{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,9]],"date-time":"2026-04-09T14:38:47Z","timestamp":1775745527383,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2021,10,21]],"date-time":"2021-10-21T00:00:00Z","timestamp":1634774400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Sulfur dioxide (SO2) degassing at Strombolian volcanoes is directly associated with magmatic activity, thus its monitoring can inform about the style and intensity of eruptions. The Stromboli volcano in southern Italy is used as a test case to demonstrate that the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Copernicus Sentinel-5 Precursor (Sentinel-5P) satellite has the suitable spatial resolution and sensitivity to carry out local-scale SO2 monitoring of relatively small-size, nearly point-wise volcanic sources, and distinguish periods of different activity intensity. The entire dataset consisting of TROPOMI Level 2 SO2 geophysical products from UV sensor data collected over Stromboli from 6 May 2018 to 31 May 2021 is processed with purposely adapted Python scripts. A methodological workflow is developed to encompass the extraction of total SO2 Vertical Column Density (VCD) at given coordinates (including conditional VCD for three different hypothetical peaks at 0\u20131, 7 and 15 km), as well as filtering by quality in compliance with the Sentinel-5P Validation Team\u2019s recommendations. The comparison of total SO2 VCD time series for the main crater and across different averaging windows (3 \u00d7 3, 5 \u00d7 5 and 4 \u00d7 2) proves the correctness of the adopted spatial sampling criterion, and practical recommendations are proposed for further implementation in similar volcanic environments. An approach for detecting SO2 VCD peaks at the volcano is trialed, and the detections are compared with the level of SO2 flux measured at ground-based instrumentation. SO2 time series analysis is complemented with information provided by contextual Sentinel-2 multispectral (in the visible, near and short-wave infrared) and Suomi NPP VIIRS observations. The aim is to correctly interpret SO2 total VCD peaks when they either (i) coincide with medium to very high SO2 emissions as measured in situ and known from volcanological observatory bulletins, or (ii) occur outside periods of significant emissions despite signs of activity visible in Sentinel-2 data. Finally, SO2 VCD peaks in the time series are further investigated through daily time lapses during the paroxysms in July\u2013August 2019, major explosions in August 2020 and a more recent period of activity in May 2021. Hourly wind records from ECMWF Reanalysis v5 (ERA5) data are used to identify local wind direction and SO2 plume drift during the time lapses. The proposed analysis approach is successful in showing the SO2 degassing associated with these events, and warning whenever the SO2 VCD at Stromboli may be overestimated due to clustering with the plume of the Mount Etna volcano.<\/jats:p>","DOI":"10.3390\/s21216991","type":"journal-article","created":{"date-parts":[[2021,10,21]],"date-time":"2021-10-21T23:27:39Z","timestamp":1634858859000},"page":"6991","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Exploiting Sentinel-5P TROPOMI and Ground Sensor Data for the Detection of Volcanic SO2 Plumes and Activity in 2018\u20132021 at Stromboli, Italy"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2980-1867","authenticated-orcid":false,"given":"Alessandra","family":"Cofano","sequence":"first","affiliation":[{"name":"Italian Space Agency (ASI), Via del Politecnico s.n.c., 00133 Rome, Italy"},{"name":"Mathematics Department, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy"},{"name":"Institute for Space Astrophysics and Planetology (IAPS), National Institute for Astrophysics (INAF), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8134-1576","authenticated-orcid":false,"given":"Francesca","family":"Cigna","sequence":"additional","affiliation":[{"name":"Italian Space Agency (ASI), Via del Politecnico s.n.c., 00133 Rome, Italy"},{"name":"Institute of Atmospheric Sciences and Climate (ISAC), National Research Council (CNR), Via del Fosso del Cavaliere 100, 00133 Rome, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0898-3569","authenticated-orcid":false,"given":"Luigi","family":"Santamaria Amato","sequence":"additional","affiliation":[{"name":"Italian Space Agency (ASI), Localit\u00e0 Terlecchia s.n.c., 75100 Matera, Italy"}]},{"given":"Mario","family":"Siciliani de Cumis","sequence":"additional","affiliation":[{"name":"Italian Space Agency (ASI), Localit\u00e0 Terlecchia s.n.c., 75100 Matera, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7242-4473","authenticated-orcid":false,"given":"Deodato","family":"Tapete","sequence":"additional","affiliation":[{"name":"Italian Space Agency (ASI), Via del Politecnico s.n.c., 00133 Rome, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2021,10,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"443","DOI":"10.1007\/s00445-010-0442-z","article-title":"Geochemical evidence of the renewal of volcanic activity inferred from CO2 soil and SO2 plume fluxes: The 2007 Stromboli eruption (Italy)","volume":"73","author":"Inguaggiato","year":"2011","journal-title":"Bull. 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