A small engineering firm is playing a pivotal role in an international effort to determine how the height and density of clouds affects climate change.

Thomas Keating, at Station Mills, Billingshurst, has designed an antenna to fit on a radar being used in the Earth- Care project, run jointly by the European Space Agency and the Japanese Aerospace Exploration Agency (JAXA).

The cloud profiling radar will emit pulses which bounce off clouds.

The returning signal will provide information about the height, density and distribution of material such as ice in clouds in the top levels of the atmosphere.

Scientists know clouds and other particles in the atmosphere can affect climate.

Low clouds cool the climate by reflecting solar radiation back into space, while high clouds warm the climate because they emit less infrared radiation to space.

At present the two effects cancel each other out. But uncertainty about the effect of clouds is a major limiting factor on predictions of future climate change.

Thomas Keating's antenna - called Quasi-Optical Feed - was designed so that the signal was sent and received via the same main 2.5m satellite dish, which makes the equipment more practical.

The National Physical Laboratory (NPL) worked closely with Thomas Keating on the design of the antenna and proved its effectiveness in controlled environments.

Richard Wylde, from Thomas Keating, said: "Our design was a departure from existing devices.

"The presence of facilities and expertise like this in Britain allowed us to refine and prove our ideas and have them accepted by the team at JAXA.

"It was difficult to predict how much time we would need but NPL worked flexibly with us. We were able to take the test results, make changes and come back and retest."

NPL scientist David Gentle said: "It can be very difficult for small companies to get involved in projects like this because even though they have technical expertise, everything needs to be tested and validated.

"Access to facilities such as NPL's is hugely important to British innovation.

The result of this collaboration is a worldleading piece of equipment that will lead to more accurate and useful climate models."