Assessing the occurrence of drought based on NDVI, LST and rainfall pattern during 2010–2014

Abstract

Now-a-days with the advancement of satellite based remote sensing technologies, spatial drought monitoring and assessment has become feasible. Drought can be significantly monitored with the satellite data. Pakistan has often undergone short and long periods of drought. In this paper, 2014 drought occurrence in Mithi taluka (district Tharparkar) was analyzed during 2010–2014. 16 days composite of Normalized Difference Vegetation Index (NDVI) from Moderate-Resolution Imaging Spectro-radiometer (MODIS) Vegetation Index MOD13Q1 product and Land Surface Temperature (LST) eight days composite product MOD11A2 were acquired from NASA. Local rainfall statistics was acquired for the period 2010 to 2014 to monitor drought. Results show that Vegetation Supply Water Index (VSWI) was quite low, indicating that the vegetation transpiration rate has declined. This confirmed the occurrence of drought. VSWI values in first six months (January to June) 2010 depicted that drought was severe as compared to 2013 and 2014. NDVI and LST maximum values were correlated to identify the drought event from May to October. A strong negative correlation (R2 =0.8255) was observed in 2010 indicating severe drought and this negative correlation trend weakened gradually from 2010 to 2014. A very weak negative correlation (R2 = 0.2753) estimated in 2014 indicating that there might not be a drought in 2014. The weakening trend was seen for the entire period from 2010 to 2014.