副热带-热带太平洋密跃层水量交换年际变化的模拟研究  

Numerical study of interannual variations of the subtropical-tropical pycnocline mass exchange in the Pacific Ocean

作　　者：容新尧[1] 张人禾[1] 苏京志[1] 

机构地区：[1]中国气象科学研究院,北京100086

出　　处：《海洋学报》2011年第5期9-22,共14页

基　　金：国家基础研究发展计划项目(2006CB816000);国家自然科学基金项目(40805037;40921003)

摘　　要：利用一个全球海洋环流模式在3组风应力资料的强迫下模拟分析了副热带太平洋向热带太平洋密跃层水量输送的年际变化特征及其和风应力的关系,并设计数值试验,研究了密跃层水量输送的变化机制。结果表明,副热带太平洋向赤道太平洋的密跃层水量输送具有显著的年际变化。在年际时间尺度上,南北太平洋西边界密跃层水量输送都起着补偿内部路径输送的作用,两者具有反相变化关系,其中南太平洋西边界和内部路径水量输送的变率要强于北太平洋,同时南太平洋两条路径水量输送的反向相关关系以及补偿效应也比北太平洋显著,但北太平洋净的密跃层水量输送的变率要强于南太平洋。南北太平洋西边界和内部路径密跃层水量输送之间的反相变化主要归因于赤道外风应力旋度的变化及与之相联系的斜压Rossby波的传播。敏感性试验的结果表明,南北太平洋净的密跃层水量输送变化主要归因于赤道及其两侧纬向风的变化,赤道外风应力旋度变化引起的斜压Rossby波的传播对南北太平洋年际尺度的密跃层水量净输送贡献较小。Interannual variations of the subtropical-tropical pycnocline mass exchange in the Pacific Ocean and its mechanisms are investigated by using a global oceanic general circulation model forcing with three wind stress datasets.The results show that the subtropical-tropical pycnocline mass exchange in the Pacific Ocean varies significantly on interannual time scales,and the variation of the interior pycnocline transport is found to be anticorrelated to the boundary pycnocline transport and the former is generally compensated by the latter.Comparison between two hemispheres shows that the variabilities of boundary and interior transports of southern hemisphere are more pronounced than those of northern hemisphere,also the correlation coefficients and compensation rate between boundary and interior transports of southern hemisphere are larger than those of northern hemisphere,but the variability of the net transport of southern hemisphere is smaller than that of northern hemisphere.In both hemispheres,the counteracting tendency of the boundary and interior transports is primarily due to the propagation of baroclinic Rossby waves induced by the changes of the off-equatorial wind stress curl.The sensitive experiments show that the net pycnocline transports in both the northern and southern hemisphere are mainly attributed to the variability of near-equatorial zonal wind stress,whereas the effect of the propagation of baroclinic Rossby waves only plays a second role and could not results in such a compensation rate in each hemisphere.

关 键 词：STC 密跃层 年际变化 海洋环流模式 

分 类 号：P721[天文地球—海洋科学] P731.26