Simulating Ground Thermal Anomaly under Conditions of Dense Vegetation Based On Lab and Field Measurements to Support Thermal Infrared Remote Sensing Techniques

The ground temperature and emissivity anomalies could be used as an indicator for the existence of geothermal surface manifestations such as hot springs, fumaroles, or altered surfaces with remaining thermal at a crater rim. The ground temperature could be measured directly at the field using ground thermometer. However, field measurements are inefficient for large investigated areas and extracting Land Surface Temperature (LST) based on satellite thermal infrared sensor is also complicated due to several unknown parameters such as noise from the environment and object emissivity. Moreover, field studies under the conditions of dense vegetation makes the problem worse due to the shallower layer penetration of the response at wavelengths of thermal infrared compared to microwave energies. Overcoming the problem, we tried to estimate the kinetic temperature from the simulated steam spot using thermal infrared camera FLIR C2 with an accuracy of 2°C. The lab simulations were performed proportionally to ground variables such as the vegetation cover, height of the sensor, and diurnal effects. According to the simulations, the steam spot from boiling water 98°C recorded by the sensor at heights more than 1.2 m equivalent to spatial resolution 0.2 cm is constant about 37.2°C. We also observed that the vegetation cover reduced the measured temperature with thermal efficiency 33%. For diurnal effect, the detected temperature is constant regardless time observations. The background temperature influenced the vegetation covering steam spot with efficiencies 30% and 50% for day and night observations, respectively. These simulation results were used for further study into thermal infrared remote sensing techniques for thermal features identification. Field investigations were also performed to clarify the applicability of the thermal infrared camera to the measured ground temperature.