Understanding the Influences of Microphysical Interactions with Pollution and Water on Dust Scattering Properties and Radiative Effects

矿物粉尘是地球系统的一个组成部分，通过一系列与能源、水和碳循环的复杂相互作用影响天气和气候。一旦进入高空，灰尘就会被风带到洲际甚至半球。在长距离迁移过程中，粉尘颗粒会与硫酸铵、硝酸铵、盐酸、生物质燃烧颗粒等污染物混合，导致粉尘成分和吸湿性的变化，进而影响粉尘与水的相互作用。过去，许多研究调查了纯净、未受污染的尘埃气溶胶如何与辐射（如阳光、红外辐射和激光雷达信号）相互作用。然而，污染粉尘和水合粉尘的散射行为仍然知之甚少，这破坏了我们对粉尘在气候系统中的作用的理解，以及我们利用先进的遥感技术检测和检索粉尘气溶胶的能力。该项目旨在研究与污染物和水的微物理相互作用如何影响粉尘气溶胶的散射特性，并评估其对粉尘辐射效应和粉尘遥感的影响。首先，利用先进的散射模型，计算不同粒径、不同波长的纯尘、包覆尘和粉尘-气溶胶混凝等不同混合状态下粉尘颗粒的散射特性；其次，将内部混合粉尘颗粒的散射特性与纯粉尘颗粒的散射特性进行比较；第三，利用辐射传输模型模拟和比较不同混合状态下粉尘的辐射效应，了解粉尘-污染-水相互作用对气候系统的影响。该项目包括指导两名研究生成为下一代大气物理学家。该奖项反映了美国国家科学基金会的法定使命，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。

Mineral dust is an integral component of the Earth system that influences weather and climate via a suite of complex interactions with the energy, water, and carbon cycles. Once aloft, dust can be carried by winds for intercontinental or even hemispherical transport. During long-range transport, the dust particles can become mixed with pollutants such as ammonium sulphate, ammonium nitrate, hydrochloric acid, and biomass burning particles, leading to changes of dust composition and hygroscopicity which in turn influence how dust interacts with water. In the past, many studies have investigated how pure, unpolluted dust aerosols interact with radiations, such as sunlight, infrared radiation and lidar signals. However, the scattering behaviors of polluted dust and hydrated dust are still poorly understood, which undermines our understanding of the role of dust in the climate system, as well as our capability to detect and retrieve dust aerosols using advanced remote sensing techniques. This project is to study how microphysical interactions with pollutants and water influence the scattering properties of dust aerosols and assess the implications for dust radiative effects and dust remote sensing. This goal is achieved through major tasks: First, the scattering properties of dust particles in different mixing states, including pure dust, coated dust and dust-aerosol coagulation, at different sizes and for different wavelengths will be computed using advanced scattering models; Second, the scattering properties of internally mixed dust particles will be compared with those of pure dust; Third, radiative transfer models will be used to simulate and compare the radiative effects of dust in different mixing states to understand the impacts of dust-pollution-water interactions on the climate system. The project involves mentoring two graduate students to be the next generation of atmospheric physicists.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.