LAND SURFACE TEMPERATURE RETRIEVAL FROM LANDSAT-8

Abstract

Land surface temperature, or LST, is the temperature of a surface that may be measured when it is in direct contact with a measuring equipment. It is known as the radiative skin temperature of land, and it is obtained from infrared radiation. The "skin" temperature is the temperature of the top surface when it is on bare soil, and the temperature of plant "canopies" is defined by the top of the canopy for effective emitting. At simple terms, LST may be described as how hot the "surface" of the earth feels when touched in a certain area. However, from a satellite's perspective, "surface" is what it sees while looking through the atmosphere to the earth. The view might be from a structure, a body of water, or any geographical or manmade surface. In this research work attempt has been made to study the temporal and spatial variation of Land surface Temperature in the northern part of India that mainly focuses on Varanasi region from May 2013 to May 2021 using Landsat 8 - OLI & TIRS satellite dataset. The variation in Land surface temperature with the various Land use and cover classes have been also analyzed this research-work aims on forming an ERDAS imagine model for retrieving the Land surface temperature (LST) with the help of Landsat 8 thermal images and metadata of band 10 data. The correlation of Land Surface Temperature (LST) with Normalized Difference Vegetation Index (NDVI) and Normalized Difference Built-up Index (NDBI) is also studied and discussed in the thesis. The result shows that LST shares a positive relationship with the NDBI but a negative relationship with the NDVI. The built-up area (urbanization) for the area of interest in 2013 was 121.7 km2 which significantly increased VI to 200.38 km2 in 2021. Hence, the total increase in the built-up area from 2013 to 2021 (8- year time-period) is 8.62% of the total land cover that is 913.48 km2 . After analysing the variation of LST with different LULC classes, it was evident that the spike in the Land surface temperature in the area of interest was caused because there has been increase in impervious area which not only increase the built-up area but also decreases per capita tree cover of the region.