Friday, May 2, 2014

The Great Southern Ocean – Part I

While we are on the subject of Lehi’s landing at the 30º south latitude (see last 10 posts), perhaps a further comment or two on the way in which Nephi’s ship reached that far shore of Chile, and the ease of the unique, but direct journey, might be in order.
Since there is a large consensus that Lehi left the southern Arabian coast as he set out onto his Irreantum Sea, we will dispense with how and why that area is used as the starting point for the voyage. And whether he left Khor Rori situated near Salalah, Oman, or whether he left Khor Kharfot along the Wadi Saya in Yemen, the winds and currents off the southern Arabian coast would be the same.
According to the Woods Hole Oceanographic Institution during the winter monsoon (left) the wind-driven currents move into the land, trapping any sailing ship in the pocket between Somalia and India. Right: However, during the summer monsoon, the currents move out from the coast and south toward the Indian Ocean
Although mariners have been aware of the existence of the Monsoon currents for nearly a thousand years, a detailed understanding did not emerge until after the International Indian Ocean Expedition of the 1960s, and the World Ocean Circulation Experiment of the mid 1990s, which permitted complete verification and detailed measurement of these currents through an extensive field campaign for the first time.
As the result of the Woods Hole Oceanographic Institution and its well organized, interdisciplinary research program with continuous data collection in conjunction with the Joint Global Ocean Flux Study (JGOFS) program, we now know that these wind-driven currents of the Arabian Sea—an area 1,491,000 square miles—from 8º north latitude, between Somalia, Africa, and the west coast of India (sometimes referred to as the North Indian Ocean region—and in Roman times its name was Mare Erythraeum—the Erythraean Sea) are governed by the wind field of the monsoon season, which is from June to around September or October—Summer Monsoon June to August, in which the winds drive the ocean currents southward at 36-knots (called the summer transport), and the Winter Monsoon September and October (called the northern transport), with lighter winds and currents being driven northward inland.
It should be noted that the northward transport brings high volumes of water from the Somali Current because of the well-stirred surface forcing that moves into the Arabian Sea, driving the currents into the Gulf of Oman, southern coast of Pakistan, and the western coast of India, eliminating any chance at sailing into the Arabian Sea at this time in a ship “driven forth before the wind.”
On the other hand, the strong surface winds of the southern transport sends currents southward (left) off the Arabian coast toward Madagascar in the Indian Ocean, and would obviously send Nephi’s ship “driven forth before the wind” in this direction. Had Lehi tried to leave any earlier or later than when this current flows, they would have had great difficulty getting out to sea, or would have been blown into the west coast of India—a fact the Lord obviously knew: “And it came to pass that the voice of the Lord came unto my father, that we should arise and go down into the ship” (1 Nephi 18:5)…”And it came to pass after we had all gone down into the ship, and had taken with us our provisions and things which had been commanded us, we did put forth into the sea and were driven forth before the wind towards the promised land” (1 Nephi 18:8, emphasis mine). Thus, Lehi set to sea sometime between June and probably the end of July, when the southern transport moves the water away from land and toward the Indian Ocean at 36 knots per hour.
According to the American Meteorological Society Journal and the Journal of Physical Oceanography, we can describe accurately the seasonal evolution of the surface circulation of the Arabian Sea, which reverses annually with the Indian monsoon winds. In fact, the last two decades of drifter and satellite data shows conclusively that the northward flow moves along the length of the Indian Ocean and Sea of Arabia’s western boundary during the northern transport, and reverses itself to flow southward in the southern transport.
Satellite measurements provide a broad overview, and show how currents vary in time and space. However, data from other sources is also needed such as instruments anchored to the sea floor (moorings), drifting with the currents (floats), or mounted on buoys, platforms and ships
