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Enhanced assessment of global land degradation


de Jong, R; Bai, Z; Dent, D; Schaepman, M E; de Bruin, S; de Wit, A (2009). Enhanced assessment of global land degradation. In: 33rd International Symposium on Remote Sensing of Environment (ISRSE), Stresa, Italy, 4 May 2009 - 8 May 2009, 1-4.

Abstract

Land degradation is a global environmental issue with social and economic impacts at many scales. Defining land degradation as a long-term decline in ecosystem function and productivity, we may measure it using long-term, remotely sensed NDVI data; deviation from the norm may serve as a proxy assessment of land degradation and improvement if other factors that may be responsible are taken into account.
Few assessments have been published, some focusing on descriptive mapping of land degradation, some based on expert opinion and qualitative assessment that cannot be reproduced. Our quantitative approach aims at reproducible mapping at the global scale that allows continual updating.
Developing existing methods, we use the GIMMS NDVI dataset (1981-2006), improving previously used linear trend and residual analysis on yearly accumulated NDVI by employing harmonic analyses of NDVI time-series (HANTS). HANTS enables correction for phase-shifted productivity cycles (instead of using simple annual cycles), providing optimal estimates of the start-of-season, multiple yearly growing cycles compensation, and non-linear trend analysis to incorporate potential greening to browning trend changes. This reduces the false alarms otherwise generated as well as providing a coherent global stratification of greenness trends, without using a priori land cover information.

Abstract

Land degradation is a global environmental issue with social and economic impacts at many scales. Defining land degradation as a long-term decline in ecosystem function and productivity, we may measure it using long-term, remotely sensed NDVI data; deviation from the norm may serve as a proxy assessment of land degradation and improvement if other factors that may be responsible are taken into account.
Few assessments have been published, some focusing on descriptive mapping of land degradation, some based on expert opinion and qualitative assessment that cannot be reproduced. Our quantitative approach aims at reproducible mapping at the global scale that allows continual updating.
Developing existing methods, we use the GIMMS NDVI dataset (1981-2006), improving previously used linear trend and residual analysis on yearly accumulated NDVI by employing harmonic analyses of NDVI time-series (HANTS). HANTS enables correction for phase-shifted productivity cycles (instead of using simple annual cycles), providing optimal estimates of the start-of-season, multiple yearly growing cycles compensation, and non-linear trend analysis to incorporate potential greening to browning trend changes. This reduces the false alarms otherwise generated as well as providing a coherent global stratification of greenness trends, without using a priori land cover information.

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Additional indexing

Item Type:Conference or Workshop Item (Paper), refereed, further contribution
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Event End Date:8 May 2009
Deposited On:03 Jan 2011 13:22
Last Modified:07 Dec 2017 04:31
Publisher DOI:https://doi.org/10.1007/978-3-540-72438-4_1
Official URL:http://isrse-33.jrc.ec.europa.eu/about-the-conference/detailed-programme.html

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