How ocean current currents affect the climate of surrounding regions?

How ocean current currents affect the climate of surrounding regions?

Ocean currents are widespread movements of water in a definite direction under the action of wind, gravity, the rotation of the Earth and other factors. They are very important for climatology because they affect temperature and atmospheric pressure in various regions and also determine the climate type.

Factors responsible for the origin and modifications of ocean currents:

There are four primary forces responsible for the origin and modifications of ocean currents:

1. Insolation: Heating by solar energy causes the water to expand. This causes a very slight gradient and water tends to flow down the slope causing ocean current. The flow is normally from east to west.
2. Planetary winds: Planetary winds are the principal cause of the origin of ocean currents. Such winds drive surface water along with them.
3. Earth rotation and gravity: The rotation of the Earth causes Coriolis force which affects the direction of movement of water and leads to formation of ocean currents. Gravity tends to pull the water down to pile and create gradient variation.
4. Coriolis force: This force intervenes and causes the water to move to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. These produce large circular currents in all the Ocean basins. One such circular current is in the Sargasso Sea.

There are also four Secondary forces responsible for the origin and modifications of ocean currents:

1. Difference of density and salinity: It is attributed to density differences in different layers of ocean waters. Heavier water sinks and causes the overlying surface water to move in its space. This gives rise to global oceanic circulation.
2. Coastline shape: The shape of coastline is also an important factor that affects the current in the oceans.
3. Other factors: Accumulation of water on east coasts leads to gravity induced movements down the slope. Wind, Coast line and inundation, large river discharge, presence of partially enclosed seas also modify ocean currents.
4. Temperature difference: Cold-water ocean currents occur when the cold water at the poles sinks and slowly moves towards the equator. Warm-water currents travel out from the equator along the surface, flowing towards the poles to replace the sinking cold water.

Effect of ocean currents on the climate of surrounding regions

Local Climate: The influence of wind on the ocean currents also affects the climate of surrounding regions. For example, when the wind blows over a warm current, they pick up heat and moisture that makes them begin to circulate in the air. As a result, winds near the coast tend to be warm and moist. Thus, along with the warm and moist air comes heavy rainfall.

Navigation: Ocean current predictions and real-time data are becoming more and more important for ships. The coastal zone is a vital source of food, drinking water, and energy for most large population centers. A great deal of the world’s trade is shipped via marine channels.

Fishing: Fish migrate to regions where they can grow and produce offspring. Fish from cold regions such as cod, herring and mackerel move towards the equator. Salmon go upstream in rivers during mating season. As cold water is denser than warm water, the food chain begins at the bottom of the sea where sunlight is not available. Along with plankton, microscopic plants and animals, food particles settle down to deeper layers.

Precipitation: Ocean currents affect the local climate of surrounding regions. Warm ocean currents bring rain to coastal areas and even interiors, where they are sometimes an important factor in the amount and distribution of precipitation. In latitudes with landmasses, it is the dominant factor that controls precipitation in coastal areas, except in the highest latitudes.

Desert Formation: The climatic conditions in deserts, are mainly affected by the ocean currents. Cold currents cause an encroachment of cold air from the poles into the critical areas surrounding the equator. The fairly uniform temperature that is found along a particular phenomenon or cold ocean current causes the surface water to form sea ice. This thick mass of ice further causes the cooling of water beneath and hence the surface sediment carries on sinking. Thus, the layers below get warmed and tend to go up in small columns of warm water.

Tropical cyclones: Tropical cyclones are rotating storm systems that derive their energy primarily from the release of heat stored in the ocean. These storm systems have a significant influence on the weather and climate in the surrounding regions. They are known to pile up warm waters in the tropics and are responsible for many tropical regions being relatively warmer than adjacent temperate regions.