What is ENSO and why is it important?
What is ENSO? ENSO is nothing but El Nino Southern Oscillation. As the name suggests, it is an irregular periodic variation of wind and sea surface temperature that occurs over the tropical eastern Pacific Ocean.
What is El Nino and ENSO?
This is the periodic change in pressure conditions which is referred to as the Southern Oscillation. These changes in the pressure conditions being developed in the Pacific and Indian oceans are connected with the phenomenon of El Nino. This connected phenomenon is referred to as the El Nino Southern Oscillations or the ENSO.
What is the warming phase of ENSO called?
The warming phase of ENSO is called El Nino, while the cooling phase is known as La Nina. What is El Nino? El Nino is a climatic cycle characterised by high air pressure in the Western Pacific and low air pressure in the eastern.
What is the ENSO cycle?
The ENSO cycle describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific. El Nino and La Nina episodes typically last nine to 12 months, but some prolonged events may last for years.
What is ENSO Upsc?
The ENSO is a recurring climatic pattern involving temperature changes in the waters of the eastern and central tropical Pacific Ocean, and changes in the patterns of upper and lower-level winds, sea level pressure, and tropical rainfall across the Pacific Basin.
What is meant by ENSO?
The El Niño-Southern Oscillation (ENSO) is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean.
What is the difference between El Niño and ENSO?
El Niño and the Southern Oscillation, also known as ENSO is a periodic fluctuation in sea surface temperature (El Niño) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean.
How is El Niño formed Upsc?
In an El Niño year, air pressure drops over large areas of the central Pacific and along the coast of South America. The normal low pressure system is replaced by a weak high in the western Pacific (the southern oscillation). This change in pressure pattern causes the trade winds to be reduced == Weak Walker Cell.
What are the 3 phases of ENSO?
We can use surface-water temperatures in the eastern equatorial Pacific to designate conditions as one of three phases of the El Nino-Southern Oscillation (ENSO) system — neutral (or “normal”), warm (El Nino), and cold (La Nina).
What is ENSO caused by?
ENSO events are not caused by climate change, they are caused by the interaction between the surface layers of the ocean and the overlying atmosphere in the tropical Pacific.
Why El Niño occurs?
An El Niño condition occurs when surface water in the equatorial Pacific becomes warmer than average and east winds blow weaker than normal. The opposite condition is called La Niña. During this phase of ENSO, the water is cooler than normal and the east winds are stronger. El Niños typically occur every 3 to 5 years.
What causes La Niña and El Niño?
El Niño and La Niña result from interaction between the surface of the ocean and the atmosphere in the tropical Pacific. Changes in the ocean impact the atmosphere and climate patterns around the globe. In turn, changes in the atmosphere impact the ocean temperatures and currents.
Why is El Niño called El Niño?
Fishermen off the west coast of South America were the first to notice appearances of unusually warm water that occurred at year's end. The phenomenon became known as El Niño because of its tendency to occur around Christmas time. El Niño is Spanish for "the boy child" and is named after the baby Jesus.
What is El Niño vs La Niña?
El Niño refers to the above-average sea-surface temperatures that periodically develop across the east-central equatorial Pacific. It represents the warm phase of the ENSO cycle. La Niña refers to the periodic cooling of sea-surface temperatures across the east-central equatorial Pacific.
What is ENSO class 9 geography?
Explanation: "ENSO" refers to the El Niño/Southern Oscillation, the interaction between the atmosphere and ocean in the tropical Pacific that results in a somewhat periodic variation between between below-normal and above-normal sea surface temperatures and dry and wet conditions over the course of a few years.
What is meant by ENSO?
The El Niño-Southern Oscillation (ENSO) is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tr...
What are the 3 stages of ENSO?
The three phases of the El Niño–Southern Oscillation (ENSO) are The neutral phase, El Niño, La Niña.
What is El Niño in simple terms?
El Niño is an abnormal weather pattern caused by the warming of the Pacific Ocean near the equator, off the coast of South America. The sun warms t...
What is El Niño vs La Niña?
El Niño refers to the above-average sea-surface temperatures that periodically develop across the east-central equatorial Pacific. It represents th...
