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

Amazon vegetation greenness as measured by satellite sensors over the last decade
Amazon vegetation greenness as measured by satellite sensors over the last decade
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
0094-8276
L19105-[6 pages]
Atkinson, P.M.
96e96579-56fe-424d-a21c-17b6eed13b0b
Dash, J.
51468afb-3d56-4d3a-aace-736b63e9fac8
Jeganathan, C.
2dd3d151-7bb1-42b9-bda6-54df0bed4ae8
Atkinson, P.M.
96e96579-56fe-424d-a21c-17b6eed13b0b
Dash, J.
51468afb-3d56-4d3a-aace-736b63e9fac8
Jeganathan, C.
2dd3d151-7bb1-42b9-bda6-54df0bed4ae8

Atkinson, P.M., Dash, J. and Jeganathan, C. (2011) Amazon vegetation greenness as measured by satellite sensors over the last decade. Geophysical Research Letters, 38 (19), L19105-[6 pages]. (doi:10.1029/2011GL049118).

Record type: Article

Abstract

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

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Published date: 12 October 2011
Organisations: Global Env Change & Earth Observation

Identifiers

Local EPrints ID: 201279
URI: https://eprints.soton.ac.uk/id/eprint/201279
ISSN: 0094-8276
PURE UUID: 1e94dce4-063a-4518-b7e2-bad5c05d9f81
ORCID for P.M. Atkinson: ORCID iD orcid.org/0000-0002-5489-6880
ORCID for J. Dash: ORCID iD orcid.org/0000-0002-5444-2109

Catalogue record

Date deposited: 28 Oct 2011 13:03
Last modified: 29 Oct 2019 02:06

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