摘要
利用高分辨率海洋和大气再分析资料研究了东中国海黑潮海洋锋的季节变化特征及其成因。研究表明,东海黑潮海洋锋存在明显的季节变化,从冬季到次年春季逐渐增强,并在春季达到最强,初夏以后强度逐渐减弱,9—10月达到全年最弱。通过诊断混合层热流量方程发现,东海黑潮区一年四季均表现为暖的温度平流,有利于海洋锋的形成和维持,该暖平流也存在季节变化并在春季达到最大,对海洋锋在春季达到最强起了重要作用。海气界面净热通量在秋冬季对海洋锋的形成有促进作用,有利于海洋锋增强,而在春夏季则起抑制作用,促进海洋锋消亡。温度垂直输送全年对海洋锋起一定程度的抑制作用。总之,在海温水平平流和海表净热通量的共同作用下导致海洋锋春季达到最强,而夏秋季海表净热通量和温度垂直输送作用的共同作用致使海洋锋减弱并最后消失。因此,海洋的动力和热力共同作用导致了东海黑潮海洋锋的季节变化,其中海温水平平流和海表净热通量对海洋锋的季节变化起主要作用,而温度垂直输送项对海洋锋的发展起抑制作用,但影响相对较小。
The seasonal variation of the sea surface temperature （SST） front in the East China Sea （ECS） and its causes are investigated based on a suite of high-resolution oceanic and atmospheric reanal- ysis datasets. Results indicate that the SST front Kuroshio in the ECS experiences a marked seasonal vari- ation. This SST front increases in intensity from winter, and reaches its maximum in early spring, after that it begins to decline and almost disappears in autumn. By diagnosing the thermodynamic equation in the mixed layer, it is found that a warm-horizontal temperature advection exists along the Kuroshio throughout the year and this warm advection is beneficial for the formation and maintenance of the SST front. Besides, this warm advection varies seasonally and also reaches its strongest in early spring, mak- ing a great contribution to the strongest SST front during the early spring. In addition to the horizontal temperature advection, the interface net heat flux is another important factor for the seasonal change of the SST front, which acts to enhance the front during autumn and winter, whereas it weakens the front in spring and summer. However, the vertical temperature advection acts to dampen the SST front all the year round although its effect is relatively small and negligible. In a word, the joint action of the horizontal temperature advection and sea surface net heat flux makes the front to be strongest in spring, while the sea surface net heat fluxes are proved to be the dominant role in leading to the front＇ s disappearance in autumn. Therefore, the oceanic dynamics and thermodynamics together result in the seasonal variation of the SST front in the East China Sea in which the horizontal advection and sea surface net heat flux play a major role.
出处
《气象科学》
北大核心
2016年第2期203-211,共9页
Journal of the Meteorological Sciences
基金
国家重大科学研究计划项目(2012CB955600)
国家自然科学基金资助项目(41275094)
江苏高校优势学科建设工程项目(PAPD)
江苏省高校"青蓝工程"
关键词
海洋锋
季节变化
东海黑潮
SST Front
Seasonal Variation
East China Sea Kuroshio
