Pole—Antarctica is consistently 11 to 14 degrees Celsius (20 to 25 degrees Fahrenheit) colder than the Arctic. Because of this, the wind patterns described above are all pushed slightly to the north, meaning that warmer weather and thus warmer water are not centered around the equator but are found at some distance above the equator. Hence, there are no hurricanes in the South Atlantic and more hurricanes in the northern hemisphere than in the southern. However, strong westerly winds blow over the Southern Ocean all winter long.6

THE WINDS OF TRADE

William Dampier (1652-1715), a British explorer and buccaneer, was the first to describe the trade winds and the fact that they blow consistently from the northeast in the northern hemisphere and from the southeast in the southern hemisphere. Dampier made many other remarkable discoveries, recognizing that the equatorial currents flow in the direction of the trade winds and that tidal streams flowing near shore are not the same as ocean currents.7

In addition to the trade winds, which for centuries facilitated sail-driven trade and transport (hence the name), the global heat engine creates other winds, some beneficial but others detrimental to the navigator. Those that are detrimental include the kamsin wind, which originates in the Sahara, blowing southwest across Egypt from April to June; the mistral, a violent northwest wind that blows down into the Gulf of Lyons; the pampero, a dry northwest summer wind that blows from the Andes across the pampas to the sea; the sirocco, from the deserts of North Africa toward Italy; and the Santa Ana, warm air from the Mojave Desert blowing west to the Pacific Ocean to give just a few of the thousands of names for local winds.

The circulation of the winds on the surface of the ocean and in the upper atmosphere is quite complicated, so a complete description is beyond the scope of this book, but one further distinction that is important to us is the variation of wind patterns with the seasons. From winter to summer there are notable shifts in the locations where some of the highs and lows of atmospheric pressure occur. These shifts have an important effect on weather patterns and therefore on wave forma-



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