The Evolution of Polar Climates: Forcings, Feedbacks, and Coupled Atmosphere-Ocean-Ice Dynamics

极地气候的演变：强迫、反馈和耦合的大气-海洋-冰动力学

• 批准号: RGPIN-2019-07211
• 负责人: Singh, Hansi
• 金额: $ 2.19万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=750985
• 关键词: Evolution; Polar; Climates; Forcings; Feedbacks

The polar regions are among the most vulnerable to anthropogenic climate change, with observed warming over the Arctic nearly triple that over the rest of the globe. This phenomenon of rapid high--latitude climate change, polar amplification, is evident over the Arctic in nearly all climate model simulations, and has been attributed to local radiative feedbacks (associated with both sea ice loss and the stability of the polar atmosphere) and changes in energy convergence by the atmosphere and ocean. This rapid rate of climate change in the polar regions has implications for global sea level, marine ecosystems, and extrapolar atmospheric circulation patterns, with anticipated societal impacts on coastal habitability, fishery productivity, and extreme weather, among others. The polar regions release much more energy to space than what they absorb from the sun, in effect acting as cooling radiator fins for the planet. This functionality, in turn, is made possible by the large--scale transport of extrapolar energy by the atmosphere and oceans into the polar regions. In a changing climate, changes in the cooling efficiency of the polar radiator fins depend on radiative feedbacks and changes in energy transport, which also affect polar and extrapolar climatology. In the proposed research program, I will investigate the evolving relationship between top--of-atmosphere polar energy loss, polar radiative feedbacks, and changing (atmosphere and ocean) energy convergence into the polar regions over a variety of time scales. Using models, observations, and applied mathematical techniques, we focus on the following objectives: 1. To quantify the temporal evolution of polar top--of--atmosphere energy loss with greenhouse gas forcing, and co--evolving contributions from radiative feedbacks and energy transport changes. 2. To understand Bjerknes compensation of atmospheric and oceanic energy transport into the high latitudes by identifying dynamic mechanisms of coupled energy transport adjustment. 3. To assess the relationship between fluctuations in polar top-of-atmosphere energy loss with natural variability and with forced climatic change. 4. To quantify the predictive power of sea ice in determining the polar climate state, top-of--atmosphere energy loss, radiative feedbacks (other than ice--albedo), and energy transport adjustments. 5. To assess the extrapolar impacts of polar climate change through a framework of varying regional forcings, radiative feedbacks, and atmospheric and oceanic energy transport adjustments. This research program will expand upon my prior work polar climate change through a lens of interacting local feedback mechanisms alongside adjustments in large--scale atmosphere--ocean coupled dynamics. More broadly, it will establish a framework for greater understanding and prediction of polar and extrapolar climate change, with particular relevance for climate change impacts, adaptation, and mitigation in the Canadian Arctic.

极地地区是最容易受到人为气候变化影响的地区之一，北极地区观测到的变暖幅度几乎是地球仪其他地区的三倍。这种高纬度气候迅速变化的现象，即极地放大现象，在几乎所有的气候模式模拟中都明显地出现在北极地区，这是由于当地的辐射反馈（与海冰损失和极地大气的稳定性有关）以及大气和海洋的能量汇聚变化。极地地区的这种快速气候变化对全球海平面、海洋生态系统和极外大气环流模式产生了影响，预计会对沿海可居住性、渔业生产力和极端天气等产生社会影响。极地地区向太空释放的能量比它们从太阳吸收的能量要多得多，实际上就像是地球的散热片。这种功能反过来又是通过大气层和海洋向极地地区大规模输送极外能量而实现的。在气候变化的情况下，极地散热器散热片的冷却效率的变化取决于辐射反馈和能量传输的变化，这也会影响极地和极外气候。在拟议的研究计划中，我将调查顶部的大气极地能量损失，极地辐射反馈，并改变（大气和海洋）的能量收敛到极地地区在不同的时间尺度之间的关系。使用模型，观察和应用数学技术，我们专注于以下目标：1。量化极地大气层顶能量损失随温室气体强迫的时间演变，以及辐射反馈和能量输送变化的共同演变贡献。2.通过识别耦合能量输送调整的动力机制，了解大气和海洋能量输送到高纬度的Bjerknes补偿。3.评估极地大气层顶能量损失的波动与自然变率和强迫气候变化之间的关系。4.量化海冰在确定极地气候状态、大气层顶能量损失、辐射反馈（除冰-冰）和能量输送调整方面的预测能力。5.通过不同区域强迫、辐射反馈以及大气和海洋能量传输调整的框架，评估极地气候变化的极外影响。这个研究计划将扩大我以前的工作极地气候变化，通过一个透镜的相互作用的本地反馈机制，同时在大尺度大气-海洋耦合动力学的调整。更广泛地说，它将建立一个更好地理解和预测极地和极地外气候变化的框架，特别是与加拿大北极地区的气候变化影响、适应和减缓有关的框架。