The Effect of Tropical Explosive Volcanic Eruptions on Surface Air Temperature

The response of surface air temperatures to four major tropical explosive volcanic eruptions is identified. The common features of the average response (the composite) are then compared with the response to the Pinatubo eruption both for global average temperatures and for the spatial pattern. The historic sample of four eruptions shows significant cooling of about 0.2°C in global mean temperatures during months 13 to 24 following each eruption. The spatial pattern of the composite shows cooling over preferred regions. The Pinatubo eruption has generated a similar magnitude cooling of O.2°C, this being only half that expected based on model results with a General Circulation Model. The cooling after Pinatubo was most marked over continental landmasses, particularly eastern North America, the Middle East and eastern Asia. All three regions were identified in the composite. One major region tends to warm slightly following major volcanic eruptions, northwestern Eurasia, and this also was evident following Pinatubo.