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George, C.; Gerard, F.

Leaf phenology synchrony for Meso- and South America

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THIS DATASET HAS BEEN SUPERSEDED The latest version is Leaf phenology synchrony for Meso- and South America v2

Data recalculated with amended algorithm, as the original was not allowing for the difference between the average amplitude or equivalently average deviation (i.e. ave amplitude time series sense) and the maximum deviation. Hence we needed to multiply the original dataset by 2.0/SQRT(0.5) to get average peak-to-trough.

If you need access to the archived version, please contact the EIDC

https://doi.org/10.5285/36795e9d-2380-465c-947b-3c9ae26f92d0
The leaf phenology product presented here shows the amplitude of annual cycles observed in MODIS (Moderate Resolution Imaging Spectroradiometer) normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) 16-day time-series of 2000 to 2013 for Meso- and South America. The values given represent a conservative measure of the amplitude after the annual cycle was identified and tested for significance by means of the Fourier Transform. The amplitude was derived for four sets of vegtation indices (VI) time-series based on the MODIS VI products (500m MOD13A1; 1000m MOD13A2). The amplitude value can be interpreted as the degree in which the life cycles of individual leaves of plants observed within a pixel are synchronised. In other words, given the local variation in environment and climate and the diversity of species leaf life cycle strategies, an image pixel will represent vegetation communities behaving between two extremes:
* well synchronized, where the leaf bud burst and senescence of the individual plants within the pixel occurs near simultaneously, yielding a high amplitude value. Often this matches with an area of low species diversity (e.g. arable land) or with areas where the growth of all plants is controlled by the same driver (e.g. precipitation).
* poorly synchronized, where the leaf bud burst and senescence of individual plants within a pixel occurs at different times of the year, yielding a low amplitude value. Often this matches with an area of high species diversity and/or where several drivers could be controlling growth.
Publication date: 2017-07-07
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View numbers valid from 01 June 2023 (information prior to this was not collected)

Format

TIFF

Spatial information

Study area
Spatial representation type
Raster
Spatial reference system
WGS 84

Temporal information

Temporal extent
2000-01-01    to    2013-12-31

Provenance & quality

The key underlying method is the Fourier Transform (FT) a well established and efficient methodology to analyse time series data. The FT can be used for the detection of regular cycles, even when hidden in a noisy background and when the time series in question contains data gaps. The FT estimates a power spectrum that indicates the average variance in a time series at different time scales or frequencies. Standard linear de-trending of the data before application of the FT allows an analysis of a 'stationary' time series as the mean and variance should ideally be more-or-less constant.

We used two approaches to evaluate the amplitude values. The first involved comparing the full extent of the amplitude data grids with the independent International Geosphere-Biosphere Programme (IGBP) land cover map. This was done with histograms showing the distribution of the amplitude values found within each of the IGBP cover classes. The second approach compared published in situ site observations that describe canopy leaf life cycles through leaf flushing and falling, LAI and litter fall or other observations, with the corresponding amplitude values of these sites.

Licensing and constraints

THIS DATASET HAS BEEN SUPERSEDED The latest version is Leaf phenology synchrony for Meso- and South America v2

Data recalculated with amended algorithm, as the original was not allowing for the difference between the average amplitude or equivalently average deviation (i.e. ave amplitude time series sense) and the maximum deviation. Hence we needed to multiply the original dataset by 2.0/SQRT(0.5) to get average peak-to-trough.

If you need access to the archived version, please contact the EIDC

This dataset is made available under the terms of the Open Government Licence

Cite this dataset as:
George, C.; Gerard, F. (2017). Leaf phenology synchrony for Meso- and South America. NERC Environmental Information Data Centre. https://doi.org/10.5285/36795e9d-2380-465c-947b-3c9ae26f92d0

© UK Centre for Ecology & Hydrology

Correspondence/contact details

George, C.
UK Centre for Ecology & Hydrology
Maclean Building, Benson Lane, Crowmarsh Gifford
Wallingford
Oxfordshire
OX10 8BB
UNITED KINGDOM
 enquiries@ceh.ac.uk

Authors

George, C.
Centre for Ecology & Hydrology
Gerard, F.
Centre for Ecology & Hydrology

Other contacts

Rights holder
UK Centre for Ecology & Hydrology
Custodian
NERC EDS Environmental Information Data Centre
 info@eidc.ac.uk
Publisher
NERC Environmental Information Data Centre
 info@eidc.ac.uk

Additional metadata

Topic categories
environment
Keywords
enhanced vegetation index (EVI) , normalized difference vegetation index (NDVI) , Phenology , vegetation index (VI)
Last updated
21 March 2025 13:36