El Nino & La Nino
Regarding general atmospheric circulation, the warming and cooling of the Pacific Ocean is crucial. Oceanic phenomena such as El Nino and La Nina are caused by atmospheric circulation. They are phenomena with a coupled ocean atmosphere. The cool Peruvian current is replaced by the warm water of the central Pacific Ocean as it slowly moves towards the South American coast. El Nino is a weather phenomenon that causes warm water to appear off the coast of Peru. El Nino, which first appears around Christmas, refers to the child Christ in Spanish.
El-Nino Condition
The ITCZ typically migrates from latitudes 10°N in August to 3°N in February. However, it might shift south of the equator in the eastern Pacific during El-Nino Southern Oscillation (ENSO) events. The trade winds become less strong as a result of this shift. The warm surface waters linger off the coast of South and Central America for at least a year.
The dominant warm ocean current continues to suppress and reduce upwelling, and the trade winds are unable to carry it away. This phenomenon is known as El Nino. Over a sizable portion of the South-East Pacific, it results in a drop in air pressure, while the Western Pacific experiences an increase. The Southern oscillation is the term used to describe the rising see-saw variation in air pressure.
Southern oscillation
The El Nino event is closely associated with the pressure changes in the Central Pacific and Australia. This change in pressure conditions over the Pacific is known as the southern oscillation. Southern oscillation refers to shifting the surface air pressure between the tropical eastern Pacific and eastern Indian oceans.
ENSO
The combined phenomenon of southern oscillation and El Nino is known as ENSO. In the years when the ENSO is strong, large-scale variations in weather occur over the world.
Effects of El-Nino
Heavy rains fall on the dry west coast of South America, Australia and occasionally, India experiences drought, and China experiences floods. Microscopic algae cannot grow in warm water because the supply of nutrients from deep water is cut off. Fish lose their lives in great numbers as a result, which is devastating to marine life. Fish decomposition releases CO2, which causes the water to become toxic and darken.
