Slicing clouds for weather research

Dr. Dmitri Moisseev’s research group investigates the clouds of Helsinki with radar.

Slicing clouds for weather research

In the ancient world, the weather was ascribed to the will of the gods; today we’ve got meteorological radars. About 15 years ago, scientists started developing a radar system that "slices" clouds in individual layers in order to provide a complete and accurate vertical profile. This technology makes weather prediction much easier and more precise.

From far away, the weather radar on the Kumpula physics department roof looks like a giant white soccer ball. One man who knows precisely what’s behind it is the Russian weather radar researcher Dr. Dmitri Moisseev.

– Radar can observe any object whose physical properties differ from its surroundings, he explains.

Inside the 'ball', there is a huge satellite antenna that continuously sends electromagnetic waves towards the sky. Droplets, ice crystals and dust particles in the atmosphere return the waves, which are then picked up by a receiver and converted to electric signals.

– To put it simply, radar actually works just like cell phones, Moisseev says.

After analysing and converting the data, the researchers can see a digital real-time image. Moisseev's research group at the University of Helsinki aims to improve the radar's signal processing qualities.

According to Moisseev, the Kumpula radar reaches 250 km and is at the same time part of a global radar network. This is important, because this kind of worldwide collection of long-term data can, for instance, help to improve climate models. Clouds are hugely important factors in climate processes since they can either block radiant energy or let it pass. Climate change can accelerate the water cycle, and researchers predict that heavy rainfall and associated floods will occur more often.

– In order to determine how much rainfall we can really expect in the future, NASA is planning to launch a satellite that will map global precipitation. The University of Helsinki group plays an important role in this project, says Moisseev.

Dmitri Moisseev will speak in Think Corner on Wednesday, June 20th. He will show examples of interesting weather phenomena in the Helsinki area, such as hole punch clouds. Visitors will also learn how human activity influences clouds and why radar observations are important for global climate studies.

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Text: Claudia Gorr
Photo: 123rf
University of Helsinki, digital communications

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