Changes in Impacts-relevant Climate in the World’s Mediterranean Climate Regions: A Mechanisms-based Investigation of Atmosphere-Ocean-Land Processes Across Seasons

世界地中海气候区影响相关气候的变化：基于机制的跨季节大气-海洋-陆地过程调查

• 批准号: 2127684
• 负责人: Richard Seager
• 金额: $ 94.68万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-15 至 2024-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2127684&HistoricalAwards=false
• 关键词: Changes; Impacts; relevant; Climate; World

The climate of the Mediterranean features warm dry summers and mild wet winters, perfect conditions for its world-renowned vinyards and olive groves. But the Mediterranean climate is not unique to the countries bordering the Mediterranean Sea, as similar conditions exist on the US west coast, central Chile, southern Africa, and southwest Australia, all situated along the west coasts of their respective continents. These Mediterranean Climate Regions (MCRs) are found at the margins of the subtropics, meaning latitudes low enough to be under the dry subtropical anticyclones in summer but high enough to receive rain from the winter weather systems of the middle latitudes. The marginal location of the MCRs makes them vulnerable to changes in climate associated with both the midlatitude winter and the subtropical summer: if the winter storm paths shift to higher latitudes, an expected consequence of greenhouse warming, the MCRs could see loss of winter rain, while summers could experience heat waves and wildfires due to the expansion of the subtropical dry zones. The issue of climate change in MCRs has taken on some urgency given the wilfdires and heat waves in California and the long-term decline in rainfall over Spain as the Atlantic storm paths have shifted northward.This project examines climate change in the MCRs, examining the issue in the framework of their shared climatic features and attempting to relate climate change on the ground to warming-induced changes in the large-scale circulation of the atmosphere. One issue is the extent to which the regions behave differently despite their commonalities, for instance California has not experienced a decline in winter rainfall comparable to the Iberian Peninsula. The specific goals of the proposal are to 1) identify the changes in storms tracks, jet streams, subtropical highs, subsidence and seasonal cycles of precipitation and temperature that matter for each MCR, 2) relate these to changes in the global atmospheric circulation and 3) determine the induced changes in climatic conditions relevant to water resources, wildfire, and agriculture. An emergent constraint methodology, in which aspects of present-day climate in model simulations, which can be checked against observations, are related to the behavior of future climate projections from the same models. The methodology provides a way to use present-day observations to assess the credibility of future climate projections.The fate of MCRs in a warming climate is a question of societal as well as scientific interest given the hazards facing people and the natural environment in these regions. The Principal Investigators work with MedCLIVAR, a subgroup of International CLIVAR that coordinates Mediterranean climate research. Local outreach is conducted through the biennial Lamont Open House. The award provides support and training to a graduate student, thereby developing the future scientific workforce in this research area.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.

