AVHRR
STATUS
CLASS Up To Present, Veg Index Updated Through 2004
AVAILABILITY
Public dataset, available on line. Historical data available on URL, real time data by request. General AVHRR level 1b data are available from NOAA's CLASS system online. Comprehensively corrected Vegetation record that spans nearly 30 years is available for analysis.
REQUEST PROCEDURE
Real time data available by email request. Level 1b data can be requested with an online search system from CLASS and the requested data will be staged for FTP delivery thus eliminating the cost factor in data delivery. The bimonthly Vegetation index record derived from AVHRR data from 1981 to 2008 can be obtained from the GIMMS group at NASA Goddard, and from the University of Maryland's Global Land Cover Facility (GLCF). http://www.landcover.org/data/gimms/
Satellite Instruments
AVHRR is a visible through thermal infrared instrument that does everything from vegetaions o sea surface temperature. Originally part of the polar orbiting weather satellite system the imagery originally served to map clouds day and night (with thermal infrared). The first instrument was flown on the TIROS satellite in Oct., 1979 and became opertation with NOAA 6 the following year. Vegetation index data derived from AVHRR sensors. Data record begins in July 1981 and continues in real time. AVHRR separates into: AVHRR a 4-channel radiometer (vis, NIR, 11 and 12 microns), AVHRR-2 a 5-channel radiometer (vis, NIR, SWIR, 11,12 microns) and the AVHRR-3 which actually has 6 channels but downlinks only 5 splitting channel 3 between 1.6 microns during the day and 3.7 microns during the night. The following table gives the AVHRR-3 channels AVHRR/3 Channel Characteristics Channel 1-Resolution at Nadir,1.09 km: Wavelength (um), 0.58 - 0.68: Typical Use, Daytime cloud and surface mapping Channel 2-Resolution at Nadir,1.09 km: Wavelength (um), 0.725 - 1.00: Typical Use, Land-water boundaries Channel 3A-Resolution at Nadir,1.09 km: Wavelength (um), 1.58 - 1.64: Typical Use, Snow and ice detection Channel 3B-Resolution at Nadir,1.09 km: Wavelength (um), 3.55 - 3.93: Typical Use, Night cloud mapping, sea surface temperature Channel 4-Resolution at Nadir,1.09 km: Wavelength (um), 10.30 - 11.30: Typical Use, Night cloud mapping, sea surface temperature Channel 5-Resolution at Nadir,1.09 km: Wavelength (um), 11.50 - 12.50: Typical Use, Sea surface temperature
CONTACT
Molly E. Brown at GSFC
NOAA POES Operations, SSAI/NASA Goddard Space Flight Center
Code 614.4 Biospheric Sciences Branch Greenbelt, MD 20771
301-614-6616
molly.brown@nasa.gov
http://gimms.gsfc.nasa.gov
SPECIFICATIONS
Measurment TypeVisible/IR-imager
Platform TypeAVHRR
OrbitSun synchronous
Spectral Coverage
Active/PassivePassive
Scan PatternCross track
Variables
Altitude
Inclination
Repeat Time~15.3 days
Wavelength0.53 to 12.8um
Number of Bandsoriginally 4 now 6
Start DateOct 1979
Temporal Coverageat least twice daily for raw AVHRR, for veg index 10 and 15 day composites
Swath Width~2,000 km
Resolution 11.1km
Resolution 24km
REFERENCES
Tucker, C.J. et al., 2005. An Extended AVHRR 8-km NDVI Data Set Compatible with MODIS and SPOT Vegetation NDVI Data. International Journal of Remote Sensing, 26(20): 4485-4498. Pinzon, J., Brown, M.E. and Tucker, C.J., 2005. Satellite time series correction of orbital drift artifacts using empirical mode decomposition. In: N. Huang (Editor), Hilbert-Huang Transform: Introduction and Applications. World Scientific, Hackensack NJ, pp. 167-186.
REMARKS
AVHRR were the core data in the Satellite Active Archive that constituted the core of the CLASS system which has now grown to include a variety of other data sources.
UPDATED ON
23 Oct 2009 11:46