Collaborative Research: Forced Trends in the Tropical Pacific and Global Tropical Cyclones

合作研究：热带太平洋和全球热带气旋的强迫趋势

• 批准号: 2217618
• 负责人: Chia-Ying Lee
• 金额: $ 83.02万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2217618&HistoricalAwards=false
• 关键词: Collaborative; Research; Forced; Trends; Tropical

The temperature contrast between the "warm pool" region of the western equatorial Pacific and the "cold tongue" in the east is remarkable: visitors to the Solomon islands find sea surface temperatures (SSTs) above 80F while visitors to the Galapagos don wetsuits to go snorkeling. Naturally the temperature contrast has a variety of effects on the weather and climate of the tropics, one of which is the relative abundance of hurricanes (also called typhoons and TCs, for tropical cyclones) which are more abundant in the western Pacific than anywhere else in the world. The influence of the SST contrast can be seen in comparisons between El Nino events, in which the contrast weakens due to warming in the cold tongue region, and La Nina events, which strengthen the contrast. El Nino years feature fewer TCs in the western Pacific and more in the central and eastern Pacific, with the opposite pattern in La Nina years.The influence of El Nino and La Nina on TCs and other aspects of tropical weather and climate begs the question: will the equatorial Pacific SST contrast be strengthened or weakened by greenhouse gas-induced global warming? The evidence is mixed since climate models generally show weakening as the earth warms but observations show strengthening over the past few decades. The mismatch could be due to the internal variability of the climate system, which operates even as greenhouse gas increases warm the world. But it is also possible that climate model biases, in particular the bias of a cold tongue which is too cold and too extensive, lead to incorrect simulations of the effects of greenhouse warming.Work under this award addresses the possible effect of the cold tongue bias on the simulated SST contrast change using a technique called flux adjustment, in which the exchange of heat and moisture between the atmosphere and ocean is modified to eliminate the cold tongue bias in present-day climate simulations. The flux-adjusted climate model is then used to simulate the response of the SST contrast to greenhouse gas increases. The work is carried out with the Community Earth System Model version 2 (CESM2).The effects of an El Nino-like or La Nina-like SST warming pattern on tropical cyclones is difficult to assess from climate model simulations because the resolution of climate models is not typically high enough to simulate TCs. One strategy pursued here is to simulate TCs using shorter simulations from a high-resolution atmosphere-only model which is run over the SST warming pattern produced by the climate model. Another is to use the Columbia HAZard model (CHAZ), an empirical TC model developed by the lead Principal Investigator (PI). CHAZ uses large-scale atmospheric conditions from the climate model or observational datasets to predict the tracks and intensities of "synthetic" TCs that are initiated at random based on a TC genesis index.The work has societal as well as scientific value given the consequences of warming-induced changes in TC behavior. It is clear that warming causes the most intense hurricanes to become stronger and more destructive, thus efforts to anticipate changes in the distribution of TCs across the Pacific are valuable for climate adaptation and disaster risk reduction. The PIs have strong ties to the World Bank, the reinsurance industry, and other relevant stakeholders through the Columbia World project. They also conduct extensive media outreach on climate change-related topics including TC risk. In addition, the project supports a postdoctoral fellow and a graduate student, thereby promoting the future 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.

