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Data Visualization

Area of vegetation productivity decrease due to water deficit, 2000-2016

Data Visualization Created 20 Aug 2020 Published 21 Aug 2020 Last modified 19 Oct 2020
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Methodology
Standardized anomalies of yearly vegetation productivity during 2000-2016 are analysed in areas with statistically significant drought pressure due to precipitation shortages and due to low soil moisture content. Anomalies are expressed in standard deviations compared to the long term average vegetation productivity conditions for each 500m grid cell in the EEA39 region. The size of the impacted area is calculated from the sum of those grid cells where the vegetation productivity anomaly was below -1 standard deviation in the given year. The vegetation index used in the indicator is the Plant Phenology Index (PPI, Jin and Eklundh, 2014). PPI is based on the MODIS Nadir BRDF-Adjusted Reflectance product (MODIS MCD43 NBAR. The product provides reflectance data for the MODIS “land” bands (1 - 7) adjusted using a bi-directional reflectance distribution function. This function models values as if they were collected from a nadir-view to remove so called cross-track illumination effects. The product is distributed with 500 m pixel size (MODIS Sinusoidal Grid) with 8-days compositing period. The web map service was derived from a 16 bit time series.

Reference: Jin, H., Eklundh, L. (2014): A physically based vegetation index for improved monitoring of plant phenology, Remote Sensing, 152, 512 – 525. Input to the PPI index was from MODIS NDVI.

Unit
The vegetation productivity index is a dimensionless measure. It is calculated as the integral value of the yearly vegetation index. Hence, digital values indicate the approximated productivity of the land surface vegetation. The anomalies are standardised and hence are expressed in standard deviation units. The affected area is expressed in km2.

Data sources

Vegetation productivity 2000-2016 provided by European Environment Agency (EEA)

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