...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Physical Oceanography >Influence of Midlatitude Winds on the Stratification of the Equatorial Thermocline
【24h】

Influence of Midlatitude Winds on the Stratification of the Equatorial Thermocline

机译：中纬度风对赤道温跃层分层的影响

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The stratification of the equatorial thermocline is a key variable for tropical climate dynamics, through its influence on the temperature of the water that upwells in the eastern equatorial ocean. In this study, two types of ocean models are used, an ocean general circulation model (GCM) and a 1(1/2)-layer model, to investigate processes by which changes in the midlatitude winds affect the equatorial stratification. Specifically, the influences of anomalous mode-water formation, Ekman pumping, and entrainment in the subpolar ocean are examined. The effects of a "sponge layer" adjacent to the northern boundary of the basin are also assessed. Solutions are forced by idealized zonal winds with strong or weak midlatitude westerlies, and they are found in rectangular basins that extend from the equator to 36°N (small basin) or to 60°N (large basin). In the GCM solutions, a prominent response to reduced winds is the thinning of the mixed layer in the northwestern region of the subtropical gyre, leading to less subduction of low-potential-vorticity mode water and hence thinning of the upper thermocline in the central-to-eastern subtropics. Almost all of this thinning signal, however, recirculates within the subtropics, and does not extend to the equator. Another midlatitude response is shallowing (deepening) of the thermocline in the subtropical (subpolar) ocean in response to Ekman pumping. This, primarily, first-baroclinic-mode (n = 1) response has the most influence on the equatorial thermocline. First-baroclinic-mode Rossby waves propagate to the western boundary of the basin where they reflect as packets of coastal Kelvin and short-wavelength Rossby waves that carry the midlatitude signal to the equator. Subsequently, equatorial Kelvin waves spread it along the equator, leading to a shoaling and thinning of the equatorial thermocline. The layer-thickness field h in the 1(1/2)-layer model corresponds to thermocline depth in the GCM. Both the sponge layer and subpolar Ekman suction are important factors for the 1(1/2)-layer model solutions, requiring water upwelled in the interior ocean to be transported into the sponge layer via the western boundary layer. In the small basin, equatorial h thins in response to weakened westerlies when there is a sponge layer, but it thickens when there is not. In the large basin, equatorial h is unaffected by weakened westerlies when there is a sponge layer, but it thins when water is allowed to entrain into the layer in the subpolar gyre. It is concluded that the thinning of the equatorial thermocline in the GCM solutions is caused by the sponge layer in the small basin and by entrainment in the subpolar ocean in the large one.
机译：赤道热跃层的分层是热带气候动态变化的关键变量，因为它对在赤道东海上升的水温产生影响。在这项研究中，使用了两种类型的海洋模型，即海洋总环流模型（GCM）和1（1/2）层模型，以研究中纬度风的变化影响赤道分层的过程。具体来说，研究了异常模式水的形成，埃克曼抽水和在极地海洋夹带的影响。还评估了与盆地北部边界相邻的“海绵层”的影响。解决方案是由理想纬向风带强或弱中纬度西风推动的，它们位于从赤道延伸至北纬36°（小盆地）或延伸至60°N（大盆地）的矩形盆地中。在GCM解决方案中，对风减弱的一个显着响应是亚热带回旋西北部混合层的变薄，这导致低势涡模式水的俯冲较少，因此中部的上层跃层也变薄了。东亚热带。但是，几乎所有的稀疏信号都在亚热带内部再循环，并且没有扩展到赤道。另一个中纬度响应是响应埃克曼抽水，使亚热带（亚极地）海洋中的温跃层变浅（变深）。这主要是第一斜压模式（n = 1）响应对赤道温跃层影响最大。第一斜斜模式的罗兹比波传播到盆地的西边界，并在其中反射为沿岸的开尔文和短波长的罗兹比波的数据包，这些波将中纬度信号传送到赤道。随后，赤道开尔文波将其沿赤道传播，导致赤道热跃层浅滩化和变薄。 1（1/2）层模型中的层厚度字段h对应于GCM中的跃线深度。海绵层和亚极Ekman吸力都是1（1/2）层模型解决方案的重要因素，要求将在内部海洋中上升的水通过西边界层运入海绵层。在小盆地中，赤道h在有海绵层时会减弱西风而变薄，但在没有海绵层时会变厚。在大盆地中，赤道h在存在海绵层时不受减弱的西风的影响，但在允许水夹带进入亚极地回旋中时，其变薄。结论是，GCM溶液中赤道温跃层变薄的原因是小盆地中的海绵层和大盆地中的亚极洋夹带。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号