Global Circulation (The Conveyor Belt)
In Partnership with Dr. Zafer Top
By: Nicole
Global Circulation
Global Circulation of the oceans is extremely important because
the oceans are reservoirs for gases like methane, and carbon
dioxide, the strong greenhouse gasses.
With global climate change becoming the primary research
topic, the information on what the oceans do and where and
when is very important to understand and predict direction of
climate.
Thermohaline Circulation
Thermohaline Circulation- (THC) (thermo- meaning temperature
and haline- meaning salt content)
Wind controls the upper 100 meters of the ocean’s surface. But
ocean currents also flow thousands of meters below the surface.
These deep-ocean currents are driven by differences in the water’s
density, which is controlled by temperature and salinity. This
process is called Thermohaline Circulation.
The paths of the
thermohaline circulation.
Blue paths represent
deep-water currents,
while red paths represent
surface currents
Thermohaline circulation starts in the polar regions. When water in
these areas gets very cold, sea ice forms. The surrounding seawater
gets saltier, increases in density and sinks.
The Conveyor Belt
1- The cold, salty, and dense
water sinks at the Earth's northern
polar region and goes south along
the western Atlantic basin.
2- The current is recharged as it
goes along the coast of
Antarctica and picks up more
cold, salty, and dense water.
3- The main current splits into
two sections, one goes
northward into the Indian Ocean,
and the other goes up into the
western Pacific.
4- The two sections of the current,
warm and rise as they go
northward, then loop back around
southward and westward.
5- The warmed surface waters
continue circulating around Earth.
The currents will go back to the
North Atlantic where the cycle
begins again.
The Final Stage
The Arctic Ice pictures (#1, 2) were taken from
the ship Polar Queen (picture #4); Dr. Zafer
Top was on it for a whole month in June, 1984,
in the northernmost part of Norway
(Svalbard), about 400 miles into the ice field.
There were many studies, including ice
thickness, which way the ice field drifted,
currents below the surface, how fast sound
traveled in water, what the bottom
topography looked like, helium and tritium in
the water, and more.
The picture (#3) of a
technician positioning a
container to collect water
sample is from the 1970s.
Many a time individual
collectors like this were
connected to a steel wire
and lowered to a desired
depth, then with a sliding
weight they were triggered
to shut; raised up to the ship
and used for different
measurements. A little later,
someone invented a
platform that contained a
dozen collectors in a circular
group saving a lot of time
and effort. The collector is
called a Niskin bottle, and
the platform is called a
rosette.
The Arctic pictures you saw
were taken from this ship,
The Polar Queen. Dr. Zafer
Top stayed on this ship for a
month.
This picture is a graph showing how deep tritium had penetrated in the North Atlantic.
Tritium was a product of atmospheric hydrogen-bomb tests conducted between 1955
and 1962 in the northern latitudes. Because it is chemically just heavy hydrogen, it was
quickly oxydized and turned into water. It then rained onto the northern ocean
below. From then on, it became very useful to trace currents deep and shallow. In this
picture North is to the right.
Bibliography
"Currents." NOAA's National Ocean Service Education: : The Global Conveyor
Belt. N.p., n.d. Web. 29 Oct. 2013.
Hyperlink to website abovehttp://oceanservice.noaa.gov/education/kits/currents/06conveyor2.html
"Thermohaline Circulation." Wikipedia. Wikimedia Foundation, 27 Oct. 2013.
Web. 29 Oct. 2013.
Hyperlink to website abovehttps://en.wikipedia.org/wiki/Thermohaline_circulation
Google images
Dr. Zafer Top’s bibliography
Dr. Zafer Top’s pictures
Dr. Zafer Top’s information
THANK YOU
• I would like to give a special thanks
to Dr. Zafer Top for being a great
mentor. And for providing me with
very useful, interesting and helpful
information.
Conclusion
In conclusion, global circulation is very
important because the oceans are great
reservoirs for the strong greenhouse gasses.