Southern Hemisphere continental temperature responses to major volcanic eruptions since 1883 in CMIP5 models

Although global and Northern Hemisphere temperature responses to volcanic forcing have been extensively investigated, knowledge of such responses over Southern Hemisphere continental regions is still limited. Here we use an ensemble of CMIP5 models to explore Southern Hemisphere temperature responses to four major volcanic eruptions: Krakatau (1883), Santa Maria (1902), Agung (1963) and Pinatubo (1991). Focus is on near-surface temperature responses over southern continental landmasses including southern South America, southern Africa and Australia and their seasonal differences. Findings indicate that for all continents, temperature responses were strongest and lasted longest following the Krakatau eruption. Responses in Australia had the shortest lag time, strongest maximum seasonal response and the most significant monthly anomalies. In contrast, southern South America records the longest lag time, weakest maximum seasonal temperature response and lowest number of monthly negative anomalies following these eruptions. In most cases, the strongest single-season response occurred in austral autumn or winter, and the weakest in summer or spring. We tentatively propose that cooler temperature responses are likely caused, at least in part, by the intensification of the westerlies and associated mid-latitude cyclones and anti-cyclones.

Automated summary

This study explores Southern Hemisphere temperature responses to four major volcanic eruptions using an ensemble of CMIP5 models. The findings indicate that the temperature responses were strongest and lasted longest following the Krakatau eruption, with Australia showing the strongest response and southern South America the weakest. In most cases, the strongest single-season response occurred in austral autumn or winter.