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The pronounced weekly variation in the ash dispersal may result from the varying eddies that pass by the region of the volcano. The eddies are mesoscale (order of 1000 km), and thus which eddy occupies the region during the eruption would serve as the main determinant of the ashes' dispersal. Moreover, the local variance has significant downstream effects. In simulation for the eruption on January 1, 2010, the ash reached the U.S. whereas in the simulation a week later on January 8, 2010, the ash reached Russia.
In order to understand over what time periods the ash dispersal would vary, one must look into the time scales of the eddys in the Icelandic region. Further simulations should explore variations in dispersal from daily changes to the eruption date.
Our simulations also give us insights into our record of past volcanoes. We often research past volcanoes through the ash they deposited in Greenland ice cores. Given that in many of our simulations the ash from our Icelandic volcano did not reach its neighboring country, we may likely not have recordings for many past local volcanoes.
April 14-16, 2010
Image 3: 3-day ash dispersal simulation for Eyjafjallajokull for actual eruption date of April 14, 2010. The plume initially moves north-eastward and then south-westard. As the plume moves northward it deflects to the east and as it moves southward it deflects to the west as predicted by the rightward deflection of the coriolis force in the northern hemisphere. The two layers closest to the Earth's surface spread the furthest.
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moves poleward cyclonically.
Concluding Remarks
In order to understand over what time periods the ash dispersal would vary, one must look into the time scales of the eddys in the Icelandic region. Further simulations should explore variations in dispersal from daily changes to the eruption date.
Our simulations also give us insights into our record of past volcanoes. We often research past volcanoes through the ash they deposited in Greenland ice cores. Given that in many of our simulations the ash from our Icelandic volcano did not reach its neighboring country, we may likely not have recordings for many past local volcanoes.