On Wednesday, April 14 2010, the Eyjafjalljokull started to erupt. The ash cloud curled around a high
pressure zone above the British Isles in the direction of northwest Europe. On Thursday, April 15, around
12:00 hours OMI detected a plume of highly elevated ash and sulfur dioxide concentrations between
Iceland and northwestern Europe. A day later, on Friday April 16, the ash plume travelled further
south and was seen from space over the north of Germany and Poland. In the subsequent days the aerosol
and sulfur concentrations started to dilute such that the ash plume over Europe is no longer noticeable
by satellite. However, from Saturday until Monday, April 17-19, the new supply of ash from Iceland is
clearly seen in the OMI measurements.
Image on the right:
An aerosol index of 1 (white) indicates relatively clean air, while an index of 3 (orange)
means the sky is polluted with dust.
The SO2 concentrations are given in "Dobson Units" (1 DU = 2.69 1016 molecules per cm2).
Typical background concentrations are lower than 0.5 DU. Close to the Eyjafjalljokkul volcano
concentrations of 1-2 DU are observed. These concentrations are not extremely high for a volcanic
eruption, for example, at the eruption of the Kasatochi in August 2008 concentrations of more
than 15 DU are observed.
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