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Solving the Coarse Dust Conundrum: What Processes Cause Large-scale Models to Underestimate Coarse Dust Transport?

解决粗尘难题：哪些过程导致大型模型低估粗尘输送？

基本信息

批准号：
1856389
负责人：
Jasper Kok
金额：
$ 79.65万
依托单位：
University of California-Los Angeles
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-06-01 至 2024-05-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1856389&HistoricalAwards=false
关键词：
Solving Coarse Dust Conundrum What

项目摘要

At any given time, our atmosphere contains tens of millions of metric tons of desert dust. This dust seeds clouds and scatters and absorbs sunlight and, when it settles from our atmosphere, fertilizes ecosystems and darkens snow and ice. Basic physics predicts that coarse dust particles - still no larger than the thickness of a human hair - quickly settle out of the atmosphere. However, measurements indicate that this is not the case; instead, coarse dust can remain in the atmosphere for days and travel thousands of kilometers from its source. This dust therefore has more time to impact the Earth and its weather and climate. This makes it critical to determine the processes that cause dust to stay in the atmosphere longer than expected, and account for these missing processes in climate and weather models.This project uses Large Eddy Simulations (LES) and other techniques to test three hypotheses of the nature of the process(es) that help keep coarse dust aloft. Specifically, this project tests whether dust asphericity, electrification, and / or turbulence in dusty layers keep dust aloft against the action of gravitational settling. The project will result in a parameterization of dust gravitational settling that includes these missing processes and that can be used in weather and climate models. This will allow these models to more accurately represent desert dust in the atmosphere and its impact on the Earth system.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.

在任何特定时间，我们的大气中都含有数千万吨的沙漠尘埃。这些尘埃在云层中播下种子，散射并吸收阳光，当它从我们的大气中沉降下来时，就会给生态系统带来肥沃的土壤，并使冰雪变暗。基础物理学预测，粗糙的尘埃颗粒（仍然不大于人类头发的厚度）会迅速从大气中沉降出来。然而，测量表明情况并非如此。相反，粗尘可以在大气中停留数天，并从其源头传播数千公里。因此，这些尘埃有更多的时间影响地球及其天气和气候。因此，确定导致灰尘在大气中停留时间超过预期的过程，并在气候和天气模型中解释这些缺失的过程至关重要。该项目使用大涡模拟 (LES) 和其他技术来测试有助于粗灰尘保持在高空的过程性质的三个假设。具体来说，该项目测试灰尘的非球面性、带电性和/或灰尘层中的湍流是否使灰尘保持在高空以抵抗重力沉降的作用。该项目将实现尘埃重力沉降的参数化，其中包括这些缺失的过程，可用于天气和气候模型。这将使这些模型能够更准确地表示大气中的沙漠尘埃及其对地球系统的影响。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。