棉兰老以东次表层环流结构变异以及水团交换研究

IOCAS-IR > 海洋环流与波动重点实验室

	棉兰老以东次表层环流结构变异以及水团交换研究
	宋丽娜
学位类型	博士
导师	王凡
	2016-06
学位授予单位	中国科学院大学
学位授予地点	北京
学位专业	物理海洋
关键词	温跃层以下环流反气旋环流棉兰老潜流半年尺度水团交换
其他摘要	本论文的重点是研究了棉兰老潜流（ MUC）的变异，与 MUC 有关的次表层反气旋环流(ACG)的结构和变异，以及 MUC 所在的棉兰老以东的半年水团交换过程和交换通道。西北热带太平洋是海洋环流变异的重要区域，表层环流可以通过卫星或浮标观测研究。然而由于观测数据空间分布不足，次表层环流很少被准确的描述。最先进的海洋环流模式 OFES，空间分辨率是 0.1×0.1° ，时间分辨率是月，使得我们能够分析棉兰老岛以东的准永久性的 ACG。 ACG 是温跃层以下环流在南菲律宾海的显著特征，被认为与北向流的棉兰老潜流（ MUC）紧密联系。在 26.8-27.3 σθ， ACG 覆盖了较大的范围。其反气旋结构与表层的哈马黑拉涡（ HE）不连续。 ACG 的时间变异与 MUC 沿着菲律宾沿岸的北向输运有关。在季节尺度上，强（弱） ACGs 在深冬-春（夏）季导致较大（较小）的 MUC 输运。在年际尺度上， SACG （ NACG）在 4-8（ 3-5）年有显著的峰值。 ACGs 的强度与 MUC 输运显著相关。超前滞后相关分析表明 ACGs 和 MUC 输运的年际变异与 ENSO 部分相关，对 ACG 的成因做了讨论。在西北热带太平洋的中层水交换主要是基于综观（ synoptic）观测或者气候态观测，很少有结合水团属性和流速的观测，或者使用长期连续的时间序列来研究其时间变异。我们利用从 2010 年开始布放在 8°N, 127.05°E 的潜标系统，测得的上层 800m 近四年的温度、盐度、流速同步数据，研究中层水团交换。首次报道了中层流具有显著的半年变异（ ~187 天），且与盐度有较好的相关性，为由北 /南向潜流携带的南/北太平洋中层水的交替输运提供了直接证据。 OFES 日资料（ 3 天）表明：半年变异在西边界局地产生，表现为较大尺度的温跃层以下的再循环，导致了棉兰老以东的南北向反转流，对于西北热带太平洋的中层水团交换起到非常有效的作用。 ; The thesis focuses on the variability of Mindanao Undercurrent (MUC), structure and variability of subthermocline anticyclonic gyre (ACG) related to the MUC, and the process/conveyer of semiannual water mass exchange east of Mindanao where the MUC locates. The northwest tropical Pacific is the important region for the circulation variability. Surface circulation could be investigated by many methods, such as satellite or buoy measurements. However, the subthermocline circulation is seldom described because of low covered observation. The state of the art ocean general circulation model for the Earth Simulator (OFES), with spatial resolution of 0.1×0.1° and time resolution of 1 month, makes it available to explore the structure and variability of the quasi-permanent ACG, which is a dominant feature of the sub-thermocline circulation in the southern Philippine Sea and is believed to be closely associated with the continuous northward flow of the Mindanao Undercurrent (MUC) east of Mindanao Island. Between 26.8-27.3 σθ, the ACG covers a large area. Its anticyclonic structure is however disconnected from the surface Halmahera Eddy (HE). Further analysis suggests that temporal variations of the ACG are linked to the variations of the northward transport of the MUC along the Mindanao coast. At seasonal timescale, stronger (weaker) ACGs during late winter-spring (summer) lead to larger (smaller) MUC transport. At the interannual timescale, the SACG (NACG) shows a power peak at 4-8 (3-5) years. Strength of ACGs is significantly correlated with the MUC transport. Lead-lag correlation analysis indicates that interannual variations of the ACGs and the MUC transport are not strongly linked with the El Niñ o-South Oscillation (ENSO). Possible causes for the ACG variability are discussed. Intermediate water exchange in northwest tropical Pacific is primily based on synoptic or climatologic observations. Few attempts have been made to confirm relationships between water mass and current, either through measurements combining water properties and velocities, or through long-term continuous time series to determine any temporal vairiablity. Here we explored intermediate water exchange through analysis of a ~4 years of synchronous temperature, salinity and velocity records in the upper 800 m, obtained since late 2010 by a mooring system at 8°N, 127.05°E. For the first time, we report prominent semi-annual variability (SAV; ~ 187 days) of intermediate-layer current and a significant correlation with salinity, providing direct evidence for the alternating transports of South and North sourced intermediate waters by northward and southward undercurrents, respectively. Using the OFES outputs with resolution of 3-day, we demonstrate that the SAV is generated locally near the western boundary, manifesting as large-scale subthermocline eddies and leading to alternating northward and southward flows near the Mindanao coast, which plays an efficient role in the intermediate water exchange in northwest tropical Pacific.
学科领域	物理海洋学
语种	中文
文献类型	学位论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/117004
专题	海洋环流与波动重点实验室
作者单位	中科院海洋所
第一作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	宋丽娜. 棉兰老以东次表层环流结构变异以及水团交换研究[D]. 北京. 中国科学院大学,2016.

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20160606宋丽娜毕业论文.pdf（8774KB）	学位论文		限制开放	CC BY-NC-SA	浏览