Monitoring thermal anomaly and radiative heat flux using thermal infrared satellite imagery - A case study at Tuzla geothermal region

摘要

Geothermal energy, which is renewable, reliable and environmentally friendly, is one of the most important energy resources. Thus, it is crucial to explore geothermal areas in order to reduce the use of other energy sources that are detrimental to the environment and ecology. Thermal Infrared (TIR) remote sensing is an effective way to detect thermal anomalies in geothermal areas and volcanoes, since it is cost and time effective, and offers to work on a large scale compared to geophysical methods. The aim of this study is to investigate thermal anomalies in Tuzla geothermal region using daytime and nighttime TIR data with reference to Land Surface Temperature (LST) and Radiative Heat Flux (RHF). Many geophysical studies have been conducted in this region; however, it can also be studied with TIR remote sensing for further exploration. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data, acquired on 15.06.2012 and 15.07.2017 as daytime image and 15.09.2013 and 31.12.2017 as nighttime image, were utilized as satellite imagery. In addition to ASTER data, we proposed a multi-sensor based LST retrieval for nighttime using Landsat 8 data for emissivity acquisition. In order to evaluate the accuracy of LST images, cross-validation method was utilized with reference to Moderate Resolution Imaging Spectroradiometer (MODIS) LST products. The coefficient of determination (r(2)) and Root Mean Square Error (RMSE) were considered as statistical metrics and the lowest result was obtained as 90% and 1.76 K, respectively. As a result of the analyses, it was observed that nighttime LST presented better results for thermal anomalies in that geothermal area than daytime LST. Considering geothermal anomaly, the geothermal area had higher LST values even though it held identical or same NDVI values as compared to non-geothermal surroundings. In addition, the net radiative heat loss values were calculated as 17.83 MW and 121.28 MW for 2013 and 2017, respectively. The obtained results proved that TIR remote sensing could be utilized in the studies of geothermal area exploration.