As an example, as the earth rotates from west to east, water near the equator tends to move from east to west, due to the prevailing winds. This leads to the formation of Equatorial currents, both North and South of the equator. Obviously, to the north is the North Pacific Gyre, which rotates clockwise, while to the south, is the South Pacific Gyre, which water rotates counter-clockwise.
Currents are part of a Gyre, which is formed
by global wind patterns and forces created by the Earth’ rotation around land
masses. The heat of the water circulating northward from the tropics regulates
the Earth’s temperatures
Thus, the rotation of earth is the primary causative factor for Equatorial Currents, it is the piling up of water and subsequent back-flow under gravity influenced by the earth’s rotation, which causes the eastward flow of the counter-current.
Due to trade winds the ocean water is piled up in the west through North and South Equatorial currents. Thus, due to higher level of ocean water in the west, water flows eastward in form of counter equatorial currents. Westward trade winds, which cause the westward surface flow of tropical waters in both the Atlantic and Pacific oceans are stronger than the winds which flows several hundred miles away from the equator. The stronger wind leads to piling up of water where the winds are weak. This excess water starts to flow eastward under the influence of earth’s rotation, giving rise to the equatorial counter-current.
In the Pacific, there are two counter currents due to its vast size—the north equatorial and the south equatorial counter currents. The counter currents have seasonal variations in intensity and latitudinal locations between summer and winter. The system is like one pouring a bucket of water with great force along a lengthy room towards the far wall, and upon hitting it, spreading out on both sides while rebounding back toward the bucket to splash on you. Something like that but with a lot other forces acting on it too. The Counter-Current is more a result of the geostrophic effect that is the equalization of the pressure gradient by the Coriolis Effect.
A geostrophic
current is an oceanic current in which the pressure gradient force is
balanced by the Coriolis effect
Consequently, when the isobars (lines of constant pressure) are parallel to the latitudes, the geostrophic force is perpendicular to it, causing the current to flow west to east. The reason that happens is the Sverdrup Balance, which flows to the north in the Northern Hemisphere, and the high pressure to the left in the Southern Hemisphere.
It can be shown, that the zonal (east west) mass transport is dependent on the change of curl of the vertical component of the wind stress. This is the reason why there is an eastward equatorial counter-current like circulation.
This counter-current in the Pacific is very strong and is definable year-round. The Atlantic Equatorial Counter-current is strongest off the coast of Ghana (Africa), where it is known as the Guinea Current. The counter-current of the Indian Ocean flows only during the northern winter and only south of the equator.
Ocean currents are generated by a number of factors including Earth's rotation, wind direction, temperature differences and salinity differences. Movements are both horizontal and vertical. Currents are designated warm or cold. This designation comes from their point of origin, not their actual temperature. Any current flowing from the equatorial region toward the polar region is designated as warm; any current flowing from the polar region toward the equator is designated as cold. In actuality, a warm current has a higher temperature than surrounding waters and a cold current has a lower temperature than surrounding waters. Coupled with wind direction and the current’s direction of flow, the temperature of the ocean current affects the formation of climate on the land.
Ocean water is always on the move, affecting
the climate, local ecosystems, and the seafood that is eaten. These currents
are abiotic features of the environment, are continuous and directed movements
of ocean water
• The major currents of the North Atlantic Ocean are: Gulf Stream (warm), North Atlantic Drift (warm) and Canary Current (cold).
• Major currents of South Atlantic Ocean are: Benguela Current (cold) and Brazil Current (warm).
• The major currents of the North Pacific Ocean are: Japan-Kuroshiro (warm), North Pacific Current (warm), Alaska Current (warm) and California Current (cold).
• Major currents of South Pacific Ocean are: Peru-Humboldt Current (cold), East Australian Current (warm).
• Major currents of the Indian Ocean are West Australian (cold), and Agulhas Current (warm).
• The chief current surrounding Antarctica is the West Wind Drift (cold). This extremely strong current is free-flowing, that is it is not hindered by land obstructing or altering the course of either wind or water.
Once again, these currents are driven constantly by the Earth’s force and have always existed and will always exist. They have not changed, and are like road maps that allow us to better understand the flow of oceans and their impact on early ship movement and in the cause of Lehi, where his ship would have gone. To ignore such criteria and just place Lehi down on some location without understanding in full how he got there is both foolhardy and misleading.
(See the next post for more on the ocean currents and how and why they exist and why it is important to understand them to know where Lehi sailed to reach the Land of Promise)
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