【作者】 马利斌；

【导师】 穆穆；

【作者基本信息】 中国科学院研究生院（海洋研究所） ， 物理海洋学， 2013， 博士

【摘要】 黑潮作为西边界流的一支，由于流量和流向的特质，黑潮将大量的热量从北太平洋低纬输送到中高纬，对东亚及东南亚周边多个国家的气候和资源都有影响；另一方面，日本南部黑潮的路径变化对日本南部的渔业和航海造成影响。由于黑潮路径变化对人类社会活动有着不可忽视的影响，因此，研究黑潮路径变化特征及其相关的物理现象，对预防其带来的影响和减少人类财产损失、对进一步了解日本南部黑潮路径变化机制、以及为提高日本南部黑潮路径预报提供理论基础有着重要的意义。本文利用现有的各种海洋观测资料，包括融合卫星高度计海表高度数据、验潮站海平面数据、风应力数据、海平面气压数据、净表面热通量数据、海表温度以及次表层温盐数据等，以“日本南部黑潮路径变化及其相关物理现象”这个科学问题为中心，分析讨论了以下几个科学现象：众所周知，日本南部黑潮路径变化导致海面高度变化；比如，当黑潮处于典型大弯曲路径状态时，日本南部具有高的海面高度。因此，为了更好地了解日本南部海表高度的变化，本文首先基于卫星高度计海表高度数据，讨论了日本南部海表高度变化的线性趋势、季节变化、年内变化以及年际变化，并探讨了导致日本南部海表高度的季节变化、年内变化以及年际变化的物理机制。分析结果表明，日本南部海表高度的季节变化主要受海水热膨胀过程引起的比容高度季节变化的影响。另一方面，对于年内变化，影响日本南部海表高度变化的扰动主要位于北太平洋中部，且主要沿着纬度和黑潮延伸体向西传播。而对于年际变化，影响日本南部海表高度的扰动主要位于北太平洋中部和东部。另一方面，吐噶喇海峡、纪伊半岛以及伊豆诸岛的海平面变化与黑潮路径变化有密切联系。因此，本文基于验潮站海平面数据以及卫星高度计海表高度数据，从年内时间尺度以及年际时间尺度讨论了吐噶喇海峡、纪伊半岛以及伊豆诸岛海平面变化与离岸海表高度变化之间的关系；并讨论了导致吐噶喇海峡黑潮路径年内变化和纪伊半岛黑潮路径年际变化的物理机制。结果表明，来自上游以及下游的海洋中尺度扰动对吐噶喇海峡、纪伊半岛以及伊豆诸岛海平面的年内变化以及年际变化有重要的影响；另外，海洋中尺度扰动对吐噶喇海峡黑潮路径年内变化和纪伊半岛黑潮路径年际变化有重要的影响。另一方面，海流的速度锋面对黑潮路径的年内变化以及年际变化过程有重要的影响。基于海表高度等数据，本文讨论了日本南部黑潮路径经向位移的年际变化以及相关的物理机制，以及黑潮路径经向位移的年际变化引起相关的海洋变化。结果表明，日本南部上游黑潮路径年际变化的经向位移扰动能够影响下游黑潮路径的经向位移。黑潮路径经向位移年际变化的EOF分析结果表明，EOF第一模态的主成分能够描述日本南部黑潮近岸大弯曲路径和离岸大弯曲路径变化，EOF第二模态的主成分能够描述日本南部黑潮路径典型大弯曲路径变化。线性回归分析结果表明，沿黑潮延伸体传播的海表高度负异常扰动影响日本南部黑潮典型大弯曲路径变化；而沿黑潮延伸体传播的海表高度正异常扰动对日本南部黑潮近岸和离岸非大弯曲路径变化有着重要的影响。另一方面，日本南部黑潮路径年际变化对日本南部海表温度异常、次表层海温异常的分布以及海洋涡动能的分布有着重要的影响。最后，本文基于海表高度等数据，分析了日本南部黑潮处于不同路径状态时，涡旋与平均流之间的能量转化和雷诺应力空间分布的统计特征。结果表明，涡旋与平均流之间的能量转化和雷诺应力的分布随黑潮路径状态变化，且主要发生在九州岛东部以及纪伊半岛南部与东南部。在黑潮路径状态维持阶段，涡动量通量流向黑潮流轴；且黑潮流轴本身的非线性不稳定性影响涡动量通量的空间分布。另外，利用次表层温盐数据，探讨了黑潮处于不同路径状态时，日本南部海流系统的稳定性问题。结果表明，当黑潮处于离岸非大弯曲路径状态时，日本南部的海流系统更容易发生斜压不稳定性。另一方面，黑潮处于近岸非大弯曲路径状态和典型大弯曲路径状态时，日本南部海流系统具有相当的允许不稳定波发生窗口，但在前者情况下，日本南部海流系统中的最不稳定波具有更长的时间尺度。更多还原

