The National Park Service and Geographic Information Network of Alaska (GINA) developed an algorithm to derive snow cover climatology for Alaska using the MODIS snow cover daily product. The algorithm is two-fold and involves both data processing and the derivation of snow cover metrics. Terra MODIS snow cover daily 500m grid data (MOD10A1) are processed to reduce cloud obscuration through iterations of cloud reduction methods that include spatial, temporal, and snow cycle filtering. A total of 12 metrics for each pixel are calculated.
Snow-metrics data file defines the following 12 snow metrics: 1) first_snow_day, first day of the full snow season (FSS start day) 2) last_snow_day, last day of the full snow season (FSS end day) 3) fss_range, last_snow_day-first_snow_day +1 4) longest_css_first_day, first day of the longest CSS segment (CSS start day) 5) longest_css_last_day, last day of the longest CSS segment (CSS end day) 6) longest_css_day_range, longest_css_last_day-longest_css_first_day +1 7) snow_days, the number of snow days 8) no_snow_days, the number of no snow days 9) css_segment_num, the number of CSS segments 10) mflag, pixel type (ocean, land, or lake/inland water) and type of snow (no snow, broken snow, or continuous snow) 11) cloud_days, number of cloud days 12) tot_css_days, total number of all days within CSS segments
MODIS_Snow_Metrics_Remote Sensing_2015.pdf (11.2 MB)
2013-asmc-snow-metrics-poster-v3.pdf (2.25 MB)
2015_49_ASMC.pdf (1.7 MB)