Chapter 2 - The Historical Setting

Chapter 2 Contents

Our knowledge of oceanic currents, winds, waves, and tides goes back thousands of years. Polynesian navigators traded over long distances in the Pacific as early as 4000 BC (Service, 1996). Pytheas explored the Atlantic from Italy to Norway in 325 BC. Arabic traders used their knowledge of the reversing winds and currents in the Indian Ocean to establish trade routes to China in the Middle Ages and later to Zanzibar on the African coast. And, the connection between tides and the sun and moon was described in the Samaveda of the Indian Vedic period extending from 2000 to 1400 BC (Pugh, 1987). Those oceanographers who tend to accept as true only that which has been measured by instruments, have much to learn from those who earned their living on the ocean.

Modern European knowledge of the ocean began with voyages of discovery by Bartholomew Dias (1487-1488), Christopher Columbus (1492-1494), Vasco da Gama (1497-1499), Ferdinand Magellan (1519-1522), and many others. They laid the foundation for global trade routes stretching from Spain to the Philippines in the early 16th century. The routes were based on a good working knowledge of trade-winds, the westerlies, and western boundary currents in the Atlantic and Pacific (Couper, 1983: 192-193).

The early European explorers were soon followed by scientific voyages of discovery led by (among many others) James Cook (1728-1779) on the Endeavour, Resolution, and Adventure, Charles Darwin (1809-1882) on the Beagle, Sir James Clark Ross and Sir John Ross who surveyed the Arctic and Antarctic regions from the Victory, the Isabella, and the Erebus, and Edward Forbes (1815-1854) who studied the vertical distribution of life in the oceans. Others collected oceanic observations and produced useful charts, including Edmond Halley who charted the trade-winds and monsoons and Benjamin Franklin who charted the Gulf Stream.

Slow ships of the 19th and 20th centuries gave way to satellites, drifters, and autonomous instruments toward the end of the 20th century. Satellites now observe the oceans, air, and land. Thousands of drifters observe the upper two kilometers of the ocean. Data from these systems, when fed into numerical models allows the study of Earth as a system. For the first time, we can study how biological, chemical, and physical systems interact to influence our environment.

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2.1 Definitions

The long history of the study of the ocean has led to the development of various, specialized disciplines each with its own interests and vocabulary. The more important disciplines include:

Oceanography is the study of the ocean, with emphasis on its character as an environment. The goal is to obtain a description sufficiently quantitative to be used for predicting the future with some certainty.

Geophysics is the study of the physics of the Earth.

Physical Oceanography is the study of physical properties and dynamics of the oceans. The primary interests are the interaction of the ocean with the atmosphere, the oceanic heat budget, water mass formation, currents, and coastal dynamics. Physical Oceanography is considered by many to be a subdiscipline of geophysics.

Geophysical Fluid Dynamics is the study of the dynamics of fluid motion on scales influenced by the rotation of the Earth. Meteorology and oceanography use geophysical fluid dynamics to calculate planetary flow fields.

Hydrography is the preparation of nautical charts, including charts of ocean depths, currents, internal density field of the ocean, and tides.

Earth-system Science is the study of earth as a single system comprising many interacting subsystems including the ocean, atmosphere, cryosphere, and biosphere, and changes in these systems due to human activity.

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