129-60 Climate Proxy Comparisons between the Gulf of Alaska and the Patagonian Icefields

Abstract:

Glacial geologic records and tree-rings are both influenced by summer temperatures and moisture. Previous studies have provided a framework to compare these proxies, from coastal settings, symmetrically along the shores of the North Pacific Gulf of Alaska (GOA) with the Southern Hemisphere’s Patagonia Icefields. Climate modes in the Pacific Basin including the El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) are reflected in glacier mass balance and tree growth in both hemispheres. Therefore, these modes can potentially drive glacial variations and tree growth along the GOA and in Patagonia symmetrically across the equator, possibly yielding insights into the climate forcings of ice fluctuations and forest growth.

Tree-ring chronologies in both regions span thousands of years and have been used to reconstruct temperature. Building on the seminal work of R. Villalba (Mendoza Tree Ring Lab), our recent comparisons show a strong correlation between a coastal Alaska (Tsuga mertensiana) tree-ring series and similar records from Northern Patagonia (Nothofagus pumilio). Comparisons yield a correlation of 0.42 (N=348 years) for year-to-year comparisons, as previously reported, and a correlation of 0.50 (N=348) where the Patagonia record lags Alaska by two years. Ongoing research will compile and compare glacier records to further investigate how the ocean-atmosphere modes of ENSO and PDO might be linked to the trees and glaciers in Alaska and Patagonia.

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