Thursday, July 12, 2012

Driven Forth Before the Wind – Eastward Across the Indian Ocean

So many Book of Mormon historians and scholars, especially those who champion a Mesoamerican model for the Land of Promise, want to take the Lehi Colony from the Arabian shore eastward across the Indian Ocean, through the Indonesian islands and then out across the Pacific Ocean to Central America. Unfortunately, they never think to consider if winds would have blown a sailing ship in that direction, nor if the ocean currents flowed along that course.

While not understood until recent years, there has always been a zonal (east to west) “throughflow” in the Indonesian Seas from the Pacific to the Indian Ocean. This system of surface currents flowing from the Pacific through the Indonesian seas is the only flow between ocean basins at low latitudes and, consequently, plays an important role in the meridional (north to south) transport of heat in the climate system, all the more so since this transport originates from the warm-pool of the Pacific and enters into the colder waters of the South Equatorial Current of the Indian Ocean.

This flow of water is governed by strong pressure gradient from the Pacific to the Indian Ocean, and blows continually from the east to the west, through all of Indonesia. Measurements of the volume transport of this throughflow has proven to be difficult due to the extremely complex coastline and topography of the Indonesian Seas, as well as the highly variable nature of currents in the throughflow region. The maximum net, relative transport through Indonesia is 12 Sverdrup (Sv = 106 m3.s-1). The winds driving this throughflow are strong, whirling, and treacherous.

Any wind-driven vessel trying to sail through Indonesia is faced with opposing winds against them all the way and whirling rip-currents, eddies, and swift currents, especially in channels of the Malacca, Sonda and Lombok Straits—the only three entrances from the Indian Ocean through Indonesia—which provide the greatest danger.

Local wind patterns, however, can greatly modify these general wind patterns, especially in the islands of central Maluku--Seram, Ambon, and Buru. This oscillating seasonal pattern of wind and rain is related to Indonesia's geographical location as an archipelago between two large continents. This is partly the reason why early sea traders in the area had to have oars for throughflow navigation.

Prevailing wind patterns interact with local topographic conditions to produce significant variations in rainfall throughout the archipelago. In general, western and northern parts of Indonesia experience the most precipitation, since the north- and westward-moving monsoon clouds are heavy with moisture by the time they reach these more distant regions. Western Sumatra, Java, Bali, the interiors of Kalimantan, Sulawesi, and Irian Jaya are the most predictably damp regions of Indonesia, with rainfall measuring more than 2,000 millimeters per year. The city of Bogor, near Jakarta, lays claim to having the world's highest number of rainstorms per year--322. To complicate the situation, some of the islands of the southern Malukus experience highly unpredictable rainfall patterns, depending on local wind currents.

Thus it would be extremely difficult, if not impossible, for a deep ocean sailing vessel “driven forth before the wind” to move from the Indian Ocean through Indonesia and out into the Pacific since it would be sailing against the winds all the way. In addition, there would be opposing currents and swift eddies all moving in treacherously swirling directions.

(See the next post, “Driven Forth Before the Wind – The Prevailing Westerlies,” to see how the Lehi Colony actually reached the Western Hemisphere by being driven forth before the wind in their sailing ship)

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