台湾以东黑潮的低频变化及机制研究

Low frequency variability and machanism of the Kuroshio in the east of Taiwan

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136km,表层流量值约为7.75×10~4 m^2/s,对应的标准差分别为28km和2.14×10~4 m^2/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1a和2.8a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。

The mean state and low frequency variability of Kuroshio in the east of Taiwan is investigated by quanti- tatively analyzing the 23-year （1993-2015） surface Absolute Dynamic Topography （ADT） data. The mean state of Kuroshio is given, with a flowing width of around 136 km and surface transport of about 7.75 × 104 m2/s, the standard deviation of the width and surface transport are 28 km and 2. 14 N 104 m2/s, respectively. The results in- dicate that the Kuroshio east of Taiwan shows both seasonal and interannual variability significantly. Results of power spectrum analysis indicate that the primary periods of the Kuroshio surface transport in east of Taiwan are 1 and 2.8 years respectively. Spatially, the Kuroshio surface transport in southeast of Taiwan has a relatively larger variability than that in the northeast of Taiwan. Correlation and composite analysis shows that PTO（Philippines- Taiwan Oscillation）has a significant correlation with the interannual variability of Kuroshio. The PDOdnduced rel- ative intensity of the anticyclonic and cyclonic eddy is the dominant factor controlling the interannual variability of Kuroshio in east of Taiwan.