海洋环流与波动重点实验室知识库

黑潮作为最强劲的西边界流之一，是连接西太平洋和中国近海物质能量交换的重要纽带，对周边海域气候变化有着重要调制作用。台湾以东黑潮主要受大尺度的洋流、大气强迫和从副热带逆流（STCC）区西传的中尺度涡的共同影响。已有研究表明，台湾以东黑潮受中尺度涡的影响具有显著的季节内变化。中尺度涡不仅对黑潮起到调制作用，对台湾以东的黑潮中层水团也会产生直接的影响。在中尺度涡和黑潮的相互作用过程中，黑潮、黑潮中层水以及中尺度涡之间的关系紧密相连，中尺度涡和黑潮的三维结构也随之变化。一直以来，受限于观测资料，对这些问题的深入的认识大都比较片面，中尺度涡、黑潮、黑潮中层水在中尺度涡与黑潮的相互作用过程中具体的变异过程目前并不清楚。本文基于长时间的锚系潜标以及布放的大规模的CPIES阵列获取的数据，重点研究了中尺度涡影响下黑潮的季节内变化、黑潮中层水的变化特征和机制、以及在这个过程中中尺度涡和黑潮的三维结构特征及其变化过程等问题。主要有以下几个结论：

利用2016年1月至2017年5月布放在台湾以东的一套锚系潜标系统的研究了台湾岛以东黑潮的季节内变化特征。观测结果表明黑潮与中尺度涡存在显著的70~90天季节内变化周期，涡旋向西传播的平均速度约为10 cm/s。台湾以东黑潮的厚度在100-800 m之内变化。结合HYCOM模式数据阐明了中尺度涡影响黑潮的机制，气旋涡（反气旋涡）产生负（正）海面高度异常和上升（下降）流，对应于等密度面倾斜角的变小（大）和垂向层化的减弱（增强），对应PV的增加（减弱），导致黑潮流速的减弱（增强）。

利用布放在台湾以东的锚系潜标获取的17个月的流速和400-800 m的温盐数据，首次证实了中尺度涡导致的台湾以东黑潮中层水（KIW）存在约80天的季节内变化周期。台湾以东的黑潮中层水主要集中在400-600 m之间，其典型平均温盐特征为：盐度极小值34.26，温度7.5℃，位势密度26.8 kg m^-3。揭示了 KIW中北太平中层水（NPIW）和南海中层水（SCSIW）的混合率和变化特征。阐明了中尺度涡、黑潮和中层水之间的关系，反气旋涡（气旋涡）对应的流速增加（减少）和中层水盐度的增加（减少）。结合HYCOM模式数据从垂向和水平运动方向上揭示了中层水的变化原因，结果也表明了反气旋涡期间能将更多的SCSIW水团输运到台湾以东而增加其盐度，气旋涡期间则是有利于相对低盐的NPIW占据主导地位。

利用CPIES（逆式回声仪）阵列数据揭示了中尺度涡与黑潮相互作用机制。结果表明在反气旋涡（气旋涡）撞击黑潮时，涡旋内部中心水体向下（向上）运动的等密度面下凹（上凸）过程，而在黑潮内则表现为中心水体的向上（向下）的运动过程。其撞击过程增加（减弱）了黑潮-涡旋中心连线的等密度面的倾斜，等密度面的倾斜增加（减弱）加大（减弱）了两侧等压面的压差，因而对应黑潮的流速增加（减少）。

利用CPIES数据构建了中尺度涡与黑潮相互作用过程中的中尺度涡和黑潮的三维结构特征。研究表明反气旋涡作用于黑潮时两者的温盐异常呈现反位相的变化特征，而气旋涡作用于黑潮时两者的温盐异常的同位相变化特征。在反气旋涡与黑潮作用过程中，反气旋涡（黑潮）中心水体向下（向上）运动使温度呈现正（负）异常结构。对应的盐度在中层600m以上出现正（负）异常，在600 m以下出现负（正）异常。而当气旋涡与黑潮作用时，两者的温度和盐度异常同步变化，温度表现为整体的负异常，而盐度则在600 m以上和以下的水体分别出现负正异常。

As one of the strongest western boundary currents, the Kuroshio is an important link connecting the material and energy exchanges between the western Pacific Ocean and China’s offshore waters, and plays an important modulating effect on climate change in the surrounding seas. The Kuroshio at east of Taiwan is affected by large-scale ocean currents, atmospheric forcing, and mesoscale eddies propagating westward from the Subtropical Countercurrent Zone (STCC) area. Previous studies have shown that the Kuroshio at east of Taiwan has significant intraseasonal variation affected by mesoscale eddies. The mesoscale eddies not only modulate the Kuroshio, but also directly affects the intermediate water at east of Taiwan. During the interaction between the mesoscale eddies and the Kuroshio, the relationship among the Kuroshio, the intermediate water and the mesoscale eddies is closely connected, and the three-dimensional structure of the mesoscale eddies and the Kuroshio also changes accordingly. For a long time, limited by the observational data, the deep understanding of these issues is mostly one-sided. The variation process of mesoscale eddies, Kuroshio, intermediate water is not detail known clearly. Based on the long-term mooring and the large-scale CPIES array observation data, this paper focus on the Kuroshio intraseasonal variations, the variations characteristics of the Kuroshio intermediate water, as well as the three-dimensional structure characteristics of the mesoscale eddies and Kuroshio between their interaction. The main innovative conclusions are as follows:

The intraseasonal variation characteristics of the Kuroshio at east of Taiwan were studied by using a by a subsurface mooring between January 2016 to May 2017. The results show that the Kuroshio and the mesoscale eddies have an intraseasonal variation period of 70-90 days, and the average westward speed of the eddies is estimated to be about 10 cm/s. This study found that the Kuroshio thickness at east of Taiwan varies within 100-800 m. Combined with the HYCOM data, the mechanism of the mesoscale eddies affecting the Kuroshio is clarified. Cyclonic (anticyclonic) eddies from the STCC cause a negative (positive) sea surface height anomaly, contribute positive (negative) PV, and lead to a decrease (increase) in the northward velocity. Cyclonic (anticyclonic) eddies also lead to stronger (weaker) vertical stratification in the upper ocean. A smaller (larger) angle of the isopycnal slope corresponds to lower (higher) Kuroshio velocity.

