波浪輸運(yùn)過程對海溫異常的影響
發(fā)布時(shí)間：2018-10-12 12:15
【摘要】：波浪是海洋微小尺度運(yùn)動的典型過程,也是海-氣界面上的一種重要運(yùn)動形式。由于波浪的持續(xù)性,它會對上層海洋產(chǎn)生難以置信的影響。波浪過程主要包括波-流相互作用、波浪破碎、近岸波的反射和繞射、波浪誘導(dǎo)的水體輸運(yùn)及波浪的攪拌混合作用等。本文主要研究了波浪誘導(dǎo)的大尺度水體輸運(yùn)與赤道東太平洋海表面溫度異常的關(guān)系和波浪輸運(yùn)通量剩余量對上層海洋影響的數(shù)值研究,分別采用了數(shù)據(jù)分析和數(shù)值實(shí)驗(yàn)的研究方法,并且使用了多種數(shù)據(jù)統(tǒng)計(jì)手段,主要包括EOF分解、帶通濾波、相關(guān)分析、誤差分析、傅立葉變換等。南、北西風(fēng)帶海域的平均波向?yàn)槲飨?熱帶海域?yàn)闁|向,南太平洋東岸的波向全年保持西南-東北方向,并以涌浪占優(yōu),波浪輸運(yùn)方向與平均波向一致。波浪輸運(yùn)量的東-西分量主要呈帶狀分布,輸運(yùn)量在西風(fēng)帶海域最大,最大值出現(xiàn)在南印度洋,中低緯度海區(qū)的輸運(yùn)量相對較小。波浪輸運(yùn)南-北分量主要表現(xiàn)為北向輸運(yùn)的特征,南半球?yàn)橄虺嗟垒斶\(yùn),北半球?yàn)殡x赤道輸運(yùn),并且在南半球的大洋東邊界有明顯的東向強(qiáng)化現(xiàn)象。波浪輸運(yùn)與Ekman輸運(yùn)的量級可比擬。在南北西風(fēng)帶海區(qū),二者輸運(yùn)量接近,但波浪輸運(yùn)以東-西輸運(yùn)為主,而Ekman輸運(yùn)的南-北分量較大。中低緯度海區(qū),Ekman輸運(yùn)量最大,方向以向南或向北的高緯度輸運(yùn)為主。對于我們比較關(guān)注的赤道東太平洋而言,由于波浪常年保持向赤道的正輸運(yùn),其年輸運(yùn)量的貢獻(xiàn)大于Ekman輸運(yùn)。波浪誘導(dǎo)的水體輸運(yùn)主要通過兩條主要路徑影響赤道東太平洋的SST異常,一是,沿赤道的東-西向水體輸運(yùn);二是,沿大洋東岸的南-北向水體輸運(yùn)。通過經(jīng)驗(yàn)正交分解的方法分析了熱帶太平洋和南大洋的波浪輸運(yùn)量的時(shí)空特征,及振蕩的主周期。分析發(fā)現(xiàn)：熱帶太平洋和南大洋的波浪輸運(yùn)的距平都存在東向傳輸?shù)奶攸c(diǎn),其主要模態(tài)的變化周期為5.2、3.7、2.45年,這與赤道東太平洋SST異常的振蕩周期相同。由此說明,這兩個(gè)海區(qū)的波浪輸運(yùn)異常與赤道東太平洋SST異常存在密切的關(guān)系。以Nino3指數(shù)作為赤道東太平洋海表面溫度異常變化的指標(biāo),將SST異常高于0.5。C并且持續(xù)6個(gè)月以上定義為暖事件,SST異常低于-0.5℃并且持續(xù)6個(gè)月以上定義為冷事件。暖事件中,春季型和夏季型沿赤道的波浪輸運(yùn)主要呈西向異常,即赤道東太平洋的暖異常爆發(fā)前,波浪輸運(yùn)持續(xù)向東輸運(yùn)暖水。而大洋東岸的波浪輸運(yùn)在春季型中貢獻(xiàn)的冷水呈負(fù)異常,在夏季型中貢獻(xiàn)的冷水呈正異常,即輸運(yùn)的冷水增多。冷事件中,夏季型沿赤道的波浪輸運(yùn)主要呈東向異常,即向東輸運(yùn)的暖水少于正常值,而大洋東岸的北向波浪輸運(yùn)則為強(qiáng)的正異常,即由高緯度向赤道輸運(yùn)的冷水增多,這兩條途徑的水體輸運(yùn)為冷事件的爆發(fā)準(zhǔn)備了條件。未發(fā)生型中,沿赤道的波浪輸運(yùn)仍延續(xù)著暖事件中的西向異常,但沒有明顯的輸運(yùn)特征,北向的波浪輸運(yùn)則呈現(xiàn)明顯的負(fù)異常,即輸運(yùn)的冷水低于正常值,這一過程一定程度上抑制了冷事件的爆發(fā)。通過Stokes熱輸運(yùn)的計(jì)算,進(jìn)一步說明了波浪誘導(dǎo)的大尺度水體輸運(yùn)對赤道東太平洋SST異常變化的貢獻(xiàn)。二者相關(guān)關(guān)系顯示：沿赤道的波浪輸運(yùn)超前于SST異常6個(gè)月,大洋東岸波浪輸運(yùn)超前于SST異常15-20個(gè)月時(shí),二者的相關(guān)系數(shù)最大。作為水體輸運(yùn)的重要部分,波浪輸運(yùn)對赤道東太平洋SST異常的影響不可忽略。波浪輸運(yùn)通量剩余量是影響上層海洋的重要機(jī)制之一。本文首先通過對比KPP方案的上邊界層深度,揭示了KPP參數(shù)化方案低估了垂向擴(kuò)散系數(shù),未包含波浪過程的影響；然后將波浪輸運(yùn)通量剩余量的參數(shù)化方案包含到KPP方案中,設(shè)置控制實(shí)驗(yàn)及若干組敏感性實(shí)驗(yàn),通過數(shù)值結(jié)果的分析顯示：考慮波浪輸運(yùn)通量剩余量過程對上層海洋的作用后,有效改善了模式對海表溫度模擬過高的問題。在垂直結(jié)構(gòu)上,敏感實(shí)驗(yàn)的28℃等值線由控制實(shí)驗(yàn)中的20m加深到35m左右,與實(shí)測數(shù)據(jù)更接近。這在一定程度上也克服了海洋上混合層深度模擬一直偏淺的問題。波浪輸運(yùn)通量剩余量對上層海洋的作用主要影響了溫度在夏季和冬季低緯度區(qū)域的數(shù)值結(jié)果。2月,敏感實(shí)驗(yàn)溫度的全場相關(guān)系數(shù)由0.9013提高到0.9162；8月,敏感實(shí)驗(yàn)溫度的全場相關(guān)系數(shù)由0.8881增大到0.9104。比較幾組敏感性實(shí)驗(yàn),當(dāng)背景系數(shù)α取0.1左右時(shí),能更合理的表征波動輸運(yùn)通量剩余量對上層海洋的作用。
[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 擄 C and is defined as a warm event for more than 6 months, SST is abnormally below-0.5 鈩，
本文編號：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 擄 C and is defined as a warm event for more than 6 months, SST is abnormally below-0.5 鈩，
本文編號：2266075
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