Diagnostics and energetics of the topographic Rossby waves generated by a typhoon propagating over the ocean with a continental shelf slope
Diagnostics and energetics of the topographic Rossby waves generated by a typhoon propagating over the ocean with a continental shelf slope
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DOI：
10.1007/s10872-019-00518-5
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发表时间：
2019-06
影响因子：
2.3
通讯作者：
Wei Yang;T. Hibiya;Yuki Tanaka;Liang Zhao;Hao Wei
中科院分区：
文献类型：
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作者：
Wei Yang;T. Hibiya;Yuki Tanaka;Liang Zhao;Hao Wei
通过一组理想数值实验，研究了台风在海底地形倾斜的海洋上传播时的亚惯性响应动力学。在波数-频率谱中，在相同的沿坡波数和两个不同的亚惯性频率下，至少识别出两个不同的地形罗斯比波（trw）。涡量平衡诊断表明，底压转矩在trw的产生和传播中都起着重要作用。两组灵敏度试验结果表明，台风的空间结构是决定顺坡波数及其频率的“决定性”参数；首先确定TRW沿坡波数作为对台风扰动的响应，然后确定相应的频率以满足理论TRW色散关系。而台风的振幅则受台风半径和台风移动速度的双重控制。对于半径较大或移动速度较慢的台风，所产生的trw可与近惯性波相当或更有能量。这表明trw可能利用台风提供的能量在陆架斜坡上诱导近底混合中起重要作用。
The dynamics of the subinertial response when a typhoon propagates over the ocean with a sloping bottom topography is investigated by carrying out a set of idealized numerical experiments. At least two different topographic Rossby waves (TRWs) are identified at the same along-slope wavenumber and two different subinertial frequencies in the wavenumber–frequency spectra. The diagnostics of vorticity balance demonstrates that the bottom pressure torque plays an important role in both the generation and propagation of TRWs. Two sets of sensitivity experiments show that the spatial structure of the typhoon is a “decisive” parameter in determining the along-slope wavenumber as well as the corresponding frequencies; the along-slope wavenumber of a TRW is first determined as a response to the typhoon-induced perturbation, and the corresponding frequencies are then determined so as to satisfy the theoretical TRW dispersion relationship. The amplitude of TRWs, in contrast, are controlled by both the typhoon radius as well as the typhoon traveling speed. For typhoons with a large radius or slow traveling speed, the resulting TRWs can be comparable to or more energetic than the near-inertial waves. This indicates that the TRWs might play an important role in inducing the near-bottom mixing along the shelf slope by using energy supplied from typhoon winds.