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，并将其扩展到气候研究的更相关的时间尺度，即大西洋热带/亚热带相互作用的年际至年代际变化。将寻求新的研究途径：环流的十年尺度变化可能在多大程度上由非线性和涡旋在确定多个平衡态与更缓慢演变的地表强迫年代际振荡的作用中产生。我们将检验两个假设。第一，以STCS为代表的大西洋热带/副热带联系的海洋分量对低纬SST年际至年代际变化有显着影响，从而对气候变化起着重要作用。第二种认为热带、副热带风生环流存在多年和年代际时间尺度上的低频变率，这些风生环流与非线性涡旋过程有关，并导致具有不同能量特征的多种状态，从而在经向热量输送中产生低频变率。大多数关于热带/副热带相互作用的可变性的研究都集中在同一光谱范围内对地面强迫的确定性响应。PI将探索一个我们以前从未在热带海洋研究过的低频变率的地点，即评估与涡旋-平均流相互作用产生的风驱动环流的多种状态有关的内部变率模式的可能作用，这些模式可能与已发现的副热带环流的类似年代际变率模式有关。该办法将使用模式/数据比较、模式/模式比较、通过数据同化进行的模式/数据合成、旨在处理假设一的粗分辨实验和旨在处理假设一和假设二的涡旋解析实验。

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.