Impact of Recent Westerly Wind Trends on the Southern Ocean.

南大洋的洋流对海洋中的生物和化学、南极海冰的形成以及热量和碳从大气层转移到海洋中，调节地球气候产生重大影响。吹过南半球的强烈近地表大气风在造成南半球和邻近海洋内的流动方面起着关键作用。观测表明，这些风在过去四十年中发生了重大变化，包括在20世纪末加强并向南极移动，自2000年以来停止。鉴于风和洋流之间的已知联系，可以合理地预期，观测到的风趋势将导致或已经导致南大洋趋势的变化。然而，这尚未得到详细研究。该项目将通过量化最近风停和风趋势区域变化对南大洋的影响来弥补知识差距。该项目将为AGU桥梁项目的研究生和几名本科生提供培训，将研究结果纳入课程计划，通过非正式的外展活动和夏令营与当地的巴尔的摩市学校接触，通过建立现有的NSF GEOPaths项目，扩大地球科学的参与。这项研究将提高我们对南大洋对时间和区域变化的响应的理解，使用海洋和气候模式模拟结合观测的南半球风应力。将分析风和浮力强迫突变的理想化模拟，以量化南大洋对西风变化的反应的幅度和时间尺度。然后，研究人员将利用观测到的大气变化和海洋观测所迫使的模拟来量化南大洋最近的变化在多大程度上可以用风的趋势来解释。通过应用于下一代海洋和气候模型的新诊断来解决关键的知识差距，将提高我们对南大洋最近变化的原因及其对南极和全球气候的影响的理解。它还将提供对未来变化的深入了解，包括近期和长期变化，届时随着臭氧空洞的缓慢恢复，预计纬向风将出现微弱趋势，在世纪后期，风的变化可能取决于平流层臭氧恢复和温室气体持续增加之间的平衡。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准。

The currents of the Southern Ocean have a major impact on the biology and chemistry in the oceans, the formation of Antarctic sea-ice, and the transfer of heat and carbon from the atmosphere into the oceans, regulating Earth’s climate. The strong near-surface atmospheric winds that blow across the southern hemisphere play a key role in causing the flow within the Southern and neighboring oceans. Observations have shown substantial changes in these winds over the last four decades, including a strengthening and movement towards the south pole of the peak winds at the end of the twentieth century, that has paused since 2000. Given the known linkages between winds and ocean flow it is reasonable to anticipate that the observed wind trends will lead, or have already led, to changes in Southern Ocean trends. However, this has not yet been examined in detail. This project will address the knowledge gap by quantifying the impact the recent wind pauses and regional variations in wind trends on the Southern Ocean. This project will provide training for an AGU Bridge program graduate student and for several undergraduate students, incorporate findings into lesson plans, engage with local Baltimore City schools through informal outreach activities and summer camps, and broaden participation in the geosciences by building on existing NSF GEOPaths projects.This research will improve our understanding of the response of the Southern Ocean to temporal and regional variations in southern hemisphere wind stresses using a combination of ocean and climate model simulations together with observations. Idealized simulations with abrupt changes in the wind and buoyancy forcing will be analyzed to quantify the magnitude and time scales of the response of the Southern Ocean to changes in westerly winds. Researchers will then use simulations forced by observed atmospheric changes and ocean observations to quantify how much of the recent changes in the Southern Ocean can be explained by trends in the winds. Addressing key knowledge gaps with new diagnostics applied to next-generation ocean and climate models will improve our understanding of the causes of recent changes in the Southern Ocean and their impact on Antarctic and global climate. It will also provide insights into future changes, both near and long-term, when weak trends in the zonal winds are expected as the ozone hole slowly recovers, and later in the century when wind changes will likely depend on the balance between stratospheric ozone recovery and continued increases in greenhouse gases.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.