Northern Hemisphere Winter Atmospheric Transient Eddy Heat Fluxes and the Gulf Stream and Kuroshio-Oyashio Extension Variability
Northern Hemisphere Winter Atmospheric Transient Eddy Heat Fluxes and the Gulf Stream and Kuroshio-Oyashio Extension Variability
复制标题
DOI：
10.1175/jcli-d-12-00647.1
复制
发表时间：
2013-12-01
影响因子：
4.9
通讯作者：
Joyce, Terrence M.
中科院分区：
文献类型：
--
作者：
Kwon, Young-Oh;Joyce, Terrence M.
基于1979-2009年的大气再分析和海洋观测资料，研究了北半球冬季（1 - 3月）大气瞬态涡旋热通量（< v' t '>和< v'q'>）与墨西哥湾流（GS）、黑潮延伸（KE）和大潮延伸（OE）路径的时空协变性。气候冬季平均，天气性（2 ~ 8 d）瞬变涡旋向北热通量表现出典型的风暴路径，其最大值与GS和KE/OE同时存在。季节内（8天-3个月）的对应值虽然总体上具有相似的振幅，但在主要地形和阻塞区附近表现出更多局部最大值的空间格局。瞬态涡旋的横向热通量发散作为两个频带的总和，与海洋锋的确切位置表现出非常密切的耦合。利用线性回归分析了瞬态涡旋向北热通量的年际变化与GS、KE和OE路径的经向变化之间的先-滞后关系。在每个海锋向北移动前1 ~ 3年，大气风暴路径向北移动并加强，这与海洋的风力变化相一致。在这三种情况下，随着洋面向北移动，天气风暴路径减弱。在各海锋向北移动之前，天气瞬变涡旋的纬向积分向北热输送增加了其最大平均值的5%左右，之后减少到相似的幅度。
Spatial and temporal covariability between the atmospheric transient eddy heat fluxes (i.e., < v'T'> and < v'q'>) in the Northern Hemisphere winter (January-March) and the paths of the Gulf Stream (GS), Kuroshio Extension (KE), and Oyashio Extension (OE) are examined based on an atmospheric reanalyses and ocean observations for 1979-2009.For the climatological winter mean, the northward heat fluxes by the synoptic (2-8 days) transient eddies exhibit canonical storm tracks with their maxima collocated with the GS and KE/OE. The intraseasonal (8 days-3 months) counterpart, while having overall similar amplitude, shows a spatial pattern with more localized maxima near the major orography and blocking regions. Lateral heat flux divergence by transient eddies as the sum of the two frequency bands exhibits very close coupling with the exact locations of the ocean fronts.Linear regression is used to examine the lead-lag relationship between interannual changes in the northward heat fluxes by the transient eddies and the meridional changes in the paths of the GS, KE, and OE, respectively. One to three years prior to the northward shifts of each ocean front, the atmospheric storm tracks shift northward and intensify, which is consistent with wind-driven changes of the ocean. Following the northward shifts of the ocean fronts, the synoptic storm tracks weaken in all three cases. The zonally integrated northward heat transport by the synoptic transient eddies increases by similar to 5% of its maximum mean value prior to the northward shift of each ocean front and decreases to a similar amplitude afterward.