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基于高分辨率MASNUM第三代海浪模式并根据Yuan等(2009)提出的波浪破碎统计物理模型,对乳山湾外海2008年各个季节波浪特征要素(有效波高和跨零周期等)与波浪破碎参数(白冠覆盖率、卷入深度和破碎能量损耗率)进行了数值模拟。利用Janson-1卫星高度计观测资料对有效波高模拟结果进行了检验,平均误差在0.17m左右。模拟结果显示,该海域波浪参数具有明显的季节变化特征,在2008-08乳山湾邻近海域受大风天气过程影响期间,有效波高在1.0~1.8m,破碎参数变化显著,白冠覆盖率最大达4.5%,卷入深度在1.5m以上,相应的破碎能量损耗率量值在6~11kg/s3。结果表明,波浪破碎过程对该区域海洋动力环境有着重要影响,是造成乳山湾口表层高溶解氧的可能机制之一。 相似文献
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绕岛理论来自于Sverdrup理论，被广泛用于估计和分析通过岛屿之间海峡的输运情况。以往的研究得到了带有侧摩擦或底摩擦的单岛理论或多岛理论。本文在线性情况下考虑了风驱动环流下的解析模型。在同时考虑侧摩擦和底摩擦的情况下，推导出了岛屿周围输运流函数的解析解，并给出了通过岛屿之间通道的流量输运。其结果与Wajsowicz相似，但摩擦常数表示不同的值。从解析解上看，摩擦常数与侧摩擦和底摩擦之间的关系比较复杂，为了推导出它们之间的相互作用原理，本文在正压β平面上随机选取了一些侧摩擦和底摩擦的值。结果表明，在构成摩擦常数方面，侧摩擦和底摩擦近似呈线性关系。我们研究了宽度对通道输运值的影响，结果表明摩擦在一定宽度内提高了流量，这种现象和只考虑侧摩擦时比较相似。本文也比较了在不同深度下的流量，发现当水平涡粘性系数和底部拖曳系数固定时，水深越大，输运减少率越小。为了进一步揭示侧摩擦和底摩擦耗散的联合作用，在两个岛屿的情况下，本文在不同宽度的通道中与Wajsowicz的只考虑底摩擦或侧摩擦的模型进行了比较。结果表明，当通道比较窄，尤其是在小于Munk边界层厚度时，侧摩擦的作用大于底摩擦。当通道宽度远大于Munk边界层厚度时，底摩擦的作用大于侧摩擦。将模型应用到印尼贯穿流，得到大约20%的输运减少量。 相似文献
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After validated by the in-situ observation, the slab model is used to study the wind-generated near-inertial energy flux(NIEF) in the South China Sea(SCS) based on satellite-observed wind data, and its dependence on calculation methods and threshold criteria of the mixed layer depth(MLD) is investigated. Results illustrate that the total amount of NIEF in the SCS could be doubled if different threshold criteria of MLD are adopted. The NIEF calculated by the iteration and spectral solutions can lead to a discrepancy of 2.5 GW(1 GW=1×109 W). Results also indicate that the NIEF exhibits spatial and temporal variations, which are significant in the boreal autumn,and in the southern part of the SCS. Typhoons are an important generator of NIEF in the SCS, which could account for approximately 30% of the annual mean NIEF. In addition, deepening of the MLD due to strong winds could lead to a decrease of NIEF by approximately by 10%. We re-estimate the annual mean NIEF in the SCS,which is(10±4) GW and much larger than those reported in previous studies. 相似文献
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首先回顾了基于海底缆线的海峡水通量观测理论方法的发展历程,对基于电压测量的水通量反演方法进行了梳理,重点阐述了其中的关键观测要素和主要误差来源。为了提升系统可靠性、摒弃外界因素干扰,提出了一种基于感应电流测量的观测方法。对比传统方法,分析了本方法的优缺点,评估了基于本方法的海洋观测系统建设需求和可能性。最后应用本系统建立的一个理想海域——青岛胶州湾湾口各类海洋要素的典型取值范围,通过合理的特征尺度估算和量纲分析,估计了基于电流测量的观测系统中的各类设备的参数要求,其中关键测量器材——电流表至少应满足观测量程覆盖10~(–1)~10~1 m A,观测精度大于1μA,取样频率大于1/60 Hz。在电学测量仪器中,适应本系统要求的器材较普遍,可选择的测量仪器种类较丰富。 相似文献
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In this study, we develop a variable-grid global ocean general circulation model(OGCM) with a fine grid(1/6)°covering the area from 20°S–50°N and from 99°–150°E, and use the model to investigate the isopycnal surface circulation in the South China Sea(SCS). The simulated results show four layer structures in vertical: the surface and subsurface circulation of the SCS are characterized by the monsoon driven circulation, with basin-scaled cyclonic