Arctic, remote sensing, NARI, anthocyanin, dwarf shrubs, Jamie Cassels Undergraduate Research Awards (JCURA)