Few things grab the world's attention like extreme weather, as the events of the 2004 tsunami in Southeast Asia so tragically demonstrated. But extreme weather patterns, as well as the more benevolent and common effects of meteorology, are a relentless focus of observation by meteorological satellites.
|Satellites overhead – the Earth & Space Expo|
EUMETSAT, the European Organisation for the Exploitation of Meteorological Satellites, uses its geo-stationary surveillance network to provide up-to-the-minute data streams on local and regional weather conditions, from mushrooming dust storms in Africa to rising fog in the Alps.
Europe takes its place among the most advanced global monitoring players, thanks largely to EUMETSAT, world-renowned for satellite systems that can observe the entire planet. EUMETSAT is expected to play a major role in the Global Earth Observation System of Systems (GEOSS), currently being developed by the Group on Earth Observations.
Operational focus versus research
On 14 February 2005, at the first in a series of Earth & Space Week daily public seminars, satellite enthusiasts met with Marianne Konig, a meteorological scientist with EUMETSAT in Darmstadt, Germany. Her presentation, entitled, ‘Depressions and Cold Fronts! Our weather systems explained’, dealt with global weather patterns and the capabilities of EUMETSAT's satellites to detect them.
But Konig made it clear EUMETSAT is not in the business of weather forecasting.
"Our satellites are not research-oriented. They do not predict the weather. They are operational and they exist to provide the information that weather forecasters and scientists need to do their work.”
Avalanches of earthly information from outer space
And, she declared, EUMETSAT sees that its recipients get plenty of meteorological information. Whereas the group's first-generation satellite, which still operates in space, sends updated ‘sweeps’ of weather patterns every 30 minutes, EUMETSAT's newer second-generation satellite, launched in August 2002, does this every 15 minutes.
Moreover, the newer satellite offers vastly more sophisticated means for analysing the earth's atmosphere and its interaction with solar energy, and the effects this has on weather patterns. Using different surveillance media – radar, infra-red, spectrum and photo-chemical analysis – it can take 12 different ‘snapshots’ of the earth at the same time, revealing weather patterns, solar effects on wind, clouds and sea currents, and the chemical composition of the atmosphere.
"Our second-generation satellite produces so much data that we don't have the bandwidth to handle all of it at once," says Konig, noting that some EUMETSAT images offer only a narrow, but very detailed, section of the earth's surface as a result.
‘Rain-spotting’ – and much more
EUMETSAT's eyes in space can use one channel or another to identify and track dust storms, hurricanes, thunderstorms, volcanic eruptions, ice clouds and even low-lying ground fog, though the latter is still tricky. "We've had some successes in identifying fog patches, but it's not easy and we're still refining the technology to do this," said Konig.
While satellite surveillance of an erupting volcano produces spectacular news footage, it has far more importance for human safety. Aside from helping vulcanologists predict lava flows and explosion vectors, EUMETSAT tracks the direction of wind-blown ash plumes. This enables air traffic controllers to steer aircraft around deadly ash particles, which can cause jet engines to malfunction.
Up next: polar surveillance
EUMETSAT's four high-orbit satellites careen through space in geo-stationary positions relative to earth and are focused mainly on surveying its tropical, sub-tropical and temperate zones of meteorological activity. But, starting next year, the organisation will launch the first of three low-orbit satellites that will circle the earth over its polar caps to gather weather and atmospheric data, every 15 minutes, 365 days a year.