Collaborative Research: Marginal instability and deep-cycle turbulence during an extreme El Nino event

合作研究：极端厄尔尼诺事件期间的边缘不稳定和深循环湍流

• 批准号: 1851390
• 负责人: Sutanu Sarkar
• 金额: $ 47.46万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-04-01 至 2025-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1851390&HistoricalAwards=false
• 关键词: Collaborative; Research; Marginal; instability; deep

The El Nino is an inter-annual coupled ocean-atmosphere phenomenon, focused in the equatorial Pacific, that influences weather patterns around the world. While the 2015-16 El Nino was the strongest on record, the best available climate models failed to predict it (as well as falsely predicting an event a year earlier that failed to materialize). This project will address the interactions of wind and large-scale oceanic variability with small-scale turbulence and its effect on sea surface temperature in the eastern equatorial Pacific Ocean. The project will use existing observations of ocean structure and turbulence along with high resolution numerical simulations to understand the deep cycling of turbulent mixing and its relation to El Nino. The results will be used to formulate new methods for capturing the effects of turbulence in ocean and climate models.This project involves analysis of existing data sets and numerical simulations to study deep cycle turbulence under the Equatorial Pacific Cold Tongue during the El Nino Southern Oscillation (ENSO). Data from TAO moorings, deployments of chi-pods, and Large Eddy Simulation (LES) modeling will be used to examine marginal instability and deep-cycle turbulence (DCT) during different phases of ENSO. The results will be used to formulate a new parameterization for turbulent mixing in the upper equatorial ocean. The PIs will also address the interactions and roles of tropical instability waves (TIW) and Kelvin waves on DCT and mixing beneath the cold tongue.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

厄尔尼诺现象是一种年际海洋-大气耦合现象，集中在赤道太平洋，影响着世界各地的天气模式。虽然2015-16年的厄尔尼诺现象是有记录以来最强的，但现有最好的气候模型未能预测到它(还错误地预测了一年前未能实现的事件)。该项目将讨论风和大尺度海洋变率与小尺度湍流的相互作用及其对赤道东太平洋海面温度的影响。该项目将利用现有的海洋结构和湍流观测以及高分辨率的数值模拟来了解湍流混合的深层循环及其与厄尔尼诺的关系。研究结果将被用于制定新的方法来捕捉海洋和气候模式中湍流的影响。该项目包括对现有数据集的分析和数值模拟，以研究厄尔尼诺南方涛动(ENSO)期间赤道太平洋冷舌下的深循环湍流。来自TAO系泊、CHIPOD展开和大涡模拟(LES)模拟的资料将被用来检验ENSO不同阶段的边缘不稳定和深循环湍流(DCT)。结果将被用来建立一个新的赤道上层海洋湍流混合的参数化。PIS还将讨论热带不稳定波(TIW)和开尔文波在DCT上的相互作用和作用，以及寒冷舌头下的混合。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Turbulence and Thermal Structure in the Upper Ocean: Turbulence-Resolving Simulations

上层海洋的湍流和热结构：湍流解析模拟

• DOI: 10.1007/s10494-019-00065-5
• 发表时间: 2019
• 期刊: Turbulence and Combustion
• 作者: Sarkar, Sutanu;Pham, Hieu T.
• 通讯作者: Pham, Hieu T.

A comparative study of turbulent stratified shear layers: effect of density gradient distribution

湍流分层剪切层的比较研究：密度梯度分布的影响

• DOI: 10.1007/s10652-022-09873-2
• 发表时间: 2022
• 期刊: Environmental Fluid Mechanics
• 影响因子: 2.2
• 作者: Pham, Hieu T.;Sarkar, Sutanu
• 通讯作者: Sarkar, Sutanu

Turbulent shear layers in a uniformly stratified background: DNS at high Reynolds number

均匀分层背景中的湍流剪切层：高雷诺数下的 DNS

• DOI: 10.1017/jfm.2021.212
• 发表时间: 2021
• 期刊: Journal of Fluid Mechanics
• 影响因子: 3.7
• 作者: VanDine, Alexandra;Pham, Hieu T.;Sarkar, Sutanu
• 通讯作者: Sarkar, Sutanu

What controls the deep cycle? Proxies for equatorial turbulence.

是什么控制着深循环？

• DOI: 10.1175/jpo-d-20-0236.1
• 发表时间: 2021
• 期刊: Journal of Physical Oceanography
• 影响因子: 3.5
• 作者: Smyth, W. D.;Warner, S. J.;Moum, J. N.;Pham, H.;Sarkar, S.
• 通讯作者: Sarkar, S.