Where the infamous Atlantic Ocean conveyor belt is concerned — inspiration for at least one climate-change thriller that brought 100-foot-deep snowdrifts over America’s East Coast and Dennis Quaid to the rescue — it’s still the “Day Before.”
A team of scientists have installed a series of mooring buoys and have actually begun to measure how the current shifts and changes over the year. And it’s still too soon to know what changes in the flow mean.
Oceanographers Stuart Cunningham and Torsten Kanzow supervised an international project to sink a string of moorings and then collect data for analysis. The scientists work for the National Oceanography Centre in Southampton, Great Britain.
“The scientists captured the fickle flow of Atlantic currents by comparing what the moorings’ current meters revealed with measurements of the streams’ effects on an unused telephone wire stretching between Florida and the Bahamas as well as satellite measurements of surface winds,” according to an online story in Scientific American.
Cunningham and Kanzow published two papers on the work in the Aug. 17 edition of Science. More detail from an online story at the National Oceanography Centre:
An international team of scientists investigating the Atlantic’s circulation — which is largely responsible for Europe’s warm climate — and its likelihood of ever ’switching off’, has for the first time been able to continuously monitor the daily variations in its strength.
In March 2004, as part of the UK Natural Environment Research Council’s 20 million pound RAPID Climate Change Programme and the National Science Foundation MOCHA project, the scientists deployed an instrument array across the Atlantic at 26 degrees N from the Saharan coast of Africa to the Bahamas.
Since then, the instruments have provided a continuous record of the salinity, temperature and density of the ocean. In combination with current measurements of the Gulf Stream in the Straits of Florida (provided by scientists from the US National Oceanic and Atmospheric Administration) and satellite measurements of the wind-driven flow across 26 degrees N, the MOC has been calculated on a daily basis.
A few years ago, some scientists theorized that the current had begun to slow down, suggesting, perhaps, that the influx of fresh water into the North Atlantic from glacial runoff was threatening to shutdown Europe’s hot water furnace. (So to speak.)
The folks at RealClimate.org say Cunningham’s new study proves the necessity of waiting for data before making claims, something that all us climate change observers, deniers and screamers-of-bloody-murder ought to keep in mind.
Scientific American posted a story online that explains the effort in plain language.
The so-called thermohaline conveyor belt — a strong northward flow of warm water near the surface of the Atlantic balanced by a southward flow of cold water near the bottom — carries heat from warm equatorial regions to the frigid north, keeping Europe relatively balmy.
The fancy term — made famous from a Hollywood disaster movie and Al Gore’s slides — is really just the Gulf Stream and other related currents. But because this circulation involves water flowing in different directions across the entire surface of the Atlantic and every layer below, it has been difficult to measure.
Now, strung between the Bahamas and the coast of Morocco, a necklace of moored wires — stretching from the seafloor to the surface, at points as much as three miles above — has for the first time revealed the Atlantic’s complex movements.
And the kicker?
“Are you seeing changes in the rate of transfer? Or storage of heat in the Caribbean?” Cunningham asks. “We can’t say we have defined the seasonal cycle yet.”
That, he notes, will require many more years of monitoring. Data has been collected for 2005 and 2006 but it has yet to be analyzed.