Atmospheric Physics (Prof. Ulrike Lohmann)

The Atmospheric Physics group, led by Prof. Ulrike Lohmann, focuses on the role of aerosols (also known as particulate matter) and clouds in the climate system. Clouds are one of the largest uncertainties for climate change predictions. Their brightness and lifetime are affected by aerosols resulting from human activities such as sulphate (SO₄) and carbonaceous aerosols (black carbon, BC and organic carbon, OC).

These anthropogenic aerosols have substantially increased within the atmosphere since pre-industrial times. Some aerosol particles reflect solar radiation (direct effect) and thus can partly offset the warming caused by increasing greenhouse gas emissions. Aerosol particles also change the microphysical properties of clouds resulting in more but smaller cloud droplets. It causes the cloud to appear brighter from space (indirect cloud albedo effect), which additionally offsets some of the greenhouse gas warming. More and smaller droplets also retard rain formation (indirect cloud lifetime effect, see Figure), which has implications for the amount and distribution of precipitation.

In our group, we address aerosol-cloud interactions by combining field measurements, laboratory experiments on ice nucleation and modelling of aerosol-cloud interactions.