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Westerlies and Atmospheric Low Pressure Systems

Steering eastwards, then on a east-southeast direction, southeast, and even we end up on a southerly course. Braced Close-hauled we follow the veering winds. 

Fair northwesterly dies down, then turns to easterly before becoming a southerly breeze. 

It all comes to Wear ship to point again eastwards while the wind picks up at the back side of a low-pressure system until it passes by, leaving us with light air. 

The sunny weather clouds up, the temperature is warm and rain starts falling before it becomes dry again. 

One of the many low pressures that sweep over the South Pacific from west to east just passed over our heads. 

Many think that in the southern part of this ocean, you run into a westerlies corridor, but in fact this zone is a passageway for atmospheric depressions that travel uninterrupted by any landmass around a belt of high latitudes. This means that atop the prevailing westerlies you have to deal with the wind shifts of these low pressures traveling eastwards one after the other. 

Now after the rain and veering winds, we find ourselves again under the sun and calm conditions. The seas are good, the ship gently rolls sailing with the breeze on our backs. Good conditions for hands-on sail-training outside and maintenance jobs both aloft and on deck. Until nighttime when we ride again the fair westerlies at northern edge of the next upcoming system located south of us. 

A feature of the South Pacific is these often ferociously blowing westerlies and the low pressures traveling with them. That made for the first couple of hundred years of European exploration and trading across the Pacific to be particularly fruitless on coming across the many islands that pepper this Ocean. Ships departing from Europe, bound westwards towards South America, and coming into the Pacific after rounding the Horn or traversing the Straits of Magellan, found great difficulties to make any headway against wind and currents at these latitudes. The most commonly taken route and the one that made the most sense was to travel north until coming across the trade winds. By then almost all navigators followed approximately the same route finding the Polynesian Islands that lay closer to it, never coming across many of the other ones. At both extremes of this lay the Tuamotus, well known by then, and Hawaii, out of these paths and actually not found by Europeans until Captain Cook stumbled onto them. He was sailing north from Tahiti on his way to find the legendary Northwest Passage during his third voyage. It was 1778 and this finding proved to be the last great Pacific discovery by any European explorer. 

Needless to say, all the atolls and islands that the Europeans gradually reached in the Pacific during a long period of time, were already inhabited since the last part of the first millennia to the beginning of the second. The seafaring Polynesians had made home of almost all of them, becoming the most closely related widely dispersed people in the world. 

For us, the 165nm sailed during the last day brought us a bit deeper into the open waters of the South Pacific. 

Less birds are spotted around, just now and then Black petrels or a solitary Wandering albatross pass by. It is springtime, may be the reason for seeing less seabirds around. It is the time of the year for them to return from their wandering in the open seas to their breeding grounds. Many of them seem now to hang around closer to the islands and islets where they nest, that we gradually leave behind. 

Geschreven door:
Jordi Plana Morales | Expedition Leader

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