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Table 2 Environmental indices calculated by the EASTWeb software

From: Integrating malaria surveillance with climate data for outbreak detection and forecasting: the EPIDEMIA system

Name Description Source
Precipitation Total amount of water falling from the atmosphere to the land surface (mm/week) \(\sum\limits_{d = 1}^{7} {P_{d} }\)
Land surface temperature Radiative skin temperature of the earth’s surface (°C) \(\frac{{\left( {T_{d} + T_{n} } \right)}}{2}\)
Normalized difference vegetation index Indicator of the amount of green vegetation. Can serve as a proxy for available soil moisture in water-limited environments \(\frac{{B_{2} - B_{1} }}{{B_{2} + B_{1} }}\)
Soil-adjusted vegetation index Similar to NDVI, but minimizes soil brightness influences \(\frac{{1.5 \times \left( {B_{2} - B_{1} } \right)}}{{B_{2} + B_{1} + 0.5}}\)
Enhanced vegetation index Similar to NDVI, but corrects for atmospheric distortion and ground cover below canopy \(\frac{{2.5 \times \left( {B_{2} - B_{1} } \right)}}{{B_{2} + 6 \times B_{1} - 7.5 \times B_{3} + 1}}\)
Normalized difference water index Indicator of water content in vegetation and at the soil surface \(\frac{{B_{2} - B_{5} }}{{B_{2} + B_{5} }}\)
\(\frac{{B_{2} - B_{6} }}{{B_{2} + B_{6} }}\)
  1. Indices were calculated from various remote sensing data products as described in the text
  2. P d daily precipitation, T d daytime land surface temperature, T n nighttime land surface temperature, B 1 MODIS band 1 (red, 620–270 nm), B 2 MODIS band 2 (near infrared, 841–876 nm), B 3 MODIS band 3 (blue, 459–479 nm), B 5 MODIS band 5 (middle-infrared, 1230–1250 nm), B 6 MODIS band 6 (middle infrared, 1628–1652 nm)