Analysis: Weather satellite heralds return of 'the wow factor' - and it could alter our lives in forecasting

The latest in satellite technology has just been blasted into space, and it will force meteorological scientists to rewrite their programs

Three years after Sputnik, the Soviet satellite that was the first to orbit Earth, went up in 1957, the Americans sent up their own satellite, Tiros 1, to take pictures of the planet. "The effect on people was – wow," said Martin Jones, head of the space programme at the UK Meteorological Office in Hadley. Weather forecasters, seeing the patterns of clouds swirling around the globe, realised that satellite pictures would revolutionise their lives, and everyone else's too.

It also meant that they had to tear up their computer programs, said Martin Shelley, head of science at the British National Science Centre. "Until then, they had just estimated how much cloud cover there was over the oceans, which makes a big difference to the weather on the land. When they saw the pictures, they had to redo all their algorithms."

On Wednesday night the latest in weather satellite technology was blasted into space from French Guyana, the first of three Meteosat Second Generation (MSG-1) satellites that will become operational over the next 12 years, in a pan-European project costing about £800m, of which Britain is contributing £95m.

MSG-1 would alter our lives too, said Dr Tillman Mohr, director general of Eumetsat, which co-ordinates meteorological satellites for 18 European countries. "This programme is the culmination of more than 10 years' work by literally hundreds of people, all acting as a team, throughout Europe."

Just like its American forebear, MSG-1 could lead to a mass scrapping of weather programs, Mr Shelley said. On board is a scientific system called GERB – Geostationary Earth Radiation Budget – which will measure how much energy the earth and the oceans receive, and how much they radiate back into space. "At present nobody knows quite how much energy is used up. It's a big debate in global warming, understanding the energy balance," he said

That, for now, remains in the future. But weather satellites have a glowing past. The first generation of Meteosat satellites began going aloft in 1977; there are seven still locked in geostationary orbit around the equator, so that they appear to remain in the same place relative to the surface.

Compared with those ageing systems, MSG will be able to send back pictures twice as often – every 15 minutes, rather than 30 – and measure reflected radiation at 12 wavelengths rather than the three that its predecessor, the first generation of Meteosat satellites, was able to do. "It will have better resolution in its pictures," said Mr Jones at the Met Office. "The combination means that we will be able to detect and measure the presence of fog – which has a very different reflection 'signature' from clouds – and low cloud, snow, and even volcanic ash."

The way we understand what is happening above us has changed drastically in the past few years. Partly that is because satellites bring better pictures; but largely it is because we have more powerful computers to marry the data collected at ground level by a network of stations, to that collected by weather balloons – which still play an important part – with the newest satellite data.

Mr Jones said: "We reckon that if all the satellites were knocked out today by something, then the quality of our forecasting would fall by 10 to 15 per cent. We reckon our accuracy is in, well, say the low 90 per cents." The comparison is made by looking at what was predicted with what weather arrives. "To put it another way, the three-day forecast now is as good – that is, as reliable, as accurate – as the one-day forecast was seven to 10 years ago."

The globe is covered by civil and military satellites collecting all sorts of data about Earth phenomena. Most recently, the key one has been the oceans – which cover most of the planet's surface, but have very few fixed monitoring stations. It is over the oceans that the huge depressions that lead to tropical storms, hurricanes and cyclones form. And phenomena such as El Niño, a cyclical warming of the sea surface in the Pacific that has the potential to affect the weather around the world, can be spotted only using satellite systems sensitive enough to detect tiny but continuous changes in the level of the sea – because an El Niño sea is slightly warmer, and hence larger. The difference in the surface height is centimetres; but the latest satellites used by the US National Oceanographic and Atmospheric Administration (NOAA) can detect it.

The NOAA's satellites are expected to pick out fires, dust storms, floods, icebergs, "severe weather", snow, storms, cyclones, volcanoes and even "unique events" such as huge clouds of smog drifting from the eastern seaboard of the United States into the Atlantic Ocean, or the plumes from the burning of forests in the Far East crossing to adjacent islands.

Though some people might hope we will be able to predict the weather far ahead, what's more likely is that our view of the future will become clearer as we understand the interactions between oceans, land, atmosphere and the Sun. As Mr Jones says, we can already make more confident predictions now than we could just a few years ago – largely because computer power has increased exponentially. The amount of satellite data has stayed roughly static, but our ability to interpret what could happen is roughly doubling every 18 months.

"MSG-1 is really about better short-range forecasts," Mr Jones said. "It means we should be able to provide better services to events like Wimbledon, Formula One racing and so on." The Met Office provides a service it calls "nowcasting" – able to forecast weather for small areas within the next few hours.

Organisers of sporting events are not the only ones who want to know about weather. The insurance industry lives and dies by its ability to forecast natural hazards; when Hurricane Andrew hit Florida in 1992, it changed the way people thought about extreme weather. The hurricane caused £10bn of damage. After that, civil planners realised the value of having the best possible forecasting.

Even after a disaster has hit, the data satellites provide can be highly useful, Mr Shelley says. "It can help to mitigate the recovery process; after the floods, it tells you where the floodwaters are going, where they're heading to."

Another programme – the Global Monitoring for Environment and Security – aims to give warnings of internationally important events even when the governments responsible do not, or are not aware. "Chernobyl was first spotted by a European satellite before anyone announced that a reactor in the Ukraine had blown its roof," Mr Shelley said. "One of the French government's SPOT visual satellites noticed the plume of smoke from what was known to be a nuclear installation in the Ukraine."

He pauses. "I guess it's lucky that it wasn't a cloudy day." But with the newest satellites, able to detect heat even through clouds, that might not make a difference. Big Brother is watching you – but as with everyone else, what he wants to talk about is the weather.