What is the cold phase of ENSO?
El Nino is often called the warm phase and La Nina is called the cold phase of ENSO. These deviations from the normal surface temperatures can have a large-scale impact on the global weather conditions and overall climate.
What is the Southern Oscillation Index?
Southern Oscillation Index (SOD) is used to measure the intensity of the Southern Oscillation. This is the difference in pressure between Tahiti in French Polynesia (Central Pacific), representing the Central Pacific Ocean, and Port Darwin, in northern Australia representing the Eastern Pacific Ocean.
What is the name of the interannual fluctuation of atmospheric pressure over the tropical Indo-Pacific region?
Southern Oscillation, in oceanography and climatology, is a coherent inter-annual fluctuation of atmospheric pressure over the tropical Indo-Pacific region. El Nino and Southern Oscillation coincide most of the times hence their combination is called ENSO – El Nino Southern Oscillation.
How did El Nino affect India?
On the other hand, a moderate El Nino in 2002 resulted in one of the worst droughts. El Nino directly impacts India’s agrarian economy as it tends to lower the production of summer crops such as rice, sugarcane, cotton, and oilseeds.
How are El Nino and Indian monsoons related?
El Nino and Indian monsoons are inversely related. The most prominent droughts in India – six of them – since 1871 have been El Nino droughts, including the recent ones in 2002 and 2009. However, not all El Nino years led to a drought in India.
What happens during El Nino?
During El Nino year. In an El Niño year, air pressure drops over large areas of the central Pacific and along the coast of South America. The normal low-pressure system is replaced by a weak high in the western Pacific (the southern oscillation ).
What are the effects of El Nino?
Effects of El Nino. The warmer waters had a devastating effect on marine life existing off the coast of Peru and Ecuador. Fish catches off the coast of South America were lower than in the normal year (Because there is no upwelling). Severe droughts occur in Australia, Indonesia, India, and southern Africa.
Which region is conductive to good monsoon rainfall?
This is known as Walker Circulation. The location of low pressure and hence the rising limb over Western Pacific is considered to be conductive to good monsoon rainfall in India. Its shifting eastward from its normal position, such as in El Nino years, reduces monsoon rainfall in India.
What is the name of the interannual fluctuation of atmospheric pressure over the tropical Indo-Pacific region?
Southern Oscillation, in oceanography and climatology, is a coherent inter-annual fluctuation of atmospheric pressure over the tropical Indo-Pacific region. El Nino and Southern Oscillation coincide most of the times hence their combination is called ENSO – El Nino Southern Oscillation.
What happens during El Nino?
During El Nino year. In an El Niño year, air pressure drops over large areas of the central Pacific and along the coast of South America. The normal low pressure system is replaced by a weak high in the western Pacific (the southern oscillation ).
How did El Nino affect India?
On the other hand, a moderate El Nino in 2002 resulted in one of the worst droughts. El Nino directly impacts India’s agrarian economy as it tends to lower the production of summer crops such as rice, sugarcane, cotton and oilseeds.
Is ENSO effective in India?
Although ENSO was statistically effective in explaining several past droughts in India, in the recent decades the ENSO-Monsoon relationship seemed to weaken in the Indian subcontinent. For e.g. the 1997, strong ENSO failed to cause drought in India.
Did ENSO cause drought?
For e.g. the 1997, strong ENSO failed to cause drought in India. However, it was later discovered that just like ENSO was an event in the Pacific Ocean, a similar seesaw ocean-atmosphere system in the Indian Ocean was also at play. It was discovered in 1999 and named the Indian Ocean Dipole (IOD).
Is the Indian monsoon related to the El Nino?
El Nino and Indian monsoon are inversely related. The most prominent droughts in India – six of them – since 1871 have been El Nino droughts, including the recent ones in 2002 and 2009. However, not all El Nino years led to a drought in India.
El Nino
El Nino was first recognized by Peruvian fishermen off the coast of Peru as the appearance of unusually warm water. The Spanish immigrants called it El Nino, meaning “the little boy” in Spanish.
La Nina
La Nina means The Little Girl in Spanish. It is also sometimes called El Viejo, anti-El Nino, or simply "a cold event."
