Collaborative Research: From Turbulence to Weather and Climate: Unraveling the Multi-scale Nature of Dust and Sand Transport in the Atmospheric Boundary Layer

这项研究项目的重点是风吹起沙子的过程，也就是所谓的跳跃，以及天气和气候模型如何描述这种现象。风沙有直接影响，如形成沙丘，但也有二次影响，当沙粒撞击并喷射出更细的粉尘颗粒时。这些颗粒被称为矿物粉尘气溶胶，是影响人类健康、天气、气候、生态系统、大气化学和水文循环的全球颗粒物的主要贡献者之一。目前的数值模型将跃迁视为一个统一的过程，研究表明，跃迁实际上是由靠近地面的湍流风驱动的，并且是高度间歇性的。研究人员计划通过理论、实地战役、精细建模(大涡模拟)和全球尺度(地球系统)建模相结合的方式来改进对跃迁过程的描述。这项工作将涉及四项主要任务：1)将沙粒输送的间歇性和强度与大气湍流联系起来；2)将大气湍流与天气和气候模式的总体大气边界层特性联系起来；3)开发一种改进的尘埃排放参数，以解释湍流驱动的间歇性；以及4)测试间歇性在沙尘事件的时间和大小中起重要作用的假设。该项目的更广泛影响将包括社会和教育与宣传部分。该项目的成功完成将导致共同体地球系统模型(CESM)和其他天气和气候模型的改进，这将导致对美国西南部和北非等多尘地区的天气和区域气候变化的更准确预测。两名研究生将在项目期间接受培训，学生们将与主要研究人员和一名专业教育工作者合作开发一个基于风蚀和湍流的教育模块，以满足一系列国家和州的物理科学标准。这些单元将通过为高中教师举办的研讨会和收集基于物理的教案的网站传播。研究人员和研究生还将通过客座讲座和参与收养物理学家计划与高中生互动。

The focus of this research project is on the lifting of sand by the wind, known as saltation, and how it is portrayed by weather and climate models. Wind-blown sand has direct impacts, such as forming dunes, but also secondary impacts when the sand particles impact and eject much finer dust particles. These particles are known as mineral dust aerosols and are one of the major contributors to global particulate matter, which affects human health, weather, climate, ecosystems, atmospheric chemistry, and the hydrological cycle. Current numerical models treat saltation as a uniform process, when studies have shown that saltation is actually driven by turbulent winds close to the surface and is highly intermittent. The researchers plan to improve the representation of the saltation process through a combination of theory, field campaigns, fine-scale modeling (Large-Eddy Simulation) and global-scale (Earth System) modeling. The work will involve four main tasks: 1) Linking the intermittency and intensity of sand transport to atmospheric turbulence, 2) linking atmospheric turbulence to the overall atmospheric boundary layer properties from weather and climate models, 3) developing an improved dust emission parameterization that accounts for turbulence-drive intermittency, and 4) testing the hypothesis that intermittency plays an important role in the timing and magnitude of dust events.The broader impacts of the project will include societal and education & outreach components. A successful completion of the project will result in an improvement to the Community Earth System Model (CESM) and other weather and climate models which should result in more accurate forecasts of weather and regional climate changes in dusty regions such as the southwestern US and North Africa. Two graduate students will be trained during the project, and the students along with the lead researchers and a professional educator will collaboratively develop an educational module, based on wind erosion and turbulence, that addresses a range of national and state standards in the physical sciences. The modules will be disseminated via a workshop for high school teachers and through a website that collects physics-based lesson plans. The researchers and graduate students will also interact with high school students through guest lectures and participation in the Adopt-a-Physicist program.