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HYSPLIT Simulations for Eyjafjallajokull (Varying Eruption Date)
By simulating Eyjafjallajokull for various eruption dates, I sought to investigate how the circulation patterns changed both seasonally and weekly and whether the seasonal versus weakly variations dominated the ash dispersal patterns. Simulations showed that the weekly changes in atmospheric circulation patterns dominated any seasonal trends. Eyjafjallajokull sits at the boundary between two different air masses (between the polar and Eddy regimes); air nearer to the poles is generally cold and dry whereas at mid-latitudes it is warmer and also influenced by the tropics.
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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Image 5: 3-day ash dispersal simulation for Eyjafjallajokull for eruption date of April 7, 2010, a week earlier from its actual eruption date. 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. As opposed to the dispersal for the prior week, part of the northward plume was swept into the polar regime. In contrast to what we would expect from theoretical predictions, the plume in the polar region moved clockwise when due to the coriolis force in the northern hemisphere, we would have anticipated it to move cyclonically.
January 1-3, 2010
opposite direction from what we would think
January 8-10, 2010
July 1-3, 2010
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