Geothermal Exploration Method Based On Landsat Images

With the continuous advancement of industrialization and informatization in the world,traditional energy reserves are limited,and the energy crisis has always been a huge issue for countries around the world.Finding natural sustainable development resources has become an important national policy for countries around the world.Geothermal resources are sustainable,green,clean,and pollution-free,and now have become one of the important clean resources.Traditional geothermal resource exploration methods require a large amount of time,manpower,material resources,and financial resources,but they also have limitations.As an efficient,low-cost,remote sensing technology,thermal infrared remote sensing can compensate for the shortcomings of traditional exploration methods to a certain extent and improve exploration efficiency.Detecting surface temperature information based on thermal infrared remote sensing data has become a new and convenient technical means for searching for geothermal resources.Land Surface Temperature(LST)is one of the important indicators reflecting the state of energy balance on the earth’s surface,and has important significance for geothermal resource exploration,hydrology,ecology,environment,and biogeochemistry research.Thermal infrared remote sensing is a very important means of obtaining surface temperature information.The thermal infrared image data used in this article(Landsat 8and Landsat 9 data)are downloaded from the official website of the USGS(United States Geological Survey).The Land Imager(OLI-2)carried by Landsat 9 has improved its data radiation accuracy from 12 bits to 14 bits compared to the Land Imager(OLI-1)carried by Landsat 8,and its thermal intensity measurement and analysis are more accurate.The research area selected for this article is Xianning,known as the "hometown of hot springs".The area is rich in geothermal resources.There are a total of 13 hot spring scenic spots and multiple hot spring geothermal fields in the city,mainly distributed in the central and northern regions of Xianning,providing a good research background and conditions for surface temperature inversion.The main research work and conclusions of this article are as follows:(1)According to three commonly used land surface temperature inversion algorithms,ENVI software is used to process image data to obtain inversion results,and meteorological data and MODIS temperature products are used as comparative data to verify the inversion effect of the three algorithms.After correlation analysis,it is found that the atmospheric correction algorithm has the best inversion effect in the study area,and this algorithm is selected as the main algorithm for land surface temperature inversion in the subsequent study area.(2)The MODIS temperature product data of the corresponding time period in the study area were used to verify the retrieval results of surface temperature in Xianning region in the past five years,and the retrieval results were proved to be accurate based on correlation analysis.(3)Statistically collate China’s land heat flow data,and obtain the distribution characteristics of China’s land heat flow density based on the land heat flow data.Combined with previous research,it is concluded that it is highly feasible to use the land heat flow density as one of the factors for searching and evaluating geothermal resources.(4)The linear proportional relationship between the retrieved surface temperature information in the study area and the terrestrial heat flow value at the corresponding point is revealed,and an appropriate prediction model is established based on this relationship.Based on the model prediction,complete heat flow data of the study area were obtained,and a heat flow contour map was drawn based on this data.Finally,by comparing and analyzing the temperature inversion results,heat flow contour maps,known geothermal resource points,and geological structures in the study area,it is preliminarily inferred that there are four abnormal locations where geothermal resources may exist.This method is expected to become a new geothermal exploration method.