Spatial structure of internal Poincaré waves in Lake Michigan
Spatial structure of internal Poincaré waves in Lake Michigan
复制标题
密歇根湖庞加莱内波的空间结构
DOI：
10.1007/s10652-013-9294-3
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发表时间：
2014
影响因子：
2.2
通讯作者：
Hawley, Nathan
中科院分区：
文献类型：
--
作者：
Ahmed, Sultan;Troy, Cary D.;Hawley, Nathan
本文研究了美国密歇根湖近惯性内庞加莱波的特征，并对其进行了现场实验和水动力模拟。重点是确定波浪的横向和垂直结构。本文介绍了2009年和2010年分别在密歇根城（美国）和马斯基贡（美国密歇根州）在密歇根湖南部进行的两次野外实验的近惯性内波特性观测结果。温跃层位移和斜压速度谱表明，动能和势斜压能主要由近惯性内庞卡罗内波控制。从经验正交函数分析可知，该能量主要为垂直模态1。利用初夏（6月）、仲夏（7月）和秋季（9月）分层进行的理想水动力模拟表明，盆地尺度的内部庞加莱波结构是单一和两个盆地单元的组合，类似于Schwab在伊利湖发现的结构，其近地表速度在北部和南部盆地中心最大。近惯性底部动能在整个盆地的大片区域中大致恒定，在湖中高原等较浅地区，与北部和南部深盆地相比，其幅度更高。绘制后的近底部近惯性动能与底部地形图相似。波浪引起的跨温跃层垂直切变主要集中在湖盆的纵轴上，近底速度和温跃层切变都可以用一个简单的期望横向变率概念模型来合理解释。
In this paper we examine the characteristics of near-inertial internal Poincaré waves in Lake Michigan (USA) as discerned from field experiments and hydrodynamic simulations. The focus is on the determination of the lateral and vertical structure of the waves. Observations of near-inertial internal wave properties are presented from two field experiments in southern Lake Michigan conducted during the years 2009 and 2010 at Michigan City (IN, USA) and Muskegon (MI, USA), respectively. Spectra of thermocline displacements and baroclinic velocities show that kinetic and potential baroclinic energy is dominated by near-inertial internal Poincaré waves. Vertical structure discerned from empirical orthogonal function analysis shows that this energy is predominantly vertical mode 1. Idealized hydrodynamic simulations using stratifications from early summer (June), mid-summer (July) and fall (September) identify the basin-scale internal Poincaré wave structure as a combination of single- and two-basin cells, similar to those identified in Lake Erie by Schwab, with near-surface velocities largest in the center of the northern and southern basins. Near-inertial bottom kinetic energy is seen to have roughly constant magnitude over large swathes across the basin, with higher magnitude in the shallower areas like the Mid-lake Plateau, as compared with the deep northern and southern basins. The near-bottom near-inertial kinetic energy when mapped appears similar to the bottom topography map. The wave-induced vertical shear across thermocline is concentrated along the longitudinal axis of the lake basin, and both near-bottom velocities and thermocline shear are reasonably explained by a simple conceptual model of the expected transverse variability.
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影响因子：
1.2
作者：
F. M. Boyce;M. Donelan;P. Hamblin;C. Murthy;T. J. Simons
通讯作者：
F. M. Boyce;M. Donelan;P. Hamblin;C. Murthy;T. J. Simons
安大略湖的内部自由振荡1
影响因子：
4.5
作者：
D. Schwab
通讯作者：
D. Schwab
影响因子：
4.5
作者：
Bouffard, Damien;Boegman, Leon;Rao, Yerubandi R.
通讯作者：
Rao, Yerubandi R.
影响因子：
4.5
作者：
Austin, Jay
通讯作者：
Austin, Jay
影响因子：
3.6
作者：
Beletsky, D;Schwab, DJ
通讯作者：
Schwab, DJ