Global Experimental Bi-Weekly Normalized Difference (GLEND) Vegetation IndexEntry ID: GLEND_NC00260
Abstract: The vigor and density of green vegetation can be monitored through
examination of the spectral reflectance of the vegetation in the visible
and near infrared areas of the electromagnetic spectrum.
The NOAA Global Vegetation Index (GVI) uses sampled visible and near IR AVHRR
GAC data to produce a vegetative index called the Normalized Difference
Vegetation ... Index (NDVI). The index is generated for each pixel by the
following formula: NDVI = (band 2 - band 1) / (band 2 + band 1)
GVI data are processed daily and then composited on a weekly basis with NDVI
calculated to produce a near global map portraying vegetation vigor. A global
experimental NDVI was computed at the EROS Data Center from weekly visible,
near IR and GVI data from NOAA. This data set is referred to as the Global
Experimental Bi-Weekly Normalized Difference (GLEND) data.
The GLEND data set utilizes bands 1 and 2 recalibrated from pre-launch
calibration- tion coefficients and also employs a weekly normalized
difference data set cal- culated from these recalibrated bands. During the
process of calculating the normalized difference, individual pixels are tagged
if they have an unaccepta- bly low solar zenith angle ( <15 degrees) or if
their NDVI value indicates a high probability of cloud cover.
The Mercator projected product of NOAA was utilized to generate this product.
The data are available from 55 degrees South to 75 degrees North. Data
resolution in the Mercator projection varies from 19.6 km at the equator to 15
km at 40 degrees (N or S).
Global Experimental Bi-Weekly Normalized Difference data are available from
the EROS Data Center and NOAA's National Geophysical Data Center (NGDC).
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Start Date: 1985-04-09Stop Date: 1991-12-31
BIOSPHERE > VEGETATION > VEGETATION COVER > VEGETATION INDEX
BIOSPHERE > VEGETATION > VEGETATION INDEX
LAND SURFACE > LAND USE/LAND COVER > LAND COVER
LAND SURFACE > SURFACE RADIATIVE PROPERTIES > REFLECTANCE
SPECTRAL/ENGINEERING > INFRARED WAVELENGTHS > INFRARED IMAGERY
SPECTRAL/ENGINEERING > INFRARED WAVELENGTHS > REFLECTED INFRARED
SPECTRAL/ENGINEERING > VISIBLE WAVELENGTHS > VISIBLE IMAGERY
ISO Topic Category
Use Constraints There is no guarantee of warranty concerning the accuracy of these data. Users should be aware that temporal changes may have occurred since the data was collected and that some parts of these data may no longer represent actual surface conditions. Users should not use these data for critical applications without a full awareness of their limitations. Acknowledgement of the originating agencies would be appreciated in products derived from these data. Any user who modifies the data set is obligated to describe the types of modifications they perform. User specifically agrees not to misrepresent the data set, nor to imply that changes made were approved or endorsed by the U.S. Geological Survey. Please refer to http://www.usgs.gov/privacy.html for the USGS disclaimer.
Role: TECHNICAL CONTACT
Phone: (704) 271-4878
Email: kgallo at ncdc.noaa.gov
Global Climate Laboratory NOAA/National Climatic Data Center Federal Building
Province or State: NC
Postal Code: 28801-2696
Role: DIF AUTHOR
Email: custserv at usgs.gov
Information Systems Management U.S. Geological Survey EROS Data Center 47914 252nd Street
City: Sioux Falls
Province or State: SD
Postal Code: 57198-0001
Kidwell, K.B., 1990. 'Global Vegetation Index Users's Guide,' U.S.
Dept. of Commerce, NOAA/NESDIS, Washington, D.C.
Kidwell, K.B., 1986. 'NOAA Polar Orbiter Data User's Guide,'
U.S. Dept. of Commerce, NOAA/NESDIS, Washington, D.C.
Ohring, G., Gallo, K., Gruber, A., Planet, W., Stowe, L., Tarpley,
J.D., 1989. 'Climate and Global Change: Characteristics of NOAA
Satellite Data,' Transactions, American Geophysical Union, 70, 41, 1989.
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Creation and Review Dates
Last DIF Revision Date: 2009-04-20