• On May 11, 2024, MODIS/Terra began experiencing geolocation errors, affecting the accuracy of the data between May 11 and 12 (DOY 132-133), 2024. Terra L2s and dailies for these two days, as well as the 8 and 16-days products from DOY 129 will be reprocessed in the coming days.

MODIS/Terra CGF Snow Cover Daily L3 Global 500m SIN Grid, Version 61
Data set id:
DOI: 10.5067/MODIS/MOD10A1F.061
This is the most recent version of these data.
Version Summary
Initial release


This global Level-3 data set (MOD10A1F) provides daily cloud-free snow cover derived from the MODIS/Terra Snow Cover Daily L3 Global 500m SIN Grid data set (MOD10A1). Grid cells in MOD10A1 which are obscured by cloud cover are filled by retaining clear-sky views of the surface from previous days. A separate parameter is provided which tracks the number of days in each cell since the last clear-sky observation. Each data granule contains a 10° x 10° tile projected to the 500 m sinusoidal grid. The terms "Version 61" and "Collection 6.1" are used interchangeably in reference to this release of MODIS data.
Data Format(s):
Temporal Coverage:
24 February 2000 to present
Temporal Resolution:
  • 1 day
Spatial Resolution:
  • 500 m
  • 500 m
Spatial Coverage:
Blue outlined yellow areas on the map below indicate the spatial coverage for this data set.
Strengths and Limitations


  • Daily cloud-gap-filled (CGF) snow-cover maps provide excellent cloud-free representations of extent of snow cover at 500-m resolution for a given day (Hall et al., 2019; Riggs and Hall, 2020).
  • MODIS daily snow-cover record begins on February 24, 2000, representing more than two decades of moderate-resolution (500 m) snow-cover maps (Hall et al., 2019).
  • The daily MODIS snow-cover record is useful to assess regional snow cover and trends (Riggs and Hall, 2020).
  • MODIS snow-cover products provide Normalized Difference Snow Index (NDSI) values from 0 – 100.  The NDSI value can be converted to binary snow cover or it can be descaled and converted to fractional snow cover (Salomonson and Appel, 2004; Riggs et al., 2019).
  • Daily CGF snow-cover maps include polar darkness and other features (Riggs et al., 2019).
  • This product is superior to MOD10A2 because a user can select a unique compositing period and is not restricted to 8-day composites; each day is a cloud-free representation of the snow conditions on that day, subject to the limitations, below.


  • The biggest limitation to the use of the CGF MODIS snow-cover products is cloud cover, which can prevent mapping of some snow (Hall and Riggs, 2007).
  • If a pixel is “cloudy,” according to the cloud mask, then the CGF algorithm uses the snow-mapping result from the last clear day, thus snow cover may not be mapped if a snowfall occurred and the resulting snow on the ground melted before the clouds cleared (Riggs et al., 2019).
  • Polar darkness prevents snow-cover mapping in polar regions during the winter (Riggs et al., 2019).
  • Areas of ephemeral snow cover and very thin snow cover may not be mapped by MODIS (Hall et al., 2010).

Data Access & Tools

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Help Articles

General Questions & FAQs

Data products from VIIRS are created to be similar to MODIS data products to ensure the continuity needed for the development of snow and sea ice climate records beyond the life expectancy of MODIS. The temporal resolution and spatial extent are identical in MODIS and VIIRS.
The lag time between observations and availability of MODIS products is only a few days. Lag time may be extended due to satellite maneuvers and extra quality assurance required for the geolocation data after the maneuver.
This short article describes the customization services available for ICESat-2 data using Earthdata Search
The Normalized Difference Snow Index (NDSI) snow cover is an index that is related to the presence of snow in a pixel and is a more accurate description of snow detection as compared to Fractional Snow Cover (FSC). Snow typically has very high visible (VIS) reflectance and very low reflectan

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All data from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC) can be accessed directly from our HTTPS file system, using wget or curl. Basic command line instructions are provided in the article below. 
NASA Earthdata Search is a map-based interface where a user can search for Earth science data, filter results based on spatial and temporal constraints, and order data with customizations including re-formatting, re-projecting, and spatial and parameter subsetting.