Regional Modeling of the Saharan Dust Cycle

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The core of this project is the development of a physically based predictive mesoscale model system of the northern African dust cycle by integrating and adapting several existing and newly developed sub-models describing various aspects of dust emission, transport and deposition to simulate the spatial and temporary evolution of northern African dust properties. In addition, we will evaluate atmospheric response to the radiative forcing by Saharan dust, and simulate the influence of long-range transported African dust on cloud microphysics by accompanying Lagrangian process studies. Northern Africa ist the major source of dust emissions under modern climate conditions. As part of the Research Group "SAharan Mineral dUst experiMent" SAMUM the project will capitalize on the planned field campaign, which will provide extensive datasets to validate and constrain the dust model. It is necessary to develop a fully mechanistic model in order to be able to predict future changes in the northern African dust cycle, which could, e.g., impact on the radiative budget and hence climate of Mediterranean Europe. However, as part of our model validation strategy, we will make simulations in which key components (e.g., source areas, vegetation cover) are prescribed using satellite derived and field derived data. This will enable us to determine how well individual components are simulated and provide guidelines for further model development. We will explore how the lessons learned in this modeling exercise can be reapplied in global models through extensive sensitivity tests examining methods of parameterizing small-scale variability in inputs and processes. An important issue of the project is the performance of process studies on the influence of long-range transported Saharan dust on atmospheric radiation and microphysics.