NOAA Climate Data Record (CDR) of AVHRR Polar Pathfinder Extended (APP-X) Cryosphere, Version 2
Extended AVHRR Polar Pathfinder (APP-x)
APP-x broadband surface albedo
NOAA Climate Data Record (CDR) of the eXtended AVHRR Polar Pathfinder (APP-X) cryosphere contains 19 geophysical variables over the Arctic and Antarctic for the period 1982 - present. All of them have undergone various degrees of validation, though not all are considered CDR quality. The variables are (those considered by the developers to be CDR-quality are identified with an asterisk): Surface temperature, all-sky, snow, ice, and land* Surface albedo, all-sky* Sea ice thickness* Surface type Cloud mask* Cloud particle thermodynamic phase Cloud optical depth Cloud particle effective radius Cloud temperature Cloud pressure Cloud type Downwelling shortwave radiation at the surface* Downwelling longwave radiation at the surface* Upwelling shortwave radiation at the surface* Upwelling longwave radiation at the surface* Upwelling shortwave radiation at the TOA* Upwelling longwave radiation at the TOA* Shortwave cloud radiative forcing at the surface Longwave cloud radiative forcing at the surface APP-x data products are mapped to a 25 km EASE grid at two local solar times: 04:00 and 14:00 for the Arctic, and 02:00 and 14:00 for the Antarctica. Using local solar time rather than standard UTC times provides better information on diurnal differences at all locations. The latest update to version 2 includes folding in the APP FCDR updates (updated calibration coefficients for AVHRR GAC visible channels) along with improved algorithms for the land mask, cloud mask, and ice thickness.
- Cite as: Key, Jeffrey; Wang, Xuanji; Liu, Yinghui; and NOAA CDR Program (2019). NOAA Climate Data Record of AVHRR Polar Pathfinder Extended (APP-X), Version 2. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.25921/AE96-0E57 [access date].
| Download Data |
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| Distribution Formats |
- XML
- NetCDF (Version: 4)
- File Specification: The NetCDF data files comply with the Climate and Forecast (CF) Metadata Conventions and the NetCDF Attribute Convention for Dataset Discovery (ACDD).
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| Ordering Instructions |
Contact NCEI for other distribution options and instructions. |
| Distributor |
NOAA National Centers for Environmental Information
ncei.info@noaa.gov
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| Dataset Point of Contact |
NOAA Climate Data Record Program Office
DOC/NOAA/NESDIS/NCDC > National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce
+1 (828) 271-4800
app_contacts@noaa.gov
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| Coverage Description |
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| Time Period |
1982-01-01 to Present (time interval: 12-hour) |
| Spatial Bounding Box Coordinates |
West: -180.0
East: 180.0
South: -90.0
North: 90.0
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| Spatial Coverage Map |
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| General Documentation |
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| Processing Documents |
- APPX Source Code
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CDR Source Code (download)
This source code is for reference only. The source code is provided to maintain transparency of the algorithm and processes used in creating the Climate Data Record (CDR). The source code is not intended to be portable to any computer system(s) beyond that of the original CDR producer's environment.
- APP-X Processing Overview
- Climate Algorithm Theoretical Basis Document (C-ATBD) Extended AVHRR Polar Pathfinder (APP-x)
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| Associated Resources |
- Arctic Surface, Cloud, and Radiation Properties Based on the AVHRR Polar Pathfinder Dataset. Part I: Spatial and Temporal Characteristics
- High-latitude surface temperature estimates from thermal satellite data
- Cloud cover analysis with Arctic AVHRR, part 1: cloud detection
- Cloud particle phase determination with the AVHRR
- A thermodynamic model for estimating sea and lake ice thickness with optical satellite data
- NOAA Climate Data Record (CDR) of AVHRR Polar Pathfinder (APP) Cryosphere, Version 2
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| Publication Dates |
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| Edition |
Version 2 |
| Data Presentation Form |
Digital image
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| Dataset Progress Status |
Ongoing - data is continually being updated |
| Data Update Frequency |
Daily |
| Purpose |
This dataset provides a high quality Climate Data Record (CDR) for use in polar climate studies, climate monitoring, and model verification. |
| Use Limitations |
- Uncertainties in most of the retrieve parameters (e.g., surface temperature, cloud optical depth, etc.) are smallest in the presence of sunlight ("polar day") and largest during the polar winter. Cloud detection in the polar regions at night is notoriously difficult. All other retrieved parameters are in one way or another dependent upon cloud detection.
- See the Algorithm Theoretical Basis Document for a description of use limitations.
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| Dataset Citation |
- Cite as: Key, Jeffrey; Wang, Xuanji; Liu, Yinghui; and NOAA CDR Program (2019). NOAA Climate Data Record of AVHRR Polar Pathfinder Extended (APP-X), Version 2. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.25921/AE96-0E57 [access date].
