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The Hawaiian Islands trigger an extraordinary interaction between wind
and ocean that extends thousands of kilometers. This island effect is
much larger than has ever been observed by scientists before.
Using data from Earth-observing satellites, researchers discovered
this unusually long island "wake," which includes a narrow
eastward-flowing ocean current extending 8,000 kilometers (4,900 miles)
from Asia to Hawaii. While scientists have known of an eastward current off of Asia for
some years, this new research shows that it extends from Asia to the
The top image above shows the winds around the Hawaiian Islands measured by the
Seawinds instrument aboard QuikScat during August 1999. Trade winds blow from east
to west (right to left in the image). Between islands the winds increase, while in the
wake of the islands the winds are remarkably weaker. The bottom image shows the
ocean current formed by the islands' wake. Arrows indicate current direction and speed
(derived from a general circulation model), while white contours show ocean
temperatures (measured by the Tropical Rainfall Measuring Mission). The warm water of the current generates winds which sustain the
current for thousands of miles.
Winds ruffling the water surface around the Hawaiian Islands create varying patterns, leaving some areas calmer than others. On the leeward sides of the islands, calmer waters show up as brighter silver coloration. Conversely, most vegetation grows on the windward sides.
Located in the southern Indian Ocean roughly midway between Africa, Australia, and Antarctica, the Kerguelen Islands experience a fierce climate, with incessant, howling winds and rain or snow nearly every day. At a latitude of about 49 degrees South, the islands lie in the path of the “Furious Fifties,” a belt of westerly winds that whip around the Southern Hemisphere, mostly unimpeded by land.