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Abstract
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Meteorologists watched as afternoon thunderstorms brewed in the mountainous region of central Guinea. By the evening of 22 October, the storms had intensified and were moving west towards the coast of Africa. At 8.20 p.m., the meteorologists received a thunderstorm alert, and for the next 45 minutes the 130,000 residents of the city of Fria were hammered by heavy rain, flash floods and winds of up to 77 kilometres per hour.
What happened that evening was not unusual. Similar storms blow through Fria and Guinea's coastal capital Conakry regularly during the rainy season. Flash flooding is a common problem, and the country is frequently buffeted by tornadoes.
What was unusual was the way the storm was detected. Government meteorologists in Guinea lack the Doppler radar system that is usually used for this, and have struggled to track weather using rudimentary equipment. Europe and the United States provide free satellite data and forecasts, but these are coarse and infrequent. Only in recent months has Guinea turned to a new, simple proxy for storms: flashes of lightning.
Lightning-detection sensors installed atop just 12 mobile-phone towers now allow the country's meteorological service to track storms nationwide as they develop (see 'Lightning fast'). "With this project, we receive virtually real-time data throughout the entire country," says Mamadou Lamine Bah, director of the service.
The project shows how lightning detection could provide a quick and relatively cheap way for poor countries to acquire basic weather services. Earth Networks, based in Germantown, Maryland, spent around US$1 million to deploy the current network. By comparison, Bah says, even a simple Doppler radar system would cost around $10 million. And beyond that initial outlay, a lack of expertise in countries such as Guinea makes those systems prohibitively difficult to maintain and operate.... |