Monitoring the 2021 Cumbre Vieja Volcanic Eruption Using Satellite Multisensor Data Fusion

Multisensor satellite data fusion merges measurements or products from imaging and sounding instruments with different spatial, spectral, and temporal resolution to obtain more comprehensive information about key atmospheric variables and processes. Here, data from low Earth and geostationary orbits, such as the Joint Polar Satellite Systems and Geostationary Operational Environmental Satellites platforms, respectively, are integrated using spatial‐temporal fusion to enhance the detection of trace gas emissions from volcanoes. Not only does this yield trace gas information with improved spatial detail but, more importantly, the fusion product is also made available at significantly increased temporal resolution to help monitor the variable dispersion of trace gas emissions. The emission and dispersion of volcanic sulfur dioxide and ash plumes from the Cumbre Vieja volcano (Canary Islands, Spain) eruptions in October 2021 are studied through the synergistic exploitation of measurements and products from the Visible Infrared Imaging Radiometer Suite, the Cross‐track Infrared Sounder, the TROPOspheric Monitoring Instrument, and the Advanced Baseline Imager. Fusion results show increased spatial and temporal detail and describe evolution and directionality of the volcanic ash plumes; the potential benefits range from improved air quality monitoring to better guidance from aircraft safety systems. Plain Language Summary Improved delineation of volcanic emissions is shown via fusion of the high spectral resolution sounder Cross‐track Infrared Sounder (CrIS) or TROPOspheric Monitoring instrument (TROPOMI), with Visible Infrared Imaging Radiometer Suite or Advanced Baseline Imager (ABI) data. Whereas ABI is onboard geostationary satellite platforms, which offer fast temporal coverage, the other instruments are on low‐Earth orbit platforms providing twice daily global coverage instead. Sulfur dioxide (SO2) and ash from the Cumbre Vieja volcano eruptions on La Palma in the Canary Islands are tracked on two separate days in October 2021. While TROPOMI, since it measures in the visible and ultraviolet spectral ranges, is limited to daytime viewing, CrIS infrared measurements offer night and day coverage of SO2. Fusion with ABI enables the extension to time sequences of the changes in the emissions and the resulting plumes. This fusion demonstration foreshadows capabilities of planned future geostationary sensors. Key Points Satellite Infrared Remote Sensing provides r