Volcanic Radiative Power Retrieval From Moderate-to-Low-Temperature Features Using a Single TIR Band: Validation Using Volcanic Crater Lakes and Hydrothermal Systems

Assessing Radiative Power (RP) output is essential for monitoring and understanding volcanic systems. While Mid-Infrared channels are used to assess thermal outputs at volcanoes exhibiting effusive activity, Thermal-InfraRed (TIR) bands are better suited for measuring moderate-to-low-temperature (?600 K) features, such as those associated with hydrothermal activity. However, failure to meet key assumptions in TIR-based calculations results in up to a∼90% RP underestimation of?600 K sources. We thus introduce the TIR-based Volcanic Radiative Power (VRP_TIR) method to accurately retrieve RP from single-band TIR (10.5–12μm) spectral radiance at systems dominated by surface temperatures of?600 K, that is, crater lakes and fumarole fields, achieving an uncertainty of ±35%. Comparison with ground truth for Ruapehu, El Chichón, Taal, Vulcano, Puracé, Poás, and White Island demonstrates the accuracy of VRP_TIR in quantifying thermal output and detecting subtle variations in volcanic activity. This exportable method will facilitate compilation of global RP inventories for moderate-to-low-temperature volcanic systems.