Study on Drought Monitoring Based on Spectral Indices in Noyyal River Sub-watershed Using Landsat-8 Imageries

Abstract

Drought is an extreme condition due to moisture deficiency and has adverse effect on society. Agricultural drought occurs when there is a reduction in soil moisture which produces serious crop stress and affects the crop productivity. The recent advances in the field of earth observation through different satellite based remote sensing systems have provided avenues for researchers to conduct continuous monitoring of soil moisture, land surface temperature and vegetation indices at a global scale. This research study is focused on Noyyal river sub-basin, which comes under a semi-arid region. In this study, Landsat 8 [Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS)] images of the year 2014, 2015, 2016 and 2017 were used for drought assessment in the summer season. The summer season spans from March to May in Coimbatore. Therefore, in the study the indices are compared corresponding to the months of summer for four consecutive years. The analysis of vegetation cover using NDVI, VCI, TCI, WSVI and VHI indices demonstrates the impact of the drought in the agricultural scenario in the sub-basin.