Weather on Oceans
The Pacific Ocean
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Winds and currents in the Pacific flow predominantly from East to
West. Above the equator Pacific Ocean trade winds blow from the
northeast. Below the equator they blow from the southeast. By
taking advantage of the different (north and south) directions of
the east-flowing winds, traditional Polynesian
navigators could sail eastward ( into the wind) north of the
equator and let the winds and currents push them southwest once
south of the equator. In this way Polynesians could navigate the
2,250 nautical miles from Hawai'i to Tahiti, by taking advantage
of the different orientation of the prevailing trade winds north
and south of the equator.
The more difficult journey for Polynesians was the one from
southernmost Polynesia (New Zealand/Aotearoa) north to Fiji. While
the same wind and current direction prevails throughout the
year--there is a regular disruption of this pattern by summer
monsoons in the region between New Guinea and Fiji. During the
winter winds blow in the opposite direction from the prevailing
one. These opposite (west flowing) winds last longer during major
El Niño events which usually begins with the weakening of
the usual trade winds. Captain Cook reported that a Polynesian
navigator told him that they waited for the summer monsoons to
make this voyage north.
The second difficult stage of the journey from southern to northern Polynesia occurred in traveling east from Fiji to Tahiti. Using the low pressure troughs from sub-tropical depressions during the summer monsoon period, Polynesian canoes could navigate from Samoa (north of Fiji) to the Society Islands, then Rarotonga and Tahiti.
* One of three large divisions of Pacific peoples. French explorer Charles de Brosses created the name "Polynesia" in 1756. Another French explorer de Surville used Micronesia and Melanesia in 1828.
