Because El Niño's warm pool feeds thunderstorms above, it creates increased rainfall across the east-central and eastern Pacific Ocean.
In South America, the effects of El Niño are direct and stronger than in North America. An El Niño is associated with warm and very wet summers (December-February) along the coasts of northern Peru and Ecuador, causing major flooding whenever the event is strong or extreme. The effects during the months of February, March and April may become critical. Southern Brazil and northern Argentina also experience wetter than normal conditions but mainly during the spring and early summer. Central Chile receives a mild winter with large rainfall, and the Peruvian-Bolivian Altiplano is sometimes exposed to unusual winter snowfall events. Drier and hotter weather occurs in parts of the Amazon River Basin, Colombia and Central America.
Direct effects of El Niño resulting in drier conditions occur in parts of Southeast Asia, increasing forest fires, and northern Australia. Drier than normal conditions are also generally observed in Queensland, inland Victoria, inland New South Wales and eastern Tasmania during June-August.
West of the Antarctic Peninsula, the Ross, Bellingshausen, and Amundsen Sea sectors have more sea ice during El Niño. The latter two and the Weddell Sea also become warmer and have higher atmospheric pressure.
In North America, typically, winters are warmer than normal in the upper Midwest states and Canada, while central and southern California, northwest Mexico and the south eastern U.S., are wetter than normal. Summer is wetter in the intermountain regions of the U.S. The Pacific Northwest states, on the other hand, tend to be drier during an El Niño. During a La Niña, by contrast, the Midwestern U.S. tends to be drier than normal. El Niño is associated with decreased hurricane activity in the Atlantic, especially south of 25º N; this reduction is largely due to stronger wind shear over the tropics.
Finally, East Africa, including Kenya, Tanzania and the White Nile basin, experiences in the long rains from March to May wetter than normal conditions. There also are drier than normal conditions from December to February in south-central Africa, mainly in Zambia, Zimbabwe, Mozambique and Botswana.
Western Hemisphere Warm Pool
Study of climate records has found that about half of the summers after an El Niño have unusual warming in the Western Hemisphere Warm Pool (WHWP). This affects weather in the area and seems to be related to the North Atlantic Oscillation.
Atlantic effect
an effect similar to El Niño sometimes takes place in the Atlantic Ocean, where water along equatorial Africa's Gulf of Guinea becomes warmer and eastern Brazil becomes cooler and drier. This may be related to El Niño Walker circulation changes over South America.
Cases of double El Niño events have been linked to severe famines related to the extended failure of monsoon rains, as in the book Late Victorian Holocausts.
Non-climate affects
East Pacific fishing along the west coast of South America; El Niño reduces the upwelling of cold, nutrient-rich water that sustains large fish populations, which in turn sustain abundant sea birds, whose droppings support the fertilizer industry.
The local fishing industry along the affected coastline can suffer during long-lasting El Niño events. The world's largest fishery collapsed due to overfishing during the 1972 El Niño Peruvian anchoveta reduction. During the 1982-83 event, jack mackerel and anchoveta populations were reduced, scallops increased in warmer water, but hake followed cooler water down the continental slope, while shrimp and sardines moved southward so some catches decreased while others increased. Horse mackerel have increased in the region during warm events.
Shifting locations and types of fish due to changing conditions provide challenges forfishing industries. Peruvian sardines have moved during El Niño events to Chilean areas. Other conditions provide further complications, such as the government of Chile in 1991 creating restrictions on the fishing areas for artisanal fishermen and industrial fleets.
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. There is some evidence that El Nino activity is correlated with incidence of red tides off of the Pacific coast of California.
It has been postulated that a strong El Niño led to the demise of the Moche and other pre-Columbian Peruvian cultures.
ENSO and global warming
A few years ago, attribution of recent changes (if any) in ENSO or predictions of future changes were very weak [1]. More recent results (e.g. Collins et al.) tend to suggest that the projected tropical warming may follow a somewhat El-Nino like spatial pattern, without necessarily altering the variability about this pattern
Australia’s climate is highly variable from year to year. For example, 1998 to 2001 were all very wet years across northern and central Australia, with some parts receiving more than double their average rainfall over the four-year period. In contrast, 2002 and early 2003 saw one of the worst droughts in Australia’s history. In eastern Victoria alone, the drought led to approximately 1.2 million hectares of land, including 41 houses and 9000 livestock, being burnt over a span of 59 days starting in January 2003. This was the largest fire event in Victoria since 1939.
Much of the variability in Australia’s climate is connected with the atmospheric phenomenon called the Southern Oscillation, a major see-saw of air pressure and rainfall patterns between the Australian/Indonesian region and the eastern Pacific.
La Niña translates from Spanish as "the girl-child". The term "La Niña" has recently become the conventional meteorological label for the opposite of the better known El Niño.