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| Cited Authors |
- Key, Jeffery
DOC/NOAA/NESDIS/STAR > Center for Satellite Applications and Research, NESDIS, NOAA, U.S. Department of Commerce
- Wang, Xuanji
UWI-MAD/SSEC/CIMSS > Cooperative Institute for Meteorological Satellite Studies, Space Science and Engineering Center, University of Wisconsin, Madison
- Lui, Yinghui
UWI-MAD/SSEC/CIMSS > Cooperative Institute for Meteorological Satellite Studies, Space Science and Engineering Center, University of Wisconsin, Madison
- NOAA CDR Program
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| Originators |
- Key, Jeffery
DOC/NOAA/NESDIS/STAR > Center for Satellite Applications and Research, NESDIS, NOAA, U.S. Department of Commerce
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| Collaborators |
- Wang, Xuanji
UWI-MAD/SSEC/CIMSS > Cooperative Institute for Meteorological Satellite Studies, Space Science and Engineering Center, University of Wisconsin, Madison
- Lui, Yinghui
UWI-MAD/SSEC/CIMSS > Cooperative Institute for Meteorological Satellite Studies, Space Science and Engineering Center, University of Wisconsin, Madison
- NOAA CDR Program
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| Publishers |
- DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
- DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
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| Theme keywords |
Global Change Master Directory (GCMD) Science Keywords- Earth Science > Cryosphere
Global Climate Observing System (GCOS) Essential Climate Variables (ECVs)
- Oceanic - Surface - Sea Ice
- Atmospheric - Upper-air - Cloud Properties
- Terrestrial - Albedo
- Atmospheric - Surface - Surface Radiation Budget (including Solar Irradiance)
- Atmospheric - Surface - Air Temperature
- Oceanic - Surface - Sea-surface Temperature
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| Data Center keywords |
Global Change Master Directory (GCMD) Data Center Keywords
- DOC/NOAA/NESDIS/NCDC > National Climatic Data Center, NESDIS, NOAA, U.S. Department of Commerce
- DOC/NOAA/NESDIS/STAR > Center for Satellite Applications and Research, NESDIS, NOAA, U.S. Department of Commerce
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| Platform keywords |
Global Change Master Directory (GCMD) Platform Keywords- NOAA POES > NOAA Polar Orbiting Environmental Satellites
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| Instrument keywords |
Global Change Master Directory (GCMD) Instrument Keywords- AVHRR > Advanced Very High Resolution Radiometer
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| Place keywords |
Global Change Master Directory (GCMD) Location Keywords
- Geographic Region > Arctic
- Continent > Antarctica
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| Project keywords |
Global Change Master Directory (GCMD) Project Keywords
- NOAA Climate Data Record (CDR) Program
- NOAA OneStop Project
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| Data Resolution keywords |
Global Change Master Directory (GCMD) Horizontal Data Resolution Keywords- 10 km - < 50 km or approximately .09 degree - < .5 degree
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| Stratum keywords |
Global Change Master Directory (GCMD) Location Keywords
- Vertical Location > Land Surface
- Vertical Location > Sea Surface
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| Use Constraints |
- Cite as: Key, Jeffrey; Wang, Xuanji; Liu, Yinghui; and NOAA CDR Program (2019). NOAA Climate Data Record of AVHRR Polar Pathfinder Extended (APP-X), Version 2. [indicate subset used]. NOAA National Centers for Environmental Information. doi:10.25921/AE96-0E57 [access date].
- See the Use Agreement for this CDR available on the CDR page.
- Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
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| Access Constraints |
- Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
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| Fees |
- In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
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| Lineage information for: dataset |
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| Lineage Statement |
This Climate Data Record (CDR) were produced by NOAA Center for Satellite Applications and Research (STAR) and University of Wisconsin and are archived at the NOAA National Climatic Data Center (NCDC). |
| Processor |
- DOC/NOAA/NESDIS/STAR > Center for Satellite Applications and Research, NESDIS, NOAA, U.S. Department of Commerce
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| Processing Steps |
- For a complete description of the processing steps, see the Algorithm Theoretical Basis Document and Data Flow Diagram.
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| Processing Documents |
- APPX Source Code
-
CDR Source Code (download)
This source code is for reference only. The source code is provided to maintain transparency of the algorithm and processes used in creating the Climate Data Record (CDR). The source code is not intended to be portable to any computer system(s) beyond that of the original CDR producer's environment.
- APP-X Processing Overview
- Climate Algorithm Theoretical Basis Document (C-ATBD) Extended AVHRR Polar Pathfinder (APP-x)
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| Source Datasets |
- NOAA Climate Data Record (CDR) of AVHRR Polar Pathfinder (APP) Climate Data Record (CDR)
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| Lineage information for: repository |
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| Processing Steps |
- 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
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Last Modified: 2023-09-19
For questions about the information on this page, please email:
ncei.info@noaa.gov
