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Advanced Very High Resolution Radiometer (AVHRR) Data from USGS EROS Data Center
2004-08-25
The Advanced Very High Resolution Radiometer (AVHRR) data set is comprised of
data collected by the AVHRR sensor and held in the archives of the U.S.
Geological Survey's EROS Data Center. Carried aboard the National Oceanic and
Atmospheric Administration's Polar Orbiting Environmental Satellite series, the
AVHRR sensor is a broad-band, 4- or 5-channel scanning radiometer, sensing in
the visible, near-infrared, and thermal infrared portions of the
electromagnetic spectrum.
The EROS Data Center houses AVHRR High Resolution Picture Transmission (HRPT)
data and Local Area Coverage (LAC) data. The HRPT data are full resolution
image data transmitted to a ground station as they are collected, while LAC
data (also full resolution data) are recorded with an onboard tape recorder for
subsequent transmission during a station overpass.
The objective of the AVHRR instrument is to provide radiance data for
investigation of clouds, land-water boundaries, snow and ice extent, ice or
snow melt inception, day and night cloud distribution, temperatures of
radiating surfaces, and sea surface temperature. The AVHRR data collection
effort also provides opportunities for studying and monitoring vegetation
conditions in ecosystems, including forests, tundra, and grasslands with
applications that include agricultural assessment, land cover mapping,
production of large-area image maps (e.g., country maps, continental maps,
world maps), and evaluation of regional and continental snow cover.
The average instantaneous field-of-view (IFOV) of 1.4 milliradians yields a
LAC/HRPT ground resolution of approximately 1.1 km at the satellite nadir from
the nominal orbit altitude of 833 km (517 mi). Additional data sets include the
Alaska twice-monthly AVHRR and the U.S. Conterminous bi-weekly composites.
These comprehensive time series data sets are calibrated, georegistered daily
observations and twice-monthly NDVI composites for each annual growing season.
Global Experimental Bi-Weekly Normalized Difference data, computed from Global
Vegetation Index (GVI) data, are analyzed to monitor global vegetation as a
potential tool in global climatic studies.
Data_Set_Credit
The EROS Data Center (EDC) AVHRR Data Acquisition and Processing System
(ADAPS), which began operation in May 1987, receives approximately six daytime
passes per day of HRPT data over the conterminous United States. Night
acquisitions are acquired upon request only. As of March 1990, all data
received at EDC are permanently archived. Prior to March 1990, approximately 40
percent of the data received were archived. The EROS Data Center AVHRR Data
Acquisition and Processing System was expanded on June 15, 1990, to acquire LAC
data via a communications satellite for areas recorded throughout the entire
globe. Priority is given to LAC acquisitions of the North American continent
not covered by EDC's direct reception. NOAA/NESDIS receives both world-wide
recorded and direct readout AVHRR data from the Wallops Island, Virginia, and
Gilmore Creek, Alaska, stations. These stations then redirect the data via a
satellite relay to NOAA/NESDIS in Suitland, Maryland, where the data are
processed, archived, and reproduced. The EROS Data Center ADAPS system was
reconfigured in July of 1997 to acquire LAC via electronic transfer from
NOAA/NESDIS, replacing the DOMSAT communications link.
Dataset Creator: U.S. Geological Survey
Dataset Title: Advanced Very High Resolution Radiometer
Dataset Release Date: 1980
Dataset Release Place: Sioux Falls, South Dakota, USA
Dataset Publisher: U.S. Geological Survey
Data Presentation Form: Remote Sensing Image
Online Resource: http://earthexplorer.usgs.gov
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Southernmost Latitude: 90.0S
Westernmost Longitude: 180.0W
Northernmost Latitude: 90.0N
Easternmost Longitude: 180.0E
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Logical_Consistency_Report:
The AVHRR sensor was designed to view cold space and one or more internal warm
blackbodies for each scan sequence while in orbit. In general, radiometric
calibration involves exposing a radiometer to sources of radiation that have
been calibrated against primary or secondary standards and determining a
relationship between the output of the radiometer and the intensity of the
incident radiation (radiance). All of the radiometers flown on the NOAA/TIROS
satellites undergo extensive prelaunch testing and calibration by their
manufacturers to characterize their performance. The NESDIS independently
analyzes the data from the prelaunch tests to determine the operating
characteristics of the instruments, such as their signal-to-noise ratios,
stability, linearity of response, and sensitivity. However, characteristics
cannot be expected to be the same in orbit as they were before the launch. One
reason is that the thermal environment varies with position in the orbit,
causing sensitivities to vary orbitally. Also, instrument components age in the
several years that usually elapse between the time of the prelaunch tests and
launch, and the aging process continues during the two or more years the
instrument typically operates in orbit.
Therefore, the NOAA/TIROS radiometers have been designed to view cold space and
one or more internal warm blackbodies as part of their normal scan sequences in
orbit.
Completeness_Report:
As the spacecraft moves through its orbit, the expected angular distance
between the nadir of adjacent LAC/HRPT scans is approximately 0.0296 degrees of
arc, or 3.2914 kilometers, as measured from the center of Earth. The actual
value of the average angular distance can vary by up to about 0.1712 kilometers
due to variations in satellite height, scan angle, and other factors. The
instantaneous field-of-view (IFOV) for all channels is specified to be 1.3 +/-
0.1 milliradians.
None
Acknowledgement of the U.S. Geological Survey would be appreciated in
products derived from these data.
Distribution Media: Tape
Distribution Size: 2 gigabyte maximum per image
Distribution Format: 8 mm
Fees: Level 1b, $50 (Researchers only); Georegistered, $190
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Distribution Media: CD-ROM
Fees: $190
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Name: INFORMATION SCIENTIST EROS DATA CENTER
Role: DIF AUTHOR
Phone: 605-594-6594
Fax: 605-594-6953
Email: meta@usgs.gov
Contact Address:
Address: Information Services Department
Address: EROS Data Center
Address: U.S. Geological Survey
City: Sioux Falls
Province or State: SD
Postal Code: 57198-0001
Country: USA
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URL: http://earthexplorer.usgs.gov
Description:
Dataset searching and ordering capabilities are available
through Earth Explorer at the above URL.
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Kidwell, K.B., 1995, NOAA polar orbiter data user's guide:
Washington, D.C., National Oceanic and Atmospheric Administration
[variously paged].
Metadata Name: CEOS IDN DIF
Metadata Version: VERSION 9.0
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DIF Creation Date: 2003-06-10
Future DIF Review Date: 2002-06-01
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