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台湾以东黑潮的低频变化及机制研究 总被引：1，自引：0，他引：1
本文基于AVISO（Archiving, Validation and Interpretation of Satellite Oceanographic data）1993-2015年间的海表面绝对动力高度数据,研究了台湾以东黑潮的低频变化特征,并探讨了影响其变化的机制。结果表明,台湾以东多年平均的黑潮流幅值约为136 km,表层流量值约为7.75×104 m2/s,对应的标准差分别为28 km和2.14×104 m2/s。台湾以东黑潮不仅具有显著的季节变化特征,还具有显著的年际变化特征。功率谱分析结果表明,台湾以东黑潮表层流量具有1 a和2.8 a的显著周期。空间上,台湾东南部黑潮的年际变化幅度比东北部强烈。相关性及合成分析结果表明,台湾以东黑潮的年际变化与PTO（Philippines-Taiwan Oscillation）之间存在显著的相关性。PTO年际震荡所导致的副热带逆流区反气旋式涡旋与气旋式涡旋的相对强度是影响台湾以东黑潮年际变化的主要动力因素。 相似文献
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东海与邻近海域水、热、盐通量的季节变化研究 总被引：1，自引：0，他引：1
本文基于高分辨率的区域海洋数值模式对东海及邻近海域进行温、盐、流的数值模拟,模拟结果与实测结果拟合较好。结果表明:东海与邻近海域的水交换过程具有显著的季节变化特征。从流量的角度看,台湾海峡、台湾-西表岛之间水道和西表岛-冲绳岛之间水道是外海水流入东海的3个主要水道,而冲绳岛-奄美大岛、吐噶喇海峡、大隅海峡、济州岛东部和黄东海断面是海水流出东海的水道;其年平均体积输运值分别为1.06×106 m3/s、20.49×106 m3/s、3.20×106 m3/s、-0.92×106 m3/s、-20.59×106 m3/s、-0.30×106 m3/s、-2.37×106 m3/s和-0.37×106 m3/s（向内为正）。对比发现,东海与邻近海域之间各水道的体积、热量和盐量输运均具有相似的季节变化趋势,其最大值往往出现在夏季（7月或8月）,最小值往往出现在冬季（1月或2月）。从7月到11月整个东海是流量净流出的过程,而从12月到翌年6月是流量净流入的过程,全年流量基本上保持平衡状态。东海终年存在向黄海的净输入,其体积、热量和盐量的年平均输运值分别为0.37×106 m3/s,0.027×1015 W和12.7×106 kg/s。 相似文献
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本文基于日本气象厅1956—2005年间在东海PN断面获得的观测资料,结合NCEP风场资料,研究了东海黑潮流量的年际和年代际变化特征,并探讨了西北太平洋风场和太平洋年代际振荡(PDO)对黑潮流量年际和年代际变化的影响。结果表明,东海黑潮流量基本服从正态分布,主要集中在19—33Sv范围内,其多年平均值为24.30Sv(1Sv=106m3/s);季平均、冬、夏季黑潮流量都存在着显著的年际和年代际变化。东海黑潮流量输送具有长期的线性增强趋势,在1956—2005年间它们分别增加了8.73Sv、9.86Sv和9.38Sv。相关与合成分析结果表明,黑潮源区和东海黑潮流域上空的经向风异常是黑潮流量年际变化的重要影响因素,而PDO则对黑潮流量的年代际变化有重要作用。 相似文献
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基于FVCOM的獐子岛附近海域三维潮汐潮流数值模拟 总被引：1，自引：1，他引：0
基于采用不规则三角网格的海洋模型FVCOM(An Unstructured Grid, Finite Volume Coastal Ocean Model), 对獐子岛附近海域的潮汐、潮流进行了精细化数值模拟研究, 模拟的潮汐、潮流与实测值符合良好, 表明建立的该海域精细化潮汐潮流数值模型合理可靠。依据计算结果绘制了M2、S2、K1和O1分潮的同潮图和潮流椭圆图, 并对该海域潮汐潮流特征进行了系统分析。结果表明, 獐子岛附近海域的潮汐主要以规则半日潮为主, 水平潮流多为旋转流, 旋转方向大部分为逆时针; 近岸海区和水道之间多为往复流, 在大鹿岛以南海域也存在一往复流的区域。在123.75°E以东存在一顺时针旋转的区域。由潮余流场的特点可看出, 獐子岛等各岛屿周围均形成气旋式的绕岛流, 流速一般位于8—12cm/s之间, 离岸线较远的外海区域余流较小, 只有1—2cm/s。本文所得结论, 有助于增加对整个獐子岛海域潮汐潮流特性的全面认识。 相似文献
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为了研究黑潮跨过200m等深线对东海入侵的年际变化特征,本文基于ROMS(Regional Ocean Modeling System)海洋模式,对西北太平洋海域进行了高分辨率的数值模拟,模式水平分辨率高达4km,该分辨率可以很好地分辨黑潮以东区域的中尺度涡旋等过程。模式首先进行了6年的气候态模拟,然后进行了1993到2015年的后报模拟。模式很好地再现了东海陆架已知的环流结构,模拟出的对马海峡和台湾海峡的年平均流量和观测结果也比较一致。基于模式结果,利用旋转经验正交函数(REOF)的方法,对黑潮跨过200m等深线流量的年际变化进行分析。REOF的主要模态表明,黑潮跨过200m等深线对东海陆架的入侵主要发生台湾东北,并且入侵主要集中在黑潮次表层水中。主要模态的时间系数表明,黑潮入侵东海陆架的年平均流量存在一个8年的变化周期。相关性分析表明,黑潮入侵东海陆架的年际变化和太平洋年代际振荡PDO(Pacific Decadal Oscillation)指标具有显著的负相关,其相关系数达–0.63。该相关可以通过如下过程解释:PDO会导致东太平洋风应力涡度异常,由Sverdrup关系可知向赤道的体积输运也会相应地产生异常,根据质量守恒,向赤道体积输运的异常必然通过西边界流-黑潮的异常来平衡,从而导致黑潮入侵东海陆架强烈的年际变化。 相似文献
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地形斜坡对东海黑潮陆架坡折锋稳定性影响研究 总被引：1，自引：1，他引：0
为了研究地形斜坡对东海黑潮陆架坡折锋稳定性的影响,利用简化的线性原始方程,在一定背景流的情况下,主要从增长率、相速度、空间结构和能量方面分析海底地形斜坡变化对坡折锋稳定性的影响。模式结果表明,平底地形时,扰动的强度大且扰动区域广,但有地形斜坡时,扰动区域变窄,强度变弱,地形对坡折锋起稳定性作用。通过能量分析得出东海黑潮陆架坡折锋是正压和斜压的混合不稳定,其中斜压不稳定占主导地位。实验分析得出,地形对东海黑潮陆架坡折锋起稳定作用,斜坡增大,斜压不稳定和正压不稳定均减弱,斜压不稳定减弱更明显。 相似文献
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Spatiotemporal variation of the surface Kuroshio east of Taiwan Island is investigated by quantitatively analyzing 23-year(1993–2015)sea surface Absolute Dynamic Topography data.The annual mean state of the Kuroshio is shown,with a flow width ~136 km and surface transport ~7.75×10~4 m~2/s.The corresponding standard deviations of these are 28 km and 2.14×10~4 m~2/s.Results of power spectrum analysis indicate that the primary periods of Kuroshio surface transport east of Taiwan Island are 1 and 2.8 years,respectively.Spatially,the Kuroshio surface transport southeast of Taiwan Island has