The snow cover is computed for the parts of the musk ox census area that is visible from the slope of Zackenberg where the automatic cameras are placed. Please find link to the shapefile for the region below.
Photos from three different camera positions are orthorectified and mosaicked together and the snow cover is computed based on these images. The dataset starts in 2008, but 2009 is missing, because there weren't enough cloudfree days during the snow melting period.
The images are captured every day at 13:20, which is solar noon in the Zackenberg valley.