The Finnish Meteorological Institute is monitoring the dispersion of ash from the volcanic eruption

The eruption of Grimsvötn volcano that started in Iceland on Saturday, 21 May has caused an ash cloud. According to preliminary forecasts, the ash emitted by the volcano will spread to Finland in mid-week. If the ash cloud affects airline traffic, the aviation authorities will give notice of any flight restrictions that may be imposed.

Photo: Mika Kalakoski

According to the Finnish Meteorological Institute’s dispersion forecasts, air currents in the upper atmosphere are moving towards Greenland, i.e. north. In the lower atmosphere, air currents are moving over the Faroe Islands and Scotland towards Southern Scandinavia, where the ash cloud will probably arrive on Tuesday. It is predicted that the ash cloud will reach the southern coast of Finland on Wednesday, 25. May. The Meteorological Institute is following the situation closely, conveying information to the authorities and the general public as new developments arise.

The Meteorological Institute notifies airline operators and the aviation safety authorities of cloud movements, and will monitor the situation if the eruption continues. The movements of the ash cloud are followed by means of dispersion models. The Meteorological Institute’s SILAM model can be used for estimating the movements of the ash cloud, but any restrictions imposed on flying are not shown on the maps because the maps have a wide scale and the model also notes very low concentrations.

Various methods are applied to obtain observations of the ash

The Finnish Meteorological Institute is closely following air quality in Finland. No exceptional sulphur or particle concentrations have been measured at the Meteorological Institute’s air quality stations. The Meteorological Institute’s measurement network, which covers the whole of Finland from Kumpula in Helsinki to Pallas in Kittilä, can quickly observe any impacts that the volcano eruption in Iceland may have on air quality. Additional observations are received, for instance, from systems monitoring air quality in municipalities, which can be followed via the air quality portal. The surface concentrations and composition of fine particles are monitored especially closely at the measurement stations operated by the Meteorological Institute and the University of Helsinki in Kumpula, Helsinki, and in Hyytiä, Southern Häme.

The Meteorological Institute is preparing to use a measurement method extending up to an altitude of about 20 or 30 kilometres for measuring the occurrence of the ash cloud in Kumpula, Helsinki. Similar measurements can also be carried out in Sodankylä. The Lidar measuring instrument (laser) gives reliable real-time data on the altitude and thickness of volcanic ash clouds and on the number of ash particles contained in the cloud. When in use, the laser can be seen as green light.

The measurement results are used to verify the correctness of model calculations.

The eruption is unlikely to impact on the climate

It has been estimated that the ash cloud from Grimsvötn volcano will rise as high as 17 kilometres. Besides particles, the ash cloud contains sulphur dioxide and carbon dioxide. Icelandic volcanoes emitting sulphur dioxide into the atmosphere may have a slight cooling effect on the climate in the northern hemisphere. According to the current information, the amount of sulphur dioxide from the eruption of Grimsvötn is so small that it is unlikely to have any discernible effect.

No exceptional sulphur or particle concentrations have been measured at the Finnish Meteorological Institute’s air quality stations. The Institute is constantly monitoring the air quality throughout Finland.

LUOVA provides information on natural disasters for the authorities

LUOVA is a joint information channel built between expert institutions and the safety authorities. It produces and transmits up-to-date and anticipatory information on natural disasters as quickly and understandably as possible.

In the LUOVA system, the Finnish Meteorological Institute is responsible for warnings concerning weather events and the sea water level, while the Institute of Seismology of the University of Helsinki provides information on earthquakes and the Finnish Environment Institute gives warnings on flooding water systems. The on-call service of the LUOVA system takes place in conjunction with the Safety Weather Service of the Finnish Meteorological Institute. Daily 24-hour service is a prerequisite for the timely functioning of the LUOVA system. Another important prerequisite is an information system that enables global monitoring of various information sources and analysis of threats, risks and natural disasters occurred.

Additional information:

Weather and dispersion data, Finnish Meteorological Institute, tel. +358 9 1929 2230, info@fmi.fi

Impact on the climate:Finnish Meteorological Institute, Professor Ari Laaksonen, tel. +358 9 1929 5530

Air quality in Finland: http://www.airquality.fi

Read more:Finavia’s press releases on restrictions on air traffic: http://www.finavia.fi/

Press releases by Finnish Transport Safety Agency (TraFi): http://www.trafi.fi/

Icelandic Meteorological Office: http://en.vedur.is/about-imo/news/2011/

Press releases by the National Institute for Health and Welfare: http://www.thl.fi