Temperature shifts in Central Antarctica after major volcanic eruptions in the second millennium of the Common Era

Abstract

Volcanic forcing is one of the major drivers of climatic variability on Earth during the last millennium before the beginning of the industrial era, combined with solar activity, Milanković orbital forcing and greenhouse gas concentration. Large volcanic eruptions (with Volcanic Explosivity Index of 6 or more) eject a huge amount of sulfur dioxide into stratosphere thus reducing the amount of incoming solar radiation. The corresponding cooling may exceed 1 °C and lasts about 5 years. The identification of the volcanic events is carried out with the use of firn and ice core data drilled in the polar ice sheets, while the climatic response to the eruptions is studied with the use of dendrochronology and other terrestrial data, mainly in the Northern Hemisphere. Thus, the reaction of the Southern Hemisphere’s climate to the volcanic forcing is understood to a lesser extent. Here we use stable water isotope data (δ18O and dxs parameter, dxs = δD – 8 · δ18O) from 4 firn cores in order to study the temperature change in central Antarctica (in the vicinity of Vostok Station) after 5 major eruptions of the 2nd millennium of the Common Era: Samalas (1257), Unknown Event 1459 CE, Huaynaputina (1600), Parker (1641) and Tambora (1815). The isotopic composition of the cores was measured in the Climate and Environmental Research Laboratory of the Arctic and Antarctic Research Institute (St. Petersburg) with the use of Picarro L2130-i and L2140-i laser analyzers. We show that a post-eruption cooling in central East Antarctica is about 0.52 °C and lasts for about 5 years. At the same time, the temperature in the moisture source decreases to a lesser extent (0.46 °C), but the cooling lasts longer. We need to emphasize that only through using 4 parallel cores was it possible to significantly reduce the amount of the “deposition noise” in the isotopic records and detect the post-volcanic cooling in central East Antarctica.