波浪输运过程对海温异常的影响
发布时间：2018-10-12 12:15
【摘要】：波浪是海洋微小尺度运动的典型过程,也是海-气界面上的一种重要运动形式。由于波浪的持续性,它会对上层海洋产生难以置信的影响。波浪过程主要包括波-流相互作用、波浪破碎、近岸波的反射和绕射、波浪诱导的水体输运及波浪的搅拌混合作用等。本文主要研究了波浪诱导的大尺度水体输运与赤道东太平洋海表面温度异常的关系和波浪输运通量剩余量对上层海洋影响的数值研究,分别采用了数据分析和数值实验的研究方法,并且使用了多种数据统计手段,主要包括EOF分解、带通滤波、相关分析、误差分析、傅立叶变换等。南、北西风带海域的平均波向为西向,热带海域为东向,南太平洋东岸的波向全年保持西南-东北方向,并以涌浪占优,波浪输运方向与平均波向一致。波浪输运量的东-西分量主要呈带状分布,输运量在西风带海域最大,最大值出现在南印度洋,中低纬度海区的输运量相对较小。波浪输运南-北分量主要表现为北向输运的特征,南半球为向赤道输运,北半球为离赤道输运,并且在南半球的大洋东边界有明显的东向强化现象。波浪输运与Ekman输运的量级可比拟。在南北西风带海区,二者输运量接近,但波浪输运以东-西输运为主,而Ekman输运的南-北分量较大。中低纬度海区,Ekman输运量最大,方向以向南或向北的高纬度输运为主。对于我们比较关注的赤道东太平洋而言,由于波浪常年保持向赤道的正输运,其年输运量的贡献大于Ekman输运。波浪诱导的水体输运主要通过两条主要路径影响赤道东太平洋的SST异常,一是,沿赤道的东-西向水体输运;二是,沿大洋东岸的南-北向水体输运。通过经验正交分解的方法分析了热带太平洋和南大洋的波浪输运量的时空特征,及振荡的主周期。分析发现：热带太平洋和南大洋的波浪输运的距平都存在东向传输的特点,其主要模态的变化周期为5.2、3.7、2.45年,这与赤道东太平洋SST异常的振荡周期相同。由此说明,这两个海区的波浪输运异常与赤道东太平洋SST异常存在密切的关系。以Nino3指数作为赤道东太平洋海表面温度异常变化的指标,将SST异常高于0.5。C并且持续6个月以上定义为暖事件,SST异常低于-0.5℃并且持续6个月以上定义为冷事件。暖事件中,春季型和夏季型沿赤道的波浪输运主要呈西向异常,即赤道东太平洋的暖异常爆发前,波浪输运持续向东输运暖水。而大洋东岸的波浪输运在春季型中贡献的冷水呈负异常,在夏季型中贡献的冷水呈正异常,即输运的冷水增多。冷事件中,夏季型沿赤道的波浪输运主要呈东向异常,即向东输运的暖水少于正常值,而大洋东岸的北向波浪输运则为强的正异常,即由高纬度向赤道输运的冷水增多,这两条途径的水体输运为冷事件的爆发准备了条件。未发生型中,沿赤道的波浪输运仍延续着暖事件中的西向异常,但没有明显的输运特征,北向的波浪输运则呈现明显的负异常,即输运的冷水低于正常值,这一过程一定程度上抑制了冷事件的爆发。通过Stokes热输运的计算,进一步说明了波浪诱导的大尺度水体输运对赤道东太平洋SST异常变化的贡献。二者相关关系显示：沿赤道的波浪输运超前于SST异常6个月,大洋东岸波浪输运超前于SST异常15-20个月时,二者的相关系数最大。作为水体输运的重要部分,波浪输运对赤道东太平洋SST异常的影响不可忽略。波浪输运通量剩余量是影响上层海洋的重要机制之一。本文首先通过对比KPP方案的上边界层深度,揭示了KPP参数化方案低估了垂向扩散系数,未包含波浪过程的影响；然后将波浪输运通量剩余量的参数化方案包含到KPP方案中,设置控制实验及若干组敏感性实验,通过数值结果的分析显示：考虑波浪输运通量剩余量过程对上层海洋的作用后,有效改善了模式对海表温度模拟过高的问题。在垂直结构上,敏感实验的28℃等值线由控制实验中的20m加深到35m左右,与实测数据更接近。这在一定程度上也克服了海洋上混合层深度模拟一直偏浅的问题。波浪输运通量剩余量对上层海洋的作用主要影响了温度在夏季和冬季低纬度区域的数值结果。2月,敏感实验温度的全场相关系数由0.9013提高到0.9162；8月,敏感实验温度的全场相关系数由0.8881增大到0.9104。比较几组敏感性实验,当背景系数α取0.1左右时,能更合理的表征波动输运通量剩余量对上层海洋的作用。
[Abstract]:Wave is the process of ocean micro-scale movement and is also an important form of motion on the sea-gas interface. Due to the persistence of the waves, it will have an incredible effect on the upper ocean. The wave process mainly includes wave-flow interaction, wave fragmentation, reflection of nearshore wave, wave-wound, wave-induced water transport and wave stirring and mixing. In this paper, the relationship between wave-induced large-scale water body transport and the equatorial east Pacific sea surface temperature anomaly and the numerical study on the influence of wave transport fluxes on the upper-layer ocean are studied, and the data analysis and numerical experiments are respectively adopted. and a plurality of data statistical methods are used, mainly including EOF decomposition, band-pass filtering, correlation analysis, error analysis, Fourier transformation and the like. The average wave in the sea area of the west wind zone in the south and the north is west, the tropical sea area is east, the waves on the east coast of the South Pacific keep southwest-northeast in the whole year, and are dominated by swell, and the wave transport direction is consistent with the average wave direction. The east-west component of wave transport is mainly in the form of zonal distribution. The transport volume is the largest in the west wind zone, and the maximum value appears in the southern Indian Ocean, and the transport volume in the middle and low latitude sea area is relatively small. The south-north component of wave transport is mainly characterized by north-to-north transport, and the southern hemisphere is transported to the equator, the northern hemisphere is transported from the equator, and there is an obvious east-facing strengthening phenomenon in the eastern boundary of the southern hemisphere. Wave transport is comparable to the order of Ekman transport. In the west wind zone of the north and south, the transport volume is close, but east-west transport of wave transport is mainly, while the south-north component of Ekman transport is larger. In the mid-low latitude sea area, the Ekman transport volume is the largest, and the direction is mainly for the high-latitude transport to the south or north. For the equatorial east Pacific which we pay close attention to, the contribution of its annual transport volume is more than Ekman's transport because the waves keep transmitting to the equator all the year round. The wave-induced water transport mainly affects the SST anomalies in the equatorial east Pacific through two main paths, one is to transport the east-west of the equator to the water body, and 2 is to transport the water to the water body along the south-north of the east coast of the ocean. The temporal and temporal features of wave transport in tropical Pacific and Southern Ocean are analyzed by means of empirical orthogonal decomposition and the main period of oscillation. It is found that the wave transport in the tropical Pacific Ocean and the Southern Ocean has the characteristics of east-to-east transmission, and the variation period of its main modes is 5. 