Numerical modeling of hydrodynamics and tracer dispersion during ice-free period in Lake Winnipeg

The three-dimensional hydrodynamic Estuary Lake Coastal Ocean Model (ELCOM) was used to study the water circulation and thermal structure of Lake Winnipeg, Canada. To assess the model performance, we simulated circulation and temperature distribution of the lake in 2007 and compared the model results with the field observations of water levels, temperature, and currents. The model showed considerable success in reproducing the thermal structure and circulation. The model predicted isothermal conditions in the South Basin and Narrows for the whole period and produced weak thermal stratification during the early summer in the North Basin. The modeled currents were used to examine the transport, dispersion of passive tracers, and local flushing time in the lake. Simulations using passive tracers qualitatively agreed well with the field measurements of hydrogen isotopes in Lake Winnipeg taken during the study period. The mean transport is towards the north in the lake with two cyclonic gyres in the North Basin and one gyre in the South Basin. The model results show that the local flushing time of Red River waters in the South Basin is about 45 days. Crown Copyright (c) 2011 Published by Elsevier B.V. on behalf of International Association for Great Lakes Research. All rights reserved.