Advancing Understanding of Super-Coarse and Giant Dust Particles via Novel Measurements of Emission and Transport

通过新颖的排放和传输测量方法增进对超粗和巨型灰尘颗粒的了解

• 批准号: 2336111
• 负责人: Amato Evan
• 金额: $ 70.21万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2336111&HistoricalAwards=false
• 关键词: Advancing; Understanding; Super; Coarse; Giant

Dust storms are ubiquitous in Earth’s atmosphere and are composed of small mineral particles having diameters of varying sizes. Theory suggests that for dust transported long distances, the diameters of these particles should be limited to approximately 10 microns or smaller, due to the downward gravitational force acting to remove larger particles from the atmosphere. However, dust particles with diameters of tens to even hundreds of microns in size have been measured thousands of kilometers away from the deserts where they were lofted into the atmosphere. To-date, there is no accepted explanation for this so-called “giant dust particle conundrum”, highlighting a gap in physical understanding of atmospheric and aerosol processes. Since the magnitudes of dust storm effects on weather and climate, ranging from the absorption of sunlight to being a catalyst for biological activity in the oceans, depend on the physical characteristics of dust, including the particle sizes, there is a need to solve this conundrum. This project aims to improve understanding of the movement of dust particles having diameters greater than 10 microns (super coarse and giant particles, or SCG dust) in the atmosphere, and make progress towards solving the giant dust particle conundrum. Size-resolved changes in the concentrations of SCG dust during vertical diffusive and horizontal advective transport will be measured. Additionally, the size-resolved vertical flux of SCG dust at the point of emission will also be measured. These measurements will then be used to test two hypotheses that could explain the conundrum: (i) that current theory grossly overestimates dry deposition of these large particles during both vertical turbulent diffusive and horizontal advective transport and (ii) that the flux of SCG dust at emission is one to several orders of magnitude greater than that predicted by theory. These data will provide a unique opportunity to evaluate the theory governing the emission and atmospheric transport of these particles, and to generate new methods to represent these processes in weather and climate models.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.

沙尘暴在地球大气层中无处不在，由直径不同的小矿物颗粒组成，理论表明，由于向下的重力，对于长距离的沙尘输送，这些颗粒的直径应限制在大约 10 微米或更小。然而，迄今为止，在距离沙漠数千公里的地方已经测量到了直径为数十甚至数百微米的尘埃颗粒。对于这个所谓的“巨型尘埃粒子难题”，目前还没有公认的解释，这突显了人们对大气和气溶胶过程的物理理解上的差距，因为沙尘暴对天气和气候的影响范围从吸收阳光到影响大气。海洋中生物活动的催化剂取决于灰尘的物理特性，包括颗粒大小，因此需要解决这个难题，该项目旨在提高对直径大于 10 微米（超级）的灰尘颗粒运动的了解。粗大颗粒，或SCG灰尘）在大气中，并在解决垂直扩散和水平平流输送过程中SCG灰尘浓度的尺寸分辨变化方面取得进展，还将测量SCG灰尘的尺寸分辨垂直通量。然后，这些测量结果将用于测试可以解释这一难题的两个假设：（i）当前的理论严重高估了这些大颗粒在垂直湍流期间的干沉积。扩散和水平平流输送以及（ii）SCG 粉尘排放时的通量比理论预测的大一到几个数量级。这些数据将为评估控制这些粉尘的排放和大气输送的理论提供一个独特的机会。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。