本文選題：伴隨同化 + 內(nèi)潮　； 參考：《中國(guó)海洋大學(xué)》2014年博士論文

【摘要】：內(nèi)潮是指具有潮汐頻率的一種低頻內(nèi)波,密度層化的海水中表面潮與海底的躍變地形發(fā)生相互作用可以生成內(nèi)潮。內(nèi)潮在大洋中是普遍存在的,是一種重要的海水運(yùn)動(dòng)形式。一方面,內(nèi)潮在表面潮能量的耗散以及深�；旌线^(guò)程中具有非常重要的作用,進(jìn)而對(duì)深海環(huán)流產(chǎn)生重要的影響。另一方面,大振幅的內(nèi)潮或者由其演變的強(qiáng)孤立內(nèi)波對(duì)石油鉆井平臺(tái)以及海底管道的安全生產(chǎn)與維護(hù)非常重要,對(duì)經(jīng)行船艦的安全也構(gòu)成嚴(yán)重威脅；同時(shí),內(nèi)潮的生成及傳播規(guī)律對(duì)海洋漁業(yè)生產(chǎn)和能源開(kāi)發(fā)等方面也具有重要的研究?jī)r(jià)值。伴隨同化方法是一種有效的四維變分同化技術(shù),它以海洋動(dòng)力模型作為約束條件,通過(guò)同化可觀測(cè)的時(shí)空分布的海洋要素對(duì)無(wú)法觀測(cè)到的海洋要素進(jìn)行反演,實(shí)現(xiàn)了數(shù)值模型與觀測(cè)資料的有機(jī)結(jié)合,提高了數(shù)值模擬的精度。本文對(duì)伴隨同化方法在南海東北部?jī)?nèi)潮數(shù)值模擬中的應(yīng)用進(jìn)行了研究。 本文首先簡(jiǎn)要介紹了等密度坐標(biāo)內(nèi)潮伴隨同化數(shù)值模型。該模型在垂向采用等密度坐標(biāo),在水平方向采用球坐標(biāo),它由正向模型(等密度坐標(biāo)內(nèi)潮數(shù)值模型)和反向模型(伴隨模型)組成,均采用內(nèi)外模態(tài)分離技術(shù)。該模型通過(guò)將內(nèi)潮數(shù)值模型與觀測(cè)數(shù)據(jù)有機(jī)結(jié)合,來(lái)優(yōu)化模型中的參數(shù),以提高內(nèi)潮模擬的精度。本文接下來(lái)圍繞該模型中控制變量的反演問(wèn)題展開(kāi)了細(xì)致的研究。隨后,基于等密度坐標(biāo)內(nèi)潮數(shù)值模型,探討該模型模擬內(nèi)潮的穩(wěn)定性。最后在優(yōu)化控制變量的基礎(chǔ)上,利用等密度坐標(biāo)內(nèi)潮數(shù)值模型將伴隨同化技術(shù)應(yīng)用到內(nèi)潮的數(shù)值模擬中,初步探討了海水季節(jié)層化因素對(duì)南海東北部?jī)?nèi)潮的影響。 本文先將等密度坐標(biāo)內(nèi)潮伴隨同化模型發(fā)展為垂向三層模式,以呂宋海峽為目標(biāo)海區(qū),探討了開(kāi)邊界條件的反演問(wèn)題。隨后對(duì)空間分布的底摩擦系數(shù)的反演問(wèn)題進(jìn)行了研究。數(shù)值實(shí)驗(yàn)研究表明：該伴隨同化模型對(duì)多種開(kāi)邊界條件和空間分布的底摩擦系數(shù)具有較強(qiáng)的反演能力；適當(dāng)?shù)莫?dú)立點(diǎn)方案可以進(jìn)一步提高控制變量的反演精度,以期精確再現(xiàn)全場(chǎng)的內(nèi)潮結(jié)構(gòu)；代價(jià)函數(shù)及其關(guān)于控制變量的梯度模和同化誤差對(duì)反演效果具有較強(qiáng)的表征能力,可以綜合反映控制變量的反演情況。 本文基于等密度坐標(biāo)內(nèi)潮數(shù)值模型在不同二維高斯地形上,對(duì)該模型模擬內(nèi)潮的穩(wěn)定性進(jìn)行了初步探討,結(jié)果表明：低地形下該模型模擬內(nèi)潮可以達(dá)到穩(wěn)定；雖然高地形下模型的穩(wěn)定性有待進(jìn)一步研究,但是利用該模型模擬第100～300個(gè)周期的結(jié)果可以用來(lái)分析內(nèi)潮。作為該模型初步的實(shí)際應(yīng)用,本文通過(guò)同化T/P (TOPEX/Poseidon)高度計(jì)資料對(duì)南海東北部呂宋海峽附近海域M2內(nèi)潮的季節(jié)變化進(jìn)行了數(shù)值模擬。數(shù)值模擬結(jié)果表明：通過(guò)優(yōu)化模型中的控制變量,實(shí)現(xiàn)了內(nèi)潮數(shù)值模型與觀測(cè)數(shù)據(jù)的有機(jī)結(jié)合；瞬時(shí)緯向斜壓流在呂宋海峽兩個(gè)海脊之間較強(qiáng)；呂宋海峽處生成的內(nèi)潮分別向東、西和西南三個(gè)方向傳播；在呂宋海峽附近海域,對(duì)于第二層緯向斜壓流的振幅,夏季的振幅大于冬季的振幅。
[Abstract]:Internal tide is a low frequency internal wave with tidal frequency. The intertidal interaction between the surface tide in the density stratified sea water and the leaping terrain of the seabed can generate internal tide. The internal tide is common in the ocean and is an important form of sea water movement. On the one hand, the internal tide is dissipated in the surface tidal energy and in the deep sea mixing process. On the other hand, large amplitude internal tides or strong isolated internal waves are very important for the safe production and maintenance of oil drilling platforms and submarine pipelines, and a serious threat to the safety of the ship ships; at the same time, the formation and propagation of internal tides are on the ocean. The study of fishery production and energy development also has important research value. The adjoint assimilation method is an effective four dimensional variational assimilation technology. It uses the ocean dynamic model as a constraint condition to invert the unobserved marine elements by assimilating the observable spatiotemporal distribution of ocean elements, and realizes the numerical model and observation. The combination of data improves the accuracy of numerical simulation. In this paper, the application of Adjoint Assimilation Method in numerical simulation of internal tide in the northeast of the South China Sea is studied.
