Data Set ID:

AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites, Version 1

This data set is no longer available because of errors in the data. See the Error Sources section of the data set documentation for details. If you have further questions, please contact NSIDC User Services by e-mail at or telephone at +1 303.492.6199.

The AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites are a collection of products for both poles, consisting of twice-daily gridded and calibrated satellite channel data and derived parameters. Data include five Advanced Very High Resolution Radiometer (AVHRR) channels, clear sky surface broadband albedo and skin temperature, average albedo and temperature, valid fraction file, solar zenith angle, satellite elevation angle, sun-satellite relative azimuth angle, surface type mask, cloud mask, cloud fraction files, and Universal Coordinated Time (UTC) of acquisition. The 25 km data are derived from the AVHRR Polar Pathfinder Twice-Daily 5 km EASE-Grid Composites, and extend poleward from 48.4 degrees north and 53.2 degrees south latitudes, spanning July 1981 through December 2000. Data are in 1-byte and 2-byte integer grid format and are available by FTP.

Note: NSIDC reccommends the use of the Extended AVHRR Polar Pathfinder (APP-x) Product instead of our AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites. The APP-x 25 km product has albedo and temperature calculations for all sky conditions. Cloud properties are modeled to estimate the albedo and temperature under the clouds. An improved cloud detection algorithm is also used in the APP-x product.

Geographic Coverage

Data Set Tabs

Spatial Coverage:
  • N: 90, S: 48.4, E: 180, W: -180

  • N: -53.2, S: -90, E: 180, W: -180

Spatial Resolution:
Not Specified
Temporal Coverage
  • 1981-07-24 to 2000-12-31
Temporal Resolution:
12 hour
  • Atmospheric Radiation > Albedo
  • Snow/Ice > Albedo
  • Surface Radiative Properties > Albedo
  • Clouds > Cloud Amount/Frequency
  • Infrared Wavelengths > Infrared Radiance
  • Land Temperature > Land Surface Temperature
  • Land Temperature > Skin Temperature
  • Infrared Wavelengths > Thermal Infrared
  • Surface Radiative Properties > Thermal Properties
  • Platform Characteristics > Viewing Geometry
  • Visible Wavelengths > Visible Radiance
NOAA-11, NOAA-14, NOAA-7, NOAA-9
Data Format(s):
  • Binary
Data Contributor(s): Chuck Fowler, Jim Maslanik, Terry Haran, Ted Scambos, Jeffrey Key, William Emery

Data Citation

As a condition of using this data, you must cite the use of this data set using the following citation. For more information, see our Use and Copyright Web page.

C. Fowler, J. Maslanik, T. Haran, T. Scambos, J. Key, and W. Emery. 2002. AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites, Version 1. [indicate subset used]. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. [Date Accessed].

Questions? Please contact:

NSIDC User Services
Phone: 1 303 492-6199
Fax: 1 303 492-2468
Contact Address:
National Snow and Ice Data Center
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Country: USA