Wikipedia:El Niño-Southern Oscillation

From Global Warming Art

The following article is a local copy of the Wikipedia article at El Niño-Southern Oscillation. (more info)

For other uses, see El Niño (disambiguation).
The 1997 El Niño observed by TOPEX/Poseidon. The white areas off the tropical coasts of South and North America indicate the pool of warm water. [1]

El Niño-Southern Oscillation is a periodic change in the atmosphere and ocean of the tropical Pacific region. It is defined in the atmosphere by changes in the pressure difference between Tahiti and Darwin, Australia, and in the ocean by warming or cooling of surface waters of the tropical central and eastern Eastern Pacific Ocean. El Niño is the name given to its warm phase, or the period when water in that region is warmer than normal. La Niña is the name given to its cold phase, or the period when the water in the tropical Eastern Pacific is colder than normal.[2] The oscillation has no well-defined period, but instead occurs every three to eight years. Mechanisms that sustain the El Niño - La Niña cycle remain a matter of research.

The El Niño-Southern Oscillation is often is abbreviated in scientific jargon as ENSO and in popular usage is commonly called simply El Niño. The name is Spanish for "the boy" and refers to the Christ child, because periodic warming in the Pacific near South America is usually noticed around Christmas.[3] Conversely the name for the cool phase of the oscillation, "La Niña," is Spanish for "the girl."

El Niño is associated with floods, droughts and is linked to other weather disturbances in many locations around the world. El Niño's effects in the Atlantic Ocean lag behind those in the Pacific by 12 to 18 months. Developing countries dependent upon agricultural and fishing are especially affected. El Niño's effects on weather vary with each event. Recent research suggests that treating ocean warming in the eastern tropical Pacific separately from that in the central tropical Pacific may help explain some of these variations.[4]

Contents

Definition

Climate scientists define El Niño and La Niña based on sustained differences in Pacific-Ocean surface temperatures when compared with the average value. The accepted difference is anything greater than 0.5C (or 0.9F) averaged over the east-central tropical Pacific Ocean. When this happens for less than five months, it is classified as El Niño or La Niña conditions; if the anomaly persists for five months or longer, it is called an El Niño or La Niña "episode."[5] Typically, this happens at irregular intervals of 2–7 years and lasts nine months to two years.[6]

The first signs of an El Niño are:

  1. Rise in surface pressure over the Indian Ocean, Indonesia, and Australia
  2. Fall in air pressure over Tahiti and the rest of the central and eastern Pacific Ocean
  3. Trade winds in the south Pacific weaken or head east
  4. Warm air rises near Peru, causing rain in the northern Peruvian deserts
  5. Warm water spreads from the west Pacific and the Indian Ocean to the east Pacific. It takes the rain with it, causing extensive drought in the western Pacific and rainfall in the normally dry eastern Pacific.

El Niño's warm current of nutrient-poor tropical water, heated by its eastward passage in the Equatorial Current, replaces the cold, nutrient-rich surface water of the Humboldt Current. When El Niño conditions last for many months, extensive ocean warming occurs and its economic impact to local fishing for an international market can be serious.[7]

Early stages and characteristics of El Niño

5-day running mean of MJO. Note how it moves eastward with time.

Although its causes are still being investigated, El Niño 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 centimeters high and hundreds of kilometers 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. The Pacific Ocean is a heat reservoir that drives global wind patterns, and the resulting change in its temperature alters weather on a global scale.[8] Rainfall shifts from the western Pacific toward the Americas, while Indonesia and India become drier.[9]

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.[10] Several mechanisms have been proposed through which warmth builds up in equatorial Pacific surface waters, and is then dispersed to lower depths by an El Niño event.[11] The resulting cooler area then has to "recharge" warmth for several years before another event can take place.[12]

While not a direct cause of El Niño, the Madden-Julian Oscillation, or MJO, propagates rainfall eastward around the global tropics in a cycle of 30–60 days, and may influence the speed of development and intensity of El Niño and La Niña in several ways.[13] For example, westerly flows between MJO-induced areas of low pressure may cause cyclonic circulations north and south of the equator. When the circulations intensify, the westerly winds within the equatorial Pacific can further increase and shift eastward, playing a role in El Niño development. [14] Madden-Julian activity can also produce eastward-propagating oceanic Kelvin waves, which may in turn be influenced by a developing El Niño, leading to a positive feedback loop.[15]


Southern Oscillation

Normal Pacific pattern. Equatorial winds gather warm water pool toward west. Cold water upwells along South American coast. (NOAA / PMEL / TAO)

The Southern Oscillation is the atmospheric counterpart of El Niño. It is an oscillation in air pressure between the tropical eastern and the western Pacific Ocean waters. 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. [16] El Niño episodes are associated with negative values of the SOI, meaning that the pressure at Tahiti is relatively low compared to Darwin.

