| dc.description.abstract | We explore the potential of Passive Microwave (PMW) sensors for analyzing volcanic ash plumes from explosive eruptions. Utilizing data from the Global Precipitation Measurement (GPM) Microwave Imager (GMI) and the Special Sensor Microwave Imager/Sounder (SSMIS), we conducted an empirical study of three volcanic eruptions, including the 2021-2022 Hunga Tonga–Hunga Ha’apai, 2021 Fukutoku-Oko-no-Ba, and the 2019 Raikoke eruptions. Our methodology involved integrating satellite observations with European Centre for Medium Range Weather Forecasts Reanalysis (ERA5) reanalysis data and employing the TIROS Operational Vertical Sounder (TOVS) Radiative Transfer Model (RTTOV) for simulating clear sky background brightness temperatures. We calculated the difference in observed and simulated clear-sky brightness temperatures (∆T B) to isolate the volcanic signal from the background. Our findings indicate that PMW sensors can distinctly differentiate signals of volcanic eruptions to other meteorological processes using ∆T B across channels as an indicator. For low frequency channels, we typically see a ∆T B of magnitude less than 20K, while high frequency channels have a ∆T B magnitude of -75K. Notably, volcanic pixels were statistically distinguishable from other meteorological clouds in the atmosphere based on 37H and 150H channels. We find that PMW observations provide different observational information compared to IR and Visible wavelengths, including the ability to retrieve information under thin volcanic cirrus shields. We also find that PMW sensors have the potential, when used in conjunction with other PMW satellites, to capture life-cycles of large eruptions. This study highlights the promising capabilities of PMW sensors in advancing volcanic detection and ash retrieval methodologies in addition to the currently utilized satellites. | |
