## ＜紀要論文＞流軸の揺れで生じる流軸に平行な向きの渦成海水輸送

作成者 著者識別子 作成者名 所属機関 所属機関名 九州大学応用力学研究所 Research Institute for Applied Mechanics, Kyushu University 日本語 Research Institute for Applied Mechanics, Kyushu University 九州大学応用力学研究所 2007-03 132 37 53 Version of Record open access https://doi.org/10.15017/26827 Numerical simulation with an eddy-permitting OGCM (Ocean General Circulation Model) revealed that western boundary currents in the North Pacific are accompanied by eddy-induced mass transport along th...e mean stream axis which is much larger than that across it, where "eddy-induced mass (thickness) transport" means the mass flux by fluctuating velocity along with the fluctuating thickness of a layer of the same density. The eddy-induced mass transport is directed downstream and upstream in the left-hand and right-hand sides of the mean stream axis, respectively. The property holds not only for the subtropical gyre (Kurohsio), but also for the subarctic gyre (Oyashio and Alaska Current). A simple mechanism is proposed for this eddy-induced mass transport along the mean current. The model is based on the fluctuation of the stream axis with its cross-stream structure invariant. The model qualitatively explains well the downstream and upstream mass transport in the left-hand and right-hand sides of the current. The magnitude and the cross-stream profile of the along-current mass transport depend on factors such as the mean distribution of the current, the characteristic amplitude of the migration of the current axis. Analytical formulas are obtained for the distribution of the eddy-induced mass transport for suitable assumptions of the Gaussian fluctuation of the stream axis and the specific profile of the thickness associated with the current. Roughly speaking, the eddy-induced mass transport has a cross-stream profile like the derivative of the probability density distribution of the Gaussian distribution. Also it is to be noted that the instantaneous current profile is recovered from the mean current profile in the model of the fluctuating stream axis.続きを見る

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PISSN 1345-5664 AA11459359 26827 査読無 eddy-induced mass (thickness) transport fluctuation of the stream axis Gent-McWilliams parametrization 紀要論文 2013.08.09 2023.02.27