西北太平洋副热带逆流与模态水的季节变化和年际变化  

The Seasonal and Interannual Variability of the Western North Pacific Subtropical Countercurrent and Subtropical Mode Water

作　　者：葛啸[1,2] 刘秦玉[1,2] 王立宜[1,2] 

机构地区：[1]中国海洋大学海洋环境学院,山东青岛266003 [2]物理海洋教育部重点实验室海洋-大气相互作用与气候实验室,山东青岛266003

出　　处：《海洋科学进展》2015年第3期279-287,共9页Advances in Marine Science

基　　金：国家重大科学研究计划项目--黑潮-黑潮延伸体-副热带逆流系统变异机理及其对全球变暖的响应(2012CB955602);国家自然科学基金项目--南;北太平洋副热带东部模态水对全球变暖响应的差异(41176006)和海洋动力过程的演变机理及其在气候变化中的作用(41221063)

摘　　要：本研究依据2004—2011年Argo观测资料的数据,对西北太平洋副热带逆流（STCC）和副热带西部模态水（STMW）的季节和年际变化进行了分析,探索了不同时间尺度上STCC强度和STMW体积变化的对应关系。研究结果再一次表明：北太平洋副热带环流中存在南、北两支向东的副热带逆流（STCC）,这2支逆流分别位于18°-20°N和23°-25°N纬带,月平均流速在5-20cm·s^-1。而位于西北太平洋温跃层内的低位势涡度（PV小于2.0×10^-10 m^-1·s^-1）的STMW主要出现在140°-170°E,25°-31°N的海域,介于25.0-25.6σθ等位势密度面之间,核心位势密度为25.3σθ。日界线以西的2支STCC强度和STMW体积都存在较显著的季节变化和年际变化。2支STCC强度的季节变化相类似,在5—7月中都较强,在11月较弱,这与前人提出的STCC在春季最强略有差异。STMW的体积在4—8月较大,9月后开始减小,该现象证实了在季节变化中STMW体积的增加和减少可以影响STCC的增强和减弱。2支STCC强度的年际变化几乎没有一致性,但STMW体积和局地风应力旋度的年际变化与STCC北支强度年际变化关系更密切。This study analyzed seasonal and interannual variation of the Subtropical Countercurrent（STCC）and the Subtropical Mode Water（STMW）in the western North Pacific using Argo observation data from 2004 to 2011and QuikSCAT wind field data from 2000 to 2009,in an attempt to explore the relationship between the zonal geostrophic velocity of STCC and the volume of STMW.The results show that there exist two branches（south and north）of STCC locating at 23°-25°N and 18°-20°N,respectively with average zonal velocity of 5-20cm/s.The STMW,which is mainly located in the western North Pacific thermocline with potential vorticity less than 2.0×10^-10 m^-1·s^-1）,is most dominate in（140°-170°E,25°-31°N）and within 25.0-25.6σθdensity surfaces.Its core potential density is 25.3σθ.The STCC and STMW both demonstrate obvious seasonal and interannual variations.The two branches of STCC share a similar seasonal variation-strong in May through July but weak in November.This is different from previous studies which found the STCC is strong in spring.This study also find that the volume of STMW strengthens from April to August and weakens after September,suggesting the seasonal variation of STMW volumes does affect the zonal velocity of STCC.There is no consistency between interannual variations of the two branches of STCC,but the relationship of the STMW and wind stress curl with northern branch of STCC is more obvious than that with southern branch of STCC on interannual scale.

关 键 词：副热带逆流 副热带模态水 北太平洋 季节变化 年际变化 

分 类 号：P722[天文地球—海洋科学]