greater variability than that to its northeast.That transport showed strong seasonality,with a maximum 8.8×104 m~2/s in summer and minimum 7.5×10~4 m~2/s in winter,which was mainly caused by local monsoon winds.A linear long-term upward trend of Kuroshio surface transport during 1993–2015 was found,during which the mean,southeast,and northeast of the Kuroshio east of Taiwan Island increased by 0.30×10~4,0.22×10~4 and 0.36×104 m~2/s,respectively.Correlation and composite analysis show that the Philippines-Taiwan Oscillation(PTO)is important in the interannual variability of the Kuroshio.PTO-induced relative intensity of anticyclonic and cyclonic eddies is the dominant influence on the interannual variability of the Kuroshio east of Taiwan Island. 相似文献
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Analysis of seasonal variation of water masses in East China Sea 总被引：5，自引：0，他引：5
Seasonal variations of water masses in the East China Sea （ECS） and adjacent areas are investigated, based on historical data of temperature and salinity （T-S）. Dynamic and thermodynamic mechanisms that affect seasonal variations of some dominant water masses are discussed, with reference to meteorological data. In the ECS above depth 600 m, there are eight water masses in summer but only five in winter. Among these, Kuroshio Surface Water （KSW）, Kuroshio Intermediate Water （KIW）, ECS Surface Water （ECSSW）, Continental Coastal Water （CCW）, and Yellow Sea Surface Water （YSSW） exist throughout the year. Kuroshio Subsurface Water （KSSW）, ECS Deep Water （ECSDW）, and Yellow Sea Bottom Water （YSBW） are all seasonal water masses, occurring from May through October. The CCW, ECSSW and KSW all have significant seasonal variations, both in their horizontal and vertical extents and their T-S properties. Wind stress, the Kuroshio and its branch currents, and coastal currents are dynamic factors for seasonal variation in spatial extent of the CCW, KSW, and ECSSW, whereas sea surface heat and freshwater fluxes are thermodynamic factors for seasonal variations of T-S properties and thickness of these water masses. In addition, the CCW is affected by river runoff and ECSSW by the CCW and KSW. 相似文献
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Depression and elevation internal solitary waves in a two-layer fluid and their forces on cylindrical piles 总被引：1，自引：0，他引：1
Both large amplitude depression and elevation internal solitary waves (ISWs) were observed on the continental shelf of the northwest South China Sea (SCS) during the Wenchang Internal Wave Experiment. In this study, we investigate the characteristics of depression and elevation ISWs based on comparisons between observational results and internal wave theories. It is suggested that the large amplitude depression wave is better represented by the extended Korteweg-de Vries (EKdV) theory than by the KdV model, whereas the large amplitude elevation wave is in better agreement with the KdV equation than with the EKdV theory. Wave-induced forces on a supposed small-diameter cylindrical pile by depression and elevation waves are also estimated using the internal wave theory and Morison formula. The wave-induced force by elevation ISWs is rarely reported in the literature. It is found that the force induced by the elevation wave differs significantly from that by the depression wave, and the elevation wave generally produces greater force on the pile in the lower water column than the depression wave. These results show that ISWs in the study area can present a serious threat to ocean engineering structures, and should not be ignored in the design of oil platforms and ocean operations. 相似文献