Published on 10 May 2012 Sections

Met Office ‘rain plane’ on course to chase storms

Science Editor

Channel 4 News Science Editor Tom Clarke joins scientists flying into the heart of the incoming storm front on a mission to explain exactly what drives the worst of our all-too-familiar storms.

We hitched a ride on the research flight heading out across the Irish Sea to meet the weather head on.

Where seats and tray-tables used to be, banks of computer screens and up to 20 scientists now sit. Slung under the wings of the plane, and crammed in its hold is a battery of meterological apparatus to measure the atmosphere.

The target is a warm front of air moving in from the Atlantic. When the warm meets the cold air coming towards it, it is forced upwards and the moisture it contains is wrung out as rain. It can be heavy and sustained.

Forecasters track warm fronts and even stormier cold fronts using satellite and radar. But to understand exactly how much rain a storm will produce, where and when it will fall scientists want to measure it directly.

The research plane, part funded by the Met Office, partly by the Natural and Environmental Research Council, takes them to the part of the storm their ground based instruments can’t reach.

The key objective on this flight is to study tiny particles like cloud droplets and ice crystals – which tell them how much heat is contained in the warm front.

“There’s a subtle link between the temperature and the dynamics of winds in the atmosphere and the way that the storm develops, and because of the chaotic nature of the atmosphere you have to know these things in quite fine detail,” says Professor Geraint Vaughan, an atmospheric scientists at the University of Manchester.

Constantly changing

And on this aircraft, fine detail is what you get. Dr Angela Dean from the Met Office images is studying images of of individual rain drops and snow-flakes on a screen in front of her. They’re being captured by a torpedo-like device strapped under the wing outside.

“Particles inside the clouds move very quickly and they’re constantly developing and changing. Those changes affect how much rain will fall and what the duration of these rain showers and how intense a storm is going to be,” she said.

As we cross through the warm front a scientists on the back of the plane releases “dropsondes”.

The opposite of a weather balloon, these sensors beam back data on the atmosphere as they descend down from the plane on a parachute. Their data, on the temperature, humidity and wind-speeds in the storm, gets fed back to forecasters on the ground.

This is just one of a number of flights studying various types of stormy weather as the approach our shores.

The objective is to take the fine-scale detail measured from the aircraft and then input that into weather forecasting models back on the ground. The end result should be improved weather forecasts that provide more detailed on exactly where the worst rain or high winds might be.