The Gulf Stream is one of the strong ocean currents
that carries warm water from the sunny tropics to higher
latitudes. The current stretches from the Gulf of Mexico up the East Coast
of the United States, departs from North America south of the
Chesapeake Bay, and heads across the Atlantic to the British Isles.
The water within the Gulf Stream moves at the stately pace of 4 miles
per hour. Even though the current cools as the water travels thousands of
miles, it remains strong enough to moderate the Northern
European climate.
The image above was derived from the infrared measurements of the
Moderate-resolution Imaging Spectroradiometer (MODIS) on a nearly
cloud-free day over the east coast of the United States. The coldest waters are
shown as purple, with blue, green, yellow, and red representing
progressively warmer water. Temperatures range from about 7 to 22
degrees Celsius.
The core of the Gulf Stream is very
apparent as the warmest water, dark red. It departs from the coast at Cape
Hatteras, North Carolina. The cool, shelf water from the north entrains
the warmer outflows from the Chesapeake and Delaware Bays. The north
wall of the Gulf Stream reveals very complex structure associated with
frontal instabilities that lead to exchanges between the Gulf Stream and
inshore waters. Several clockwise-rotating warm core eddies are evident
north of the core of the Gulf Stream, which enhance the exchange of heat
and water between the coastal and deep ocean. Cold core eddies, which
rotate counter clockwise, are seen south of the Gulf Stream. The one
closest to Cape Hatteras is entraining very warm Gulf Stream waters on
its northwest circumference. Near the coast, shallower waters have warmed due
to solar heating, while the deeper waters offshore are markedly cooler
(dark blue). MODIS made this observation on May 8, 2000,
at 11:45 a.m. EDT.
For more information, see the MODIS-Ocean web page.
The sea surface temperature image was created at the University
of Miami using the 11- and 12-micron bands, by Bob Evans, Peter Minnett,
and co-workers.