Abstract
Snow cover dynamics impact a whole range of systems in mountain regions, from society
to economy to ecology; and they also affect downstream regions. Monitoring and analyzing snow
cover dynamics has been facilitated with remote sensing products. Here, we present two
high-resolution daily snow cover data sets for the entire European Alps covering the years 2002 to
2019, and with automatic updates. The first is based on moderate resolution imaging
spectroradiometer (MODIS) and its implementation is specifically tailored to the complex terrain,
exploiting the highest possible resolution available of 250 m. The second is a nearly cloud-free
product derived from the first using temporal and spatial filters, which reduce average cloud cover
from 41.9% to less than 0.1%. Validation has been performed using an extensive network of 312
ground stations, and for the cloud filtering also with cross-validation. Average overall accuracies
were 93% for the initial and 91.5% for the cloud-filtered product using the ground stations; and
95.3% for the cross-validation of the cloud-filter. The data can be accessed online and via the R and
python programming languages. Possible applications of the data include but are not limited to
hydrology, cryosphere and climate .