Florida current is weaker now than at any point in the past century


Date:
August 7, 2020
Source:
Woods Hole Oceanographic Institution
Summary:
A key component of the Gulf Stream has markedly slowed over the
past century -- that's the conclusion of a new research paper.



FULL STORY ==========================================================================
A key component of the Gulf Stream has markedly slowed over the past
century - - that's the conclusion of a new research paper in Nature Communications published on August 7. The study develops a method of
tracking the strength of near-shore ocean currents using measurements
made at the coast, offering the potential to reduce one of the biggest uncertainties related to observations of climate change over the past
century.


==========================================================================
"In the ocean, almost everything is connected," said Christopher Piecuch,
an assistant scientist in the Physical Oceanography Department at the
Woods Hole Oceanographic Institution (WHOI) and author of the study. "We
can use those connections to look at things in the past or far from
shore, giving us a more complete view of the ocean and how it changes
across space and time." Piecuch, who specializes in coastal and regional
sea level change, used a connection between coastal sea level and the
strength of near-shore currents to trace the evolution of the Florida
Current, which forms the beginning of the Gulf Stream. The Gulf Stream
flows north along the Southeast Atlantic Coast of the United States
and eventually east into the North Atlantic Ocean, carrying heat, salt, momentum, and other properties that influence Earth's climate.

Because nearly continuous records of sea level stretch back more than a
century along Florida's Atlantic Coast and in some parts of the Caribbean,
he was able to use mathematical models and simple physics to extend the
reach of direct measurements of the Gulf Stream to conclude that it has weakened steadily and is weaker now than at any other point in the past
110 years.

One of the biggest uncertainties in climate models is the behavior of
ocean currents either leading to or responding to changes in Earth's
climate. Of these, one of the most important is the Atlantic Meridional Overturning Circulation, or AMOC, which is a large system or "conveyor
belt" of ocean currents in the Atlantic that includes the Gulf Stream
and that helps regulate global climate. Piecuch's analysis agrees with relationships seen in models between the deeper branches of the AMOC and
the Gulf Stream, and it corroborates studies suggesting that the deeper branches of AMOC have slowed in recent years. His method also offers the potential to monitor ocean currents like the Gulf Stream from the coast, complementing existing but difficult-to- maintain moored instruments
and expensive research cruises.

"If we can monitor something over the horizon by making measurements
from shore, then that's a win for science and potentially for society,"
said Piecuch.


========================================================================== Story Source: Materials provided by
Woods_Hole_Oceanographic_Institution. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Christopher G. Piecuch. Likely weakening of the Florida Current
during
the past century revealed by sea-level observations. Nature
Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-17761-w ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200807111929.htm

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