NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Satellite Observation of El Nino Effects on Amazon Forest Phenology and ProductivityClimate variability may affect the functioning of Amazon moist tropical forests, and recent modeling analyses suggest that the carbon dynamics of the region vary interannually in response to precipitation and temperature anomalies. However, due to persistent orbital and atmospheric artifacts in the satellite record, remote sensing observations have not provided quantitative evidence that climate variation affects Amazon forest phenology or productivity, We developed a method to minimize and quantify non-biological artifacts in NOAA AVHRR satellite data, providing a record of estimated forest phenological variation from 1982-1993. The seasonal Normalized Difference Vegetation Index (NDVI) amplitude (a proxy for phenology) increased throughout much of the basin during El Nino periods when rainfall was anomalously low. Wetter La Nina episodes brought consistently smaller NDVI amplitudes. Using radiative transfer and terrestrial biogeochemical models driven by these satellite data, we estimate that canopy-energy absorption and net primary production of Amazon forests varied interannually by as much as 21% and 18%, respectively. These results provide large-scale observational evidence for interannual sensitivity to El Nino of plant phenology and carbon flux in Amazon forests.
Document ID
20010048013
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Asner, Gregory P.
(Colorado Univ. Boulder, CO United States)
Townsend, Alan R.
(Colorado Univ. Boulder, CO United States)
Braswell, Bobby H.
(Max-Planck-Inst. for Biogeochemistry Jena Greece)
Date Acquired
August 20, 2013
Publication Date
April 1, 2000
Publication Information
Publication: Geophysical Research Letters
Publisher: American Geophysical Union
Volume: 27
Issue: 7
ISSN: 0094-8276
Subject Category
Environment Pollution
Report/Patent Number
Paper-1999GL011113
Funding Number(s)
CONTRACT_GRANT: NAGW-5253
CONTRACT_GRANT: NAG5-8709
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available