2001-2022 Snow Season Metrics for Alaska Derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) Terra Snow Cover Daily Product

The National Park Service and Geographic Information Network of Alaska (GINA) developed an algorithm to derive snow cover climatology for Alaska using the Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover daily product from the Terra satellite. The algorithm is two-fold and involves data processing and snow cover metrics derivation. Terra MODIS Snow Cover Daily 500-meter (m) Grid Data (MOD10A1) are processed to reduce cloud obscuration through iterations of cloud-reduction methods, including spatial, temporal, and snow-cycle filtering. The MODIS Reprojection Tool (MRT) is used to mosaic daily tile files and re-sample the data. A total of 12 metrics (e.g., date of first snow, date of persistent snow cover) for each pixel are calculated per snow year (August 1 of the previous year to July 31 of the snow year).