EUNADICS early warning system dedicated to support aviation in case of crisis from natural airborne hazard and radionuclide cloud
Authors: Brenot Hugues , Theys Nicolas , Clarisse Lieven , van Gent Jeroen , Hurtmans Daniel R. , Vandenbussche Sophie , Papagiannopoulos Nikolaos , Mona Lucia , Virtanen Timo , Uppstu Andreas , Sofiev Mikhail , Bugliaro Luca , Vázquez-Navarro Margarita , Hedelt Pascal , Parks Michelle Maree , Barsotti Sara , Coltelli Mauro , Moreland William , Arnold-Arias Delia , Hirtl Marcus , Peltonen Tuomas , Lahtinen Juhani , Sievers Klaus , Lipok Florian , Rüfenacht Rolf , Haefele Alexander , Hervo Maxime , Wagenaar Saskia , Som de Cerff Wim , de Laat Jos , Apituley Arnoud , Stammes Piet , Laffineur Quentin , Delcloo Andy , Lennart Robertson , Rokitansky Carl-Herbert , Vargas Arturo , Kerschbaum Markus , Resch Christian , Zopp Raimund , Plu Matthieu , Peuch Vincent-Henri , Van Roozendael Michel , Wotawa Gerhard 
Published: May 2021

Abstract. The purpose of the EUNADICS prototype Early Warning System (EWS) is to proceed the combined use of harmonise data products from satellite, ground-based and in situ instruments to produce alerts of airborne hazard (volcanic, dust, smoke and radionuclide clouds), satisfying the requirement of ATM stakeholders (www.eunadics.eu). The alert products developed by EUNADICS EWS (i.e. NRT observations, email notifications and NetCDF Alert data Products, called NCAP) have shown shows the significant interest in using selective detection of natural airborne hazards from polar orbiting satellite. The combination of several sensors inside a single global system demonstrates the advantage of using a triggered approach to obtain selective detection from observations, which cannot initially discriminate the different aerosol types. Satellite products from hyperspectral UV and IR sensors (e.g. TROPOMI, IASI) and broadband geostationary imager (SEVIRI), and retrievals from ground-based networks (e.g. EARLINET, E-PROFILE and the regional network from volcanic observatories), are combined by our system to create tailored alert products (e.g. selective ash detection, SO2 column and plume height, dust cloud and smoke from wildfires). A total of 23 different alert products are implemented, using 1 geostationary and 12 polar orbiting satellite platforms, 3 external existing service, 2 EU and 2 regional ground-based networks. This allows the identification and the traceability of extreme events. EUNADICS EWS has also shown the interest to proceed a future relay of radiological data (gamma dose rate and radionuclides concentrations in ground-level air) in case of nuclear accident, highlighting the capability of operating early warnings with the use of homogenised dataset. For the four types of airborne hazard, EUNADICS EWS has demonstrated its capability to provide NRT alert data products to trigger data assimilation and dispersion modelling providing forecasts, and inverse modelling for source term estimate. All our alert data products (NCAP files) are not publicly disseminated. Access to our alert products is currently restricted to key users (i.e. Volcanic Ash Advisory Centres, National Meteorological Services, World Meteorological Organization, governments, volcanic observatories and research collaborators), as these are considered pre-decisional products. On the other hand, thanks to the SACS/EUNADICS web interface (https://sacs.aeronomie.be), the main part of the satellite observations used by EUNADICS EWS, are shown in NRT, with public email notification of volcanic emission and delivery of tailored images and NCAP files. All the ATM stakeholders (e.g. VAACs, NMSs, WMOs, Airlines and Pilots) can access and benefit of these alert products through this free channel.