First Aircraft‐Based VOC Measurements Using Thermal Infrared Remote Sensing: Mapping Fire Plumes With the Scanning High‐Resolution Interferometer Sounder (S‐HIS)

Abstract Wildfires emit volatile organic compounds (VOCs) that contribute to ozone and aerosol pollution. Quantification is challenged by the diversity of emitted species and by their complex dependence on fire characteristics, with scarce field observations available for model evaluation. Remote sensing in the thermal infrared (IR) is a powerful tool for detecting fire VOCs: many compounds exhibit distinct signatures at these wavelengths, and measurements are unaffected by fine aerosols prevalent in smoke. Here, we develop the first thermal IR VOC measurements from an aircraft‐based platform, using radiance observations from the Scanning High‐resolution Interferometer Sounder (S‐HIS) deployed aboard the NASA ER‐2 during the 2019 FIREX‐AQ campaign. We focus on methanol and ethene, and employ a neural network retrieval adapted from Cross‐track Infrared Sounder (CrIS) algorithms. The S‐HIS retrievals achieved high precision ( R 2 = 0.95–0.99) and accuracy (median absolute bias