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. 2021 Jun 22;15(6):e0009466. doi: 10.1371/journal.pntd.0009466

Table 1. Environmental variables used with their characteristics, sources and indexes used to calculate them.

Environmental Variables Source Characteristics/ Sentinel-2A Indexes
Precipitation WorldClim version 2.1 climate data for 1979–2000 (New version released in January 2020) Spatial resolution of 30 seconds (~1 km2)/ NA
Temperature WorldClim version 2.1 climate data for 1979–2000 (New version released in January 2020) Mean temperature from monthly January/ NA
Normalized Difference Vegetation Index (NDVI) Satellite imagery Sentinel-2A of 01 Feb 2017*
Level 1C product		 Numerical indicator highly associated with vegetation content/ (B8 –B4) / (B8 + B4)
Normalized Difference Built-up Index (NDBI) Satellite imagery Sentinel-2A of 01 Feb 2017*
Level 1C product		 Highlights urban areas/ (B11-B8)/(B11+B8)
Moisture Stress Index (MSI) Satellite imagery Sentinel-2A of 01 Feb 2017*
Level 1C product		 Index of hydric stress/ (B11 / B08)
Bare Soil Index (BSI) Satellite imagery Sentinel-2A of 01 Feb 2017*
Level 1C product		 Numeric indicador that enhances the identification of bare soil areas and fallow lands/ (B11 + B4)–(B8 + B2) / (B11 + B4) + (B8 + B2)

*Note: Source of ESA, image courtesy of the U.S. Geological Survey. Free Sentinel-2A imagery was downloaded from the ESA Sentinel data hub (https://scihub.copernicus.eu).