Variability of African Easterly Waves and Their Interactions with Saharan Mineral Dust Aerosols

非洲东风波的变化及其与撒哈拉矿物尘气溶胶的相互作用

基本信息

批准号：
2108233
负责人：
Christopher Thorncroft
金额：
$ 49.5万
依托单位：
SUNY at Albany
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：
2021-07-15 至 2024-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2108233&HistoricalAwards=false
关键词：
Variability African Easterly Waves Their

项目摘要

Just as weekly weather reports for the US focus on warm fronts and cold fronts, a summer weather report for West Africa might feature African Easterly Waves (AEWs), weather patterns with troughs and ridges separated by perhaps 1,500km that move eastward over the Sahel and across much of the downwind Atlantic. The report might also mention a vast plume of airborne Saharan dust moving along a similar trajectory to the AEWs. The proximity of Saharan dust plumes and AEWs suggests that the two might interact, since winds associated with an AEW could stir up dust and transport it, while solar radiation absorbed by the dust could cause atmospheric heating that would affect the evolution of the AEW. But the interaction of AEWs and dust plumes has not been extensively studied, and the extent to which dust lofted and transported by AEWs in turn affects the AEWs is not well understood. Previous work by the Principle Investigators (PIs) of this award shows, in an idealized context, that radiative heating from dust can contribute to the development of AEWs (see award #1524767).Work under this award uses a combination of observational analysis and numerical model experiments to better understand the interactions of AEWs and Saharan dust plumes. On the observational side the project takes advantage of the Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2) produced by the NASA Global Modeling and Assimilation Office). MERRA-2 is a valuable resource for the work because it tracks desert dust based on satellite observations and provides dust optical depth and radiative heating along with the standard meteorological variables. The modeling component uses the Weather Research and Forecast (WRF) model in an idealized configuration to identify unstable modes corresponding to AEWs. The simulations are performed with and without dust radiative heating so that its effects on the wavelength, phase speed, and growth rates of the AEW modes can be assessed. Additional experiments are performed using the Unified Forecast System model, again with and without dust radiative heating, to assess the influence of dust heating in a more realistic setting.The work has societal relevance due to its potential contribution to improving weather and air quality forecasts. Better forecasts of AEWs would benefit the US as well as the nations of West Africa since AEWs play a key role in generating hurricanes, including those that make landfall on the eastern seaboard. Saharan dust is also an intercontinental problem as it affects air quality in Africa, the Caribbean, and the US. The PIs work with the Africa Desk of the National Weather Service's Climate Prediction Center to incorporate research results into weekly weather outlooks and short-range dust forecasts. In addition, the project provides support and training to a graduate student.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.

正如美国每周的天气报道有关美国的临时和寒冷阵线的关注一样，西非的夏季天气报告可能包括非洲东部的海浪（AEWS），天气模式，槽和山脊被大概1,500公里隔开，可能向东移动，这些浪潮向东移动，越过了萨赫勒，并且在下兰大西洋上。该报告还可能提到沿着与AEWS类似的轨迹移动的大量空中撒哈拉尘羽。撒哈拉尘羽和AEW的接近性表明两者可能相互作用，因为与AEW相关的风可以搅动灰尘并运输灰尘，而被灰尘吸收的太阳辐射可能会导致大气加热，从而影响AEW的演变。但是，尚未对AEW和灰尘羽毛的相互作用进行广泛的研究，而AEWS的尘埃抬高和运输的程度又影响了AEWS。该奖项的主要研究人员（PIS）的先前工作表明，在理想化的背景下，尘埃的辐射加热可以有助于AEWS的发展（请参阅奖项＃1524767）。根据该奖项的工作结合了观察性分析和数值模型实验的组合，以更好地了解AEWS和Saharan Dust Plume的相互作用。在观察方面，该项目利用了现代的研究和应用程序回顾性分析，由NASA全球建模和同化办公室生产的版本2（MERRA-2））。 MERRA-2是工作的宝贵资源，因为它根据卫星观测来跟踪沙漠灰尘，并提供尘埃深度和辐射加热以及标准气象变量。建模组件在理想化的配置中使用天气研究和预测（WRF）模型来识别与AEWS相对应的不稳定模式。在有或没有尘埃辐射加热的情况下进行模拟，以便评估其对AEW模式的波长，相速和生长速率的影响。使用统一的预测系统模型进行了其他实验，并在更现实的环境中评估灰尘加热的影响。该工作具有社会相关性，这是由于其潜在的贡献了改善天气和空气质量预测。自AEWS在产生飓风中起着关键作用，包括在东部沿海地区登陆的人，对AEWS的预测更好将使美国以及西非国家受益。撒哈拉尘埃也是一个洲际问题，因为它影响了非洲，加勒比海和美国的空气质量。 PIS与国家气象局气候预测中心的非洲办公桌合作，将研究结果纳入每周的天气前景和短期灰尘预测中。此外，该项目为研究生提供了支持和培训。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影响的评论标准来评估值得支持的。