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1.From exploration of the seas to oceanography
Humans have been sailing to and fro over the seas since Ancient times. The first
navigators, and not long afterwards the merchant seafarers, observed the winds and
currents in order to define the best routes and make them secure. The XIXth Century
saw this concern become part of a scientific quest with the appearance of the first great
oceanographic expeditions. Knowledge about the winds, currents, sea floors and marine
life then made great advances and lay the foundations of oceanography.
2. Operational oceanography
From the 1950s, the need to take into account the whole ocean system in order to gain understanding and predict the climate
led scientists to develop new devices for observation and forecasting that provide continuous
real-time pictures of this fluid sphere and its dynamics.
5
3. The globalized ocean
The different ocean observation
systems
With the aim of learning more about the oceans, their dynamics, their variability and their role
in the behaviour of the climate, the international community set up large-scale ocean and
meteorological networks, combining in situ measurements (survey ships, buoys, floats) and
data from remote-sensing instruments in space. The information gathered feeds into the
1
predictive oceanic and climatological models.
3
4
4. The oceans seen from above
The oceans are observed by satellites
continuously in almost real time, spatially
and
E
60 °
1 Surface drifting buoy with a measuring
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instrument in tow
2 Line of measurement instruments hooked
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to a mooring on the sea floor
3 Measuring instrument lowered into the
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water from an oceanographic survey ship
4 Independent drifting measuring
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instrument in the marine environment
5 Satellite
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l. /
D
cro
s
equipped
with altimeters can provide highly
accurate measurements of sea level.
In this way they can give a picture of
the humps and troughs generated by
© NASA
the oceanic circulation and see the ocean
moving ! Satellites can also give a view of the
colour, the water temperature, winds and
currents.
70 °
©
CN
il
S/
avi
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temporally. Satellites
World map of marine
phytoplankton concentrations
This satellite image shows up the distinct oceanic areas rich
in phytoplankton (sky-blue colour). Note that the Equator is
traced in the Pacific and the Atlantic by sites of production
of plant matter generated by upwellings of nutrient-salt rich
waters from the ocean depths.
80 °
2