East Pacific Easterly Waves: Interactions With Wind Jets in Current and Future Climate

东太平洋东风波：当前和未来气候中与风喷射的相互作用

基本信息

批准号：
2217785
负责人：
Eric Maloney
金额：
$ 40.02万
依托单位：
Colorado State 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=2217785&HistoricalAwards=false
关键词：
East Pacific Easterly Waves Interactions

项目摘要

East-to-west moving waves with wavelengths of about 1,000km are an important weather feature in the region spanning West Afria, the subtropical and tropical Atlantic, the Caribbean, and the low-latitude equatorial Pacific. These easterly waves (or EWs, meaning waves moving from the east) are best known as the precursors to hurricanes but they are also important rain-bearing systems in West Africa the Caribbean, and Central America. Despite the importance of EWs their formation mechanisms and sensitivities to ambient conditions are still not fully understood. One issue of particular interest for East Pacific EWs is their interaction with the Central American topography. Central America is known for its gap winds, strong winds that funnel through gaps in the American Cordillera, one at the Isthmus of Tehuantepec, another at the Gulf of Papagayo in northern Costa Rica, and a third that channels air through the mountains and into the Panama Bight. Previous work by the Principal Investigator (PI) considered the role of the gap jets, in particular the horizontal shear of the jets, in promoting the generation of East Pacific EWs and reinvigorating EWs which have crossed Central America from the Caribbean. Work conducted under this award would use eddy kinetic energy and vorticity budget calculations to elucidate the effects of the gap jets. Further work uses computer models to study the effects of gap winds by creating simulations in which the Central American topography is artifically altered to fill in the gaps and block the jets. In addition to the direct effects of the jets and associated wind shear on developing EWs the project considers the potential impact of the cooling of the ocean surface by strong surface winds. Cooler sea surface temperatures (SSTs) can inhibit convection and precipitation, which could hinder the development of EWs.Additional work examines the effects of climate change on gap flows and EWs. The PI's recent analysis of climate model simulations suggests that gap flows near the Gulf of Papagayo will strengthen as the world warms, and the strengthening could enhance EW formation. Work conducted here revisits this issue using the regional Weather Research and Forecasting (WRF) model, which can be run at considerably higher resolution to better resolve the gap topography and the mesoscale dynamics of EWs. A further consideration is that EWs may shift away from the Central American coast, causing potentially serious reductions in rainfall and water resources in the region. Changes in the location of fully-developed EWs may be strongly influenced by the pattern of Pacific SST trends, and WRF simulations are used in combination with climate model simulations from the Community Earth System Model (CESM) to address the effects of SST trends.The work has societal value due to the importance of EWs for hurricane formation and as rain-bearing weather systems for agriculture and water resources. In addition, the PI's group mentors undergraduate summer interns through the Earth System Modeling and Education Institute (ESMEI), a Research Experiences for Undergraduates (REU) program at Colorado State University. The PI also works with the Bridge Program of the American Geophysical Union to recruit graduate students from diverse backgrounds. The project provides support and training to one graduate student, thereby developing 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.

波长约1,000公里的东到西部移动波是跨越西阿发场，亚热带和热带大西洋，加勒比海地区和低纬度赤道太平洋地区的重要天气特征。这些东非的海浪（或EWS，意味着从东方移动的海浪）是飓风的前体，但它们也是西非加勒比海和中美洲的重要雨水系统。尽管EWS的重要性很重要，但它们的形成机制和敏感性对环境条件仍然尚未完全理解。东太平洋EWS特别感兴趣的一个问题是它们与中美洲地形的互动。中美洲以其间隙的风，强风，在美国山脉的缝隙中漏出的强风，一个在Tehuantepec的地峡，另一个位于哥斯达黎加北部的帕帕加约湾，三分之一，通道通过山脉，进入山区，进入了巴拿马。首席研究员（PI）先前的工作考虑了间隙喷射的作用，特别是喷气机的水平剪切，在促进东太平洋EWS的产生和重新振奋的EWS中，这些EWS已从加勒比海跨越中美洲。根据该奖项进行的工作将使用涡流能量和涡度预算计算来阐明差距喷气机的影响。进一步的工作使用计算机模型来研究差距风的效果，通过创建中美洲地形的模拟进行了人工修改以填补空白并阻止喷气机。除了喷气机和相关的风剪对开发EWS的直接影响外，该项目还考虑了强表面风向海面冷却的潜在影响。较冷的海面温度（SST）可以抑制对流和降水，这可能会阻碍EWS的发展。 PI最近对气候模型模拟的分析表明，随着世界的温暖，帕帕加约湾附近的间隙流将加强，并且加强可以增强EW的形成。这里进行的工作使用区域天气研究和预测（WRF）模型重新审视了此问题，该模型可以以更高的分辨率运行，以更好地解决EWS的间隙地形和中尺度动力学。另一个考虑因素是，EWS可能会从中美洲海岸转移，从而导致该地区降雨和水资源可能严重减少。完全发达的EWS位置的变化可能会受到太平洋SST趋势模式的强烈影响，WRF模拟与社区地球系统模型（CESM）的气候模型模拟结合使用，以解决SST趋势的效果。该工作具有社会价值，因为EWS对于飓风形式和雨水供应的天气和水资源的重要性，因此具有社会价值。此外，PI的小组导师通过地球系统建模和教育研究所（ESMEI）的本科生实习生是科罗拉多州立大学的本科生（REU）计划的研究经验。 PI还与美国地球物理联盟的桥梁计划合作，以招募来自不同背景的研究生。该项目为一名研究生提供了支持和培训，从而在该研究领域开发了未来的劳动力。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优点和更广泛的影响评估标准通过评估来获得支持的。