Spring Convection in Ice-Covered Freshwater Lakes
Spring Convection in Ice-Covered Freshwater Lakes
复制标题
冰雪覆盖的淡水湖中的春季对流
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
A. Terzhevik
中科院分区：
文献类型：
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作者：
D. Mironov;A. Terzhevik
考虑了由垂直非均匀辐射加热驱动的穿透对流状态。在被冰覆盖的淡水湖中也观察到类似的对流，那里的水温在春末低于最高密度温度。介绍了对流长度、速度和温度尺度，它们适合于描述垂直非均匀加热驱动的对流。在这些尺度的基础上，结合对流混合层中垂直温度分布和湍流特征的相似假设，提出了一个考虑对流状态的简单模型。研究了冰雪覆盖的湖泊对流的携流特征。结果表明，如果将基于流体表面浮力流动的Deardorff对流尺度替换为考虑辐射吸收的三维特征的对流尺度，则这种对流可以用大气层和海洋层的对流方程满意地描述。模式计算结果与观测资料吻合较好。
The regime of penetrative convection driven by a vertically inhomogeneous radiation heating is considered. Similar convection is observed in ice-covered freshwater lakes, where the water temperature is below the maximum-density temperature during late spring. The convective length, velocity, and temperature scales are introduced, which are suitable for the description of convection driven by a vertically inhomogeneous heating. On the basis of these scales and the similarity hypotheses for the vertical temperature profiles and tur- bulence characteristics in the convective mixed layer, a simple model of the convection regime under consider- ation is proposed. The entrainment regimes characteristic of the convection in ice-covered lakes are studied. It is shown that such convection is satisfactorily described by the equation used for convection in both the atmo- spheric and oceanic layers if the Deardorff convective scales based on the buoyancy flow through a fluid surface are replaced by the convective scales, which take into account the three-dimensional character of radiation absorption. The results of model calculations are in good agreement with observational data.