ENSO and India
El Nino: Strong El Nino events contribute to weaker monsoons and even droughts in India Southeast Asia.
What is ENSO known for?
ENSO is best-known for its association with floods, droughts and other weather disturbances in many regions of the world, which vary with each event. Developing countries dependent upon agriculture and fishing, particularly those bordering the Pacific Ocean, are the most affected.
How long has ENSO been around?
ENSO conditions have occurred at two- to seven year intervals for at least the past 300 years, but most of them have been weak. There is also evidence for strong El Niño events during the early Holocene epoch 10,000 years ago.
How does ENSO affect birds?
The ENSO variability may contribute to the great success of small fast-growing species along the Peruvian coast, as periods of low population removes predators in the area. Similar effects benefit migratory birds which travel each spring from predator-rich tropical areas to distant winter-stressed nesting areas.
What causes ENSO?
Although its causes are still being investigated, ENSO events begin when trade winds, part of the Walker circulation, falter for many months. A series of Kelvin waves—relatively warm subsurface waves of water a few centimetres high and hundreds of kilometres wide—cross the Pacific along the equator and create a pool of warm water near South America, where ocean temperatures are normally cold due to upwelling.
What did Jacob Bjerknes suggest about ENSO?
Jacob Bjerknes in 1969 helped toward an understanding of ENSO, by suggesting that an anomalously warm spot in the eastern Pacific can weaken the east-west temperature difference, disrupting trade winds that push warm water to the west. The result is increasingly warm water toward the east.
What is the name of the oceanic component of the enso?
ENSO is composed of an oceanic component, called El Niño (or La Niña, depending on its phase), which is characterised by warming or cooling of surface waters in the tropical eastern Pacific Ocean, and an atmospheric component, the Southern Oscillation, which is characterised by changes in surface pressure in the tropical western Pacific.
How is the strength of the Southern Oscillation measured?
The strength of the Southern Oscillation is measured by the Southern Oscillation Index (SOI). The SOI is computed from fluctuations in the surface air pressure difference between Tahiti and Darwin, Australia.
What is the warming phase of ENSO?
The warming phase of ENSO is called El Nino, while the cooling phase is known as La Nina.
What is the climatic cycle of El Nino?
El Nino is a climatic cycle characterised by high air pressure in the Western Pacific and low air pressure in the eastern. In normal conditions, strong trade winds travel from east to west across the tropical Pacific, pushing the warm surface waters towards the western Pacific.
How does El Nino affect the ocean?
El Nino reduces upwelling of cold water, decreasing the uplift of nutrients from the bottom of the ocean. This affects marine life and sea birds. The fishing industry is also affected. Drought caused by El Nino can be widespread, affecting southern Africa, India, Southeast Asia, Australia, and the Pacific Islands.
What is the effect of El Nino on India?
The Indian Ocean is warmer than the adjoining oceans and so, has relatively lower pressure.
What is the oceanic nino index?
The Oceanic Nino Index (ONI) is used to measure deviations from normal sea surface temperatures. The Oceanic Niño Index is a measure of the departure from normal sea surface temperature in the east-central Pacific Ocean, is the standard means by which each El Nino episode is determined, gauged, and forecast.
How does El Nino affect the world?
El Nino Effects. El Nino results in the rise of sea surface temperatures. It also weakens the trade winds of the affected region. In India, Australia, it can bring about drought conditions. This affects the crop productivity largely.
What is El Nino?
El Nino can be understood as a natural phenomenon wherein the ocean temperatures rise especially in parts of the Pacific ocean. It is the nomenclature which is referred to for a periodic development along the coast of Peru. This development is a temporary replacement of the cold current along the coast of Peru. El Nino is a Spanish word.
What is a buoy in the ocean?
A buoy is a type of object that floats in water and is used in the middle of the seas as locators or as warning points for ships. They are generally bright (fluorescent) in color. These buoys measure ocean and air temperatures, currents, winds, and humidity.
Does El Nino cause drought?
It has been also observed certain times, that EL Nino may not bring drought but cause heavy rainfall. In both the cases, it causes heavy damage. However, in some other countries it may result in a complete reversal, i.e., excessive rainfall.