Filter forecast

Engineers at Queen's University Belfast have developed a dual-polarised Frequency Selective Surface filter that could lead to more accurate weather forecasts and a better understanding of climate change.

The team, from the university's Institute of Electronics, Communications and Information Technology (ECIT), has developed the filter for use in future European Space Agency (ESA) missions.

The filters will be installed in instruments being developed by the ESA for meteorological satellites it plans to launch between 2018 and 2020. The ESA instruments are used to detect thermal emissions in the Earth's atmosphere.

The data measures temperature, humidity profiles, and gas composition, which are in turn entered into operational systems and used to forecast weather and pollution.

Raymond Dickie, lead ECIT engineer, said: ‘Measuring just 30mm in diameter and 1/100mm thick, the devices will help to provide a much more comprehensive analysis of conditions in the Earth's atmosphere than has been possible previously.

‘Up to now, spaceborne remote sensing instruments have only been capable of separating either the vertically or horizontally polarised components of naturally occurring thermal emissions from gases in the Earth's atmosphere – but not both at the same time.

'The invention of the filter resolves this problem and will enable complex imaging of clouds to be undertaken for the first time at very short wavelengths.'

Patent applications have been filed for the filters, which are constructed by ECIT engineers and research staff at Queen's University's Northern Ireland Semiconductor Research Centre in Belfast.

The filters have been developed as a result of a £1.2m investment in Queen's by the Engineering and Physical Science Research Council, EADS Astrium and the ESA, and have taken more than 10 years to develop.

Robert Cahill, a member of the project team, added: ‘As a result of the new filter, scientists will gain access to completely new data on a range of phenomenon including ozone depletion and the size of water particles in cirrus clouds.

'This in turn will enable more accurate global weather forecasts to be compiled and will provide important new insights into climate change.'

The ECIT research team that developed the filters is also working on versions that operate at much higher frequencies in a project funded by the UK Centre for Earth Observation Instrumentation, the ESA and EADS Astrium.