1-1-1-1-1-1-1-1-1-1-1-1-1-1 From: Yasser Maghsoudi Mehrani <Y.Maghsoudi@xxxxxxxxxxx> Dear Colleagues, COMET (The Centre for Observation and Modelling of Earthquakes, Volcanoes, and Tectonics) invites you to the next installment of our COMET+ webinar series, viewable from the home office. *Using local GNSS observations for improving InSAR atmospheric corrections over tropical volcanoes* *Wednesday 27th March 2024 at 4pm UK time* (4pm UTC / 5pm CET / 9am PDT) *Fabien Albino* Institute of Earth Sciences (ISTerre) *Please register at: * https://universityofleeds.zoom.us/webinar/register/WN_03EJEnVpSVSK6VTXgag40w <https://urldefense.com/v3/__https://universityofleeds.zoom.us/webinar/register/WN_03EJEnVpSVSK6VTXgag40w__;!!IKRxdwAv5BmarQ!bW3JVL2ellvekzznH7_KaJfzn2OXt6x6EjsF5u9xGmM7djt3Fpp679FnqIjXUCwJkY-hPCnqVPaZdJkw6Z2iL13Ghg$> (After registering, you will receive a confirmation email containing information on how to join the webinar) *Abstract:* >From differential radar interferometry, tropospheric artefacts often prevent the detection of subtle ground deformation signals. In recent years, tropospheric corrections derived from global weather-based models delivered by the ECMWF have been implemented in several InSAR processing chains. Here, we test the performance of the common weather models, ERA5 and GACOS, on two tropical volcanoes: Piton de la Fournaise and Merapi. For Piton de la Fournaise, we show that the reduction of the atmospheric noise is efficient for only ~30% and ~60% of the datasets for GACOS and ERA5, respectively. For Merapi, the performance reaches ~40% for GACOS and ~50% for ERA5. In addition, we implement a workflow to produce tropospheric correction maps based on GNSS Zenith Tropospheric Delays. We then compare the performance of GNSS models to the one obtained from global weather-based models. For well-instrumented volcanoes as Piton de la Fournaise, the gain of performance is about 25%. For Merapi, GNSS models based on 5 stations are as efficient as ERA5 models with the advantage that GNSS models can be obtained in near real-time. The proposed workflow can be implemented in many volcanoes where few GNSS stations are available, contributing to more accurate monitoring of volcanic unrest. Catch up on past COMET and COMET+ webinars on our YouTube page: *https:/www.youtube.com/channel/UCtFDytX1hgjvlS4NH48M2oQ/video <https://urldefense.com/v3/__https://www.youtube.com/channel/UCtFDytX1hgjvlS4NH48M2oQ/videos__;!!IKRxdwAv5BmarQ!bW3JVL2ellvekzznH7_KaJfzn2OXt6x6EjsF5u9xGmM7djt3Fpp679FnqIjXUCwJkY-hPCnqVPaZdJkw6Z3-Mj2y9A$>* Best wishes, Isabelle Taylor & Yasser Maghsoudi COMET - Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics *https://comet.nerc.ac.uk/ <https://urldefense.com/v3/__https://comet.nerc.ac.uk/__;!!IKRxdwAv5BmarQ!bW3JVL2ellvekzznH7_KaJfzn2OXt6x6EjsF5u9xGmM7djt3Fpp679FnqIjXUCwJkY-hPCnqVPaZdJkw6Z3DSjzIrQ$>* 1-1-1-1-1-1-1-1-1-1-1-1-1-1 ============================================================== Volcano Listserv is a collaborative venture among Arizona State University (ASU), Portland State University (PSU), the Global Volcanism Program (GVP) of the Smithsonian Institution's National Museum of Natural History, and the International Association for Volcanology and Chemistry of the Earth's Interior (IAVCEI). ASU - http://www.asu.edu/ PSU - http://pdx.edu/ GVP - https://volcano.si.edu/ IAVCEI - https://www.iavceivolcano.org/ To subscribe to the volcano list, send the message: subscribe volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx To unsubscribe from the volcano list, send the message: signoff volcano to: listserv@xxxxxxx, or write to: volcano-request@xxxxxxx. To contribute to the volcano list, send your message to: volcano@xxxxxxx. Please do not send attachments. ============================================================== ------------------------------ End of Volcano Digest - 14 Mar 2024 to 15 Mar 2024 (#2024-24) *************************************************************
