Speaker: Mussie Beyene, PhD Candidate, Civil & Environmental Engineering

Maine has over 5000 lakes and winter ice cover over these lakes is a seasonal phenomenon, which plays a vital role in the ecological and socio-economic health of the state. In recent times, there have been dramatic shifts in the timing and duration of lake ice cover in Maine. This has caused fears on the state of these lakes as the lengthening of ice-free period has been linked with increased algal growth and declining water quality, warmer temperatures and alterations in aquatic biodiversity, and shortening of winter activities. Using historical ice out date and temperature data from eight lakes and five meteorological stations in Maine, I will present my finding on the (a) relationship between spring ice out dates in Maine and antecedent winter temperatures (and derived degree day variables) including the identification of thresholds winter temperatures (b) role of tropical Pacific sea surface temperatures and associated large scale atmospheric circulation patterns on the variability of winter temperature and spring ice out date in Maine. I will also discuss the implication of these findings on the lake sustainability studies in Maine.