The term La Niña refers to the extensive cooling of the central and eastern Pacific Ocean. In Australia (particularly eastern Australia), La Niña events are associated with increased probability of wetter conditions.
Changes to the atmosphere and ocean circulation during La Niña events include:
Cooler than normal ocean temperatures across the central and eastern tropical Pacific Ocean.
Increased convection or cloudiness over tropical Australia, Papua New-Guinea, and Indonesia.
Stronger than normal (easterly) trade winds across the Pacific Ocean (but not necessarily in the Australian region).
High (positive) values of the SOI (Southern Oscillation Index).
A La Niña event is sometimes called an anti-ENSO (anti-El Niño-Southern Oscillation) event.
term what La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C. In the United States, an episode of La Niña is defined as a period of at least 5 months of La Niña conditions. The name La Niña originates from Spanish, meaning "the girl," analogous to El Niño meaning "the boy."
La Niña, sometimes informally called "anti-El Niño", is the opposite of El Niño, where the latter corresponds instead to a higher sea surface temperature by a deviation of at least 0.5 °C, and its effects are often the reverse of those of El Niño. El Niño is famous due to its potentially catastrophic impact on the weather along both the Chilean, Peruvian and Australia.
Much of the variability in Australia’s climate is connected with the atmospheric enomenon called the Southern Oscillation, a major see-saw of air pressure and rainfall patterns between the Australian/Indonesian region and the eastern Pacific.
When the eastern Pacific Ocean is much cooler than normal, the SOI is usually persistently positive (about +7) and the Walker Circulation (upper panel of Figure 2) is stronger than average. These changes often bring widespread rain and flooding to Australia – this phase is called La Niña.
During La Niña phases, temperatures tend to be below normal, particularly over northern and eastern parts of Australia. The cooling is relatively strongest during the October to March period.
La Niña phases tend to have a effect on temperatures than El Niño phases; that is, temperatures are much cooler than average during La Niña events than they are warmer than average during El Niño events.
Scientists have made important advances in understanding the El Niño/La Niña phenomenon in recent decades as a result of research undertaken at the Bureau of Meteorology and other organisations world-wide. This has led to the development of computer models which can be used to forecast the behaviour of El Niño and La Niña some months in advance.
La Nina is an abnormal oceanic phenomenon that is one of the Severe Weather Conditions on the surface of the earth. During La Nina, the temperature of the water surface of the oceans becomes abnormally cool. La Nina is generally observed in the Equatorial Pacific Ocean. La Nina is just the opposite of El Nino. In the case of El Nino, the temperature of the water surface of the oceans becomes warmer than the normal temperature instead of becoming cooler.
The causes of this kind of severe natural phenomenon are hidden in the major fluctuations of temperature in the surface of waters of the Equatorial Pacific Ocean. La Nina occurs when the difference between atmospheric pressures in South America and Indonesia increases to a certain level. La Niña usually occurs just after an El Nino has occurred. In fact due to the change of the air pressures, trade winds are produced. These strong trade winds blow the hot water from the surface of the oceans to the Southeast Asia. Then the inner cold water that is there in the depth of the ocean comes upward. The temperature of this water surface is much cooler than the normal temperature of the ocean.
La Niña translates from Spanish as "the girl-child". The term "La Niña" has recently become the conventional meteorological label for the opposite of the better known El Niño.
The term La Niña refers to the extensive cooling of the central and eastern Pacific Ocean. In Australia (particularly eastern Australia), La Niña events are associated with increased probability of wetter conditions.
Changes to the atmosphere and ocean circulation during La Niña events include:
Cooler than normal ocean temperatures across the central and eastern tropical Pacific Ocean.
Increased convection or cloudiness over tropical Australia, Papua New-Guinea, and Indonesia.
Stronger than normal (easterly) trade winds across the Pacific Ocean (but not necessarily in the Australian region).
High (positive) values of the SOI (Southern Oscillation Index).
A La Niña event is sometimes called an anti-ENSO (anti-El Niño-Southern Oscillation) event.
term what La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C. In the United States, an episode of La Niña is defined as a period of at least 5 months of La Niña conditions. The name La Niña originates from Spanish, meaning "the girl," analogous to El Niño meaning "the boy."
La Niña, sometimes informally called "anti-El Niño", is the opposite of El Niño, where the latter corresponds instead to a higher sea surface temperature by a deviation of at least 0.5 °C, and its effects are often the reverse of those of El Niño. El Niño is famous due to its potentially catastrophic impact on the weather along both the Chilean, Peruvian and Australia.
Much of the variability in Australia’s climate is connected with the atmospheric enomenon called the Southern Oscillation, a major see-saw of air pressure and rainfall patterns between the Australian/Indonesian region and the eastern Pacific.
When the eastern Pacific Ocean is much cooler than normal, the SOI is usually persistently positive (about +7) and the Walker Circulation (upper panel of Figure 2) is stronger than average. These changes often bring widespread rain and flooding to Australia – this phase is called La Niña.