Low atmospheric pressure tends to occur over warm water and high pressure occurs over cold water, in part because deep convection over the warm water acts to transport air. El Niño episodes are defined as sustained warming of the central and eastern tropical Pacific Ocean. This results in a decrease in the strength of the Pacific trade winds, and a reduction in rainfall over eastern and northern Australia. Conversely, La Niña episodes are associated with positive values of the SOI and are accompanied by stronger Pacific trade winds and warmer sea temperatures to the north of Australia. Waters in the central and eastern tropical Pacific Ocean become cooler during this time.

Walker circulation

El Niño Conditions. Warm water pool approaches South American coast. Absence of cold upwelling increases warming.
La Niña Conditions. Warm water is further west than usual.

During non-El Niño conditions, the Walker circulation is seen at the surface as easterly trade winds which move water and air warmed by the sun towards the west. This also creates ocean upwelling off the coasts of Peru and Ecuador and brings nutrient-rich cold water to the surface, increasing fishing stocks. The western side of the equatorial Pacific is characterized by warm, wet low pressure weather as the collected moisture is dumped in the form of typhoons and thunderstorms. The ocean is some 60 centimetres (24 in) higher in the western Pacific as the result of this motion.[17][18][19][20]

In the Pacific, La Niña is characterized by unusually cold ocean temperatures in the eastern equatorial Pacific, compared to El Niño, which is characterized by unusually warm ocean temperatures in the same area. The La Niña condition and El Niño condition alternate over a several year cycle.

Effects of ENSO's warm phase (El Niño)

South America

Because El Niño's warm pool feeds thunderstorms above, it creates increased rainfall across the east-central and eastern Pacific Ocean. The effects of El Niño in South America 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. 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. This leads to fish kills offshore Peru.[7]

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.[21] Horse mackerel have increased in the region during warm events. Shifting locations and types of fish due to changing conditions provide challenges for fishing 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 self-employed 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 Niño activity is correlated with incidence of red tides off the Pacific coast of California.

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.

North America

Regional impacts of warm ENSO episodes (El Niño).
See also: Effects of the El Niño-Southern Oscillation in the United States

In North America, El Niño creates warmer-than-average winters in the upper Midwest states and the Northeast. Meanwhile, central and southern California, northwest Mexico and the southwestern U.S. become significantly wetter while the northern Gulf of Mexico states and northeast Mexico are wetter and cooler than average during the El Niño phase of the oscillation.[22][23] Summer is wetter in the intermountain regions of the U.S. The Pacific Northwest states, on the other hand, tend to experience dry, mild but foggy winters and warm, sunny and early springs.

In Canada, both warmer and drier winters (due to forcing of the Polar Jet further north) occur with warmer and less stormy summers, although relatively little variation is seen in the Maritime Provinces. However, it is believed that the ice-storm freezing rain event of January 1998 which devasted parts of Southern Ontario and Southern Quebec may have been caused or at least accentuated by El Nino's warming effects. [24]

El Niño is also associated with increased wave-caused coastal erosion along the United States Pacific Coast.

Tropical cyclones

Most tropical cyclones form on the side of the subtropical ridge closer to the equator, then move poleward past the ridge axis before recurving into the main belt of the Westerlies.[25] When the subtropical ridge position shifts due to El Nino, so will the preferred tropical cyclone tracks. Areas west of Japan and Korea tend to experience much fewer September-November tropical cyclone impacts during El Niño and neutral years. During El Niño years, the break in the subtropical ridge tends to lie near 130°E which would favor the Japanese archipelago.[26] During El Niño years, Guam's chance of a tropical cyclone impact is one-third of the long term average.[27] The tropical Atlantic ocean experiences depressed activity due to increased vertical wind shear across the region during El Niño years.[28]

Elsewhere

In Africa, 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. Direct effects of El Niño resulting in drier conditions occur in parts of Southeast Asia and Northern Australia, increasing bush fires and worsening haze and decreasing air quality dramatically. Drier than normal conditions are also generally observed in Queensland, inland Victoria, inland New South Wales and eastern Tasmania from June to 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.

