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Satellite data from El Niño and La Niña of 1997-1998 are used, on the left, to show conditions encountreed by Kon-Tiki. It provides examples of westward moving tropical waves and surfacing of eastward flowing equitorial undercurrent. The warmest composite of GOES satellite, sea surface temperatures (SST), lower left, September 9, 1998 shows the equatorial cold tongue (green) surrounded by warmer (red) waters. The South Equatorial Current (SEC) flows westward on both sides of the equator and maximum west- ward flow occurs north of the equator. The North Equatorial Counter-Current (NECC) flows eastward between latitudes 5°N and 10°N. The eastward flow near the equator (160°W-140°W) may be the surfaced Equatorial Under- Current (EUC). |
Voyage of Kon-TikiA raft drifting on the ocean is at the mercy of the elements. When a sailor describes this experience, one begins to understand the meaning of “in situ,” of being in touch with the water. The senses feel the wind, waves, rain, humidity, and temperature and recognize the change in the patterns of swell, clouds, flying fish, and sea birds. Thor Heyerdahl (1950) described these events vividly as he and five companions crossed 7,700 kilometers of the equatorial Pacific on Kon-Tiki in 1948. Detractors predicted that they would be lost at sea. It is of interest to investigate modern, in situ, and satellite ocean measurements to determine why and how the voyage succeeded. The Kon-Tiki was constructed from wooden balsa logs in an attempt to duplicate Peruvian rafts described by early Spanish explorers in the sixteenth century. The native rafts were equipped with sails and an unusual steering system that made them effective in carrying large cargoes along the western coast of South America. Heyerdahl proposed that such rafts allowed the natives to sail from South America to the Polynesian Islands. To test this |
Heyerdahl provided the following descriptions of the ocean currents encountered by the Kon-Tiki: “There was not one day on which we moved backward toward America, and our smallest distance in twenty-four hours was 9 sea miles, while our average run for the voyage as a whole was 42.5 sea miles in twenty four hours. The Kon-Tiki expedition opened my eyes to what the ocean really is. It is a conveyor and not an isolator. The ocean has been man's highway from the days he built the first buoyant ships, long before he tamed the horse, invented wheels and cut roads through the virgin jungles."
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