黑潮延伸体的变化及其与北太平洋风暴轴的关系
发布时间：2019-03-22 16:51
【摘要】：利用18年的AVSIO卫星高度计和SODA资料，分析了黑潮延伸体急流及其中尺度涡能量(EKE)的变化特征。结果显示，黑潮延伸体急流在经向上存在从变宽（双支）到变窄（单支）的年代际振荡信号。这与中尺度涡涡动能量在黑潮延伸体区域强迫而成的异常的低频海表面高度（SSH）偶极子模态有关。当涡动强迫的偶极子呈北正南负（负位相）的结构时，与气候态的海表面高度场叠加会使黑潮延伸体区域SSH梯度减弱，黑潮延伸体急流变宽并表现出双支结构，而当偶极子模态呈北负南正（正位相）结构时，黑潮延伸体急流则变为窄的单支结构。这可以认为是黑潮延伸体自身低频波动、高频中尺度涡和平均流之间相互作用的结果。 除了自身相互作用外，大尺度的海气相互作用因子也会对黑潮延伸体产生影响。因此，本文使用回归分析等方法分析了黑潮延伸体EKE的强度和位置与北太平洋风暴轴之间的关系。结果表明，黑潮延伸体中尺度涡强时有利于北太平洋风暴轴增强，而EKE位置偏北(南)时对应的北太平洋风暴轴也偏北(南)，同时当EKE的位置偏东（偏西）时北太平洋风暴轴则西退（东移）。此外，北太平洋风暴轴的变化对黑潮延伸体也有一定的反馈作用，黑潮延伸体中尺度涡EKE强度的变化与北太平洋风暴轴EOF第一和第三个模态（第二个模态）回归的海表面高度距平模态有明显的3-4年滞后的正（负）相关，，而黑潮延伸体中尺度涡EKE位置的变化则相反。这种滞后相关可能是通过北太平洋风暴轴驱动的遥相关型环流改变海表面风应力旋度并强迫出的海表面高度距平的西传导致的。
[Abstract]:Based on the AVSIO altimeter and SODA data of 18 years, the variation characteristics of jet and mesoscale vortex energy (EKE) of Kuroshio extensor are analyzed. The results show that there is an inter-decadal oscillation signal from widening (double branch) to narrowing (single branch) in the meridional direction of the Kuroshio extensor jet. This is related to the anomalous low-frequency sea surface height (SSH) dipole mode caused by the forcing of the mesoscale vortex energy in the Kuroshio extension region. When the vortex-forced dipole is north positive and negative (negative phase), the SSH gradient of the Kuroshio extension region will be weakened and the jet current of the Kuroshio extension body will be broadened and the two-branch structure will be displayed when the sea surface height field superimposed with the climatological state will weaken the Kuroshio extension region. When the dipole mode is north-negative-south positive (positive phase), the Kuroshio extensor jet becomes a narrow one-branch structure. This can be considered as the result of the interaction between low-frequency fluctuations, high-frequency mesoscale vortices and mean currents of the Kuroshio extensor itself. In addition to self-interaction, large-scale air-sea interaction factors also affect the extension of Kuroshio. Therefore, the relationship between the strength and position of the Kuroshio extensor EKE and the storm axis in the North Pacific is analyzed by regression analysis and other methods. The results show that the mesoscale vortex intensity of the Kuroshio extension is beneficial to the enhancement of the storm axis in the North Pacific Ocean, and the corresponding North Pacific Storm Axis in the north (south) of the EKE position is also north (south). At the same time, when the position of EKE is eastward (westward), the north Pacific storm axis retreats westward (eastward). In addition, the variation of the storm axis in the North Pacific also has a feedback effect on the extension of the Kuroshio. The variation of the mesoscale vortex EKE intensity of the Kuroshio extension is positively (negatively) correlated with the sea surface height anomaly mode regressed by the first and third modes (the second mode) of the North Pacific Storm Axis EOF, and there is a significant positive (negative) correlation between the 3-4 year lag and the sea surface height anomaly mode. However, the change of the mesoscale vortex EKE position of the Kuroshio extensional body is opposite. This hysteresis correlation may be caused by the westward propagation of the sea surface height anomaly driven by the teleconnective circulation driven by the storm axis of the North Pacific, which changes the wind stress curl on the sea surface and forces the sea surface height out of the sea to travel westward.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.27;P732
本文编号：2445760
[Abstract]:Based on the AVSIO altimeter and SODA data of 18 years, the variation characteristics of jet and mesoscale vortex energy (EKE) of Kuroshio extensor are analyzed. The results show that there is an inter-decadal oscillation signal from widening (double branch) to narrowing (single branch) in the meridional direction of the Kuroshio extensor jet. This is related to the anomalous low-frequency sea surface height (SSH) dipole mode caused by the forcing of the mesoscale vortex energy in the Kuroshio extension region. When the vortex-forced dipole is north positive and negative (negative phase), the SSH gradient of the Kuroshio extension region will be weakened and the jet current of the Kuroshio extension body will be broadened and the two-branch structure will be displayed when the sea surface height field superimposed with the climatological state will weaken the Kuroshio extension region. When the dipole mode is north-negative-south positive (positive phase), the Kuroshio extensor jet becomes a narrow one-branch structure. This can be considered as the result of the interaction between low-frequency fluctuations, high-frequency mesoscale vortices and mean currents of the Kuroshio extensor itself. In addition to self-interaction, large-scale air-sea interaction factors also affect the extension of Kuroshio. Therefore, the relationship between the strength and position of the Kuroshio extensor EKE and the storm axis in the North Pacific is analyzed by regression analysis and other methods. The results show that the mesoscale vortex intensity of the Kuroshio extension is beneficial to the enhancement of the storm axis in the North Pacific Ocean, and the corresponding North Pacific Storm Axis in the north (south) of the EKE position is also north (south). At the same time, when the position of EKE is eastward (westward), the north Pacific storm axis retreats westward (eastward). In addition, the variation of the storm axis in the North Pacific also has a feedback effect on the extension of the Kuroshio. The variation of the mesoscale vortex EKE intensity of the Kuroshio extension is positively (negatively) correlated with the sea surface height anomaly mode regressed by the first and third modes (the second mode) of the North Pacific Storm Axis EOF, and there is a significant positive (negative) correlation between the 3-4 year lag and the sea surface height anomaly mode. However, the change of the mesoscale vortex EKE position of the Kuroshio extensional body is opposite. This hysteresis correlation may be caused by the westward propagation of the sea surface height anomaly driven by the teleconnective circulation driven by the storm axis of the North Pacific, which changes the wind stress curl on the sea surface and forces the sea surface height out of the sea to travel westward.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P731.27;P732
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