【Abstract】 As one of the western boundary currents, Kuroshio carries large amount of heattransporting from low latitudes to high latitudes due to its specific features of volumetransports in the North Pacific. This impacts the climates and resources of countries inthe East Asia and Southeast Asia. On the other hand, variations in Kuroshio path southof Japan also impact the fishery and voyage in that region. Due to the influences ofvariations in Kuroshio path on the human activities can not be ignored, studies on thecharacteristics of variations in Kuroshio path and its related physical phenomena havesignificant senses on reducing the property loss of human, making further understandthe mechanisms of variations in Kuroshio path, and providing basic theories to highlypredict its path.In this study, several oceanic observations, including merged altimetric seasurface height (SSH), sea level from tide gauge, wind stress, sea level pressure, netsurface heat flux, sea surface temperature (SST) and subsurface temperature/salinity,are used to investigate the variations in Kuroshio path south of Japan and its relatedphysical phenomena. During this investigation, descriptions in this study focus on thefollowing interesting phenomena.It is well-known that variations in Kuroshio path south of Japan lead to changesin sea surface height; such as, there is high sea surface height when Kuroshio takestypical lager meander path. In order to make variations in sea surface height clearly,spatiotemporal characteristics and driving mechanisms of linear trend, seasonalvariations, intraannual variations and interannual variations of SSH south of Japan,based on altimetric SSH, is firstly explored. Results show that changes in seasonalsteric height, which caused by thermal expansion of water column, have vital impactson the seasonal variations of SSH. The disturbances generated in the central North Pacific, transporting westward along latitudes and Kuroshio extension jet, have greatinfluences on the intraanual SSH south of Japan. On the other hand, the disturbanceswhich have important impacts on the interannual SSH south Japan are generated inthe central and eastern North Pacific.On the other hand, changes in Kuroshio path south of Japan have closerelationship with variations in sea level at Tokara Strait, Kii Peninsula and Izu Islands.Thus, the next problem in this study focuses on the intraannual and interannualvariations in sea level at Tokara Strait, Kii Peninsula and Izu Islands using sea leveldata from tide gauge and altimetric SSH. Moreover, intraannual variations inKuroshio path at Tokara Strait and interannual changes in Kuroshio path at KiiPeninsula are also explored. Results show that the mesoscale perturbations fromupstream and downstream significantly impact the intraannual and interannualvariations of sea level at Tokara Strait, Kii Peninsula and Izu Ridge. On the other hand,oceanic mesoscale perturbations and velocity front of currents have importantinfluences on the intraannual variation of Kuroshio path at Tokara Strait andinterannual variations of Kuroshio path at Kii Peninsula.Another point addressed in this study is the interannual meridional shifts ofKuroshio path south of Japan using altimetric SSH. The mechanism and relatedoceanic phenomena of interannual meridional shifts of Kuroshio path south of Japanare also addressed. Our result shows that perturbations of interannual meridionalshifts of Kuroshio path in the upstream could have influences on the changes ofKuroshio path in the downstream. After applying EOF analysis to the time series ofinterannual meridinal shifts of Kuroshio path, results show that the principlecomponent of the first EOF mode can represent near-and off-shore non-largemeander of Kuroshio path south of Japan; while the principle component of thesecond EOF mode can represent typical large meander of Kuroshio path south ofJapan. Moreover, results obtained by linear regression show that negative sea surfaceheight anomalies, which propagate along Kuroshio extension, can significantly impactthe typical large meander of Kuroshio path south of Japan; whereas positive seasurface height anomalies, which propagate along Kuroshio extension, can vitally influence the near-and off-shore non-large meander of Kuroshio path south of Japan.On the other hand, the interannual meridional displacements of Kuroshio path playimportant roles in the spatial distributions of changes in interannual sea surfacetemperature, subsurface temperature and eddy kinetic energy.The last issue discussed in this study is to explore the spatially statistical featuresof energy conversion between eddies and mean flow and Reynolds stresses whenKuroshio path south of Japan under different states using the altimetric sea surfaceheight. Our results show that distributions of energy conversion and Reynolds stressesdepend on the states of Kuroshio path south of Japan. And these distributions mostlylocate at the eastern of Kyushu and the southeast of Kii peninsula. During the periodof Kuroshio south of Japan taking a certain path, the eddy momentum fluxes flow toKuroshio jet. On the other hand, the nonlinear instabilities of Kuroshio jet haveinfluences on the spatial distribution of eddy momentum flux. Moveover, the currentstability south of Japan also discussed under different states of Kuroshio path usingsubsurface temperature and salinity data. Results show that the baroclinic instabilitywould be easily occurred for the current system south of Japan when Kuroshio pathtaking offshore non-large meander state. when Kuroshio path south of Japan takesnear-shore nonlarge meander and typical large meander, however, the both havecomparably permissible windows for unstable wave; whereas the most unstable wavesin current system south of Japan have longer timescale under the formercircumstances.更多还原