El Niño's effects on Europe are not entirely clear, but certainly it is not nearly as affected as at least large parts of other continents. There is some evidence that an El Niño may cause a wetter, cloudier winter in Northern Europe and a milder, drier winter in the Mediterranean Sea region. The El Niño winter of 2006/2007 was unusually mild in the UK and Western Europe, and the Alps recorded very little snow coverage that season.[29]

Effects of ENSO's cool phase (La Niña)

Sea surface skin temperature anomalies in November 2007 showing La Niña conditions

La Niña is the name for the cold phase of ENSO, during which the cold pool in the eastern Pacific intensifies and the trade winds strengthen. The name La Niña originates from Spanish, meaning "the little girl", analogous to El Niño meaning "the little boy". It has also in the past been called anti-El Niño, and El Viejo (meaning "the old man").[30]

North America

Regional impacts of La Niña.

La Niña causes mostly the opposite effects of El Niño. Atlantic tropical cyclone activity is generally enhanced during La Niña. La Niña causes increased rainfall across the United States' Midwest. Other potential impacts include above average precipitation in the Northern Rockies, Northern California, and in southern and eastern regions of the Pacific Northwest. Below-average precipitation is expected across the southern tier, particularly in the southwestern and southeastern states."[31]

In Canada, La Nina will generally cause a cooler, snowier winter, such as the near record-breaking amounts of snow recorded in the La Nina winter of 2007/2008 in Eastern Canada.[32]

Asia

During La Niña years, the formation of tropical cyclones, along with the subtropical ridge position, shifts westward across the western Pacific ocean, which increases the landfall threat to China.[26] In March 2008, La Niña caused a drop in sea surface temperatures over Southeast Asia by an amount of 2°C. It also caused heavy rains over Malaysia, Philippines and Indonesia.[33]

Recent occurrences

There was a strong La Niña episode during 1988-1989. La Niña also formed in 1995, from 1998-2000, and a minor one from 2000-2001. The most recent occurrence of El Niño started in September 2006[34] and lasted until early 2007.[35] From June 2007 on, data indicated a moderate La Niña event, which strengthened in early 2008 and weakened by early 2009; the 2007-2008 La Niña even was the strongest since the 1988-1989 event. According to NOAA, El Niño conditions have been in place in the equatorial Pacific Ocean since June 2009. Therefore the 2009/2010 season is expected to be an El Niño year.[36]

Atlantic counterpart

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 is related to El Niño's effect on the Walker circulation over South America, which causes the easterly trade winds in the western Atlantic Ocean region to strengthen. 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. Cases of El Niño-type events in both oceans simultaneously have been linked to severe famines related to the extended failure of monsoon rains.[37]

ENSO and global warming

A few years ago, attribution of recent changes (if any) in ENSO or predictions of future changes were very weak.[38] More recent results tend to suggest that the projected tropical warming may follow a somewhat El Niño-like spatial pattern, without necessarily altering the variability about this pattern,[39] while the ENSO cycle may be minimally shortened.[40]

El Niño "Modoki"

Map showing Nino3.4 and other index regions

One recent study suggests that El Niños have been changing.[41] This study says there are two similar forms of warming in the Pacific Ocean. One is the eastern Pacific Warming, which is the same as a typical El Niño. The central Pacific Warming has temperature anomalies near the dateline rather than near South America. There is some reason to believe that this warming in the central Pacific reduces El Niño's usual suppression of Atlantic hurricane activity.[4] Warming in the central Pacific is typical of La Niñas. This new type of El Niño has been dubbed "El Niño Modoki". The change from El Niño to El Niño Modoki may be due to a weakening of the southeasterly trade winds. It is not known whether this is due to natural variablity, the effects of climate change, or some other cause. Research is ongoing to determine whether a similar thing is happening to La Niña.[41]

Cultural History and Pre-historic Information

Average equatorial Pacific temperatures

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.[42]

El Niño affected pre-Columbian Incas [43] and may have led to the demise of the Moche and other pre-Columbian Peruvian cultures.[44] A recent study suggests that a strong El-Niño effect between 1789-93 caused poor crop yields in Europe, which in turn helped touch off the French Revolution.[45]

An early recorded mention of the term "El Niño" to refer to climate occurs in 1892, when Captain Camilo Carrillo told the Geographical society congress in Lima that Peruvian sailors named the warm northerly current "El Niño" because it was most noticeable around Christmas. The phenomenon had long been of interest because of its effects on the guano industry and other enterprises that depend on biological productivity of the sea.

