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Using Alaskan Tree-Rings to Reconstruct Lake Michigan-Huron Levels

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

Presenting Author:

Lynnsey Delio

Authors:

Delio, Lynnsey¹, Wiles, Greg C.², Wiesenberg, Nick³, Gaglioti, Benjamin V.⁴

(1) College of Wooster, Wooster, OH, USA, (2) The College of Wooster, Wooster, OH, USA, (3) College of Wooster Department of Earth Sciences, Wooster, OH, USA, (4) University of Alaska Fairbanks, Fairbanks, AK, USA,

Abstract:

Reconstructing and understanding historical lake levels provides information about past climate variability, which can improve our understanding of lake level controls important to managers in coastal great lakes communities. Precipitation, runoff, and evaporation determined by large-scale ocean atmosphere phenomena must be considered to predict the lake levels of the Laurentian Great Lakes. Tree-rings have been used to reconstruct lake levels of Michigan-Huron (MH) and Erie back several hundred years leveraging teleconnections with the Midwest and the Pacific sector. Building on these previous efforts, we consider an updated suite of tree-ring records from Alaska as predictors of the MH winter and spring season (January - June) lake levels observed back to 1860 CE.

Initial results indicate that combinations of Alaska tree-ring records can explain much of the variance of MH lake levels. Efforts to optimize the lake level modeling, comparisons with existing reconstructions, and further verification are ongoing. Alaska tree-ring records provide the basis for reconstruction, explaining over 50% variance using a 2 PC model of principal component regression analysis. This analysis yields a viable long season for reconstruction (January - June) with a relatively stable model for the full calibration interval. These initial modeling results going back to 1650 CE based on a 130-year calibration period (1860-1990) illustrate the potential for a strong reconstruction of MH lake levels, enhancing our understanding of historical lake levels and associated climate conditions.