![Sample our Geography journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/5937/TOC-Subject-Sample-2021-Geography.jpg"})
Abstract
Daily daytime Advanced Very High Resolution Radiometer (AVHRR) 4‐km global area coverage data have been processed to produce a Normalized Difference Vegetation Index (NDVI) 8‐km equal‐area dataset from July 1981 through December 2004 for all continents except Antarctica. New features of this dataset include bimonthly composites, NOAA‐9 descending node data from August 1994 to January 1995, volcanic stratospheric aerosol correction for 1982–1984 and 1991–1993, NDVI normalization using empirical mode decomposition/reconstruction to minimize varying solar zenith angle effects introduced by orbital drift, inclusion of data from NOAA‐16 for 2000–2003 and NOAA‐17 for 2003–2004, and a similar dynamic range with the MODIS NDVI. Two NDVI compositing intervals have been produced: a bimonthly global dataset and a 10‐day Africa‐only dataset. Post‐processing review corrected the majority of dropped scan lines, navigation errors, data drop outs, edge‐of‐orbit composite discontinuities, and other artefacts in the composite NDVI data. All data are available from the University of Maryland Global Land Cover Facility (http://glcf.umiacs.umd.edu/data/gimms/).
Acknowledgements
The dataset we describe would not have been possible without the work of two people: Martha Maiden and Stanley Schneider. We thank Martha Maiden of NASA Headquarters for her support that made this dataset possible. We thank Stanley Schneider for convincing NOAA management in 1977 to alter the spectral configuration of the TIROS‐N channel 1 band pass from 0.55–0.90 µm to 0.55–0.70 µm. None of the extensive and widespread AVHRR NDVI work would be possible without Schneider's unilateral action in 1977 which restricted AVHRR channel 1 to the upper portion (0.55–0.70 µm) of the visible spectrum.