Amazon vegetation greenness as measured by satellite sensors over the last decade

Atkinson, P.M. and Dash, J. and Jeganathan, C. (2011) Amazon vegetation greenness as measured by satellite sensors over the last decade. Geophysical Research Letters, 38. pp. 1-6. ISSN 0094-8276

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Abstract

[1] During the last decade two major drought events, one in 2005 and another in 2010, occurred in the Amazon basin. Several studies have claimed the ability to detect the effect of these droughts on Amazon vegetation response, measured through satellite sensor vegetation indices (VIs). Such monitoring capability is important as it potentially links climate changes (increasing frequency and severity of drought), vegetation response as observed through vegetation greenness, and land-atmosphere carbon fluxes which directly feedback into global climate change. However, we show conclusively that it is not possible to detect the response of vegetation to drought from space using VIs. We analysed 11 years of dry season (July–September) Moderate Resolution Imaging Spectroradiometer (MODIS) enhanced vegetation index (EVI) and normalised difference vegetation index (NDVI) images. The VI standardised anomaly was analysed alongside the absolute value of EVI and NDVI, and the VI values for drought years were compared with those for non-drought years. Through a series of analyses, the standardised anomalies and VI values for drought years were shown to be of similar magnitude to those for non-drought years. Thus, while Amazon vegetation may respond to drought, this is not detectable through satellite-observed changes in vegetation greenness. A significant long-term decadal decline in VI values is reported, which is independent of the occurrence of drought. This trend may be caused by environmental or noise-related factors which require further investigation.

Item Type:
Journal Article
Journal or Publication Title:
Geophysical Research Letters
Additional Information:
M1 - L19105 Copyright 2011 American Geophysical Union.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900
Subjects:
ID Code:
77015
Deposited By:
Deposited On:
10 Dec 2015 11:52
Refereed?:
Yes
Published?:
Published
Last Modified:
09 Aug 2020 03:48