Charles Todd, in 1893, suggested that droughts in India and Australia tended to occur at the same time; Norman Lockyer noted the same in 1904. An El Niño connection with flooding was reported in 1895 by Pezet and Eguiguren. In 1924 Gilbert Walker (for whom the Walker circulation is named) coined the term "Southern Oscillation".

The major 1982-83 El Niño lead to an upsurge of interest from the scientific community. The period from 1990-1994 was unusual in that El Niños have rarely occurred in such rapid succession.[46] An especially intense El Niño event in 1998 caused an estimated 16% of the world’s reef systems to die. The event temporarily warmed air temperature by 1.5°C, compared to the usual increase of 0.25°C associated with El Niño events.[47] Since then, mass coral bleaching has become common worldwide, with all regions having suffered ‘severe bleaching’.[48] Global warming may according to some evidence increase the intensity and/or frequency of El Niño episodes.

Major ENSO events were recorded in the years 1790-93, 1828, 1876-78, 1891, 1925-26, 1972-73, 1982-83, and 1997-98.[37] Recent El Niños have occurred in 1986-1987, 1991-1992, 1993, 1994, 1997-1998, 2002-2003, 2004-2005 and 2006-2007.

See also

References

  1. ^ "Independent NASA Satellite Measurements Confirm El Niño is Back and Strong". NASA/JPL. http://www.jpl.nasa.gov/news/releases/97/elninoup.html. 
  2. ^ Climate Prediction Center (2005-12-19). "Frequently Asked Questions about El Niño and La Niña". National Centers for Environmental Prediction. http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensofaq.shtml#DIFFER. Retrieved 2009-07-17. 
  3. ^ "El Niño Information". California Department of Fish and Game, Marine Region. http://www.dfg.ca.gov/marine/elnino.asp. 
  4. ^ a b Hye-Mi Kim, Peter J. Webster, & Judith A. Curry. "Impact of Shifting Patterns of Pacific Ocean Warming on North Atlantic Tropical Cyclones (Abstract)". Science 335: 77-80. http://www.sciencemag.org/cgi/content/abstract/325/5936/77. Retrieved 2009-07-06. 
  5. ^ National Climatic Data Center (June 2009). "El Niño / Southern Oscillation (ENSO) June 2009". National Oceanic and Atmospheric Administration. http://www.ncdc.noaa.gov/oa/climate/research/enso/?year=2009&month=6&submitted=true. Retrieved 2009-07-26. 
  6. ^ Climate Prediction Center (2005-12-19). "ENSO FAQ: How often do El Niño and La Niña typically occur?". National Centers for Environmental Prediction. http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensofaq.shtml#HOWOFTEN. Retrieved 2009-07-26. 
  7. ^ a b WW2010 (1998-04-28). "El Niño". University of Illinois at Urbana-Champaign. http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/eln/home.rxml. Retrieved 2009-07-17. 
  8. ^ Stewart, Robert (2009-01-06). "El Niño and Tropical Heat". Our Ocean Planet: Oceanography in the 21st Century. Department of Oceanography, Texas A & M University. http://oceanworld.tamu.edu/resources/oceanography-book/heatbudgets.htm. Retrieved 2009-07-25. 
  9. ^ Dr. Tony Phillips (2002-03-05). "A Curious Pacific Wave". National Aeronautics and Space Administration. http://science.nasa.gov/headlines/y2002/05mar_kelvinwave.htm. Retrieved 2009-07-24. 
  10. ^ Nova (1998). "1969". Public Broadcasting System. http://www.pbs.org/wgbh/nova/elnino/reach/1969.html. Retrieved 2009-07-24. 
  11. ^ De-Zheng Sun (2007). Nonlinear Dynamics in Geosciences: 29 The Role of El Niño—Southern Oscillation in Regulating its Background State. Springer. doi:10.1007/978-0-387-34918-3. ISBN 978-0-387-34917-6. http://www.springerlink.com/content/r48078945n5w086v/. Retrieved 2009-07-24. 
