This repository contains the daily Snow Cover Extent (SCE) of the Global SnowPack (GSP), a 500 m resolution global mosaic derived from interpolated MODIS snow information of the Platforms Terra (MOD10A1) and Aqua (MYD10A1).

The data set is available as 8-bit Cloud Optimized GeoTIFF (COG) in the WGS84 projection (EPSG:4326). Its dimensions are 86,400 pixels (X-axis) and 43,200 pixels (Y-axis), resulting in a pixel size of 0.004167 degrees (0.25 arc minutes).

The individual bit positions indicate the class to which they belong (bits 4-8) or the interpolation level (bits 1-3). The meaning of the bytes is as follows (little-endian):

Bit	Value	Description
1	1	Classified by 3-day interpolation
2	2	Classified according to topographical interpolation of absolute snow lines
3	4	Classified according to seasonal interpolation of the previous days
4	8	Class: ocean
5	16	Class: inland water
6	32	Class: snow-free land
7	64	Class: snow covered with low NDSI (greater than 0.1, smaller than 0.4) - snow in the forest
8	128	Class: snow covered with high NDSI (greater than 0.4)

The value of the pixels can be read as follows: A value of 132 (128+4) indicates that there is snow cover (value 128), but this was only detected with the seasonal interpolation (value 4). If a binary mask is required, all pixels with a value greater than or equal to 64 should be selected.

A comprehensive publication with all technical details and accuracy information is currently being finalized. For now, please note: Dietz, A.J., Kuenzer, C., Dech, S., 2015. Global SnowPack: a new set of snow cover parameters for studying status and dynamics of the planetary snow cover extent. Remote Sensing Letters 6, 844–853. https://doi.org/10.1080/2150704X.2015.1084551

For further information please contact: sebastian.roessler@dlr.de