地中海气候夏季温暖干燥，冬季温和潮湿，为世界著名的葡萄园和橄榄园提供了完美的条件。 但地中海气候并不是地中海沿岸国家所独有的，美国西海岸、智利中部、非洲南部和澳大利亚西南部也存在类似的情况，这些国家都位于各自大陆的西海岸。 这些地中海气候区（MCR）位于亚热带边缘，这​​意味着纬度足够低，可以在夏季受到干燥的亚热带反气旋的影响，但又足够高，可以接收来自中纬度冬季天气系统的降雨。 MCR 的边缘位置使它们容易受到与中纬度冬季和亚热带夏季相关的气候变化的影响：如果冬季风暴路径转移到高纬度地区（温室变暖的预期后果），MCR 可能会出现冬季降雨减少，而由于亚热带干旱区的扩大，夏季可能会出现热浪和野火。 鉴于加利福尼亚州的野火和热浪，以及大西洋风暴路径向北移动，西班牙降雨量长期下降，MCR 地区的气候变化问题变得更加紧迫。该项目研究了 MCR 地区的气候变化，研究了在它们共同的气候特征的框架内讨论问题，并试图将地面气候变化与变暖引起的大规模大气环流变化联系起来。 一个问题是，尽管各地区有共同点，但其表现却有所不同，例如，加利福尼亚州的冬季降雨量并未像伊比利亚半岛那样减少。 该提案的具体目标是 1) 确定对每个 MCR 重要的风暴路径、急流、副热带高压、沉降以及降水和温度的季节性循环的变化，2) 将这些变化与全球大气环流的变化联系起来，3) ）确定与水资源、野火和农业相关的气候条件的诱发变化。 一种新兴约束方法，其中模型模拟中当前气候的各个方面（可以根据观测进行检查）与相同模型预测的未来气候的行为相关。 该方法提供了一种利用当前观测来评估未来气候预测可信度的方法。考虑到这些地区的人类和自然环境面临的危害，MCR 在气候变暖中的命运是一个社会和科学关注的问题。首席研究员与 MedCLIVAR 合作，MedCLIVAR 是国际 CLIVAR 的一个小组，负责协调地中海气候研究。通过两年一度的拉蒙特开放日活动进行当地宣传。该奖项为研究生提供支持和培训，从而培养该研究领域的未来科学人才。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Record Low North American Monsoon Rainfall in 2020 Reignites Drought over the American Southwest

2020年北美季风降雨量创历史新低，美国西南部地区再次出现干旱

• DOI: 10.1175/bams-d-21-0129.1
• 发表时间: 2022-03-01
• 期刊: Bulletin of the American Meteorological Society
• 影响因子: 8
• 作者: A. Hoell;X. Quan;M. Hoerling;R. Fu;J. Mankin;I. Simpson;R. Seager;C. He;F. Lehner;Joel Lisonbee;B. Livneh;Am;a Sheffield;a
• 通讯作者: a

Climate Dynamics Preceding Summer Forest Fires in California and the Extreme Case of 2018

加州夏季森林火灾前的气候动态以及 2018 年的极端情况

• DOI: 10.1175/jamc-d-21-0198.1
• 发表时间: 2022-08
• 期刊: Journal of Applied Meteorology and Climatology
• 影响因子: 3
• 作者: Jacobson, Tess W.;Seager, Richard;Williams, A. Park;Henderson, Naomi
• 通讯作者: Henderson, Naomi

Water Year 2021 Compound Precipitation and Temperature Extremes in California and Nevada

2021 年水年加利福尼亚州和内华达州的复合降水量和极端温度

• DOI: 10.1175/bams-d-22-0112.1
• 发表时间: 2022-12-01
• 期刊: Bulletin of the American Meteorological Society
• 影响因子: 8
• 作者: A. Hoell;X. Quan;M. Hoerling;H. Diaz;R. Fu;C. He;Joel Lisonbee;J. Mankin;R. Seager;Am;a Sheffield;a;I. Simpson;E. Wahl
• 通讯作者: E. Wahl

Ocean-forcing of cool season precipitation drives ongoing and future decadal drought in southwestern North America

冷季降水的海洋强迫导致北美西南部持续和未来的十年干旱

• DOI: 10.1038/s41612-023-00461-9
• 发表时间: 2023-09
• 期刊: npj Climate and Atmospheric Science
• 影响因子: 9
• 作者: Seager, Richard;Ting, Mingfang;Alexander, Patrick;Liu, Haibo;Nakamura, Jennifer;Li, Cuihua;Newman, Matthew
• 通讯作者: Newman, Matthew

Mechanisms of a Meteorological Drought Onset: Summer 2020 to Spring 2021 in Southwestern North America

气象干旱发生机制：北美西南部 2020 年夏季至 2021 年春季

• DOI: 10.1175/jcli-d-22-0314.1
• 发表时间: 2022-11
• 期刊: Journal of Climate
• 影响因子: 4.9
• 作者: Seager, Richard;Ting, Mingfang;Alexander, Patrick;Nakamura, Jennifer;Liu, Haibo;Li, Cuihua;Simpson, Isla R.
• 通讯作者: Simpson, Isla R.