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

Abstract

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 ((Formula presented.)) method to accurately retrieve RP from single-band TIR (10.5–12 μm) 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 (Formula presented.) 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.