Name
Hydrometeorological responses of Lake Superior to warm winters
Date & Time
Wednesday, May 29, 2024, 11:00 AM - 11:15 AM
Description

During the winter of 2023-2024 the Laurentian Great Lakes experienced historic low ice extent. This was associated with a strong El Nino 3.4 anomaly of 1.6 from July – December 2023 that kept air temperatures above normal for much of the end of the year. Lake ice was absent from Lake Superior except in Thunder, Nipigon and Batchawana Bays. In this presentation, data from the 15-year period of record collected at the offshore Stannard Rock lighthouse will be used to demonstrate that the absence of ice associated with previous strong El Nino events is typically accompanied by 1) suppressed evaporation, 2) a warmer lake in spring, 3) an earlier start to the subsequent evaporation season, but 4) a wide diversity in lake level responses. While variable precipitation and runoff complicate predictions of lake level response, the evaporative response can be more predictable. It is hypothesized that two types of responses occur, controlled by atmospheric conditions above the lake. If it continues to be warm into the subsequent autumn, evaporation rates continue to be suppressed by gentle vapour pressure gradients despite an earlier onset of the autumn evaporation season. Conversely, if cold conditions return, the early start to the evaporation season in combination with strong vapour pressure gradients can result in above average evaporation. This dichotomy explains the diversity in lake level response to warm winters and highlights the several temporal scales that must be considered when assessing how atmospheric conditions control the hydrological regime of Lake Superior.

Location Name
Conference Room - 2200
Full Address
Carleton University - Richcraft Hall
1125 Colonel By Dr
Ottawa ON K1S 5B6
Canada
Session Type
Breakout Session