AGS-PRF: Estimating the Dust Climate Feedback by Developing and Using an Improved Parameterization of Dust Aerosol Emission

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This award provides funds for a 2-year Postdoctoral Research Fellowship for the PI, who will work under the mentorship of Professor Natalie Mahowald at Cornell University. During the Postdoctoral Research Fellowship the PI will develop and evaluate a physically-based parameterization of the emission of dust, primarily from deserts and semi-arid regions. The parameterization is based on a formal equivalence between the saltation process, through which dust aerosols are ejected from the surface as a result of impacts with bouncing sand grains, and the fragmentation of brittle materials such as glass. The project has three broad tasks: 1) Developing an improved dust emission parameterization that rigorously accounts for the dependence of the dust flux emitted by an eroding soil on wind speed, soil properties, and vegetation; 2) Implementing the dust emission parameterization into the NCAR Community Earth System Model (CESM), and using simulations of the present day dust cycle to further evaluate the parameterization against a wide range of ground-based and satellite measurements; and 3) Using the dust module to quantify the dust climate feedback in transitions from the preindustrial to the present day climate, and from the present day to a future climate in which carbon dioxide concentrations rise to twice their pre-industrial values.The work will have broader impacts both practically and scientifically, as dust plays an important role in establishing the earth's climate, and the radiative effects of dust may constitute an important feedback for climate change. Thus, better representation of dust emission in climate and weather models may lead to better climate and weather predictions. In addition, dust emission plays an important role in cloud formation, drought physics, and atmospheric chemistry, and research in all these fields would be enhanced by better representation of dust emission in atmospheric models. Finally, the postdoctoral research fellowship, under the mentorship of an established scientist, will help to build the career of the PI, thereby providing support for the future workforce in this scientific discipline.