Collaborative Research: Dynamical Mechanisms for Midlatitude-Arctic Interactions and Associated Weather Extremes in a Warming Climate

合作研究：气候变暖中中纬度-北极相互作用及相关极端天气的动力机制

• 批准号: 2232582
• 负责人: Pengfei Zhang
• 金额: $ 14.29万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-15 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2232582&HistoricalAwards=false
• 关键词: Collaborative; Research; Dynamical; Mechanisms; Midlatitude

Persistent weather systems in winter cause cold spells, heavy rainfall, or snow. These weather extremes are closely related to the location and intensity of midlatitude jet streams, which blow from west to east and often shift to the north and south. As Earth’s climate gets warmer, the jet streams are affected by the tug-of-war between the rapid surface warming over the Arctic and the enhanced upper-tropospheric warming in the tropics. The investigators will examine several interrelated dynamical mechanisms for midlatitude-Arctic interactions and the associated weather extremes. The first theme is the linkage between the planetary waves in the stratosphere and the risk of cold events. This task will test the hypothesis that extreme wave events in the stratospheric polar vortex serve as a source of intraseasonal predictability for cold events over North America. This linkage between the stratosphere and surface temperature will be analyzed in observations and climate models. Secondly, the investigators will examine a hypothesis that a weaker jet stream under rapid Arctic warming would lead to more frequent weather extremes in mid-latitudes. This task will perform idealized numerical simulations to examine the effect of jet speed or jet structure on the north and south shifts of a jet and thus attempt to reconcile different views on the changes in midlatitude circulation waviness in response to climate warming. The third task is on atmospheric rivers, the narrow intense moisture transport associated with midlatitude cyclones. Atmospheric rivers dominate the poleward moisture flux in the middle and high latitudes, which contribute to Arctic warming. Intense moisture transport can be influenced by either wind speed or temperature, and the two factors will be studied in an atmospheric transport model of water vapor and cloud tracers.Midlatitude weather extremes have profound socioeconomic impacts. Predictive skills from extreme stratospheric events could improve the sub-seasonal forecast of winter cold spells over North America, with important implications for energy consumption and transportation. A better understanding of extreme cold events in a warming climate can foster better communications of global warming science between the scientific community and the public. Improved predictions of the intense moisture transport by midlatitude cyclones into the Arctic help better adapt to the changing Arctic. Besides supporting an early career scientist at Penn State University, the proposal will train two graduate student researchers at UCLA in the analysis of observations and climate models. Several UCLA undergraduates will be trained in statistical analysis of climate data, particularly for STEM majors and underrepresented minorities. The idealized models developed in this study will be made available on a GitHub website with sample python scripts.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.

冬季持续的天气系统会导致寒冷，大雨或降雪。这些极端的天气与中纬度喷气流的位置和强度密切相关，后者从西到东，经常向北和南方转向。随着地球的气候变暖，喷气流受到北极上快速表面变暖与热带热带的上层对流层变暖的影响。研究人员将检查几种相互关联的动态机制，用于中纬度 - 北极相互作用和相关的天气极端。第一个主题是稻草圈中的行星波与发生冷事件的风险之间的联系。该任务将检验以下假设：平流层极性涡流中极端波动事件是北美寒冷事件的季节内可预测性的来源。平流层和表面温度之间的这种联系将在观测和气候模型中进行分析。其次，研究人员将研究一个假设，即在快速北极变暖下的较弱的喷射流将导致纬度中间更频繁地极端天气。该任务将执行理想化的数值模拟，以检查喷气速度或喷气速度结构对射流的北班和南方的影响，从而试图调和对中纬度循环循环变化的不同观点，以响应攀登变暖。第三个任务是大气河流，这是与中纬度旋风相关的狭窄强烈水分传输。大气河流在中间和高纬度的极端水分通量中占主导地位，这有助于北极变暖。强烈的水分传输可能会受风速或温度的影响，这两个因素将在水蒸气和云示踪剂的大气传输模型中进行研究。极端的极端天气具有深远的社会经济影响。极端平流层事件的预测能力可以改善北美冬季寒冷的次季节预测，这对能源消耗和运输具有重要意义。在温暖气候下，对极端寒冷事件的更好理解可以促进科学界和公众之间对全球变暖科学的沟通。改善了中纬度气旋进入北极的强烈水分传输的预测，有助于更好地适应不断变化的北极。除了支持宾夕法尼亚州立大学的早期职业科学家外，该提案还将在UCLA培训两名研究生研究人员，以分析观察和气候模型。加州大学洛杉矶分校的本科生将接受攀登数据的统计分析，特别是对于STEM专业和代表性不足的少数民族的培训。本研究中开发的理想化模型将在带有示例Python脚本的GitHub网站上提供。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，认为通过评估被认为是珍贵的支持。

项目成果

North Atlantic Oscillation contributes to the subpolar North Atlantic cooling in the past century

• DOI: 10.1007/s00382-023-06847-y
• 发表时间: 2023-06
• 期刊: Climate Dynamics
• 影响因子: 4.6
• 作者: Yifei Fan;Wei Liu;Pengfei Zhang;Rui Chen;Laifang Li

Contrasting physical mechanisms linking stratospheric polar vortex stretching events to cold Eurasia between autumn and late winter

• DOI: 10.1007/s00382-023-07030-z
• 发表时间: 2023-12
• 期刊: Climate Dynamics
• 影响因子: 4.6
• 作者: Chuntao Zou;Ruonan Zhang;Pengfei Zhang;Lei Wang;Ruhua Zhang