Observed and Simulated Ice Characteristics of Five Freshwater Lakes and Extrapolation to a Projected 2xC02 Climate Scenario

Abstract

The MINLAKE97 model was employed to simulated ice-on and ice-off dates, ice cover duration and ice thicknesses for four lakes in the us and one lake in Canada. MINLAKE97 is a one dimensional, year-round, deterministic water quality model which simulates vertical temperature and dissolved oxygen profiles in lakes and has the ability to simulate ice on-dates, ice growth, ice decay and ice-off dates. A new ice and snow albedo submodel was incorporated into the MINLAKE96 model to produce MINLAKE97, The average standard errors between simulated and measured values were 10 days, 9 days and 11 days for ice on-dates, ice-off dates and ice cover duration, respectively, without calibrating the model. The model was also employed to simulate the effect of a projected 2xC02 climate scenario on the ice characteristics of the same five lakes. To illustrate the climate change effect, time series for the ice-on dates, ice-off dates, ice cover duration and maximum ice thicknesses under past and 2xC02 climate scenarios were simulated. The root mean. square of changes for ice-on dates, ice-off dates, ice cover duration and maximum ice thicknesses between past and 2xC02 climate scenarios were projected to be 13 days, 21 days, 31 days and 0.27 m, respectively. Under the 2xC02 climate scenario the average ice-on dates are 7 days to 12 days later; the average ice-off dates are 15 days to 23 days earlier; the ice cover durations are 25 days to 33 days shorter; and the maximum ice thicknesses are 0.18 m to 0.30 m thinner. The results were compared with empirical projections by Adams and Stefan (1997). The two models gave similar results for the projected changes of ice-on and iceoff dates between 2xC02 and past conditions, but gave different results for the projected changes of ice cover duration. The overall conclusion is that a doubling of atmospheric carbon dioxide (2xC02) would have a significant effect on lake ice characteristics.