Saharan dust and wildfire smoke from southern Europe darkened the skies and turned the sun red in Sweden

On Tuesday morning 17th of October unusual weather phenomena could be seen in Sweden, with a much darker sky over Stockholm and a subdued reddish orange sun in many parts of southern Sweden. Several reports state a similar reddish sun was also observed in the Netherlands, northern Germany and Finland, whilst it was seen over Great Britain the day before. These phenomena were caused by a combination of Saharan dust and smoke particles from the severe wildfires in Spain and Portugal, which have been brought up with air masses influenced by large weather patterns over central Europe and the Atlantic in connection to storm Ophelia. SMHI states it is likely that the observed weather phenomena in Sweden are caused by this event as well, while a passing thunderstorm additionally underlined the apocalyptic impression in the Stockholm area.

Although ICOS Sweden is not conducting any aerosol measurements, data from Hyltemossa showed a peak of carbon monoxide (CO) early in the day on the 17th of October. This peak is likely correlated to the increased levels of smoke, even though the measurements cannot distinguish which source the detected CO originates from.

Aerosol particle forecast 2017-10-17 CAMS (Copernicus Atmosphere Monitoring Service) aerosol particle forecast on Tuesday 17th between 00:00 and 06:00.

Aerosol concentration from satellite 2017-10-17 Actual satellite observations of aerosol concentrations from OMI/AURA via FMI/KNMI/NASA/NSO on Tuesday 17th.

CAMS 2017-10-17 Carbon monoxide (CO) concentration measured at ICOS Sweden station Hyltemossa on 16th and 17th of October, at the heights of 30, 70 and 150 m. The picture shows the red sun which was visible over Lund (photo: Tobias Biermann).