Toward an Improved Understanding of Particle Dry Deposition Velocity

本项目的研究人员将进行实验和理论工作，以提高我们对颗粒干沉积速率的理解，这是颗粒沉降和存款到表面上的过程之一。粒子经历干沉积的速度是我们理解粒子和大气的基础，由于在发生这一过程的小空间尺度上进行观测的复杂性，它仍然具有很大的不确定性。项目团队将在受控实验室环境和现场进行测量，并利用所获得的知识更新颗粒干沉积过程的模型表示。这项研究有望改善空气质量和气候模型。项目组还将开发一个为期5周的气象学和空气质量仪器研讨会，该研讨会将计入大学学分，面向大三和大四的本科生。这项工作有两个主要的科学目标：（1）探索尺寸，化学和其他参数对干沉积速度的影响的室测量;（2）采用涡度相关法和过滤沉积法对难熔炭黑通量进行环境测量。该项目将为研究界提供最新的参数，用于表示干沉积速度，可用于各种模型。干沉积速度的持续大的不确定性（大约两个数量级）激励着项目团队。为了减少这种不确定性，项目小组将：（1）进行气溶胶室测量，以评估气溶胶的大小、相态和形状对干沉积速度的影响;（2）优化测量过滤器提取物中黑碳的技术;（3）对耐火黑碳湍流通量和过滤器沉积进行环境测量;以及（4）改进目前用于气溶胶干沉积模型的分析公式。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The investigators in this project will conduct experimental and theoretical work in order to improve our understanding of the rate of the dry deposition of particles, one of the processes by which particles settle and deposit onto surfaces. The speed at which particles undergo dry deposition, which is fundamental to our understanding of particles and our atmosphere, still has large uncertainties due to the complexity of making observations at the small spatial scales in which this process occurs. The project team will take measurements in controlled laboratory settings as well as in the field and use the knowledge gained to update model representations of the particle dry deposition process. This research is expected to lead to improvements in air quality and climate models. The project team will also develop a 5-week meteorology and air quality instrumentation seminar, which will count towards college credits, geared towards junior and senior undergraduate students.There are two primary scientific objectives in this work: (1) chamber measurements for exploring the impact of size, chemistry, and other parameters on dry deposition velocity; and (2) ambient measurements of refractory black carbon fluxes using both eddy covariance methods and filter deposition techniques. This project will provide the research community with updated parameters for the representation of dry deposition velocity, which could be used by a wide variety of models. The project team is motivated by the persistent large uncertainty (approximately two orders of magnitude) for dry deposition velocity. In order to reduce this uncertainty, the project team will: (1) carry out chamber measurements to assess the effects of aerosol size, phase, and shape on dry deposition velocity; (2) optimize techniques for measuring black carbon from filter extracts; (3) conduct ambient measurements of refractory black carbon turbulent fluxes and filter deposition; and (4) improve the current analytical formulation used in models for aerosol dry deposition.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.