Abstract

Reconstructing and understanding historical lake levels provides information about how climate influences lake level fluctuations, which is important for managing Lake Michigan-Huron’s (MH) coasts. This study reconstructs historical MH lake levels using ten ring-width chronologies from Southeast Alaska, which are significantly correlated at the 0.01 confidence level with January – June average MH lake levels. The model based on principal component regression analysis (PCReg) explains 33.8% of the variance in MH lake levels (January – June) over the 131-year calibration period (1860 – 1990). Model performance was assessed by using early (1860 – 1925) and late (1926 – 1990) calibration periods, confirming a well-verified stable relationship through time.

Historical lake level fluctuations that respond to altered climate conditions are identified and may inform the future of lake levels. Reconstructed high lake levels are attributed to volcanic activity in the 1690s, 1673, 1755, and 1809 and a strong El Niño event from 1876 to 1878, whereas lows are attributed to droughts, corresponding with the conditions of the 1930s Dust Bowl. MH lake levels are negatively correlated with the Pacific North American Pattern (PNA), indicating higher lake levels during a negative PNA. There is a 170-year return interval of high lake levels, suggested by spectral analysis, potentially informing future high lake levels. MH lake level fluctuations are primarily based on large-scale atmospheric climate patterns that may be altered by human activity, volcanic eruptions, or strong climate events.

Advisor

Wiles, Greg

Department

Earth Sciences

Keywords

dendrochronology, tree-rings, climate, teleconnections, Alaska

Publication Date

2026

Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis

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