Ocean currents are the directional movement of seawater caused by gravity, wind (Coriolis Effect), and water density. Water in the ocean flows in two directions: horizontally and vertically. Currents are horizontal motions, while upwellings and downwellings represent vertical movements. This abiotic system is in charge of heat transport, biodiversity variations, and the Earth's climate system.
Factors that impact the ocean current formations are:
Planetary winds are constant winds (Trade winds, Westerlies, and Polar Easterlies) that blow between pressure belts. The oceanic circulation pattern closely resembles that of the earth's atmosphere.
Temperatures: The Sun's differential heating at the equator and poles results in a temperature difference in ocean water. The equator's warm water slowly creeps along the sea's top toward the poles, while the poles' cold water slowly creeps along the sea's bottom toward the equator.
Salinity: Because low salinity waters have a lower density, they can flow on the surface of high salinity waters, whereas high salinity waters flow at the bottom.
Coriolis force deflects winds and freely moving objects to the right in the northern hemisphere and to the left in the southern hemisphere, according to Ferrel's law. Thus, ocean currents flow clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere.
A landmass obstructs the passage of ocean currents and divides them, causing them to travel in opposite directions.
Ocean currents play a significant role in defining the climates of various places of the world, particularly those that border the ocean.
Local Climate: Warm and cold currents have an effect on a region's local climate. For example, the North Atlantic Drift keeps the shores of the North Sea (western Europe's western coast) warm, which is rare at such latitudes. Similarly, the Kuroshio current in the North Pacific ocean keeps the Alaskan coast's ports ice-free during the winter.
Precipitation: Warm currents flow along the east coasts of continents, creating warm, rainy climates; cold currents flow along the west coasts of continents, creating cold, dry climates.
Desert Formation: Cold ocean currents play a direct role in the formation of deserts on the tropical and subtropical continents' west coasts. For instance, the Peru Stream, also known as the Humboldt Current, is a cold-water current in the southeast Pacific Ocean that is primarily responsible for the Atacama desert's aridity (driest desert of the world).
They have a moderating impact on temperatures around the coasts. For example, the warm North Atlantic Drift in England, the Canary cold current in Spain and Portugal, and so forth.
Tropical cyclones: They accumulate warm water in the tropics, which is the primary cause of tropical cyclones.
Surface currents have a significant impact on climate. These currents transport heat energy from the equator to cooler regions of the ocean. Let's take the Gulf Stream as an example; the Gulf Stream in the North Atlantic Ocean.
The Gulf Stream is an ocean stream that brings warm water from the equator to Europe via the east coast of North America. It is approximately 160 kilometers broad and one kilometer deep. The warm waters of the Gulf Stream keep Europe substantially warmer than other regions at the same latitude. Temperatures in Europe would drop if the Gulf Stream were seriously disturbed.
Deep within the ocean, equally significant currents known as deep currents exist. These currents are not caused by wind, but by changes in the densities of water masses. The density of matter is the amount of mass contained within a particular volume. The density of ocean water is determined by two key factors:
Salinity (the amount of salt dissolved in the water) and temperature. The more salt dissolved in the water, the denser it becomes. Density is also affected by temperature: the colder the temperature, the higher the density. This is because the temperature has an effect on volume but not on mass. Colder water takes up less space than water that is warmer (except when it freezes). Thus, cold water is denser than warm water. Warm water undergoes thermal expansion.