  12. ^ Soon-Il An and In-Sik Kang (2000). "A Further Investigation of the Recharge Oscillator Paradigm for ENSO Using a Simple Coupled Model with the Zonal Mean and Eddy Separated". Journal of Climate 13 (11): 1987-1993. doi:10.1175/1520-0442(2000)013<1987:AFIOTR>2.0.CO;2. http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2F1520-0442(2000)013%3C1987%3AAFIOTR%3E2.0.CO%3B2. Retrieved 2009-07-24. 
  13. ^ Jon Gottschalck and Wayne Higgins (2008-02-16). "Madden Julian Oscillation Impacts". Climate Prediction Center. http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/MJO_1page_factsheet.pdf. Retrieved 2009-07-24. 
  14. ^ Air-Sea Interaction & Climate (2005-09-06). "El Niño Watch from Space". Jet Propulsion Laboratory California Institute of Technology. http://airsea-www.jpl.nasa.gov/ENSO/welcome.html. Retrieved 2009-07-17. 
  15. ^ Eisenman, Ian; Yu, Lisan; Tziperman, Eli (2005). "Westerly Wind Bursts: ENSO’s Tail Rather than the Dog?". Journal of Climate 18 (24): 5224–5238. doi:10.1175/JCLI3588.1. 
  16. ^ Australian Bureau of Meteorology
  17. ^ Pidwirny, Michael (2006-02-02). "Chapter 7: Introduction to the Atmosphere". Fundamentals of Physical Geography. physicalgeography.net. http://www.physicalgeography.net/fundamentals/7z.html. Retrieved 2006-12-30. 
  18. ^ "Envisat watches for La Niña". BNSC. 2006-03-03. http://www.bnsc.gov.uk/content.aspx?nid=5989. Retrieved 2007-07-26. 
  19. ^ "The Tropical Atmosphere Ocean Array: Gathering Data to Predict El Niño". Celebrating 200 Years. NOAA. 2007-01-08. http://celebrating200years.noaa.gov/datasets/tropical/welcome.html. Retrieved 2007-07-26. 
  20. ^ "Ocean Surface Topography". Oceanography 101. JPL. 2006-07-05. http://sealevel.jpl.nasa.gov/gallery/presentations/oceanography-101/ocean101-slide14.html. Retrieved 2007-07-26. "Annual Sea Level Data Summary Report July 2005 - June 2006" (PDF). The Australian Baseline Sea Level Monitoring Project. Bureau of Meteorology. http://www.bom.gov.au/fwo/IDO60202/IDO60202.2006.pdf. Retrieved 2007-07-26. 
  21. ^ Pearcy, W. G.; Schoener, A. (1987). "Changes in the marine biota coincident with the 1982-1983 El Niño in the northeastern subarctic Pacific Ocean". Journal of Geophysical Research 92 (C13): 14417–14428. doi:10.1029/JC092iC13p14417. http://www.agu.org/pubs/crossref/1987/JC092iC13p14417.shtml. 
  22. ^ Climate Prediction Center. Average October-December (3-month) Temperature Rankings During ENSO Events. Retrieved on 2008-04-16.
  23. ^ Climate Prediction Center. Average December-February (3-month) Temperature Rankings During ENSO Events. Retrieved on 2008-04-16.
  24. ^ http://www.davidsuzuki.org/Climate_Change/Impacts/Extreme_Weather/El_Nino.asp
  25. ^ Joint Typhoon Warning Center (2006). 3.3 JTWC Forecasting Philosophies. United States Navy. Retrieved on 2007-02-11.
  26. ^ a b M. C. Wu, W. L. Chang, and W. M. Leung (2003). Impacts of El Nino-Southern Oscillation Events on Tropical Cyclone Landfalling Activity in the Western North Pacific. Journal of Climate: pp. 1419–1428. Retrieved on 2007-02-11.
  27. ^ Pacific ENSO Applications Climate Center. Pacific ENSO Update: 4th Quarter, 2006. Vol. 12 No. 4. Retrieved on 2008-03-19.
  28. ^ Edward N. Rappaport (September 1999). "Atlantic Hurricane Season of 1997". Monthly Weather Review 127: 2012. http://www.aoml.noaa.gov/general/lib/lib1/nhclib/mwreviews/1997.pdf. Retrieved 2009-07-18. 
  29. ^ http://news.bbc.co.uk/2/hi/europe/6185345.stm
  30. ^ Tropical Atmosphere Ocean project (2008-03-24). "What is La Niña?". Pacific Marine Environmental Laboratory. http://www.pmel.noaa.gov/tao/elnino/la-nina-story.html. Retrieved 2009-07-17. 
  31. ^ "ENSO Diagnostic Discussion". Climate Prediction Center. 2008-06-05. http://www.cpc.noaa.gov/products/analysis_monitoring/enso_advisory/ensodisc.html. 