2, 3. 7, 2. 45 years, which is the same as that of the equatorial eastern Pacific SST anomaly. Therefore, the wave transport anomalies in the two sea areas are closely related to the SST anomalies in the eastern equatorial Pacific. Using the Nino3 index as an index of abnormal changes in the surface temperature of the equatorial east Pacific Ocean, SST is abnormally higher than 0. 5 掳 C and is defined as a warm event for more than 6 months, SST is abnormally below-0.5 鈩，
本文编号：2266075
[Abstract]:Wave is the process of ocean micro-scale movement and is also an important form of motion on the sea-gas interface. Due to the persistence of the waves, it will have an incredible effect on the upper ocean. The wave process mainly includes wave-flow interaction, wave fragmentation, reflection of nearshore wave, wave-wound, wave-induced water transport and wave stirring and mixing. In this paper, the relationship between wave-induced large-scale water body transport and the equatorial east Pacific sea surface temperature anomaly and the numerical study on the influence of wave transport fluxes on the upper-layer ocean are studied, and the data analysis and numerical experiments are respectively adopted. and a plurality of data statistical methods are used, mainly including EOF decomposition, band-pass filtering, correlation analysis, error analysis, Fourier transformation and the like. The average wave in the sea area of the west wind zone in the south and the north is west, the tropical sea area is east, the waves on the east coast of the South Pacific keep southwest-northeast in the whole year, and are dominated by swell, and the wave transport direction is consistent with the average wave direction. The east-west component of wave transport is mainly in the form of zonal distribution. The transport volume is the largest in the west wind zone, and the maximum value appears in the southern Indian Ocean, and the transport volume in the middle and low latitude sea area is relatively small. The south-north component of wave transport is mainly characterized by north-to-north transport, and the southern hemisphere is transported to the equator, the northern hemisphere is transported from the equator, and there is an obvious east-facing strengthening phenomenon in the eastern boundary of the southern hemisphere. Wave transport is comparable to the order of Ekman transport. In the west wind zone of the north and south, the transport volume is close, but east-west transport of wave transport is mainly, while the south-north component of Ekman transport is larger. In the mid-low latitude sea area, the Ekman transport volume is the largest, and the direction is mainly for the high-latitude transport to the south or north. For the equatorial east Pacific which we pay close attention to, the contribution of its annual transport volume is more than Ekman's transport because the waves keep transmitting to the equator all the year round. The wave-induced water transport mainly affects the SST anomalies in the equatorial east Pacific through two main paths, one is to transport the east-west of the equator to the water body, and 2 is to transport the water to the water body along the south-north of the east coast of the ocean. The temporal and temporal features of wave transport in tropical Pacific and Southern Ocean are analyzed by means of empirical orthogonal decomposition and the main period of oscillation. It is found that the wave transport in the tropical Pacific Ocean and the Southern Ocean has the characteristics of east-to-east transmission, and the variation period of its main modes is 5. 2, 3. 7, 2. 45 years, which is the same as that of the equatorial eastern Pacific SST anomaly. Therefore, the wave transport anomalies in the two sea areas are closely related to the SST anomalies in the eastern equatorial Pacific. Using the Nino3 index as an index of abnormal changes in the surface temperature of the equatorial east Pacific Ocean, SST is abnormally higher than 0. 5 掳 C and is defined as a warm event for more than 6 months, SST is abnormally below-0.5 鈩，
本文编号：2266075
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