# An Autonomous Thermal Camera System for Monitoring Fumarole Activity
## 3 Deployment
### Comparison with Other Sources  
Figure 6 illustrates the data acquired by the camera at the \"Oloblutotot\" lava field. Figure 6a shows an example of a recorded thermal infrared image, while Figure 6b shows a corresponding image of the time-lapse camera. This geothermal surface manifestation is characterized by a fumarole that vents hot gases and steam through multiple cracks in the ground surface, which can be seen in Figure 6b. The red box in the thermal infrared image in Figure 6a reveals in bright tones that the soil surrounding these cracks is relatively warm. The area in the background, indicated by the blue box, is not part of the lava field and appears cooler with darker tones in the thermal image. The soil with patches of vegetation, indicated by the green box to the right of the fumarole and in the foreground, is cooler than the fumarole itself.  
Figure 5: Camera system parameters at the “Oloblutot” lava field. From top to bottom, the records of (**a**) data availability and (**b**) camera lens temperature, available since the installation of the camera in July 2019, and the records of (**c**) core temperature of the Raspberry Pi in the control unit and (**d**) the battery voltage at the Arduino, measured as of July 2020.  
Figure 6c shows a month of temperature readings, sampled from the ground with cracks (red box), the direct surroundings of the fumarole (green box), and the distant background outside of the lava field (blue box). This figure shows that the temperature in the fumarole is relatively high and that the temperature of the background is relatively low. Fumarole temperatures also do not typically drop below 30\({}^{\circ}\)C at night. The direct surroundings of the fumarole (green box) reach the high temperatures of the fumarole during the day but come close to the background temperature at night.  
Figure 6d compares the camera data with air temperature readings of the Davis metao-station mounted at the same location, at 4 m above the soil surface. These time series are also  
Figure 6: The observations made at the “Oldbutot” lava field. (**a**) shows the complete view of the thermal IR camera (bright equals warm); (**b**) shows an image of the SLR time-lapse camera covering the same area. The coloured regions in (**a**) indicate the area of pixels sampled for fumarole (\(\bullet\)) values, the direct surroundings with bits of vegetation (\(\bullet\)), and background temperatures in the distance (\(\bullet\)). (**c**) shows the average values of the sampled pixels in the three boxes over January 2022. (**d**) shows a comparison of the thermal infrared camera records against other data sources over time. The camera data (\(\ast\)) are compared to the air temperature measured by the metaostation (\(\bullet\)) installed at the same location, as well as the topsoil (\(\ast\)) temperature of the ERA5-Land reanalysis model.  
compared to temperature data taken from the ERA5-Land reanalysis model of the European Centre for Medium-Range Weather Forecasts (ECMWF) [27], which comes at an approximately 11 km spatial resolution. The model parameter used is \"soil_temperature_level_1\", which is the soil temperature at 0 cm to 7 cm depth. All three datasets highlight the weather event that took place from 15 to 19 January.