Physics Colloquium, Herman Russenberg, TU Delft Climate Institute, Faculty of Civil Engineering and Geosciences, Delft University of Technology

Abstract:

The role of clouds in a changing climate remains one of the larges puzzles of climate science. The physical processes are complex: atmospheric dynamics is intertwined with aerosol chemistry and thermo-dynamics, and in addition the processes manifest themselves on a multitude of temporal and spatial scales.

Of particular interest is the activation of aerosols into cloud droplets, as this has a direct impact on cloud microphysics, the cloud lifetime and the formation of rainfall. The impact is potentially large – there are signs that for instance the monsoon in India is changing because of enhanced emission of aerosols through human activities – but the process is far from understood.

One of the factors hampering our knowledge is the spatial variability of the processes: droplet activation is a small-scale process embedded in large-scale systems. To be able to measure these processes better, national funding was made available to start the Ruisdael Observatory: a network of advanced observation stations across The Netherlands combined with high-resolution modelling facilities to study the processes that link the emission of aerosol and trace gases to clouds and rainfall in unprecedented detail.

This presentation will address the state-of-the-art of our knowledge of clouds and aerosol in the climate system, as well as the potential of the Ruisdael Observatory for the atmospheric research community in The Netherlands.