The Modulation of Gulf Stream Influence on the Troposphere by the Eddy-Driven Jet
The Modulation of Gulf Stream Influence on the Troposphere by the Eddy-Driven Jet
复制标题
涡驱动射流调节墨西哥湾流对对流层的影响
作者：
R. Parfitt;Young‐Oh Kwon
这项研究表明，墨西哥湾流对冬季北大西洋对流层的影响是最明显的涡驱动射流（EDJ）是最远的南部和更好地搭配与墨西哥湾流。利用1979-2009年12 - 2月的再分析数据集NCEP-CFSR，每日EDJ纬度分为三个区域（北方，中部和南部）。结果表明，大气锋的平均轨迹与EDJ纬度存在协变关系。在南部EDJ制度（约19%的时间），近地面大气锋，通过墨西哥湾流的频率最大化。分析表明，这导致强烈的海气感热通量梯度（由于大气和海洋中的强烈温度梯度）导致近地面大气锋面辐合显着加强。在最近的研究中，它表明，在墨西哥湾流的时间平均近地面风辐合的显着带是由大气锋。在这里，它表明，一个更小的子集的大气锋-那些与南部EDJ-主要设置的时间平均值，由于增强的墨西哥湾流海气相互作用。此外，在统计上显着的异常垂直速度延伸到边界层以上的确定与EDJ纬度的变化。这些异常是特别强大的南部EDJ和空间一致的增加近地面大气锋面辐合在墨西哥湾流。这些结果意味着墨西哥湾流对时间平均大气的影响在天气时间尺度上是调制的，并且当EDJ最远时增强。
This study suggests that the Gulf Stream influence on the wintertime North Atlantic troposphere is most pronounced when the eddy-driven jet (EDJ) is farthest south and better collocated with the Gulf Stream. Using the reanalysis dataset NCEP-CFSR for December–February 1979–2009, the daily EDJ latitude is separated into three regimes (northern, central, and southern). It is found that the average trajectory of atmospheric fronts covaries with EDJ latitude. In the southern EDJ regime (~19% of the time), the frequency of near-surface atmospheric fronts that pass across the Gulf Stream is maximized. Analysis suggests that this leads to significant strengthening in near-surface atmospheric frontal convergence resulting from strong air–sea sensible heat flux gradients (due to strong temperature gradients in the atmosphere and ocean). In recent studies, it was shown that the pronounced band of time-mean near-surface wind convergence across the Gulf Stream is set by atmospheric fronts. Here, it is shown that an even smaller subset of atmospheric fronts—those associated with a southern EDJ—primarily sets the time mean, due to enhanced Gulf Stream air–sea interaction. Furthermore, statistically significant anomalies in vertical velocity extending well above the boundary layer are identified in association with changes in EDJ latitude. These anomalies are particularly strong for a southern EDJ and are spatially consistent with increases in near-surface atmospheric frontal convergence over the Gulf Stream. These results imply that much of the Gulf Stream influence on the time-mean atmosphere is modulated on synoptic time scales, and enhanced when the EDJ is farthest south.
影响因子：
4.6
作者：
Lee, Robert W.;Woollings, Tim J.;Masato, Giacomo
通讯作者：
Masato, Giacomo