Analysis of the 2012-2016 drought in the northeast Brazil and its impacts on the Sobradinho water reservoir

The northeast region of Brazil (NEB) suffers with the worst drought during 2012-2016 that has greatly affected water availability in general, in particular the hydropower reservoirs. We have analyzed a large dataset of satellite measurements and images to understand the variability of precipitation, land surface temperature (LST) and their association with the Normalized Difference Vegetation Index (NDVI), indicator of water and vegetation stress. The drought conditions during 2012-2016 show association of poor rainfall in the year 2012, an increase of LST 7oC above the average, reduction in NDVI upto 30% and a sharp decrease upto 28% in Relative Humidity (RH). The largest reservoir of the NEB, Sobradinho, shows decline in surface water upto about 50% which is clearly evident from the Normalized Difference Water Index (NDWI) for the period 2015-2016 compared to the year 2011.