WHOI Examines Links Between Ocean Currents and the Sea Level

WOODS HOLE – A new study by the Woods Hole Oceanographic Institution finds no direct link between North Atlantic Ocean currents and the sea level along the New England coast.

The study, which was published June 13^th in the journal “Geophysical Research Letters”, examined both the strength of the Atlantic Meridional Overturning Circulation (AMOC), a conveyor belt of currents that move warmer waters north and cooler waters south in the Atlantic, and historical records of sea levels in coastal New England.     

“Scientists had previously noticed that if the AMOC is stronger in a given season or year, sea levels in the northeast U.S. go down, if the AMOC weakens, average sea levels rise considerably,” said Chris Piecuch, a physical oceanographer at WHOI and lead author on the Paper.

“During the winter of 2009-2010, for example, we saw the AMOC weaken by 30 percent, at the same time, sea levels in our region rose by six inches, that doesn’t sound like a lot, but a half foot of sea level rise can have serious coastal impacts.”

These findings are particularly important for residents along the northeast coast of the U.S. as sea levels along the New England coast will rise greater than the global average.

Scientists have traditionally assumed that the heighted future sea level rise in the north east U.S. is inextricably tied to a weakening of the AMOC, which climate models also predict.

Given the study’s findings however, that assumption might need to be revised.

According to Piecuch, a study like this was not even possible until recently, for the past few decades, satellite imagery has given scientists a record of movement at the ocean’s surface but has been unable to detect currents below the surface.

Starting in 2004 however, an international team of scientist began maintaining a chain of instruments that stretch across the Atlantic between Florida and Morocco.

The instruments, which are collectively called the RAPID array, hold a variety of sensors that measure currents, salinity, and temperature.

Also collaborating on the study were Geln G. Gawarkiewicz and Jiayan Yang of WHOI; Sonke Dangendorf of Universitat Siegen in Germany; and Christopher M. Little and Rui M. Ponte of Atmospheric and Environmental Reaserch, Inc.

The Woods Hole Oceanographic Institution is a private, non-profit organization on Cape Cod dedicated to marine research, engineering, and higher education.