Mechanisms of Intrinsic and Anthropogenically Forced Climate Variations

内在和人为强迫气候变化的机制

• 批准号: 1951713
• 负责人: Sarah Larson
• 金额: $ 64.39万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1951713&HistoricalAwards=false
• 关键词: Mechanisms; Intrinsic; Anthropogenically; Forced; Climate; Mechanisms; Intrinsic; Anthropogenically; Forced; Climate

Influenced by air-sea heat exchange, rainfall, and evaporation, the buoyancy of the ocean’s uppermost layer can impact the overturning oceanic circulation. Winds above the ocean surface can generate currents and promote mixing. The combined effects of wind and buoyancy on the ocean are ultimately felt throughout the entire ocean. In response to the changing ocean conditions (especially, the sea surface temperature or SST), atmospheric circulations can arise to govern patterns of clouds and rain, which in turn impact the wind and buoyancy forcings on the ocean. To this end, mechanisms involving buoyancy and winds at the air-sea interface are critical in establishing the timescales, patterns, and amplitudes of many climate variations we observe and simulate in climate models. Yet, complete understanding of these mechanisms remains elusive due to sparse ocean observations and complicated dynamics. The research will decompose the relative effects of winds versus buoyancy forcing using climate model experiments, with emphasis on two features expected to substantially change in a future climate, namely the surface temperature and the Atlantic Meridional Overturning Circulation (AMOC).In particular, many open questions remain about the importance of winds versus buoyancy forcing as pathways through which the atmosphere communicates intrinsic and externally forced variations to the ocean. Addressing these questions is made more difficult by a wide gap in the model hierarchy, between fully coupled models with a complete dynamical representation of both the ocean and atmosphere and models that represent the ocean as a motionless slab that is only thermally coupled to the atmosphere. This work will be implemented by closing said gap in the model hierarchy via leveraging a mechanically decoupled (MD) version of a climate model, which isolates variations in the ocean circulation that are driven solely by buoyancy from the wind-driven variability captured by fully coupled models. With the MD as an intermediate step between fully coupled and slab ocean models, a clearer mechanistic understanding of the drivers of climate variations is possible. These three model versions will be used together to identify the relative roles of buoyancy and wind variations in driving intrinsic SST variability, anthropogenic trends in surface temperature, and intrinsic and anthropogenically forced AMOC variations.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.

受空气热交换，降雨和经济的影响，海洋上层的浮力会影响倾覆的海洋循环。海面上方的风可以产生电流并促进混合。风和浮力对海洋的综合​​影响最终在整个海洋中都感受到。为了响应不断变化的海洋条件（尤其是海面温度或SST），可能会出现大气循环以控制云和雨的模式，从而影响海洋上的风和浮力强迫。为此，在气海界面上涉及浮力和风的机制对于确定我们在气候模型中观察到和模拟的许多气候变化的时间标准，模式和放大器至关重要。然而，由于海洋观察稀疏和动态复杂，对这些机制的完全理解仍然难以捉摸。这项研究将使用气候模型实验分解风与浮力强迫的相对影响，重点是预期的两个特征将在未来的气候中发生实质性变化，即表面温度和大西洋子午的倾覆循环（AMOC）。在特定的特定问题上，许多开放性的问题仍然是风的重要性，促进风向促进途径的综合态度和众多大气层的综合态度，而这是众多的综合性。在模型层次结构中，解决这些问题的问题变得更加困难，在完全耦合的模型之间，具有完全动态的海洋和大气层，以及代表海洋作为一动不动的平板，仅热耦合到大气。这项工作将通过利用机械脱钩（MD）版本的气候模型来实现模型层次结构中的上述差距，该差距隔离了海洋循环中的变化，这些变化仅由浮力从浮力驱动的变异性驱动而驱动。由于MD是完全耦合和平板海洋模型之间的中间步骤，因此可以对气候变化的驱动因素有更清晰的机械理解。这三个模型版本将共同使用，以确定浮力和风变化在推动内在的SST变异性，表面温度中的人为趋势以及固有和人为强迫的AMOC变化中的相对作用。这奖反映了NSF的法定任务，并通过使用基础的智力效果评估了诚实的支持。