Pollution transported by hurricane Ophelia: 3D observations by ground-based, aircraft and satellite data compared with CAMS atmospheric composition analyses
Résumé
With the remnants of hurricane Ophelia reaching the British Isles, a rare pollution event crossed Europe in October 2017, with transport of dust from the Sahara and of thick smoke from disastrous wildfires in northern Portugal/Spain. On October 15-16, both dust and smoke were rapidly advected by Ophelia-energized strong southerly winds into the Bay of Biscay, north-western France and across the UK. Two unusual events were intersecting: a tropical storm and high intensity late-season fires. We now benefit from a range of observations above Europe allowing us to track the transport of such a pollution plume. We used an integrated observational approach for analysing this event in near-real-time, combining both observations and model analysis.
Using near real time radiance observations from the IASI thermal infrared remote sensors onboard the two Metop satellites, focused maps of dust, carbon monoxide and ammonia (two proxies for fire plumes) could be derived. The European lidar/ceilometer network established the overpass time for both dust and the smoke plumes at different locations, along with altitude information. The IAGOS network on passenger aircraft also reported large peaks of CO during departures and landings, with a measured CO concentration matching well with the IASI observations.
Finally, the smoke and dust particle-size distributions are compared with aerosol forecasts and analyses produced by the Copernicus Atmosphere Monitoring Service (CAMS) using the ECMWF IFS, constrained by MODIS and PMAp satellite observations of aerosol optical depth, to inform on the different aerosol sources.