The temperature of the ocean is rising
MEASURING the temperature of something as stratified as the ocean has never been easy. Before the 1980s, ships automatically recorded the temperature of water flowing through their ports, but the great depth variance of these ports and the dearth of data outside major shipping routes made the figures incomplete and unreliable. Next came satellites, which were able to capture more surface-temperature data in three months than the total compiled in all the years prior to their advent. Nonetheless, they too have limitations: for example, their infrared sensors are susceptible to cloud contamination.
Continuous monitoring of sea temperatures only began in 2000, run by an international collaboration called Argo. This is a regularly replenished fleet of untethered buoys, now numbering nearly 4,000, which divide their time between the surface and the depths, drifting at the whim of the currents. Over ten-day cycles they sink slowly down to about 2,000 metres (6,560 feet) and back up, measuring temperature and salinity as they go. Although the network is still sparse—one float for every Honduras-sized patch of ocean—their data have revolutionised oceanographers’ understanding of their subject.
Read more at: The Economist