In this paper, the numerical model of tidal concomitant assimilation in equal density coordinates is briefly introduced. The model uses the equal density coordinate in vertical direction and the spherical coordinates in the horizontal direction. It consists of the forward model (the tidal numerical model in the ISO density coordinate) and the reverse model (the adjoint model). The model is used for the internal and external modal separation technology. The model is combined with the observation data to optimize the parameters in the model to improve the accuracy of the internal tide simulation. Next, this paper focuses on the inverse problem of the control variables in the model. Then, based on the tidal numerical model in the ISO density coordinate, the stability of the model is discussed. Finally, the base of the control variable is optimized. On the basis of this, the adjoint assimilation technology is applied to the numerical simulation of internal tide by using the tidal numerical model in ISO density coordinates, and the influence of seasonal stratification factors on the internal tide in the northeast of the South China Sea is preliminarily discussed.
In this paper, the tidal adjoint assimilation model in the ISO density coordinate is first developed into a vertical three layer model, and the inverse problem of the open boundary condition is discussed in the Luzon Strait as the target sea area. Then the inverse problem of the bottom friction coefficient of the spatial distribution is studied. The bottom friction coefficient of the inter distribution has a strong inversion ability, and the appropriate independent point scheme can further improve the inversion accuracy of the control variables, in order to reproduce the internal tide structure of the whole field, and the cost function and the gradient model and the assimilation error of the control variables have strong characterization, which can reflect the control of the inversion. Inversion of variable variables.
In this paper, based on the tidal numerical model of ISO density coordinates in different two-dimensional Gauss terrain, the stability of the model is preliminarily discussed. The results show that the model can be stable under the low terrain. Although the stability of the model in the highland shape needs to be studied further, the model is used to simulate 100th ~ 30. The results of the 0 cycles can be used to analyze the internal tide. As a preliminary practical application of this model, the numerical simulation of the seasonal variations of the internal tide in the waters near the Luzon Strait in the northeast of the South China Sea is simulated by assimilating the T/P (TOPEX/Poseidon) altimeter data. The numerical simulation results show that the control variables in the model have been achieved by optimizing the control variables in the model. The tidal numerical model is combined with the observation data; the instantaneous zonal pressure flow is stronger between the two ridges in the Luzon Strait, and the internal tides in the Luzon Strait spread to three directions in the East, West and southwest respectively. In the waters near the Luzon Strait, the amplitude of the second latitudinal pressure flow is greater than the amplitude in the winter.

【學(xué)位授予單位】：中國(guó)海洋大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：P731.23

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本文編號(hào)：1841753