Improved Understanding of the Moist Dynamics of the Extratropical Storm Tracks and Their Response to Climate Change

更好地了解温带风暴路径的潮湿动力学及其对气候变化的响应

基本信息

批准号：
2031472
负责人：
Paul O'Gorman
金额：
$ 44.01万
依托单位：
Massachusetts Institute of Technology
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：
2021-02-01 至 2025-01-31
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2031472&HistoricalAwards=false
关键词：
Improved Understanding Moist Dynamics Extratropical

项目摘要

At a fundamental level the frontal weather systems we see on maps can be explained by the theory of baroclinic instability, in which small disturbances grow by extracting energy from the temperature contrast between the warm tropics and the cold poles. The theory works but it neglects the enormous heat release that occurs when water vapor condenses to form clouds and precipitation. It is reasonable to assume that condensational heating is destabilizing but our understanding of its effects on the growth rate, propagation speed, precipitation intensity, and other aspects of weather systems is quite limited. The role of condensational heating is a practical concern as the amount of water vapor in the atmosphere increases with temperature, thus one might expect more intense precipitation and stronger storms as climate warms.Work under this award seeks to develop a theoretical basis for the effects of condensational heating on baroclinic instability and the dependence of these effects on global temperature. One target of the study is diabatic Rossby vortices (DRVs, also called diabatic Rossby waves), which are relatively small-scale weather systems fueled by condensational heating which propagate quickly and can intensify rapidly into powerful storms. DRVs were first identified in simplified model simulations but have now been implicated in the development of severe storms like winter storm Lothar in 1999, among the most destructive to hit western Europe in several decades. A more theoretical concern is the effect of condensational heating on the most unstable baroclinic mode, meaning the pattern of troughs and ridges that grows most rapidly for a given middle-latitude temperature contrast and its accompanying upper-level jet stream. Earlier work by the Principal Investigator and others shows that condensational heating causes the regions of upward motion in the mode to contract and become more intense relative to the regions of downward motion. The narrowing and intensification of the updraft regions is important as it increases the likelihood of extreme precipitation.The work has societal relevance due to its focus on the strength of weather systems, the intensity of precipitation they generate, and the extent to which warmer temperatures lead to more destructive storms. The project also provides support and training to a graduate student, thereby contributing to the future workforce in this research area. In addition, the Principal Investigator serves as a faculty mentor in the MIT Summer Research Program, which seeks to increase the engagement of undergraduate students from underserved minority groups in science and engineering.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.

在基本层面上，我们在地图上看到的额叶天气系统可以用斜压不稳定性理论来解释，在这种理论中，小干扰通过从温暖的热带和冷杆之间的温度对比中提取能量来生长。该理论起作用，但它忽略了水蒸气凝结形成云和降水时发生的巨大热量释放。可以合理地假设凝聚力加热是不稳定的，但是我们对其对天气系统的生长速度，繁殖速度，降水强度和其他方面的影响的理解非常有限。凝结加热的作用是一个实际问题，因为大气中的水蒸气量随温度的增加而增加，因此，随着气候温暖，人们可能会期望更强烈的降水量和更强烈的暴风雨。在该奖项下，工作旨在为凝聚力加热对Baroclinic不稳定性的影响和对全球温度的影响而产生理论基础。该研究的一个目标是绝热的rossby涡流（DRV，也称为绝生Rossby Wave），它们是相对较小的天气系统，其由凝聚的加热燃料加油，可以迅速传播，并可以迅速加强到强大的风暴中。 DRV首先在简化的模型模拟中确定，但现在与1999年冬季风暴洛萨（Winter Storm Lothar）这样的严重风暴的发展牵涉，这是几十年来最受袭击的西欧。一个理论上的关注点是冷凝性加热对最不稳定的斜压模式的影响，这意味着在给定的中纬度温度对比度及其伴随的上层喷射流的槽和山脊模式。首席研究人员和其他研究人员的早期工作表明，凝结加热会导致模式下的向上运动区域收缩，并相对于向下运动的区域变得更加强烈。上升气流区域的狭窄和强化很重要，因为它增加了极端降水的可能性。由于其专注于天气系统的强度，它们产生的降水量以及更高的温度导致更具破坏性的风暴，因此该工作具有社会相关性。该项目还向研究生提供支持和培训，从而为该研究领域的未来劳动力做出了贡献。此外，首席研究员是麻省理工学院夏季研究计划的教师导师，该计划旨在增加科学和工程领域服务不足的少数群体的本科生的参与。该奖项反映了NSF的法定任务，并被认为是通过使用该基金会的知识分子和更广泛影响的评估来评估CRITERIA的评估。