Analysis of Drought at Terai Regions in Uttarakhand using Multiple Remotely Sensed Data

With developments in remotely sensed imageries, nowadays satellite images provide more narrow wavelength bands in higher resolution and frequent revisit time such as Sentinel-2. Sentinel-2 can be used to generate Normalized Difference Water Index (NDWI) which explains the water or moisture content of the object of interest. In this study, ERA5-Land total precipitation data and Sentinel-1 SAR C-band were also used to assess drought that happened in Terai Region around Uttarakhand in 2021. Study area is divided into three study sites: Lower Terai, Reservoir, and Hilly Area to accommodate three different landscape condition. The results show that NDWI values fluctuates between 0.25 to -0.05 around croplands but not in the densely vegetated area. Also, the changes in NDWI values around Lower Terai follow the trend in the Hilly Area but not the Reservoir. The results from three remotely sensed data also show that the minimum NDWI value was captured around November to December 2021 in Lower Terai and Hilly Area, while in Reservoir area it was in September. Overall, the three datasets had shown the ability to detect changes in moisture and water in Terai region, Uttarakhand.