The response of the thermal stratification of South Bay (Lake Huron) to climatic variability

Abstract

The 37-year record (1955-1992) of water temperature profiles and corresponding meteorology for South Bay (Lake Huron) provide an extensive empirical data set for the study of climate variability and corresponding alterations in lake thermal structure. Thermoclines became shallower over this period and epilimnetic temperatures increased. Canonical analyses correlated warm May-July air temperatures and high July-August solar radiation with warmer epilimnia, larger thermal gradients across the thermocline, and shallower thermoclines. Multivariate canonical scores indicate that these thermal responses have increased in parallel with the recent warming trend since the mid-1960s. Anomalous multivariate scores correspond to El Niño events, and an extreme low score corresponds to the Mount Pinatubo cooling effect of 1992.