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Research
Many activities including collecting and compiling past satellite and
climate information are carried out. Information on these activities
and research findings will be published here as they are available.
Vegetation Indices as Indicators of Drought
- Biomass accumulation is related to the visible
sunlight that plants absorb.
- Satellite remote sensing can help to quantify what
fraction of the photosynthetically active radiation is absorbed by vegetation.
- By appropriately combining remote sensors' spectral
information, different vegetation indices can be produced.
- These indices reveal both the vigor of plant growth
and its biomass accumulation.
- Enhanced Vegetation Index (EVI) and Normalized
Difference Vegetation Index (NDVI) are two of these indices.
- NDVI is calculated from the visible and near-infrared
light reflected by vegetation as shown in the figure at right (numbers in the figure
are illustrative.)
- EVI is also calculated similarly, but uses additional
spectral information in the visible light spectrum.
- As plant growth is mostly limited by water
availability, an indication of persistent lessening of vegetation indices is a good
indicator of drought conditions.
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