Using 17-month current and temperature and salinity data of 400~800 m measurement from mooring located at east of Taiwan. It’s first time proved that the periods of intraseasonal variability of Kuroshio intermediate water (KIW) at east of Taiwan caused by mesoscale eddies is about ~80 days. The typical average temperature and salinity characteristics of the KIW east of Taiwan are revealed: the minimum salinity is 34.26, the temperature is 7.5°C, and the potential density is 26.8 kg m^-3, and its mainly located at 400-600 m. The mixing proportion of NPIW and SCSIW in KIW and its variability are revealed. The relationship between mesoscale eddies, current and IW is clarified. The anticyclonic eddies (cyclonic eddies) corresponds to the increase (decrease) of the current speed and the increase (decrease) of the salinity of IW. Combined with HYCOM data, the change process of IW in vertical and horizontal movement is analyzed. It is also proved that more SCSIW water mass can be transported to the east of Taiwan during the anticyclonic to increase its salinity, while the relatively fresh salinity NPIW dominates during the cyclonic.

Using the CPIES (Current- Pressure Inverted Echo Sounder) array data, the interaction process between the mesoscale eddies and Kuroshio was explained. It’s reveal that anticyclonic (cyclonic) eddies impinging the Kuroshio, the pycnocline depression (heaving). while the pycnocline present the opposite changes on the Kuroshio side. The impact of the anticyclonic (cyclonic) eddies increases (weakens) the inclination of the isopycnal connecting the Kuroshio and eddy center, and the inclination of the isopycnal corresponds to the isobaric surface, so corresponding to increase (decrease) the Kuroshio velocity.

The detailed three-dimensional structural characteristic of the mesoscale eddies and the Kuroshio are both constructed during its interaction by using CPIES data. This study shows that the anticyclonic eddies impinging Kuroshio, the temperature and salinity anomalies are in the opposite phase, while the cyclone eddies acts on the Kuroshio, the temperature and salinity anomalies are in the same phase. During the interaction between the anticyclonic eddies and the Kuroshio, the center water of anticyclonic eddies (Kuroshio) moves downward (upward), causing the temperature to show a positive (negative) abnormal structure. While the salinity has a positive (negative) anomaly above 600 m, and a negative (positive) anomaly below 600 m. When the cyclone eddies interaction with the Kuroshio, the temperature and salinity anomaly are consistent, showing the temperature appears as an overall negative anomaly, while salinity above and below 600 m have negative and positive anomalies respectively.

目  录

第1章  绪论. 1

1.1   研究意义. 1

1.2   研究进展. 2

1.2.1   中尺度涡对台湾以东黑潮影响. 2

1.2.2   台湾以东黑潮中层水的研究进展. 4

1.2.3   中尺度涡的三维结构研究. 6

1.2.4   CPIES简介及应用研究进展. 8

1.3   科学问题提出. 12

第2章  资料来源与方法. 15

2.1   锚系潜标数据. 15

2.2   卫星高度计资料. 18

2.3   HYCOM模式数据. 18

2.4   WOD温盐数据. 18

2.5   Argo数据. 19

2.6   大面调查数据. 20

2.7   CPIES数据. 20

2.8   台湾以东四维温盐流场的反演. 21

2.8.1   台湾以东GEM构建. 21

2.8.2   CPIES数据处理及反演. 30

第3章  中尺度涡引起的台湾以东黑潮季节内变化特征. 40

3.1   台湾以东黑潮流速和变化特征. 40

3.1.1   台湾以东黑潮流速直接测量结果. 40

3.1.2   台湾以东黑潮季节内变化. 41

3.1.3   台湾东部的涡旋特征. 43

3.2   中尺度涡引起的黑潮变化及机制. 46

3.2.1   中尺度涡与黑潮季节内变化关系. 46

3.2.2   中尺度涡引起台湾以东黑潮变异机制. 49

3.3   本章小结. 51

第4章  中尺度涡引起的黑潮中层水季节内变化和机制. 53

4.1   台湾以东黑潮中层水直接观测结果. 53

4.1.1   中层水时间变化特征. 53

4.1.2   中层水TS特征. 54

4.2   中尺度涡引起的台湾以东黑潮中层水的季节内变化. 57

4.2.1   中层水的季节内变化特征. 57

4.2.2   中尺度涡引起的中层水季节内变化. 60

4.2.3   中尺度涡引起的中层水盐度变化机理. 63

4.3   本章小结. 64

第5章  基于CPIES的台湾以东中尺度涡和黑潮相互作用. 66

5.1   中尺度涡与黑潮的相互作用影响过程. 67

5.2   中尺度涡与黑潮的三维结构特征. 70

5.2.1   平均温盐特征. 71

5.2.2   反气旋涡及黑潮的三维结构. 72

5.2.3   气旋涡及黑潮的三维结构. 76

5.3   本章小结. 81

第6章  总结与展望. 83

6.1   论文总结. 83

6.2   研究展望. 85

参考文献  87

致 谢    97