关于内波的跃层谱表达法、自适应识别和MODIS应用

发布时间：2018-12-11 02:11

【摘要】：本文提出了海洋跃层的全水层剖面谱表达法,通过海洋要素的垂直变化梯度零线和分布曲线把跃层形态、垂直变化过程及特征全面、系统、完整、准确地凸显出来;分别利用曲率区域最值和小波变换自适应检测法,将跃层谱峰根部的转折特征提取出来,确定了跃层与上下层水体的分界;从而形成了全面表征跃层自然属性特征的五点三要素‖法,即跃层上界点、强跃层上界点、跃层最值点、强跃层下界点、跃层下界点这五个跃层属性特征点和跃层最大强度、强跃层平均强度、跃层平均强度这三个跃层强度要素。基此,建立了一套关于跃层的定义、表达、确定和识别的系统方法。采用此种方法,利用EN4(Levitus)温盐剖面再分析数据,对南海北部跃层特征进行了分析,并基于2014年MODIS光学遥感数据,得到南海内波及其反演的参数分布特征,结果表明:南海内波主要分布在巴士海峡以西至东沙、流花等海区、珠江口海区以及200米水深及以浅的陆架坡折区。其分布情况正好与南海内波的三大源区,即巴士海峡区、珠江口区以及陆架坡折区对应。南海内波的出现呈现明显的季节性变化,夏季出现频次最高,春、秋次之,冬季出现最少。这与海水层化强度有明显的相关性,夏季南海跃层强度最强;春、秋季次之;冬季南海跃层强度最弱。南海北部内波振幅从几米至上百米不等,流花、东沙、宝岛、番禹等海域均出现了超大振幅的内波。南海北部内波从吕宋海峡向西传播过程中,波速不断减小。南海北部内波波长从几百米到几千米不等,内波从巴士海峡向西传播过程中,波长呈逐渐减小的趋势。
[Abstract]:In this paper, the whole water layer profile spectral expression of marine cline is proposed. The vertical variation process and characteristics of the cline are fully, systemically, completely and accurately highlighted by the vertical variation gradient zero line and distribution curve of ocean elements. By using the curvature region maximum and wavelet transform adaptive detection method, the transition feature of the peak-peak of the cline layer is extracted, and the boundary between the cline layer and the upper and lower layer water body is determined. Thus, a 5.3 element method is formed to characterize the characteristics of the natural attributes of the cline, namely, the upper boundary of the cline, the upper boundary of the strong cline, the maximum value of the cline, the lower bound of the strong cline, the lower bound of the cline, and the maximum strength of the cline. The average strength of the strong cline and the average strength of the cline are three elements of the strength of the cline. Based on this, a set of systematic methods for the definition, expression, determination and identification of clines are established. Using this method, the characteristics of the northern South China Sea cline are analyzed by using the EN4 (Levitus) thermohaline profile reanalysis data. Based on the 2014 MODIS optical remote sensing data, the distribution characteristics of the internal waves and their inversion parameters in the South China Sea are obtained. The results show that the internal waves in the South China Sea are mainly distributed in the west of the Basse Strait to the east sand, Liuhua and other sea areas, the Pearl River Estuary and the 200 meters deep and shallow continental shelf slope break area. Its distribution coincides with the three major sources of the internal waves in the South China Sea, namely, the Basi Strait region, the Pearl River Estuary region and the continental shelf slope break area. The occurrence of internal waves in the South China Sea shows obvious seasonal variation, with the highest frequency in summer, followed by spring and autumn, and the least in winter. There is a significant correlation between the intensity of sea water stratification and the intensity of the South China Sea cline in summer, followed by spring and autumn, and the weakest in winter. The amplitude of internal wave ranges from several meters to hundreds of meters in the northern South China Sea. During the propagation of internal waves from Luzon Strait to the west, the velocity of internal waves in the northern South China Sea decreases continuously. The internal wave length of the northern South China Sea ranges from several hundred meters to several kilometers, and the wavelength decreases gradually during the propagation of the internal wave from the Bash Strait to the west.
【学位授予单位】：国家海洋局第一海洋研究所
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731.24

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