Mapping and Measuring Thermal Areas in Yellowstone using ASTER and Landsat 8 Thermal Infrared Data

ASTER thermal infrared (TIR) data, combined with field observations and pre-existing maps have been used to map Yellowstone’s thermal areas. Thermal anomaly maps and estimates of the radiant geothermal heat flux are important for establishing the baseline thermal activity to better detect and understand future anomalous hydrothermal and/or volcanic activity, and also for monitoring changes in the geothermal system to support decisions regarding infrastructure development, preservation and protection of Yellowstone’s resources, and ensuring visitor safety.

One of the critical measurement parameters in the use of spaceborne TIR for studying subtle (sub-pixel, sub-boiling) thermal features is the acquisition of TIR data at night. Acquisition of night time data reduces the influence of solar radiance and increases the temperature difference between thermal targets and the cooler background, thus improving estimates of the geothermal component of heat flux.

ASTER night time TIR data (90-m pixels) are acquired too infrequently and irregularly for regular monitoring purposes. However, the new Landsat 8 platform with the Thermal Infrared Sensor (100-m pixels) has been tasked to regularly collect night time TIR imagery (every 16 days). These data show promise for continued satellite-based thermal monitoring at Yellowstone, and could also be useful in monitoring subtle thermal activity at other volcanic/geothermal systems around the world. This presentation will highlight results of a comparative analysis of Landsat 8 TIRS and ASTER TIR data for measuring and mapping Yellowstone’s thermal areas.