北太平洋副热带逆流区涡旋动能谱的季节性变化及其机制

发布时间：2018-04-17 15:50

本文选题：动能谱 + 能量尺度　；参考：《海洋与湖沼》2017年05期

【摘要】：本文利用了23年的卫星高度计数据和WOA13气候态月平均温盐资料,考察了北太平洋副热带逆流(STCC)区涡旋动能谱及其涡旋尺度季节变化的动力过程。为了揭示其动力机制,本文采用了斜压2.5层模式并结合动能串级的理论进行分析。结果表明,在STCC区由于海洋层结及地转流的垂向剪切发生了季节性变化,从而产生的斜压不稳定是导致涡旋动能谱季节变化的原因。涡旋动能最大的时间发生在5—6月份,滞后于斜压最不稳定发生的时间(3月份)约2—3个月左右,这是由于斜压不稳定产生的扰动需要一定时间才能发展成振幅足够大的涡旋。斜压不稳定提供的能量使得涡旋相互作用加强,产生了动能逆向串级,动能谱向更大尺度转移。涡旋能量尺度在3月份仅为280km,而在9月份达到最高值335km左右。另一方面,我们发现STCC区动能谱斜率及动能谱通量也有季节变化,在涡旋动能最大的5—6月份,当尺度小于罗斯贝变形尺度时,谱斜率达到1k 3,而动能谱通量达到最大值。对STCC区涡动能谱及涡旋尺度季节变化的研究,对深入认识中尺度涡旋的产生及其演变机制有着重要的意义。
[Abstract]:Based on the satellite altimeter data of 23 years and the monthly mean temperature and salt data of WOA13 climate, the kinetic energy spectrum of vortex and the dynamic process of seasonal variation of vortex scale in the subtropical countercurrent in the North Pacific Ocean are investigated.In order to reveal its dynamic mechanism, the baroclinic 2.5 layer model is used and the kinetic energy cascade theory is used to analyze it.The results show that the seasonal variation of vortex kinetic energy spectrum is caused by the seasonal variation of oceanic stratification and vertical shear of geostrophic currents in the STCC region and the resulting baroclinic instability.The maximum vortex kinetic energy occurred in May-June and lagged behind the most unstable time of baroclinic in March.This is because the disturbance caused by baroclinic instability takes some time to develop into a vortex with large amplitude.The energy provided by baroclinic instability strengthens the vortex interaction and results in the reverse cascade of kinetic energy and the transfer of kinetic energy spectrum to a larger scale.The vortex energy scale was only 280 km in March, and reached its maximum value of 335km in September.On the other hand, we find that the slope of kinetic energy spectrum and the flux of kinetic energy spectrum also vary seasonally in STCC region. In May-June, when the scale is smaller than the scale of Rossby deformation, the slope of spectrum reaches 1 K ~ (3) and the flux of kinetic energy spectrum reaches the maximum.The study of vortex kinetic energy spectrum and seasonal variation of vortex scale in STCC region is of great significance in understanding the generation and evolution mechanism of mesoscale vortex.
【作者单位】：中国科学院海洋研究所;中国科学院大学;
【基金】：国家重点研发计划项目,2016YFC1401004号,2016YFC1401008号国家自然科学基金面上项目,41676168号,41376028号;国家自然科学基金创新研究群体项目,41421005号国家重点研发计划(973)项目,2013CB956202号国家自然科学基金委-山东省联合项目,U1406401号遥感科学国家重点实验室开放项目,OFSLRESS201504号青岛市创新领军人才项目,13-CX-26号山东省自然科学基金项目,ZR2014DQ027号
【分类号】：P731.2

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