The effect of atmospheric aerosols on the Earth's radiative energy budget and hydrological cycle constitutes the largest uncertainty in present-day climate simulations, which aim to predict future global temperatures and sea levels. Aerosols influence the climate system directly by altering the amount of short and long wave radiation reaching the Earth.
However, aerosols also have important indirect effects, whose net magnitude - and even sign - are not yet constrained i.e. the cloud albedo and cloud lifetime indirect aerosol effects. The proposed research project will constrain the indirect effect of aerosols on the climate system, thereby improving the prognostic capability of present-day climate models.
Recent results highlight the importance of mineral dust aerosols to the formation of ice clouds and ice precipitation rates. It is now clear that different types of mineral dust aerosols have different abilities to act as ice nuclei, and therefore, they alter the cloud albedo and cloud lifetime to a different extent.
Recent results also show that mineral dust aerosols act as heterogeneous reaction surfaces in chemical reactions that influence the concentration of key tropospheric oxidants and acid rain precursors. Again, different types of mineral dust aerosols participate in different reactions, with different consequences for their ability to act as ice nuclei.
The proposed research project will use available satellite data of aerosol size and composition, in combination with air parcel trajectory calculations and photochemical box modelling, to trace the origin and the changing chemical composition of three different types of mineral dust aerosol particles in the troposphere.
Results derived from the modelling of real dust events will be incorporated into a state-of-the-art 3-D chemistry-climate model of the atmosphere and used to further constrain the indirect effect of aerosols on the climate system.
Fields of science
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