  32. ^ http://www.ec.gc.ca/doc/smc-msc/2008/s3_eng.html
  33. ^ Hong, Lynda (2008-03-13). "Recent heavy rain not caused by global warming". Channel NewsAsia. http://www.channelnewsasia.com/stories/singaporelocalnews/view/334735/1/.html. Retrieved 2008-06-22. 
  34. ^ Pastor, Rene (2006-09-14). "El Niño climate pattern forms in Pacific Ocean". USA Today. http://www.usatoday.com/weather/climate/2006-09-13-el-nino_x.htm. 
  35. ^ Borenstein, Seth (2007-02-28). "There Goes El Nino, Here Comes La Nina". CBS News. http://www.cbsnews.com/stories/2007/02/28/tech/main2523483.shtml. 
  36. ^ http://www.cpc.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
  37. ^ a b Davis, Mike (2001). Late Victorian Holocausts: El Niño Famines and the Making of the Third World. London: Verso. pp. 271. ISBN 1859847390. 
  38. ^ "9.3.5.2 Interannual variability ENSO". Climate change 2001. Intergovernmental Panel on Climate Change. 2001. http://www.grida.no/climate/ipcc_tar/wg1/361.htm. Retrieved 2006-12-30. 
  39. ^ Collins, Matthew; et al. (2005). "El Niño- or La Niña-like climate change?". Climate Dynamics 24 (1): 89–104. doi:10.1007/s00382-004-0478-x. 
  40. ^ Merryfield, William J. (2006). "Changes to ENSO under CO2 Doubling in a Multimodel Ensemble". Journal of Climate 19 (16): 4009–4027. doi:10.1175/JCLI3834.1. http://www.ocgy.ubc.ca/~yzq/books/paper5_IPCC_revised/Merryfield2006.pdf. 
  41. ^ a b CBC News (2009-07-02). "Changing El Nino making hurricanes more frequent, research suggests". http://technology.sympatico.msn.cbc.ca/News/ContentPosting?newsitemid=science-nino-hurricane&feedname=CBC-TECH-SCIENCE-V3&show=False&number=0&showbyline=True&subtitle=&detect=&abc=abc&date=True&pagenumber=1. Retrieved 2009-07-06. 
  42. ^ Carrè, Matthieu; et al. (2005). "Strong El Niño events during the early Holocene: stable isotope evidence from Peruvian sea shells". The Holocene 15 (1): 42–47. doi:10.1191/0959683605h1782rp. 
  43. ^ http://news.bbc.co.uk/2/hi/science/nature/25433.stm
  44. ^ Brian Fagan (1999). Floods, Famines and Emporers: El Niño and the Fate of Civilizations. Basic Books. pp. 119-138. ISBN 0-465-01120-9. 
  45. ^ Grove, Richard H. (1998). "Global Impact of the 1789–93 El Niño". Nature 393 (6683): 318–319. doi:10.1038/30636. 
  46. ^ Trenberth, Kevin E.; Hoar, Timothy J. (1996). "The 1990-1995 El Niño-Southern Oscillation Event: Longest on Record". Geophysical Research Letters 23 (1): 57–60. doi:10.1029/95GL03602. http://www.agu.org/pubs/crossref/1996/95GL03602.shtml. 
  47. ^ Trenberth, K. E.; et al. (2002). "Evolution of El Niño – Southern Oscillation and global atmospheric surface temperatures". Journal of Geophysical Research 107 (D8): 4065. doi:10.1029/2000JD000298. 
  48. ^ Marshall, Paul; Schuttenberg, Heidi (2006). A reef manager’s guide to coral bleaching. Townsville, Qld.: Great Barrier Reef Marine Park Authority. ISBN 1876945400. http://coris.noaa.gov/activities/reef_managers_guide/pdfs/reef_managers_guide.pdf. 

Further reading

External links

Search Wikimedia Commons Wikimedia Commons has media related to: ENSO

 W The content appearing above is a local copy of the El Niño-Southern Oscillation article from Wikipedia, the free encyclopedia. It was written by various Wikipedians (contributor history) and is distributed under the Creative Commons CC-BY-SA 3.0 License (license text).

The version shown above has Revision ID: 350178746 and was last updated March 16, 2010, 10:33 am.

Current version on Wikipedia: view / edit Read Wikipedia's disclaimers.
Retrieved from "http://globalwarmingart.com/wiki/Special:GWArtMirrorPage"
Sea Level Explorer
Random image
Toolbox