Variability of the Climate System

该项目旨在加强对当前气候的可变性和可预测性的了解，特别是与北大西洋涛动(NAO)有关的气候在季节间到年代际时间尺度上的可变性和可预测性。由于在实际的全球气候系统中不可能进行实现这一目标所需的受控实验类型，真实地模拟观测到的气候学和变率的耦合GCM(大气环流模式)将是研究的基本工具。气候将由COLA(大气-海洋陆地研究中心)全球耦合GCM的更新版的多世纪控制模拟来表示。Cola耦合GCM对低频气候变化的许多方面进行了逼真的模拟，包括年际和年代际厄尔尼诺/拉尼娜，以及北大西洋、北太平洋和北极/南极的振荡。将进行一系列修改GCM的实验，以帮助理解在控制模拟中发现的NAO可变性的潜在机制。这些实验将利用GCM的异常耦合能力，在局部地区允许单向或完全耦合的大气-海洋或大气-陆地相互作用，同时指定其他地方的气候边界条件。将研究的机制包括局地大气-海洋耦合、局地海洋动力学、热带海温异常的远程影响、大气-陆地耦合过程以及随机大气强迫的作用。该项目有可能促进几个重要领域的知识。它们是：1)了解与NAO相关的低频变率；2)指示这种类型的内部气候变率是否是可预测的；3)评估内部产生的气候变率是否足以解释上个世纪在北大西洋观测到的变率，或者是否必须寻求替代解释；4)发展和评估一类新的实验，以了解耦合CMS中的气候变率。

AbstractATM-9907915SchneiderThe project is designed to enhance understanding of the variability and predictability of the current climate, especially that associated with the North Atlantic Oscillation (NAO), on inter-seasonal to inter-decadal time scales. Since it is impossible to do the type of controlled experiments necessary to accomplish this goal in the actual global climate system, a coupled GCM (general circulation model) that simulates the observed climatology and variability realistically will be the basic tool for the investigation.The climate will be represented by a multi-century control simulation with an updated version of the COLA (Center for Atmosphere-Ocean Land Studies) global coupled GCM. The COLA coupled GCM produces a realistic simulation of many aspects of low frequency climate variability, including interannual and decadal El Nino/La Nina, and the North Atlantic, North Pacific, and Arctic/Antarctic Oscillations. A series of experiments in which the GCM is modified will be made to help understand the mechanisms underlying the NAO variability found in the control simulation. These experiments will utilize the anomaly coupling capabilities of the GCM to allow one-way or fully coupled atmosphere-ocean or atmosphere-land interactions in localized regions, while specifying climatological boundary conditions elsewhere. The mechanisms that will be examined are local atmosphere-ocean coupling, local ocean dynamics, remote influence of tropical SST anomalies, coupled atmosphere-land processes, and the role of stochastic atmospheric forcing. The project has the potential to advance knowledge in several important areas. These are: 1) understanding low frequency NAO associated variability; 2) indicating whether this type of internal climate variability is or is not predictable; 3) evaluating whether internally generated climate variability is sufficient to explain observed variability over the North Atlantic over the last century, or whether alternative explanations must be sought; 4) developing and evaluating a new class of experiments to understand climate variability in coupled CMS.