Field observations of the variability of dust emission, its size-spectrum and mineralogy

Atmospheric mineral dust consists of tiny mineral particles that are produced by the wind erosion of arid and semi-arid surfaces of the Earth, and it is one of the most important aerosols in terms of mass in the global atmosphere [1]. The physical and chemical properties of dust, that is, its particle size distribution (PSD), mineralogical composition, shape and mixing state determine its impact on the Earth’s system. Dust mineralogy in particular has been identified by the Intergovernmental Panel on Climate Change (IPCC) as a key uncertainty in the overall contribution of aerosols to radiative forcing [2] and many studies over recent years have shown its potential importance [3,4]. Despite this, Earth System models typically assume dust aerosols to have a globally uniform composition, neglecting the known local and regional variations in the mineralogical composition of the sources [5,6] and therefore, preventing further understanding of the role of dust in the Earth system. However, this simplification is justified by the current incomplete understanding of the physical processes at emission, the lack of coincident measurements of individual mineral PSDs for emitted dust and the parent soil, the fundamental disagreements among existing dust emission schemes on multiple aspects, the limited global knowledge of soil mineral content and the insufficient knowledge of the mixing state of the minerals. The ERC Consolidator Grant called FRAGMENT (FRontiers in dust minerAloGical coMposition and its Effects upoN climaTe) aims to address these limitations and to better understand and constrain the global mineralogical composition of dust along with its effects upon climate. This ambitious and multidisciplinary project combines theory, field measurements, laboratory analyses, remote spectroscopy and modelling