Summer Research Fellowship Programme of India's Science Academies

Drought Monitoring in the Dharmapuri District of Tamil Nadu using Remote Sensing and VHI Techniques

S. Nitheshnirmal

4th year M.Sc. Geography (Intg.), Department of Geography, Bharathidasan University, Tiruchirappalli 620024

Dr. S Arivazhagan

Assistant Professor, Centre for Applied Geology, Gandhigram Rural Institute (Deemed to be University), Dindigul 624302


Drought is a recurrent climatic phenomenon that occurs in a large, geographical space with uneven spatio-temporal characteristics over an extended period of time. Due to its severe impact on agriculture and vegetation, monitoring of drought and its severity using satellite-derived drought indices is becoming popular in disaster, desertification and climate change studies. This project is aimed at continuous yearly monitoring of the effect of drought using Normalised Difference Vegetation Index, Land Surface Temperature, Vegeatation Condition Index, Temperature Condition Index and Vegeatation Health Index over the agricultural lands of Dharmapuri, with the help of the level 1 Landsat data products from Thematic Mapper (TM) and Operational Land Imager/ Thermal Infrared Sensor (TIRS) during the summer months (April-May) of 2006 to 2018. The objective of this present study is to determine the satellite image-based Normalised Differential Vegetation Index (NDVI) and the Land Surface Temperature (LST), by using spatio-temporal images of Landsat satellite images. The Vegetation Condition Index (VCI) and the Temperature Condition Index (TCI) are determined from the NDVI and the LST. By using VCI and TCI, the Vegetation Health Index (VHI) is determined for the agricultural region of the study area. A total number of 3 bands (band 4 (NIR), band 3 (Red) and band 6 (Thermal)) from Landsat TM (4-5), and 4 bands (band 5 (NIR), band 4 (Red), band 10 (TIRS-1) and band 11 (TIRS-2) from Landsat OLI/TIRS, for the period of 2006-2018 are used in this study. Based on the stressed and healthy vegetation, the drought-affected agricultural land is classified into extreme drought region (<10), severe drought region (<20), moderate drought region (<30), mild drought region (<40) and no drought region (≥40). This study will help in identifying them and calculating the aerial coverage of the affected area. This approach of using satellite remote sensing data will greatly help the decision makers in monitoring, investigating, resolving and adopting the management strategies for drought conditions more effectively.

Keywords: Vegetation Health Index, Vegetation Condition Index, Temperature Condition Index, Normalised Difference Vegetation Index, Land Surface Temperature

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