Radars to teach us more about rainy weather

How big is a torrential rainstorm? How quickly is it moving? How is its intensity changing? These are the questions that researchers are trying to answer by processing radar information to find out more about rainfall. Ultimately, this could lead to improved risk assessment in the context of extreme rainfall.

For many years, weather radars have collected information about the weather situation in Sweden. The information is used for the weather forecasts issued by SMHI, but also in research and development. Now researchers are developing information processing from weather radar facilities to produce the most accurate estimation of rainfall possible.

"We will develop the existing methods by, for example, filtering out false signals from interferences such as birds, insects and melting snow in the atmosphere, and converting the radar signal to rainfall intensity, where we currently have an inaccurate relationship," says Jonas Olsson, a researcher in hydrology at SMHI.

Increased understanding and better data

The data generated will develop descriptions of torrential rain, or extreme short-term rainfall, which is important both for increasing the understanding of the processes in the atmosphere and for developing a better basis for the design of hydrological systems (such as storm water systems). The project will also assess how well extreme rainfall is simulated in both forecasting and climate modelling, which is important for the interpretation of both short-term forecasts and climate projections.

The three-year project is a joint project between SMHI and SGI (The Swedish Geotechnical institute) and will run between 2016 and 2018. The research is funded by The Swedish Research Council Formas.