Volcano So2 columns

Composite image of maximum observed SO2 columns for the period 20 May to 30 June 2011. The value for each grid cell equals the maximum observed SO2 columns in that grid cell for the given time period during which three major volcanic eruptions took place. Grimsvotn ( ¨ −17.33◦, 64.42◦) erupted first on 21 May, then Puyehue-Cordon Caulle ( ´ −40.59◦, −72.12◦) on 3 June and finally Nabro (13.37◦, 41.70◦) on 12 June. A plume altitude of 10 km was assumed.