Trawling the oceans for climate clues

Six countries, including the UK, have launched an ambitious project to map temperature and salinity changes across the world’s oceans. The aim is to gather data, which may greatly improve forecasting of both short-term weather patterns and longer-term climate change.

Over the next few years, up to 3,000 instrument-laden cylindrical buoys will be dropped into seawater and used to measure temperatures from the surface to a mile deep. The battery-driven observation buoys will be programmed to dive and surface up to 100 times during their four-year lifetime. Each time they surface, after drifting with the ocean current, the data they have stored will be bounced by satellite, within hours, to scientists around the world. The information will be made freely available to whoever wants to access it.

Named Argo, the project officially got under way in September when a US ship set sail from San Diego, California, to deploy six buoys after test trials proved successful.

“We are taking the plunge to understand our oceans. What we’ve done in the past is piecemeal,” declared US Commerce Secretary Norman Mineta at the launch. He emphasised that Argo would be especially useful for improving computer models used to calculate both present and future impacts of global warming. By tracking the impacts of melting ice caps and hotter air temperatures on ocean currents, the project will “help us to figure out what we have to be doing in terms of greenhouse gas control”, he said.

The United States will deploy the lion’s share of the buoys, which cost $12,000 each to build and $9,000 to monitor. The National Oceanic and Atmospheric Administration (NOAA) has funds to deploy and operate 187 probes and seeks congressional support for a further 1,125. About 230 more buoys have so far been funded by the UK, France, Canada, Australia and Japan, with 1,100 more planned within a few years. The buoys are initially being dropped 185 miles apart in the Pacific and Atlantic Oceans. The eventual goal is an evenly distributed network across the three-quarters of the world’s surface made up of water.

NOAA, +1 202 482 3567

28 May 2001

Polly Ghazi