Publication: A procedure to derive intra- and inter-annual changes on vegetation
from NDVI time series. A case study in Spain.
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Date
2020-04-03
Authors
Gilabert, M.A. ; Martínez, B. ; Meliá, J.
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Departament de Física de la Terra i Termodinàmica, Universitat de València.
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Publisher
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DOI
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info:eu-repo/semantics/other
Description
Abstract
The NDVI time series are characterized by patterns like seasonality, trends and localized
abrupt changes or discontinuities resulting from disturbance events. Therefore, they allow us
to characterize vegetation dynamics on the basis of different temporal scales. In particular,
the subtle, long-term changes convey relevant information on land degradation.
The objective of this work is to study the spatial patterns of vegetation activity over Spain and
its temporal variability throughout the period 1989-2002. A multi-resolution analysis (MRA)
based on the wavelet transform has been implemented on NDVI time series from the
MEDOKADS database. The MRA decomposes the original signal as a sum of series
associated with different temporal scales. Specifically, the intra-annual series is processed to
define several key features in relation with the vegetation phenology. In contrast, the interannual
component of the signal is used to detect trends by means of a Mann-Kendall test
and map the magnitude of the land-cover change. Finally, a comprehensive identification of
the areas presenting a negative value of the magnitude of change is carried out to select
those linked to land degradation processes. Results show a major presence of these areas
the Southeast of Spain.
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Este ítem está sujeto a una licencia Creative Commons. http://creativecommons.org/licenses/by-nc-nd/4.0/