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随处可见，由直径大小不一的小矿物颗粒组成。理论表明，对于长距离输送的尘埃，由于向下的重力作用，这些颗粒的直径应该限制在大约10微米或更小，以将较大的颗粒从大气中移走。然而，直径从几十微米到数百微米的尘埃颗粒在距离沙漠数千公里的地方进行了测量，它们被排放到大气中。到目前为止，对于这一所谓的“巨大尘埃粒子难题”还没有得到公认的解释，这突显了对大气和气溶胶过程的物理理解的差距。由于沙尘暴对天气和气候的影响--从吸收阳光到成为海洋生物活动的催化剂--的程度取决于尘埃的物理特征，包括颗粒大小，因此需要解决这一难题。该项目旨在提高对直径大于10微米的尘埃颗粒(超粗和巨型尘埃，或称SCG尘埃)在大气中运动的了解，并在解决巨型尘埃粒子难题方面取得进展。将测量垂直扩散和水平平流输送过程中SCG粉尘浓度的尺寸分辨变化。此外，还将测量SCG粉尘在排放点的尺寸分辨垂直通量。然后，这些测量将被用来检验两个可以解释这个难题的假设：(I)当前的理论严重高估了这些大颗粒在垂直湍流扩散和水平平流输送过程中的干沉积，以及(Ii)SCG尘埃排放时的通量比理论预测的要大一到几个数量级。这些数据将提供一个独特的机会来评估管理这些颗粒的排放和大气传输的理论，并产生新的方法来在天气和气候模型中表示这些过程。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。