發(fā)布時(shí)間：2018-01-11 00:09

  本文關(guān)鍵詞：基于細(xì)尺度參數(shù)化的西北太平洋和南大洋的湍流混合研究　出處：《中國科學(xué)院研究生院(海洋研究所)》2015年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 跨等密度面混合 風(fēng)生近慣性能量 穿透深度 經(jīng)向翻轉(zhuǎn)環(huán)流

【摘要】：內(nèi)波是普遍存在于穩(wěn)定層化的海洋內(nèi)部的一種波動,影響著海洋中的質(zhì)量、動量和能量的輸送。內(nèi)波間的非線性相互作用將海洋中的能量從大尺度不斷地向小尺度傳遞,從而引起內(nèi)波破碎,導(dǎo)致跨等密度面的湍流混合(簡稱湍流混合)。小尺度的湍流混合對于熱量輸運(yùn)、水體交換和溶解物質(zhì)(營養(yǎng)物質(zhì)與污染物)的垂向輸運(yùn)以及全球氣候、熱鹽環(huán)流、海洋環(huán)境與生態(tài)系統(tǒng)的變化都有重要影響。因此,研究湍流混合的時(shí)空變化特征及其影響因素具有重要意義。海洋內(nèi)部的湍流混合主要是由內(nèi)波破碎導(dǎo)致,而大量研究表明風(fēng)生近慣性能量、潮汐以及海流與海底地形的相互作用(尤其在南大洋)是內(nèi)波場的主要能量來源。本文利用8年JODC (Japan Oceanographic Data Center)和KESS計(jì)劃(Kuroshio Extension System Study)的溫鹽深儀(conductivity-temperature-depth, CTD)水文觀測剖面資料,基于細(xì)尺度參數(shù)化方法研究了在西北太平洋地區(qū)的跨越等密度面的混合的時(shí)空變異,發(fā)現(xiàn)：海洋上層300-1800 m湍流混合呈現(xiàn)顯著的季節(jié)性變化特征,并且在統(tǒng)計(jì)上與風(fēng)生近慣性能量有明顯的相關(guān)關(guān)系：相對于平滑地形,湍流混合系數(shù)在地形粗糙的區(qū)域加強(qiáng)。因風(fēng)生近慣性能量和粗糙海底地形而強(qiáng)化的湍流混合可分別穿透到海洋內(nèi)部1800 m和距海底3300 m處,該穿透距離隨著風(fēng)生近慣性能量和地形粗糙程度的變化而變化。該研究證明了風(fēng)生近慣性能量的驅(qū)動和海底地形的影響對于維持海洋內(nèi)部的湍流混合有著重要的作用。深海的混合過程使深海的冷水上升到海洋上層,從而形成大洋的經(jīng)向翻轉(zhuǎn)環(huán)流(Meridional Overturning Circulation, MOC)的閉合。在南大洋,28 kgm-3中性密度面可以近似作為上下兩層經(jīng)向翻轉(zhuǎn)環(huán)流的分界面。在南極繞極流(Antarctic Circumpolar Current, ACC)區(qū)域,本文聯(lián)合使用Argo (Array for Real-time Geostrophic Oceanography)剖面數(shù)據(jù)和DIMES (Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean)中的CTD剖面數(shù)據(jù),應(yīng)用細(xì)尺度參數(shù)化方法研究了湍流混合在28 kgm-3中性密度面的特征。研究發(fā)現(xiàn)在該中性密度面,垂向混合率達(dá)到(1.13±0.14)×10-4 m2s-1,比開闊大洋中的擴(kuò)散率大一個(gè)量級。這里強(qiáng)混合的形成有多方面因素,一方面上層強(qiáng)烈的西風(fēng)帶輸入大量能量,另一方面在深層海洋,強(qiáng)勁的南極繞極流與地形的相互作用為內(nèi)波場提供能量。此外,MOC的下支流環(huán)通過28 kgm-3中性密度面的向MOC上支流環(huán)的體積輸送可以達(dá)到4.8±0.6 Sv,是冷水下沉到MOC下支流環(huán)的體積的一半之多。而經(jīng)向翻轉(zhuǎn)環(huán)流的下支控制著深海中的水體、熱量、C02以及營養(yǎng)物質(zhì)的輸送,這對估計(jì)全球的氣候和生物化學(xué)變化過程有著重要的價(jià)值。
[Abstract]:The internal wave is a kind of wave which exists in the stable stratified ocean and affects the quality of the ocean. Transport of momentum and energy. The nonlinear interaction between internal waves transfers energy from large scale to small scale, which results in the breakup of internal waves. Turbulent mixing across the isodensity surface. Small-scale turbulent mixing for heat transport, vertical transport of water exchange and dissolved substances (nutrients and pollutants), and global climate. Thermohaline circulation, changes in the marine environment and ecosystems have important effects. It is of great significance to study the temporal and spatial characteristics of turbulent mixing and its influencing factors. The turbulence mixing in the ocean is mainly caused by the breakup of internal waves, and a large number of studies show that wind generated near inertial energy. Tides and the interaction between currents and seabed topography (especially in the Southern Ocean) are the main sources of energy in the internal wave field. Japan Oceanographic Data Center and KESS Program (. Kuroshio Extension System study (Kuroshio Extension System study), conductivity-temperature-depth. Based on the data of CTD hydrological profile, the temporal and spatial variation of cross isodensity surface in the Northwest Pacific is studied based on the method of fine scale parameterization. It is found that the turbulence mixing between 300m and 1800m in the upper ocean has a significant seasonal variation and is statistically correlated with the wind-generated near inertial energy: relative to the smooth terrain. The turbulent mixing coefficient is strengthened in the rough terrain. The turbulent mixing enhanced by wind generated near inertial energy and rough submarine topography can penetrate to the interior of the ocean 1800m and to the sea floor 3300m respectively. The penetration distance varies with wind generated near inertial energy and terrain roughness. This study proves that the driving of wind-generated near-inertial energy and the influence of submarine topography are important for maintaining turbulent mixing in the ocean. The mixing process of the deep sea causes the cold water of the deep sea to rise to the upper layer of the ocean. Thus the meridional Overturning circulation (MOC) is closed in the Southern Ocean. The 28 kgm-3 neutral density surface can be used as an interface between the upper and lower layers of meridional reversal circulation. Antarctic Circumpolar Current. ACCA area. This article combines Argo Array for Real-time Geostrophic Oceanographywith DIMES (. Diapycnal and Isopycnal Mixing Experiment in the Southern Ocean. The CTD profile data in. The characteristics of turbulent mixing on the 28 kgm-3 neutral density surface are studied by using the fine scale parameterization method. The vertical mixing rate is 1.13 鹵0.14) 脳 10 ~ (-4) m ~ (-2) s ~ (-1), which is one order of magnitude higher than that in the open ocean. On the one hand, the strong westerly belt in the upper layer invests a lot of energy, on the other hand, in the deep ocean, the strong interaction between the polar current and the topography provides the energy for the internal wave field. The volume transport of the lower tributary ring of MOC to the tributary ring of MOC through the neutral density surface of 28 kgm-3 can reach 4.8 鹵0.6 Sv. It is as much as half the volume of cold water sinking into the lower tributary ring of MOC, and the lower branch of the reverse loop controls the transport of water, heat and nutrients in the deep sea. This is of great value in estimating global climate and biochemical processes.
【學(xué)位授予單位】：中國科學(xué)院研究生院(海洋研究所)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：P731.26

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相關(guān)期刊論文 前1條

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本文編號：1407333