Oceanography

The oceanography (of “Ocean” and the Greek γράφειν / gráphein , to write) is the study of the Océan S and the Mer S of the Earth. The oceanographers study a very great number of subjects, including the Plate tectonics , biogeochemical major cycle, the oceanic currents or the organizations and the ecosystem S sailors or the bonds between oceans and climatic Modifications. These varied fields reflect the multitude of disciplines which the oceanographers integrate in order to include/understand the interdependence which there exists between the Biologie, the Géologie, the Météorologie and the Physique of the Océan.
On distinguishes oceanography from the Océanologie, which relates to the use of the oceanography applied to the exploitation of the oceanic resources and environmental protection sailors.
Beaucoup of oceanographer was also interested in the extraterrestrial life, and the astronauts are trained under water before being sent in space.

Holistic science

Oceanography is Holistique in what the ocean influences the Climat and which it is in return influenced by the terrestrial ecosystem S, and that it memorizes via its Sédiment S the contributions not only terrigenous, but also space. Hans Pettersson marked of the oceanographer such as Arrhenius in their recalling that the sediments have better than the grounds kept the memory of the cosmic contributions of particles (but less although ice).

Branches of oceanography

One distinguishes four large branches from oceanography:

  • the Biologie marinades (or ecology marinades) which studies the fauna and the flora of the oceans like their ecological interactions ;

    • the Ichtyology, the science which studies the fish
  • the chemical Océanographie studies the Chimie oceans;
  • the Géologie marinades studies the Géologie ocean floor of which the Plate tectonics ;
  • the physical Océanographie studies the physical characteristics of the ocean (such as the Structure thermohaline, the Vague S, the Marée S and the current sailors).

These various branches show that often the oceanographers initially studied the exact sciences.

Are added to it sometimes the Météorologie marinades as well as the maritime Ingénierie

Short history of oceanography

By nature, the exploration of the oceans was long and difficult and did not begin that only a few centuries ago with the development of the Navigation and of the first large remote Exploration S. Up to one recent period, only the ships brought the essence of knowledge of this medium, but the data were dispersed in time and space.

The first investigations were limited to surface and with some creatures which the fishermen caught but when Bougainville and Cook carries out their explorations, the seas they-even are a share of their report/ratio.

At the end of XVIIIe and the beginning of the XIXe centuries, James Rennell wrote the first scientific texts on the currents in the oceans Atlantique and Indien. Sir James Clark Ross proceeded to the first modern surveys of the deep seas in 1840 and Charles Darwin published an article on the reefs and the formation of the atolls.

One discovered the steep slope beyond the continental shelf in 1849. Matthew Fontaine Maury published, in 1855, the first text which one can describe as oceanographical, Physical Geography off the Sea ( Géopraphie Physique of the Sea ). Three years later, in August 1858, the successful installation of the first transatlantic telegraphic cable, thanks to work of lieutenant M.F. Maury, the presence of an underwater dorsal in the middle of the ocean confirms.

In second half of the XIXe century, the scientific companies receive and treat a flood of new ground observations and maritime and the specialists in natural history in Europe have a presentiment of the need for information other than anecdotic on the oceans.

Oceanography became a science quantifiable in 1872 when the Scot Charles Wyville Thompson and John Murray set in motion forwarding Challenger (1872-76). Other European and American nations sent scientific expeditions, as well private individuals as of the institutions.

Since about thirty years, the techniques of space observations allowed considerable progresses while bringing a new capacity to supervise the oceans overall, in a permanent and instantaneous way: by measurement of the Topography of the seas (one speaks then about hydrography) and of its temporal evolution, by that of the vague , the temperature of surface and the biological indicators, by data acquisition oceanographical measured in situ on board buoys and boats, etc

The Altimetry satellitale, today in the center of the activity of space oceanography, is a space technique making it possible to measure the relief of the oceans, development in the Années 1970 then 1980, and which saw its capacities multiplied by ten in terms of precision and space-time cover. This progress was in particular obtained thanks to the data of the Franco-American satellite TOPEX/Poséidon launched by the rocket ARIANE in August 1992. Today, the successor of this last satellite from now on to the retirement, is Jason-1, satellite first of what should become a genuine space die as regards oceanographical follow-up in the long run.

In addition to this aspect of observation and analysis of measurements in situ , another great field of oceanography is the theoretical study of the concerned physical processes: one speaks about physical oceanography. That results in the writing and the resolution of a set of more or less simplified equations representing the flows geophysics met in the ocean. These equations, known as Navier-Stokes equations, often very complex, cannot always be solved analytically by the methods Mathématiques traditional, from where the massive recourse to the use of numeric digital codes requiring a great power of calculation. The appearance of supercomputers offering power more and more caused an intensive development of the use of the numeric digital codes in oceanography in the 20 last years. Thus models appeared representing the world Océan and having for goal a total comprehension of oceanic circulation.

Ocean and atmosphere

The oceans play a fundamental role in the thermal balance of the Earth and their interaction with the atmosphere is the key of the evolution of the ic system Climat. This system resembles an immense heat engine whose mechanisms are based on the exchanges between atmospheric circulations (winds, for example the Mousson) and ic Océan (currents, such as for example El Niño), which contributes for shares comparable with the transport and the redistribution of energy of the tropical areas towards the polar regions. The oceans are thus to some extent a regulating thermostat of the climate. Moreover, they have immense capacities for absorption of chemical components , like the Carbon dioxide at the origin of the Greenhouse effect, which finally oblige to consider the unit “ocean-atmosphere”.

Famous oceanographers

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