UCL in the News: Know the flow

The advantage of the new technology is that it will use phased array multiwaveform radar, so the team will be able to take 100 measurements a second from five different avalanche waveforms to create a 2D animated image that should provide more information about the effects of friction and fluctuations in velocity.

"The advantage of radar is it can see below the powder cloud," explained UCL's Prof Paul Brennan [UCL Electronic & Electrical Engineering]. "If you use an optical camera you can only see what's on top which is a very light powder cloud. With this advanced version [of the radar] operating at 5.3GHz we should be able to penetrate the powder cloud and see what's going on underneath and in particular see the velocity distribution of all the components.

"The system currently being used is only a range radar so it can't give a 2D impression of the avalanche and I gather the resolution is only 50m which is very coarse. We are proposing a resolution of 1m that can also image in azimuth so we can generate an animated reconstruction of the avalanche. All in all, the instrument will be much more sophisticated." …

"We will have five different animations of the avalanche, produced from a different waveform and each will have different properties," said Brennan. "We can then merge the results from the different waveforms to give us more information and try and resolve some of the ambiguities that you would otherwise have with radar." …

"It's all a trade off," said Brennan, "depending on the number of frames a second taken. If we take 100 a second I think we can use five waveforms - 10 images a second means we could use 50 waveforms. I think five will be about right." …