Atlantic Ocean Tropical/subtropical Processes from the Seasonal to the Decadal Time Scales: Models/Data, Model/Model Comparisons and Model/Data Synthesis through Assim

该项目以以前的研究为基础，并将其扩展到与气候研究更相关的时间尺度，即大西洋热带/亚热带相互作用的年际至十年变化。将寻求新的研究途径：在何种程度上，十年尺度的环流变化可能会导致非线性和涡旋的作用，在确定多个平衡状态与更缓慢地演变的表面强迫十年振荡。将检验两个假设。第一，以STC为代表的大西洋热带/副热带联系中的海洋成分显著影响低纬SST的年际至年代际变率，从而在气候变率中起着重要作用。第二种观点认为，热带、副热带风驱动环流存在多年和十年尺度的低频变率，这种低频变率与非线性涡动过程有关，并导致以不同能量特征为特征的多个状态，从而产生纬向热量输送的低频变率。大多数热带/亚热带相互作用的变率的研究集中在确定性的响应地面强迫在同一光谱范围内。PI将探索我们所知的热带海洋中从未研究过的低频变率的场所，即评估与涡动平均流相互作用产生的风驱动环流的多个状态相关的内部变率模式的可能作用，模式可能与已经发现的副热带环流的十年变率的类似模式相关。该方法将使用模型/数据比较、模型/模型比较、通过数据同化进行的模型/数据合成、旨在解决假设一的粗分辨率实验和旨在解决假设一和假设二的涡流分辨率实验。

This project builds on previous studies and extend them to the more relevant time scales for climate studies, i.e. the interannual to decadal variability of tropical/subtropical interaction in the Atlantic ocean. New research avenues will be pursued: the degree to which decadal-scale changes in the circulation may result from the role of nonlinearities and eddies in determining multiple equilibria states versus more slowly evolving surface forced decadal oscillations. Two hypotheses will be tested. The first one is that The oceanic component of the tropical/subtropical connections in the Atlantic ocean as represented by the STCs significantly affects the interannual to decadal low-latitude SST variability and hence plays a significant role in climate variability. The second one poses that Low-frequency variability in the multi-annual and decadal time scales exist in the tropical.subtropical wind-driven circulation that are associated with nonlinear eddy processes and lead to multiple states characterized by different energetics which produce lo-frequency variability in the meridional heat transport. Most studies of the variability of tropical/subtropical interactions have focused on the deterministic response to surface forcings in the same spectral range. The PI's will explore a venue of low-frequency variability to our knowledge never investigated before in the tropical ocean, i.e. to assess the possible role of internal modes of variability linked to multiple states of the wind-driven circulation produced by eddy-mean flow interactions, modes possibly connected to the analogous modes of decadal variability already found for the subtropical circulation. The approach will use models/data comparisons, model/model comparisons, model/data synthesis through data assimilation, coarse resolution experiments aimed to address hypothesis I and eddy-resolving experiments aimed to address both hypothesis I and II.