PCO oceanography

8/7/2019 PCO oceanography

1/13

History of oceanography

The first contribution was made by fishermen,merchants and traders as they explored oceanmargins in search of new routes or fishing

grounds Some basic principles of oceanography were

understand by ancient scientists

Aristotle, for instance noted in the fourth century

B.C. that the sea neither dries up nor overflows;thus the amount of rainfall is equal toevaporation over the earth


2/13


Ptolemy (A. D. 150) developed a scheme oflatitude and longitude for charting the knownworld and made surprisingly accurate maps of

the Eastern hemisphere The Venerable Bede (673- 735) knew that the

moon controls the tides

In 15th century, cardinal Nicholas tries to devise

a method of calculating the seas depth withoutusing a line. He suggested the rate of rise of abuoyant object in, diverse waters of knowndepth.


3/13


During later, the explorers circled the earth andmade charts as they went

During seventeenth century scientists as Sir

Robert Boyle (1627- 1691) studied oceantemperatures, water pressure, sea salts and theeffect of storm waves

Study of oceanic processes were expensive and

time consuming, most major advances havebeen sponsored by Governments or by verywealthy individuals


4/13


The voyages of Vasco da Gama, Colombus,Balboa, Magellan and Captain Cook mapped themajor outlines of land and ocean

Sir James Clark Ross (1800- 1862), sailedunder his uncle, Sir John Ross and had tried toreach the North Pole. From 1839 to 1843 hisships Erebus and Terror made three separate

voyages, circling Antarctica and chartinghundreds of miles of its coastal waters(biological specimens were collected from greatdepths and measured temperature.


5/13


Edward Forbes (1815- 1854) claimed to have

proven the absence of life below 600 m and

concluded that most of the ocean was azoic

Charles Darwin (1809- 1882) given theories

about the origin of species through evolution

Primitive animals on stalks, called crinoids, had

recently been discovered by Michael Sars Royal Society of London and Admirallyprovided

an important source of financial support


6/13


Edward Forbes (1815- 1854) claimed to

have proven the absence of life below 600

m. He concluded that most of the oceanwas azoic or devoid of animal life


7/13

World oceans

Oceans Area (m

Km2)

Volume

(m Km3)

Av.

depth

(m)

Av.

Temp.

(0C)

Av.

Salinity

(ppt)

Pacific 180. 3940 3.36 34.62

Atlantic 107 3310 3.72 34.76

Indian 74 3840 3.73 34.90

World 361 3730 3.52 34.72


8/13

Evaporation, precipitation and river

inflow for oceansOceans Evaporation

(cm/yr)

PPT (cm/yr) River inflow

(cm/yr)

Atlantic 124 89 23

Pacific 132 133 07

Indian 132 117 09

World 126 114 12


9/13

Ocean profile


10/13

Ocean floor


11/13

Ocean floor


12/13

Beach profile


13/13

Ocean beach

Documents

PCO oceanography