Landsat Science Products

Landsat Fractional Snow Covered Area

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Landsat Fractional Snow Cover Area Example

Left: Landsat Surface Reflectance (Landsat 8 bands 4,3,2) and Right: Fractional Snow Covered Area for an area within Landsat CONUS ARD h003v007 acquired on  April 27, 2017. Snow covered areas are displayed in white.

Snow cover is spatially and temporally variable and is often concentrated in remote or inaccessible land regions making spaceborne remote sensing the most feasible approach to measure and monitor snow cover change. Landsat’s spatial resolution offers the capability to resolve snow cover patterns across topographically complex mountainous regions.

While Landsat’s acquisition frequency limits analysis of short-term snow cover variations, longer term changes in snow cover duration and persistence can be detected.The Landsat Fractional Snow Covered Area (fSCA) product provides per-pixel fractional snow cover maps that indicate the percentage of a pixel covered by snow for Landsat 4-8 data.

Available for Landsat 4-5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 8 Operational Land Imager (OLI) data, the Landsat Fractional Snow Covered Area product is generated from U.S. Landsat Analysis Ready Data (ARD) Surface Reflectance and Top of Atmosphere Relflectance data.

The Landsat Fractional Snow Covered Area product is processed to 30-meter spatial resolution in Albers Equal Area (AEA) projection using the World Geodetic System 1984 (WGS84) datum and gridded to a common tiling scheme.

Product Availability

Landsat Fractional Snow Covered Area product is available for the Western U.S. and Alaska for the following date ranges:

  • Landsat 8 OLI: April 2013 to 2017
  • Landsat 7 ETM+: July 1999 to 2017
  • Landsat 5 TM: March 1984 to May 2012
  • Landsat 4 TM: March 1984 to December 1993

Package Content

The Landsat Fractional Snow Covered Area product indicates the percentage of a pixel covered by snow.  Additional product specifications can be found in the Landsat Fractional Snow Covered Area Product Guide. The Fractional Snow Covered Area package includes a metadata file in Extensible Markup Language (.xml) format.

The list below describes the products and filenames that are delivered with the Landsat Fractional Snow Covered Area product.

Fractional Snow Covered Area (SNOW): Indicates the percentage of the pixel covered by snow
Delivered file name: *_SNOW.tif
Approximate file size: 3.8 MB

Revised Cloud Mask (REVCM): Flags pixels identified as clear, cloud, water, and fill  (based on C Function of Mask (CFMask)). This revised mask more accurately differentiates between snow and cloud, compared to the original CFMask. The water component of this mask is produced using the Landsat LEvel-3 Dynamic Surface Water Extent (DSWE) product.
Delivered file name: *_REVCM.tif
Approximate file size: 290 KB

Statistics Products: The Fractional Snow Covered Area statistics products (5 total) are in final development and are expected to be available for download in 2019.

Caveats and Constraints

  • The scale factor in the Extensible Markup Language (.xml) file for the SNOW band is incorrect. The scale factor should be 0.001 instead of the current 0.0001 shown in the .xml file. The valid range for these fractions when unscaled should be between 0.0 and 1.0.
  • A Quality Assessment process is applied to the Fractional Snow Covered Area product prior to public release, which includes visually assessing each scene-level Fractional Snow Covered Area product for excessive commission errors caused by factors such as incorrect cloud masks or poor georeferencing. Therefore, while the majority of Landsat scenes are used to generate the Fractional Snow Covered Area product, certain scenes may not be able to be processed to produce a scientifically viable Fractional Snow Covered Area product.
  • Occasionally some burned areas are incorrectly classified as being water in the Fractional Snow Covered Area product. This occurs if the input ARD Pixel Quality Assessment (PIXELQA) band includes pixels that are flagged as “water, terrain, low-confidence cloud”.

User Communities

Landsat Fractional Snow Covered Area User Communities
Community Potential Use
Colorado State University Western U.S. snowpack
Various conference connections Planning and mangement of fire occurence or managed lands
Landsat science Reference for other Landsat Science Products

Data Access

Landsat Fractional Snow Covered Area product is available for download from EarthExplorerThe data are located under the Landsat category, Landsat Collection 1 Level-3 subcategory, and listed as Fractional Snow Covered Area.

Visit the Landsat Data Access webpage for information about bulk download options.  

Documentation

Landsat Fractional Snow Covered Area Product Guide

Landsat Fractional Snow Covered Area Algorithm Description Document (ADD)

Landsat Fractional Snow Covered Area Digital Object Identification (DOI): doi.org/10.5066/F7XK8DS5

List of Fractional Snow Covered Area ARD tiles

Citation Information

There are no restrictions on the use of Landsat Science Products. It is not a requirement of data use, but the following citation may be used in publication or presentation materials to acknowledge the USGS as a data source and to credit the original research.

Landsat Level 3 Fractional Snow Covered Area Science Product courtesy of the U.S. Geological Survey.

The Fractional Snow Covered Area product is based directly on work described in:

Painter, T. H., Rittger, K., McKenzie, C., Slaughter, P., Davis, R. E., & Dozier, J., 2009. Retrieval of subpixel snow covered area, grain size, and albedo from MODIS. Remote Sensing of Environment, 113(4), 868-879.

Selkowitz, D.J., Painter, T.H., Rittger, K.E., Schmidt, G., & Forster, R., 2017. "The USGS Landsat Snow Covered Area Products: Methods and Preliminary Validation." Automated Approaches for Snow and Ice Cover Monitoring Using Optical Remote Sensing. D. Selkowitz. Salt Lake City, UT: The University of Utah. pp. 76-119. Available online: https://www.researchgate.net/publication/331024289_The_USGS_Landsat_Snow_Covered_Area_Products_Methods_and_Preliminary_Validation

References

Selkowitz, D. J., & Forster, R. R., 2016. Automated mapping of persistent ice and snow cover across the western U.S. with Landsat. ISPRS Journal of Photogrammetry and Remote Sensing, 117, 126-140. DOI: 10.1016/j.isprsjprs.2016.04.001

Selkowitz, D.J, Painter, T., Schmidt, G., Rittger, K., and Forster, R., 2015, The USGS Landsat Snow Covered Area Science Data Product [poster], in Fall Meeting, San Francisco, Calif., 14-18 December 2015, Fall Meeting Abstracts: Washington, D.C., American Geophysical Union, abstract number C41D-0759.

Selkowitz, David. 2011. Landsat-derived Patterns of Snow Covered Area (SCA) and the Potential for Enhancing the Spatial Resolution of MODIS-derived SCA Estimates. AGU Fall Meeting Abstracts 05.

 

 

 

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