Radar

A brand new instrument that can measure wind and precipitation within clouds has just arrived at the University of Leeds. The Facility for Ground based Atmospheric Measurement's (FGAM) newest instrument is a radar capable of measuring clouds and precipitation in extraordinary detail.

Measurements of weather phenomena such as thunderstorms are possible with the new radar. This sort of weather in the UK can cause flooding and high winds that are extremely dangerous and costly to the UK's population and economy. It is expected that the data collected using the radar will lead to improvements in forecasting.

The new FGAM instrument is the only mobile radar in the UK, and will allow measurements to be taken from almost any location. The flexibility of a mobile radar means that meteorologists can target a specific phenomena and get close to collect high resolution data.

Dr Lindsay Bennett who will operate the radar said, 'It would be great to collect data about an intense thunderstorm', going on to say, 'This new radar is exciting because it provides a huge step towards furthering our understanding of what happens within clouds.'

Dr Bennett is an instrument scientist for FGAM, based in the School of Earth and Environment at the University of Leeds. Lindsay has lots of experience working with radars, particularly mobile radars most recently studying thunderstorms in the Black Forest in Germany.

Dr Bennett says 'It's exciting to have this technology in the UK; it means that we can 'see' the processes within clouds.'

Manufactured by Selex Gematronik in Germany, the radar uses pulses of electromagnetic energy with a 3cm wavelength. The types of particles that a Radar can 'see' include precipitation and insects. The radar pulse reflects off the raindrops and ice particles in the clouds, and a small amount is reflected back towards the radar receiver. This reflected energy allows the scientists to observe properties such as rainfall intensity and wind.

The interesting thing about the radar being able to see insects is that when there are no clouds or rain drops, the insects can be useful to tell us about the air motions in the lower atmosphere. Using a radar in this way is known as making clear air measurements. The radar also has Doppler capabilities meaning it is able to measure if objects are moving towards or away from the radar.

Additionally this particular type of radar has what's known as a dual-polarisation capability – it can detect differences in size and shape of the objects that the radar pulse reflects off. It can determine if a particle is a rain drop, ice or a hail stone or even an insect. This technology is cutting edge and can provide more accurate estimates of the quantity of precipitation falling from a cloud. This capability is important for understanding the flooding caused by storms.

FGAM instrumentation, including the radar is a facility for the whole UK atmospheric science community. The instruments are regularly deployed all over the UK and often work to compliment the FAAM Atmospheric Research Aircraft. To find out more about FGAM please visit their website.