AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites  View Catalog Page Entry ID
NSIDC-0094
Summary
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, located at http://stratus.ssec.wisc.edu/products/appx/appx.html, 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
Spatial Coordinates:
N: -54°
S: -90°
E: 180°
W: -180°
N: 90°
S: 48°
E: 180°
W: -180°
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Data Set Citation
Dataset Creator: C. Fowler, J. Maslanik, T. Haran, T. Scambos, J. Key, and W. Emery.
Dataset Title: AVHRR Polar Pathfinder Twice-Daily 25 km EASE-Grid Composites
Dataset Release Date: 2002-01-01
Dataset Release Place: Boulder, CO U.S.A.
Dataset Publisher: National Snow and Ice Data Center (NSIDC)
Online Resource: http://nsidc.org/data/nsidc-0094.html
Temporal Coverage
Start Date: 1981-07-24
Stop Date: 2000-12-31
Data Resolution
Temporal Resolution: Twice-daily
Location Keywords
- Continent Antarctica
- Geographic Region Arctic
- Geographic Region Polar
Science Keywords
- Atmosphere Atmospheric Radiation Albedo
- Atmosphere Clouds Cloud Amount/Frequency
- Cryosphere Snow/Ice Albedo
- Land Surface Land Temperature Land Surface Temperature
- Land Surface Land Temperature Skin Temperature
- Land Surface Surface Radiative Properties Albedo
- Land Surface Surface Radiative Properties Thermal Properties
- Spectral/Engineering Infrared Wavelengths Infrared Radiance
- Spectral/Engineering Infrared Wavelengths Thermal Infrared
- Spectral/Engineering Platform Characteristics Viewing Geometry
- Spectral/Engineering Visible Wavelengths Visible Radiance
- Terrestrial Hydrosphere Snow/Ice Albedo
Ancillary Keywords
- Antarctic
- Arctic
- AVHRR
- Cryosphere
- DAAC
- EOSDIS
- NASA
- NOAA
- NSIDC
- Pathfinder
- Polar
- Radiance
- Remote Sensing
- Satellite
Platform
- NOAA-11 National Oceanic & Atmospheric Administration-11
- NOAA-14 National Oceanic & Atmospheric Administration-14
- NOAA-7 National Oceanic & Atmospheric Administration-7
- NOAA-9 National Oceanic & Atmospheric Administration-9
Instrument
- AVHRR Advanced Very High Resolution Radiometer
- RADIOMETERS
Project
- NOAA/NASA PATHFINDER NOAA/NASA Pathfinder Program
Quality
Channel data are accurate to within approximately +/- 0.2 percent based on sensor noise level of 0.4 data number (DN). Temperatures are accurate to within approximately 2 degrees Kelvin. Relative albedos in adjacent grid cells are accurate to within approximately 5 percent. However, absolute albedo values are approximate. Accuracies for the products are difficult to determine, given the limited nature of existing case studies. Also, conditions vary substantially across the large product domains and over time. Plans are being developed to further define product accuracies for snow-covered areas, sea ice, and ice sheets. Based on studies to date, accuracies in general are approximately +/- 2 degrees Kelvin for AVHRR-derived skin temperatures and +/- 0.05 degrees for surface albedo. Much of this error is likely due to uncertainties in the performance of the cloud detection methods. For clear sky conditions, accuracies for albedo and temperature products are expected to be in the range noted in the Barrow test, with temperatures accurate to +/- 0.5 degrees Celsius. Data and related information will be updated as appropriate. Additional comparisons with in-situ measurements of albedo and temperature are planned. See also Maslanik et al. (2000) for other accuracy discussions relative to SHEBA data.
Data Set Progress
IN WORK
Data Center
National Snow and Ice Data Center
Data Center URL: http://nsidc.org
Data Set ID: NSIDC-0094
Data Center Personnel
Name: NSIDC User Services
Phone: +1 (303) 492-6199
Fax: +1 (303) 492-2468
Email: nsidc@nsidc.org
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Country: USA
NSIDC Distributed Active Archive Center
Data Center URL: http://nsidc.org/daac/index.html
Data Set ID: NSIDC-0094
Data Center Personnel
Name: NSIDC DAAC User Services
Phone: +1 (303) 492-6199
Fax: +1 (303) 492-2468
Email: nsidc@nsidc.org
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Country: USA
Distribution
Distribution Media: ftp
Distribution Size: North: 230,642 bytes (2-byte grid) and 130,321 bytes
Distribution Format: 1-byte and 2-byte integer grids
Personnel
Chuck Fowler
Role: INVESTIGATOR
Contact Address:
Colorado Center for Astrodynamics Research
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0431
JIM MASLANIK
Role: INVESTIGATOR
Phone: (303) 492-6199
Fax: (303) 492-2468
Email: nsidc@kryos.colorado.edu
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309
Terry Haran
Role: INVESTIGATOR
Contact Address:
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Ted Scambos
Role: INVESTIGATOR
Email: scambos@nsidc.org
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Jeffrey Key
Role: INVESTIGATOR
Contact Address:
Space Science and Engineering Center
University of Wisconsin at Madison
1225 W. Dayton St.
City: Madison
Province or State: WI
Postal Code: 53706
William Emery
Role: INVESTIGATOR
Contact Address:
Colorado Center for Astrodynamics Research
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0431
NSIDC USER SERVICES
Role: TECHNICAL CONTACT
Phone: +1 (303) 492-6199
Fax: +1 (303) 492-2468
Email: nsidc@nsidc.org
Contact Address:
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
City: Boulder
Province or State: CO
Postal Code: 80309-0449
Country: USA
Reference
Key, J. 1999. The cloud and surface parameter retrieval (CASPR) system for polar AVHRR. Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin, Madison.
Key, J., J. Collins, C. Fowler, and R.S. Stone. 1997. High-latitude surface temperature estimates from thermal satellite data. Remote Sensing of the Environment 61:302-309.
Kidwell, K.D. 1995. NOAA Polar Orbiter Data User's Guide, U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, NESDIS.
Maslanik, J., C. Fowler, J. Key, T. Scambos, T. Hutchinson, and W. Emery, 1998. AVHRR-based Polar Pathfinder products for modeling applications. Annals of Glaciology 25:388-392.
Rao, C.R.N. and J. Chen. 1999. Revised post-launch calibration of channels 1 and 2 of the Advanced Very High Resolution Radiometer on board the NOAA-14 spacecraft. http://140.90.207.25:8080/EBB/ml/niccal1.html.
Schweiger, A., C. Fowler, J. Key, J. Maslanik, J. Francis, R. Armstrong, M.J. Brodzik, T. Scambos, T. Haran, M. Ortmeyer, S. Khalsa, D. Rothrock, and R. Weaver. 1999. P-Cube: A multisensor data set for polar climate research. Proceedings on the 5th Conference on Polar Meteorology and Oceanography, American Meteorological Society, Dallas, TX, 15-20 Jan., 136-141.
Metadata Name and Version
Metadata Name: CEOS IDN DIF
Metadata Version: 9.7
Creation and Review Dates
DIF Creation Date: 2002-03-06
Last DIF Revision Date: 2009-06-26
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