By Sid Perkins
Scientists seeking to deploy an armada of 3,000 robotic probes to take the pulse of Earth’s oceans are halfway to their goal.
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As of Nov. 30, 2004 oceanographers had launched 1,516 of the sensor-laden Argo floats, says project director John Gould of the Scripps Institution of Oceanography in La Jolla, Calif. Those probes, each costing about $15,000, measure temperature, salinity, and other water characteristics in the uppermost layers of the ocean (SN: 2/1/03, p. 75: Available to subscribers at Electronic Jetsam). Each device is programmed to sink to a depth of 2,000 meters, drift with ocean currents for 10 days, and then collect data as it bobs back to the surface. In general, a float’s data are available on the Internet within 24 hours of the time of transmission.