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.
