Assessment of the Accuracy of Satellite-Derived Land Surface Temperature with IMD In-Situ Air Temperature: A Case Study for Kullu Region, Himachal Pradesh, India

Abstract

In this study we compared Land Surface temperature (LST) computed from the high spatial resolution Landsat 8 and the high temporal resolution MODIS Aqua and Terra satellites to in situ near-surface air temperature (T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">air</inf> ) provided by IMD from 2013 to 2020. This study was carried out on Bhuntar station located in data sparse Kullu valley of Higher Himalayas. After spatiotemporal analysis with the IMD station, a total of 117 clear sky Landsat 8 scenes and 1771 clear sky MODIS scenes were analyzed using Google Earth Engine (GEE). LST was computed on these scenes on GEE using the Statistical Mono-Window (SMW) technique. The satellite derived LST values were extracted at the Bhuntar station and compared with IMD in-situ data. The result revealed strong correlation (R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> around 0.84) between Landsat-8 LSTs and T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">air</inf> . The averaged Night time LSTs obtained from MODIS Aqua and Terra satellites performed better than averaged Day time LSTs as the RMSE is lower during night time as compared to day time. The correlation between Landsat 8 derived LST is more in case of maximum T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">air</inf> than mean T <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">air</inf> . Based on these correlation, we proposed empirical equations for calculating air temperature from remotely observed LSTs. We expect that our findings will be valuable in bridging data gaps in in situ monitoring with daily resolution.