Dynamic Winter Climate Response to Large Tropical Volcanic Eruptions since 1600

• Main Authors: Drew T. Shindell, Gavin A. Schmidt, Michael E. Mann, G. Faluvegi
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2004
• Subjects: Arctic; Greenland; Labrador Sea; North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.408.38; http://www.meteo.psu.edu/holocene/public_html/shared/articles/Shindelletal-jgr04.pdf

[1] We have analyzed the mean climate response pattern following large tropical volcanic eruptions back to the beginning of the 17th century using a combination of proxybased reconstructions and modern instrumental records of cold-season surface air temperature. Warm anomalies occur throughout northern Eurasia, while cool anomalies cover northern Africa and the Middle East, extending all the way to China. In North America, the northern portion of the continent cools, with the anomalies extending out over the Labrador Sea and southern Greenland. The analyses confirm that for two years following eruptions the anomalies strongly resemble the Arctic Oscillation/Northern Annular Mode (AO/NAM) or the North Atlantic Oscillation (NAO) in the Atlantic-Eurasian sector. With our four-century record, the mean response is statistically significant at the 95 % confidence level over much of the Northern Hemisphere land area. However, the standard deviation of the response is larger than the mean signal nearly everywhere, indicating that the anomaly following a single eruption is unlikely to be representative of the mean. Both the mean response and the variability can be successfully reproduced in general circulation model simulations. Driven by the solar heating induced