通过环极洋流引起的延迟反馈稳定大规模海洋环流中的千年振荡
Stabilising millennial oscillations in large-scale ocean circulation with a delayed feedback due to a circumpolar current
AI总结：
本研究通过中等复杂度地球系统模型cGENIE和改进的海洋箱式模型，引入环极洋流引起的延迟反馈，揭示了环极洋流作为驱动因素可产生稳定的千年经向翻转环流振荡，并重现了分岔结构，为地质过去及南极环极洋流对大西洋经向翻转环流稳定性的影响提供了新见解。
摘要：
全球海洋环流在调节地球气候中起着关键作用。环流的具体模式和强度也决定了碳和营养物质的循环方式，并通过由此产生的溶解氧分布，决定了适合海洋动物栖息地的位置。然而，地质数据和模型的证据表明，过去曾发生过环流模式的状态转变。要理解对海洋环境条件和生物多样性的控制，需要充分认识这种转变的本质和驱动因素。在此，我们展示了在中等复杂度的地球系统模型 cGENIE 中，经向翻转环流的稳定千年振荡，这种振荡似乎仅在存在环极洋流时才会发生。为了证明环极洋流可以作为稳定振荡的驱动因素，我们改进了一个简单的海洋箱式模型，引入了延迟反馈，以表示环极洋流对经向翻转环流的影响。我们通过分岔分析研究了箱式模型中出现的千年振荡解，并表明该模型能够重现地球系统模型中观察到的相同分岔结构。我们的结果为地质过去某些大陆构造下可能发生的振荡本质提供了新见解，并强调了不断变化的南极环极洋流速度对大西洋经向翻转环流稳定性的潜在影响。
英文摘要：
The global ocean circulation plays a pivotal role in the regulation of the Earth's climate. The specific pattern and strength of circulation also determines how carbon and nutrients are cycled and via the resulting distribution of dissolved oxygen, where habitats suitable for marine animals occur. However, evidence from both geological data and models suggests that state transitions in circulation patterns have occurred in the past. Understanding the controls on marine environmental conditions and biodiversity requires a full appreciation of the nature and drivers of such transitions. Here we present stable millennial oscillations of meridional overturning circulation in an Earth system model of intermediate complexity, cGENIE, that appear to only occur in the presence of a circumpolar current. To demonstrate that a circumpolar current can act as a driver of stable oscillations, we adapt a simple ocean box model to include a delayed feedback to represent the effect of a circumpolar current on meridional overturning circulation. We investigate the millennial oscillatory solutions that arise in the box model by bifurcation analysis and show that the model can reproduce the same bifurcation structure observed in the Earth system model. Our results provide new insights into the nature of oscillations that could have occurred under certain continental configurations in the geological past, and also highlight the potential influence of the changing Antarctic circumpolar current speed on the stability of the Atlantic meridional overturning circulation.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
