Correlation between Land Surface Temperature and Normalized Difference Vegetation Index of North Lakhimpur Revenue Circle of Lakhimpur District, Assam, India

Abstract

Rising Land Surface Temperature (LST) has become a critical indicator of climate change, strongly influenced by urbanization, deforestation, and land use modifications. Vegetation cover, often represented by the Normalized Difference Vegetation Index (NDVI), plays a significant role in regulating surface thermal dynamics. Understanding the relationship between NDVI and LST is therefore essential for monitoring climate impacts at local and regional level. This study analyses the correlation between LST and NDVI over a 20-year period (2001–2021) in the North Lakhimpur Revenue Circle, Assam, India, using multi-temporal Landsat 7 ETM+ and Landsat 8 OLI/TIRS imagery. LST was derived from the thermal bands, while NDVI was computed from the red and near-infrared reflectance values. Geospatial processing and statistical analysis were conducted in ERDAS Imagine 9.1, ArcGIS 10.4.1, and QGIS 3.30.3. Results show a clear warming trend, with mean LST increasing by approximately 2–6 °C over the study period. Seasonal variations were evident: in October, NDVI and LST exhibited a weak positive correlation (R² < 0.02), while in December, the relationship was negative (R² up to 0.05), indicating the cooling effect of vegetation during the dry season. Regression analysis further confirmed that vegetation influence on surface temperature has strengthened in December, despite overall rising baseline temperatures. These findings highlight the dual role of vegetation in modulating thermal environments and the growing importance of sustainable land management to mitigate local climate warming in Northeast India.