The current from Arabia southward along the western edge of the Sea of Arabia and the Indian Ocean is seen on satellite scatterometer wind velocity measurements of radar backscatter calculations from the European Remote Sensing Satellite (ERS-1). This provides a new source of data for studies of seasonal-to-interannual ocean-atmosphere interactions in the Sea of Arabian, where the largest and steadiest wind speeds occur in northern summer from June to July—the time when Lehi would have set out so he could be “driven forth before the wind.” None of this, of course, would have been known to Lehi, but it obvious was known to the Lord. He knew when the right time to set sail was and told Lehi when to enter the ship and set sail.
With the current moving rapidly southward, the pull of the counter-clockwise South Indian Ocean Gyre began to pull the current eastward that would have brought Lehi’s ship further out into the middle of the Indian Ocean in a slow arc. This gyre is one of the five major oceanic gyres, which are large systems of rotating ocean currents, that together form the backbone of the global conveyer belt—the Thermohaline Circulation.
Left: Lehi’s ship would be moved southward along the westward edge of the Sea of Arabia and the Indian Ocean, however, (Right) the pull of the South Indian Ocean Gyre, moving counter-clockwise, would pull the ship toward the east in a slow arc where it would be picked up by the Southern Ocean—a swift circumpolar current that moves rapidly around the Planet without land-mass interruptions
Once in the Southern Ocean, Lehi’s ship would have moved swiftly and uninterrupted around the narrowest circumference of the planet from the Indian Ocean to South America, where it would have taken the least amount of time to cross the Pacific and where no land masses exist that might have tempted Laman, Lemuel and the sons of Ismael to attempt another mutiny.
Those who try to tell us that Lehi island-hopped across the Pacific seem to forget that these renegades in the group did not want to continue with the journey, and on more than one occasion threatened to kill those who opposed them. One can only wonder what they might have done if there were tropical islands beckoning to them almost daily crossing among the islands others claim they passed.
After eight years in the wilderness, mostly Arabian desert, an island of trees, beautiful beaches and clear water would seem like paradise. Hard to imagine Laman and Lemuel not taking over the ship and forcing a landing and permanent residence
On the other hand, the seas are empty in the Southern Ocean, nothing but ocean and sky for anyone to see for the entire trip. Not much chance anything could incite a riot. As an example, passing New Zealand in the Southern Ocean, Nephi’s ship would have picked up the Prevailing Westerlies, running before huge seas with the crew on deck huddled in blankets or warm clothing, and those below, “holding on tight,” as forty to fifty knot winds crossed over the deck and the vessel moved along smartly at speeds over 14-knots or more, making about 300 miles a day in rough conditions.
A simple voyage, dropping down to the Westerlies of the Southern Ocean and running before the wind in a short passage to the Land of Promise
Imagine 40-50 knot winds, ship doing 14-15 knots, moving 55 to 65 knots an hour over the water—300 miles a day in rough conditions. A remarkably fast, though fearful voyage (that is easily achieved by modern boats along this Southern Ocean), and having already been in a storm that nearly cost them their lives—the southern ocean presented a threatening event for those who had little trust in the Lord.
The shortness of the voyage is understood when we realize the Pacific Ocean stretches 12,300 miles across from Indonesia to Colombia, South America, along its widest girth, but is only 5,778 miles from Melbourne, Australia, to Tierra del Fuego, South America, a savings in sea passage of just over 6,500 miles.
This, indeed, would be the shortest route across the Pacific. And the simplest. And one that would be uneventful—each day just like the one before
Maybe this is why after Nephi, when released by his mutinous brothers during the terrible storm, said: “I, Nephi, did guide the ship, that we sailed again towards the promised land. And it came to pass that after we had sailed for the space of many days we did arrive at the promised land” (1 Nephi 18:22-23). What else could you write about when all that you see is wind, ocean and sky? If they had been passing island after island, stopping to replenish food and water supplies, one might think that Nephi would have mentioned something about it—but he was silent. The trip of several thousand miles and “many days” drew a blank in the record.
(See the next post, “The Great Southern Ocean-Part II,” for more on understanding this quickest, shortest, and uneventful voyage of Lehi across the Irreantum Sea to the Land of Promise)

No comments:

Post a Comment