We are investigating a possible link between changes in air pollution and a trend towards more hazardous extreme precipitation. In the first stages of our project, we are currently preforming a review of existing research and gathering observational data that form the basis for our study. Our overall goal is to increase our understanding of what controls extreme precipitation and reduce the uncertainty in estimates of future extremes.
Heavy precipitation events are getting more intense and more common. Extreme precipitation can cause serious damage from access surface water, floods and mudslides and pose a considerable risk to human health and safety. We know that global warming increases the amount of water that is available in the air for each extreme precipitation event, but we do not have a full understanding of what controls the intensity nor the frequency of extreme precipitation. Outcomes from our project are therefore important to give policy makers more knowledge when implementing climate change mitigation measures. Increased knowledge will also leave city planners and engineers better equipped to prepare our infrastructure for coming extreme precipitation events.
We know that particles in air pollution change cloud properties such as the size of cloud droplets and the amount of water present in the clouds. These properties help determine whether a cloud starts to precipitate. In recent decades, particle emissions in Europe have decreased due to cleaner production and emission restrictions. In other regions, economic growth has led to increased emissions. Since the particles affect both cloud microphysics and the environment clouds form in, we study whether large changes in particle concentrations have influenced the trends in heavy precipitation observed over the last decades. We do this by analyzing observations taken at the surface, in the air and from satellites, and by using global climate models and cloud models. By comparing regions of increased particle numbers to regions with reduced air pollution, we will know more about how particles affect extreme precipitation.
EPIC investigates the link between extreme precipitation and aerosol particles in the atmosphere. Extreme precipitation is a topic of high societal relevance, with high costs and a considerable risk to human health and safety. Observations show that it is intensifying, but we currently do not fully understand what controls the events. Aerosol particles influence precipitation and large changes in their concentrations have occurred over the last decades. Yet, the effect of aerosols on extreme precipitation remains unclear.
In EPIC, we aim to constrain the unclear role that aerosols have played for extreme precipitation by identifying key processes through which aerosols and extreme precipitation are connected. This will be achieved by combining statistical analysis on a range of observations with detailed fine-scale model simulations. The historical importance of aerosols for the observed trend in extreme precipitation will thereafter be assessed through dedicated global-scale model simulations validated against observations. We will use this combined knowledge to study how precipitation extremes are likely to be affected by coming regulations to improve air quality and cleaner air in what is now polluted regions.
EPIC represents the next step towards a more fundamental understanding of the behavior of extreme precipitation and the broad climate impact of anthropogenic aerosols. It will deliver improved capability to make projections of extreme precipitation and will provide up-to-date scientific evidence for climate policy makers. The project leader will build on her own experience, gained scientific competence and the expertise of the project group, to become an international expert in a new direction of climate research.