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Investigating Volcanically Forced Shifts in North Pacific Climate in Model Simulations and Alaska Tree Ring Records

Session: 37th Annual Undergraduate Research Exhibition Sponsored by Sigma Gamma Epsilon (Posters)

Presenting Author:

Lev Sugerman-Brozan

Authors:

Sugerman-Brozan, Lev¹, Lawman, Allison², Wiles, Greg³, Wiesenberg, Nick⁴

(1) Department of Geology, Colorado College, Colorado Springs, CO, USA, (2) Environmental Studies and Science Program, Colorado College, Colorado Springs, CO, USA, (3) Department of Earth Sciences, College of Wooster, Wooster, OH, USA, (4) College of Wooster Department of Earth Sciences, Wooster, OH, USA,

Abstract:

Volcanic eruptions can have long-lasting effects on climate, yet the response of North Pacific climate variability remains unclear. For example, previous work has identified volcanically forced shifts in PDO phase, including 50-70 year PDO cycles triggered by volcanic eruptions. Here we use the Community Earth System Model Last Millenium Ensemble (CESM-LME) and a selection of mountain hemlock tree ring chronologies from Alaska to investigate the North Pacific temperature and hydroclimate responses to volcanic forcing. The mountain hemlock chronologies show regional changes following volcanic eruptions in 1452, 1697-1698 and 1809 CE. We then use superposed epoch analysis to investigate the magnitude and duration of both the proxy-inferred and simulated surface temperature responses at the sites of the tree-ring chronologies during known volcanic events. This comparison helps identify both similarities and discrepancies between the model and data, therefore providing insights into the response of North Pacific climate to volcanic forcings. These findings will provide much-needed context for better understanding current and future changes in the North Pacific ocean-atmosphere system, and its response to external climate forcings.