During La Niña phases, temperatures tend to be below normal, particularly over northern and eastern parts of Australia. The cooling is relatively strongest during the October to March period.
La Niña phases tend to have a effect on temperatures than El Niño phases; that is, temperatures are much cooler than average during La Niña events than they are warmer than average during El Niño events.
Scientists have made important advances in understanding the El Niño/La Niña phenomenon in recent decades as a result of research undertaken at the Bureau of Meteorology and other organisations world-wide. This has led to the development of computer models which can be used to forecast the behaviour of El Niño and La Niña some months in advance.
La Nina is an abnormal oceanic phenomenon that is one of the Severe Weather Conditions on the surface of the earth. During La Nina, the temperature of the water surface of the oceans becomes abnormally cool. La Nina is generally observed in the Equatorial Pacific Ocean. La Nina is just the opposite of El Nino. In the case of El Nino, the temperature of the water surface of the oceans becomes warmer than the normal temperature instead of becoming cooler.
The causes of this kind of severe natural phenomenon are hidden in the major fluctuations of temperature in the surface of waters of the Equatorial Pacific Ocean. La Nina occurs when the difference between atmospheric pressures in South America and Indonesia increases to a certain level. La Niña usually occurs just after an El Nino has occurred. In fact due to the change of the air pressures, trade winds are produced. These strong trade winds blow the hot water from the surface of the oceans to the Southeast Asia. Then the inner cold water that is there in the depth of the ocean comes upward. The temperature of this water surface is much cooler than the normal temperature of the ocean.
La Niña translates from Spanish as "the girl-child". The term "La Niña" has recently become the conventional meteorological label for the opposite of the better known El Niño.
The term La Niña refers to the extensive cooling of the central and eastern Pacific Ocean. In Australia (particularly eastern Australia), La Niña events are associated with increased probability of wetter conditions.
Changes to the atmosphere and ocean circulation during La Niña events include:
Cooler than normal ocean temperatures across the central and eastern tropical Pacific Ocean.
Increased convection or cloudiness over tropical Australia, Papua New-Guinea, and Indonesia.
Stronger than normal (easterly) trade winds across the Pacific Ocean (but not necessarily in the Australian region).
High (positive) values of the SOI (Southern Oscillation Index).
A La Niña event is sometimes called an anti-ENSO (anti-El Niño-Southern Oscillation) event.
term what La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C. In the United States, an episode of La Niña is defined as a period of at least 5 months of La Niña conditions. The name La Niña originates from Spanish, meaning "the girl," analogous to El Niño meaning "the boy."
La Niña, sometimes informally called "anti-El Niño", is the opposite of El Niño, where the latter corresponds instead to a higher sea surface temperature by a deviation of at least 0.5 °C, and its effects are often the reverse of those of El Niño. El Niño is famous due to its potentially catastrophic impact on the weather along both the Chilean, Peruvian and Australia.
Much of the variability in Australia’s climate is connected with the atmospheric enomenon called the Southern Oscillation, a major see-saw of air pressure and rainfall patterns between the Australian/Indonesian region and the eastern Pacific.
When the eastern Pacific Ocean is much cooler than normal, the SOI is usually persistently positive (about +7) and the Walker Circulation (upper panel of Figure 2) is stronger than average. These changes often bring widespread rain and flooding to Australia – this phase is called La Niña.
During La Niña phases, temperatures tend to be below normal, particularly over northern and eastern parts of Australia. The cooling is relatively strongest during the October to March period.
La Niña phases tend to have a effect on temperatures than El Niño phases; that is, temperatures are much cooler than average during La Niña events than they are warmer than average during El Niño events.
Scientists have made important advances in understanding the El Niño/La Niña phenomenon in recent decades as a result of research undertaken at the Bureau of Meteorology and other organisations world-wide. This has led to the development of computer models which can be used to forecast the behaviour of El Niño and La Niña some months in advance.
La Nina is an abnormal oceanic phenomenon that is one of the Severe Weather Conditions on the surface of the earth. During La Nina, the temperature of the water surface of the oceans becomes abnormally cool. La Nina is generally observed in the Equatorial Pacific Ocean. La Nina is just the opposite of El Nino. In the case of El Nino, the temperature of the water surface of the oceans becomes warmer than the normal temperature instead of becoming cooler.
The causes of this kind of severe natural phenomenon are hidden in the major fluctuations of temperature in the surface of waters of the Equatorial Pacific Ocean. La Nina occurs when the difference between atmospheric pressures in South America and Indonesia increases to a certain level. La Niña usually occurs just after an El Nino has occurred. In fact due to the change of the air pressures, trade winds are produced. These strong trade winds blow the hot water from the surface of the oceans to the Southeast Asia. Then the inner cold water that is there in the depth of the ocean comes upward. The temperature of this water surface is much cooler than the normal temperature of the ocean.
