19 Aug 08

A composite view of Hurricane Katrina on 28 August 2005. It shows data from several instruments aboard two satellites. Blue indicates at least a quarter of an inch of rain an hour, whereas green represents half an inch, yellow an inch and red two inches. Image courtesy of NASA/JAXA.

The advances made possible by 50 years of observing Earth from satellites are celebrated by Oxford scientists this week.

The cover feature of this week’s American Scientist examines the contribution of satellites, from Sputnik to Landsat, to our understanding of the Earth and our impact on it.

‘The last half-century has seen satellite remote sensing come of age,’ said Dr Andy Tatem of Oxford University’s Department of Zoology, co-author of the article. ‘Over 150 satellites are currently orbiting above our heads beaming back vital data about everything from our changing climate to the health of our oceans and the growth of our cities.’

Remote sensing from satellites relies on linking measurements of electromagnetic energy emitted from the Earth – or reflected from its surface – to natural phenomena such as melting ice caps or weather systems.

‘Increases in computing power and more affordable satellite imagery could see satellite remote sensing find many more applications,’ commented Dr Tatem. ‘It could provide realtime imagery to handheld devices to help people negotiate traffic jams or see what the weather is like where they are travelling to, as well as potentially revolutionising areas of science as diverse as wildlife conservation and disease control. However, it also raises significant security and privacy concerns.’

The article, entitled ‘Fifty years of Earth-observation satellites’, is published in American Scientist. The authors are Dr Andy Tatem and Dr Simon Hay of Oxford’s Department of Zoology and Scott Goetz of the Woods Hole Research Centre, USA.

Malaspina Glacier in southeastern Alaska. This unique perspective of the way the glacier spread out was created by combining an image from Landsat, made with both visible and infrared light, with data from radar measurements taken from the Space Shuttle Endeavour. Image courtesy of NASA/JPL/NIMA.