The apparent effects of the Mt Pinatubo eruption on the Greenland ice sheet melt extent

The indirect climatological effects of major volcanic eruptions can be of great importance because of the complex feedbacks that exist in the global climate system. One such effect is the melt area reduction on the Greenland ice sheet. Using passive microwave satellite data for the period 1979-1995, the melt conditions of the ice sheet before and after the 1991 Mt. Pinatubo eruptions are examined. Statistical tests indicate that an observed drop following the eruptions has a 97% to 99% probability of being outside the limits of undisturbed variability. Furthermore, this anomaly diminishes as the time from the eruption increases. These characteristics, in conjunction with an observed increasing melt trend prior to the eruptions indicate that Mt. Pinatubo has had a significant effect on the melt conditions, and consequently the energy balance characteristics of the Greenland ice sheet.