Aerosols-Climate Interactions: Development and Tests of a Dust Lifting Model

气溶胶通过散射和吸收太阳和红外辐射产生直接辐射强迫，通过改变云过程产生间接辐射强迫。由于人类活动已经引起大气气溶胶浓度的显著增加，因此了解气溶胶对气候的影响是极其重要的。了解天然气溶胶的作用以及它们如何受到人类的影响，对于量化气溶胶对气候的辐射强迫具有重要意义。最近发现的证据表明，粉尘带电和由此产生的电力在扬尘中起着重要作用。这个气溶胶气候问题正在通过发展一个基于物理的扬尘模型来解决，并利用它来研究电力对扬尘的影响，并通过定期的风吹跳跃、沙尘暴、对流羽流和涡旋来运输。该模型是第一个包括粉尘电气化和电力对粉尘提升的潜在重要影响。该模型一经开发和测试，就将提供给科学界。在风沙跃迁、沙尘暴、对流涡旋等各种自然扬尘过程中，均测量到高达100- 200kv /m的电场。实验室研究表明，这些电场可以直接将土壤颗粒从表面提起。计算表明，这些电场可以大大降低引发跃迁所需的阈值风速。弹跳是指较大的沙粒被风移动并在表面反弹，将较小的沙粒喷射到空气中的过程。静电效应可以增强这一过程。正在实地和实验室环境中进行测量。这些观测结果构成了在天气和气候模拟模式中将静电效应包括在对流羽流和涡旋的扬尘和输送参数化中的基础。这种尘埃通量参数化包括从大气表层到对流层顶部的天然和人造气溶胶的输送。这项研究对科学和社会有几个更广泛的影响。除了研究对我们理解全球气候变化至关重要的科学问题外，扬尘模型和扬尘通量参数化将为科学界提供广泛的建模环境。一个教育网站正在开发，对对流羽流、尘卷风和沙尘暴的形成进行简单的物理解释。这个网站比较了地球和其他行星的天气现象。将扩大到对跳跃、粉尘电气化、电力对粉尘提升的影响等内容的说明。最后，这个研究项目将有助于培养一名研究生。

Aerosols produce direct radiative forcing by scattering and absorbing solar and infrared radiation, and indirect radiative forcing by altering cloud processes. Since human activity has been causing significant increases in the concentration of atmospheric aerosols, it is extremely important to understand the effects of aerosols on climate. Understanding the role of natural aerosols and how they are influenced by humans is important to the quantification of aerosols' radiative forcing on climate. Recently found evidence suggests that dust electrification and the resulting electrical forces play an important role on dust lifting. This aerosol-climate problem is being addressed by developing a physically-based dust lifting model and using it to study the effects of electric forces on dust lifting and transport by regular wind-blown saltation, dust storms, and convective plumes and vortices. The model is the first to include dust electrification and the potentially important effects of electric forces on dust lifting. The model will be made available to the scientific community as soon as it is developed and tested.Electric fields as high as 100-200 kV/m have been measured in all types of natural dust lifting processes such as wind-blown saltation, dust storms and convective vortices. Laboratory research shows that these electric fields can directly lift soil particles from the surface. Calculations show that these electric fields can greatly reduce the threshold wind speed necessary to initiate saltation. Saltation is the process by which larger sand particles are moved by the wind and bounce on the surface, ejecting smaller dust particles into the air. Electrostatic effects may enhance this process. They are being measured in field and laboratory settings. These observations form the basis for including electrostatic effects in a parameterization for the dust lifting and transport by convective plumes and vortices in weather and climate simulation models. This dust flux parameterization includes the transport of both natural and man-made aerosols from the atmospheric surface layer up to the top of the convective layer.The research has several broader impacts on science and society. Besides studying an important scientific problem key to our understanding of global climate change, the dust lifting model and dust flux parameterization will be available to the scientific community for use in a wide variety of modeling contexts. An educational website is being developed with simple physical explanations of the formation of convective plumes, dust devils, and dust storms. This website compares weather phenomena on Earth and other planets. It will be expanded to include explanations of saltation, dust electrification, and the effects of electric forces on dust lifting. Finally, this research project will contribute to the training of a graduate student.