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Seasonal Variations of Major Global Wind Patterns
Global wind patterns have both an historical and a contemporary significance for transportation. Historically, wind patterns were linked with the trade routes of sailships. For instance, there is a relatively stable wind pattern over the North Atlantic that enabled ships to set sail from Europe using the westbound dominant wind on the southern part of the North Atlantic and to come back using the eastbound dominant wind of the northern part of the North Atlantic. A similar pattern exists over the North Pacific. The monsoon over the Indian Ocean have also been linked with maritime trade far in the past, as ships were sailing from the Middle East to Asia in the winter and undertaking the westbound voyage back in the summer when the dominant wind direction shifted. With the progressive abandonment of sailing in the 19th century, wind patterns have stopped to play a significant role in maritime transportation. Intercontinental maritime shipping now follows the great circle distance, regardless of wind direction.
The growing importance of air transportation is constrained by wind direction, particularly for long distance hauls. Eastbound crossings over the North Atlantic and the North Pacific are shorter than westbound crossings because of the cumulative wind effect. For instance, a flight between New York and London is scheduled to last about 7 hours (from gate to gate) eastbound and about 7 hours and 45 minutes westbound. The scheduled difference of 45 minutes is accounted by dominant winds. Thus, the westbound transatlantic flight consumes more energy than the eastbound flight.