...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Physical Oceanography >Persistent Turbulence in the Samoan Passage
【24h】

Persistent Turbulence in the Samoan Passage

机译：萨摩亚海峡的持续湍流

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

Abyssal waters forming the lower limb of the global overturning circulation flow through the Samoan Passage and are modified by intense mixing. Thorpe-scale-based estimates of dissipation from moored profilers deployed on top of two sills for 17 months reveal that turbulence is continuously generated in the passage. Overturns were observed in a density band in which the Richardson number was often smaller than 1/4, consistent with shear instability occurring at the upper interface of the fast-flowing bottom water layer. The magnitude of dissipation was found to be stable on long time scales from weeks to months. A second array of 12 moored profilers deployed for a shorter duration but profiling at higher frequency was able to resolve variability in dissipation on time scales from days to hours. At some mooring locations, near-inertial and tidal modulation of the dissipation rate was observed. However, the modulation was not spatially coherent across the passage. The magnitude and vertical structure of dissipation from observations at one of the major sills is compared with an idealized 2D numerical simulation that includes a barotropic tidal forcing. Depth-integrated dissipation rates agree between model and observations to within a factor of 3. The tide has a negligible effect on the mean dissipation. These observations reinforce the notion that the Samoan Passage is an important mixing hot spot in the global ocean where waters are being transformed continuously.
机译：形成全球翻转循环下肢的深海水流过萨摩亚通道，并通过剧烈混合而改变。基于索普规模的估计，从分布在两个门槛顶部的系泊轮廓线耗散了17个月，发现通道中不断产生湍流。在密度带中观察到了倾覆，在该密度带中，理查森数通常小于1/4，这与在快速流动的底部水层的上界面处发生的剪切不稳定性一致。发现耗散的大小在数周到数月的长时间范围内都是稳定的。第二个12个系泊轮廓仪的第二个阵列部署了较短的持续时间，但是以较高的频率进行配置能够解决从几天到几小时的时间尺度上的耗散差异。在某些系泊位置，观察到了消散速率的近惯性和潮汐调节。但是，调制在整个通道上在空间上并不连贯。将主要门槛之一处观测值的耗散量和垂直结构与理想的二维数值模拟（包括正压潮汐强迫）进行了比较。深度积分耗散率在模型和观测值之间达到3倍以内。潮汐对平均耗散的影响可忽略不计。这些观察结果强化了萨摩亚海峡是全球海洋不断变化的重要混合热点的观念。

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