【作者】 徐龙；

【导师】 郭佩芳； 兰健；

【作者基本信息】 中国海洋大学 ， 物理海洋学， 2003， 硕士

【摘要】 本文选用美国海军GDEM全球气候月平均温盐资料，空间分辨率为0.5°×0.5°，应用P矢量方法对日本以南黑潮和黑潮延续体三维流场进行了诊断计算和分析研究。计算结果较好地反映了该海域(25°N～40°N，134°E～178°E)流场的基本特征，特别是黑潮路径的弯曲情况。研究表明，该研究海域的流场特征，包括流轴、流幅、流速、流量等存在较明显的季节变化。 本文选用的P矢量方法是基于β螺旋方法和热成风关系建立起来的一种新动力诊断方法，将P矢量方法用于本文研究海域(日本以南黑潮和黑潮延续体)得到较好的三维流场诊断结果。这表明了基于β螺旋方法和热成风关系建立起来的P矢量方法是可行的；该方法在大洋海区有较好的适用性，并能得到较好的诊断结果。 日本以南黑潮弯曲路径呈一“V”字型，黑潮延续体西段的大弯曲路径呈现一“M”字型，即“两峰一谷”的弯曲形态，两峰分别位于144°E和150°E，且弯曲程度和弯曲位置都呈现较明显的季节变化。黑潮延续体东段分为南北两支，北强南弱，分支点的位置亦随季节变化。另外流幅的宽度也存在着夏宽冬窄的季节变化规律。 黑潮最大流速主轴在日本以南海域，春、夏、秋季路径与年平均路径基本一致，冬季流轴偏离海岸，位于三季的外侧。黑潮延续体最大流速主轴在西段的第一个峰处，冬季的峰值点比其它各季向东移了一个经度；第二个峰处，则以夏季弯曲最为平缓，且在155°E附近有一个向南的小弯曲路径。在东段夏季流轴波动幅度最大，秋季流轴最为平直。 黑潮表层流速最大值同样存在着季节性变化特征：日本以南黑潮表层流速最大值由12月份的71.6cm/s(最大值)变化到5月份的55.4cm/s(最小值)，极值均出现在纪伊半岛以南海域。黑潮延续体的表层流速最大值则由6月份的61.5cm/s(最大值)变化到3月份的48.1cm/s(最小值)，极值则出现在黑潮延续体西段大弯曲路径的第一个峰处。当深度增加时，各层的极值均相应减小，且出现极值的月份和位置均有所变化。 本文共选取了136“E、140“E、152oE和170“E四个经向断面来研究黑潮流速、流量的季节变化规律。结果表明:穿过这四个断面的流量均呈现夏大冬小的季节变化趋势，其中140“E和170“E两个断面的季节变化比较明显。 黑潮延续体另一显著特征是主轴南北两侧的多涡结构。总体而言，涡旋在春季较弱，夏季最强，秋末冬初较强，随后又逐渐变弱。其中比较明显的涡旋包括中心位置分别位于34oN，164oE和33“N，176“E附近的两个气旋涡和中心位置在33ON，175OE和32oN，162.5OE的两个反气旋涡。本文认为涡旋的形成、发展与消亡与黑潮路径的弯曲程度以及主轴流速的大小有着密切的因果关系。 从三维流场图可以看出，黑潮的强度随深度明显地减弱。200m层的流场特征与表层基本一致，且存在相似的季节变化规律;当深度增至soom甚至1000m时，黑潮的流轴己经无法辨认。更多还原

【Abstract】 Based on the U.S. Navy Generalized Digital Environmental Model (GDEM) climatological temperature and salinity data on a 0.5 X 0.5 grid, the three-dimensional current system in the Kuroshio south of Japan and Kuroshio Extension is determined and analyzed by using the P-vector method. The Kuroshio meander is well identified in the sea area(25 N~40 N, 134 E-178 E). The result presents the characteristics of the current system, including current path, width, velocity, volume transport, display seasonal variation evidently.In this paper, the P-vector method which is based on -spiral method andthermal wind relation is used and a good result is obtained, which indicates the P-vector method can be used in the large-scale ocean area and invert the current system well.The Kuroshio meander south of Japan and the two lee-wave meanders in the Kuroshio Extension are well presented by the P-vector method. The path of the Kuroshio meander, the position of the meanders in the Kuroshio Extension, the bifurcation of the Kuroshio Extension and the width of the current display seasonal variation evidently.South of Japan, the Kuroshio path of maximal velocity is outside the other three seasons in winter. In the Kuroshio Extension, the two points of the lee-wave also shows seasonal variabilities, and the path is most winding in summer, straight in fall.The surface current velocity displays the seasonal variability, too. The velocity varies from 71.6cm/s (maximum) in December to 55.4cm/s (minimum) in May in the Kuroshio south of Japan, and the position 01 extreme appear to the south of Kii Peninsula. The velocity varies from 61.5cm/s (maximum) in June to 48.1cm/s (minimum) in March in the Kuroshio Extension, and the extreme appear at the position of the first meander. The extreme minish, and the month and position of theextreme change accordingly as it deepens.In this paper, four meridional sections which are 136?E, 140?E, 152?E and 170 E have been chosen to study the seasonal variability of the volume transport and velocity. The result shows the volume transport in the four sections have the maximum in summer and the minimum in winter, especially in the two sections of 140 Band 170 E.The eddy structure in both sides of the Kuroshio Extension is another distinct character. The eddies are strongest in summer and weakest in spring as a whole. There are two evident cyclonic eddies whose centers lie at 34 N,164 Band 33 N,176 E, and two evident anti-cyclonic eddies whose centers lie at 33 N,175 E and 32 N, 162.5 E. The result seems to suggest a causal relation between the formation, evolution and disappearance of the eddy and the Kuroshio meander path.From the pictures of the three-dimensional current system, we can see that the magnitude of the Kuroshio current minishes as it deepens. The current field in 200m displays the same seasonal variation as the surface, but at the 500m even 1000m depth, we cannot identify them at all.更多还原