西赤道太平洋地区的“温暖池”区域与东方的“冷舌”之间的温度对比是显着的：所罗门群岛的游客发现了高于80F的海面温度（SST），而访客的访客是Galapagos Don Wetsuits的访客进行浮潜。自然地，温度对比对热带的天气和气候具有多种影响，其中之一是飓风的相对丰度（也称为台风和TC，对热带气旋）在西太平洋地区比世界其他任何地方都更丰富。 在El Nino事件之间的比较中，可以看到SST对比度的影响，在El Nino事件之间，由于冷舌区域的变暖而削弱了对比度，以及La Nina事件，从而增强了对比度。 埃尔尼诺（El Nino）年份在西太平洋地区的TC较少，在中部和东部太平洋地区的TC较少，在La Nina时期的模式相反。ElNino和La Nina对TCS和热带天气和气候的其他方面的影响会引起问题：赤道太平洋SST对比会被温室气体加强或弱化吗？ 由于气候模型通常随着地球的变暖而显示出弱，但观察结果在过去几十年中表现出加强，因此证据混合在一起。 不匹配可能是由于气候系统的内部变异性，即使温室气体增加了温暖的世界，也可以运作。 But it is also possible that climate model biases, in particular the bias of a cold tongue which is too cold and too extensive, lead to incorrect simulations of the effects of greenhouse warming.Work under this award addresses the possible effect of the cold tongue bias on the simulated SST contrast change using a technique called flux adjustment, in which the exchange of heat and moisture between the atmosphere and ocean is modified to eliminate the cold tongue bias in present-day climate模拟。 然后，使用通量调整的气候模型来模拟SST与温室气体增加的响应。这项工作是使用社区地球系统模型2版（CESM2）进行的。很难通过气候模型模拟来评估El Nino样或类似La Nina的SST变暖模式对热带旋风的影响，因为气候模型的分辨率通常不足以模拟TCS。 这里采取的一种策略是使用来自高分辨率大气模型的较短模拟来模拟TC，该模型通过气候模型产生的SST变暖模式运行。 另一个是使用哥伦比亚风险模型（CHAZ），这是由主要主要研究员（PI）开发的经验TC模型。 Chaz使用来自气候模型或观察数据集的大规模大气条件来预测基于TC Genesis Index随机启动的“合成” TC的轨道和强度。鉴于TC行为变暖引起的变化的后果，这项工作具有社会价值以及科学价值。 显然，变暖会导致最激烈的飓风变得更加强大，更具破坏性，因此预期在太平洋中TC分布的变化的努力对于气候适应和减少灾害风险是有价值的。 PI通过哥伦比亚世界项目与世界银行，再保险行业和其他相关利益相关者有着密切的联系。 他们还对包括气候变化有关的主题在内进行了广泛的媒体宣传，包括TC风险。 此外，该项目还支持博士后研究员和一名研究生，从而促进了该研究领域的未来劳动力。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子和更广泛影响的评估评估标准的评估来支持的。

项目成果

State of the Climate in 2022. The Tropics

2022 年气候状况。热带地区

• DOI: 10.1175/bams-d-23-0078.1
• 发表时间: 2023
• 期刊: Bulletin of the American Meteorological Society
• 影响因子: 8
• 作者: Diamond, Howard J.;Schreck, Carl J.;Allgood, Adam;Becker, Emily J.;Blake, Eric S.;Bringas, Francis G.;Camargo, Suzana J.;Chen, Lin;Coelho, Caio A.S.;Fauchereau, Nicolas
• 通讯作者: Fauchereau, Nicolas

An Update on the Influence of Natural Climate Variability and Anthropogenic Climate Change on Tropical Cyclones

• DOI: 10.1016/j.tcrr.2023.10.001
• 发表时间: 2023-10
• 期刊: Tropical Cyclone Research and Review
• 影响因子: 2.9
• 作者: Suzana J. Camargo;Hiroyuki Murakami;N. Bloemendaal;S. Chand;Medha S. Deshpande;Christian Dominguez-Sarmiento-Christian-Domi

Near-term tropical cyclone risk and coupled Earth system model biases

近期热带气旋风险和耦合地球系统模型偏差

• DOI: 10.1073/pnas.2209631120
• 发表时间: 2023
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Sobel, Adam H.;Lee, Chia-Ying;Bowen, Steven G.;Camargo, Suzana J.;Cane, Mark A.;Clement, Amy;Fosu, Boniface;Hart, Megan;Reed, Kevin A.;Seager, Richard
• 通讯作者: Seager, Richard