科研之友
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摘要
Polar lakes are highly sensitive to changes in the climate. As a contribution to the International Polar Year (IPY), the impact of climate warming on the thermal characteristics of Great Bear Lake is studied. During the summer of 2008, time series observations of meteorological, hydrological and physical limnological parameters in the lake were obtained to characterize the thermal regime. These observations and the forecasted forcing from a regional version of the Canadian operational Global Environmental Multiscale (GEM) model are used to simulate the ice-free hydrodynamics in Great Bear Lake using the high-resolution, three-dimensional hydrodynamic Princeton Ocean Model (POM). The model results of surface and sub-surface temperatures are first compared with satellite and in-lake measurements. The model simulates weak stratification and predicts mean cyclonic circulation reasonably well. The impact of climate warming caused by greenhouse gases is studied using Canadian Regional Climate Model (CRCM) scenarios for the base climate (1970-2000) and future warmer climate (2041-70). This scenario predicts an increase in surface temperature of over 2 degrees C in the northeast corner, whereas in the rest of the lake the increases vary from 0.5 degrees to 1 degrees C. The results show that brief thermal stratification is possible in the deeper waters. The increase in water temperature caused by climate warming in the lake appears largely because of the positive increase in net longwave radiation and sensible heat flux, which result from changes in the temperature gradient between the air and the lake and slightly reduced wind speeds in the climate warming projections.
- 出版日期2012
- 单位南京大学
