Basin-scale internal wave dynamics during a winter cooling period in a large lake
Basin-scale internal wave dynamics during a winter cooling period in a large lake
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大湖冬季降温期间盆地尺度内波动力学
DOI：
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发表时间：
2003
期刊：
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通讯作者：
S. Pálmarsson
中科院分区：
文献类型：
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作者：
F. Rueda;S. Schladow;S. Pálmarsson
采用现场观测与三维数值方法相结合的方法对盆地尺度内波进行了研究。野外现场，太浩湖（CA-NV）冬季，其特点是存在弱密度分层和几个不同特征的风暴锋。在这些条件下，周期大于5天的内波和30米的位移是可能的。所使用的模型具有可忽略不计的数值耗散，并且在表示盆地尺度波所需的时间周期内具有足够小的相位滞后。数值结果和观测结果都确定了三个开尔文模和一个庞加莱模的存在。虽然波周期与理论预测一致，但空间特征远比理论预测复杂。通过对模型产生的综合势能场和动能场的分析，揭示了其空间特征。这说明盆地地形对开尔文波和庞加莱波都有影响。可变风暴的影响，特别是风暴相对于内波的相位，表明是引起盆地尺度波的放大和湮灭的原因。
[1] Basin-scale internal waves are examined using a combined field observation and 3-D numerical approach. The field site, Lake Tahoe (CA-NV) during winter, is characterized by the presence of a weak density stratification and the passage of several storm fronts of varying character. Under these conditions internal waves with periods greater than 5 days and displacements of 30 m are possible. The model used is shown to have negligible numerical dissipation and sufficiently small phase lag over the time periods needed to represent basin-scale waves. Both the numerical results and the observations identify the presence of three Kelvin modes and one Poincare mode. While the wave periods are consistent with theoretical predictions, the spatial characteristics are far more complex than theory can predict. The spatial features are revealed through analysis of the integrated potential and kinetic energy fields yielded by the model. This shows that the basin topography exerts an influence on both Kelvin and Poincare waves. The effect of the variable storms and, in particular, the phasing of the storms with respect to the internal waves is shown to be responsible for the amplification and annihilation of the basin-scale waves.