Drought disaster monitoring using MODIS derived index for drought years: A space-based information for ecosystems and environmental conservation

Abstract

Drought disaster is one of the major factors restricting the development of vegetation across a wide variety of environments. Monitoring the temporal and spatial dynamics of drought episodes in the study area is crucial for environmental and ecosystem conservation. This study assesses drought disaster by utilising space-based data and R programming for drought years 2003, 2007, 2012 and 2019 in the Free State Province, South Africa. Results revealed that the study area witnessed drought events in the year 2003 where March, August, September, October, November and December were more affected by drought disaster events. It was further observed that February and March were affected by extreme drought conditions in the year 2007. In year 2012, January, October, November and December, there exist moderate to severe drought conditions in the study area where some regions were more affected than the other. Finally, year 2019 witnessed variations in drought event distributions across the months with January, October and November witnessing severe to extreme drought conditions from about 0 to 30% drought values. Overall, this study shows that the 16-day Terra-MODIS composite and EVI products are sensitive to stressors associated with drought. The Vegetation Condition Monitoring Index (VCI) based on MODIS is suited for monitoring drought disasters. The technique used in this study revealed the suitability of MODIS data for assessing drought conditions and their potential environmental impacts.

Keywords: Drought disaster; Environmental conservation; MODIS; Space-based information; VCI.