gyre in winter and anti-cyclonic gyre in summer. The intermediate layer circulation is opposite to the upper layer, showing anti-cyclonic gyre in winter but cyclonic gyre in summer. The circulation in the deep layer is much weaker in spring and summer, with the maximum velocity speed below 0.6 cm/s. In fall and winter, the SCS deep layer circulation shows strong east boundary current along the west coast of Philippine with the velocity speed at 1.5 m/s, which flows southward in fall and northward in winter. The results have also revealed a fourlayer vertical structure of water exchange through the Luzon Strait. The dynamics of the intermediate and deep circulation are attributed to the monsoon driving and the Luzon Strait transport forcing. 相似文献
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通过海洋中的各类海底缆线,可以搭建海洋观测系统,有效地开展长期海洋观测。虽然我国该类系统建设起步较晚,但是具有理论和硬件多方面的后发优势。只要海洋管理和科研部门注意沟通协作和前期筹划,可以保证我国此类系统建设的速度和质量。文章将从我国近海与海底缆线有关的海洋现状出发,分析建设基于海底缆线的海洋观测系统在我国近海的重要意义,梳理我国建设该系统所面临的机遇与挑战,展望该类系统在我国近海的应用前景,并考虑我国近海的实际情况,提出在青岛胶州湾湾口海区建立本系统示范应用的设计方案。 相似文献
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Through analysis of the results of a verified high-fidelity numerical model, the intra-seasonal variations(ISVs) in the depth of the 22°C isotherm(D22) in the South China Sea(SCS) basin are investigated. The results show that the ISVs in the D22 exhibit distinct seasonality in the SCS. The ISVs in the D22 are quite significant, especially within a band along the northwestern boundary of the basin and at the southern end of the basin during boreal winter. In these areas, the ratio of the standard deviations(STDs) of intra-seasonal band to the STDs of total data could exceed 0.6. Although the ISVs in the D22 are detectable in the area affected by the Vietnam Offshore Current during boreal summer and autumn, these variations are sometimes overwhelmed by oscillations with other frequencies. An analysis of the causes of the ISVs in the D22 in the SCS indicates that sea surface fluxes and wind stirring are not the dominant external driving mechanisms of the phenomena described above. The ISVs in the D22 are thought to be induced mainly by the thermodynamic adjustment of the ocean itself and the associated instabilities. The energy of the northern and southern bands that display strong ISVs in the D22 may be derived from eddy kinetic energy, rather than eddy available potential energy. The diversity of the propagation of the ISVs in the D22 is very conspicuous within these two bands. 相似文献
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在Wajsowicz(1993)多岛环流理论的基础上,给出了一种摩擦-地形阻力作用的参数化方案,并应用于南海域际环流动力学的研究。结果表明,不考虑阻力时理论结果在海水输运方向上与实测一致,但在输运量的量值上与实测差别很大;考虑了摩擦-地形阻力作用后计算所得的各通道的流量与实测结果不但在方向上完全一致,在数值上也具有一定的一致性。因而在考虑了摩擦-地形阻力作用后,基于Sverdrup环流理论的多岛环流理论能够很好解释南海域际环流形成的主要动力机制。采用1948—2014年NCEP逐年风应力资料计算结果表明,各海峡流量均存在明显的年际变化,其中吕宋海峡和民都洛海峡更为明显。相关分析显示,吕宋、民都洛和卡里马塔海峡的流量相互之间存在较强的正相关性,而与望加锡海峡流量呈现显著的负相关。El Nio正位相期间太平洋-印度洋贯穿流南海分支加强而望加锡海峡流量减弱。计算结果还表明,吕宋海峡、民都洛海峡的西、南向流量在1948—2014年期间都存在明显的增强趋势,而卡里马塔海峡基本上未受影响。 相似文献