El Nino - Made Simple

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El Nino & La Nina - ENSO phenomena

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Slide 1: 

El Nino & La Nina made simple For IB Diploma Geography First Examination 2011 Made by: Arvind Tirkey Jakarta, Indonesia. Dated: 27 Dec 2009

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Photo coursey: National Geographic Magazine 4

Global Wind Circulation : 

Global Wind Circulation Made by Arvind Tirkey 5

Terminology to remember : 

Terminology to remember ENSO – El Nino Southern Oscillation. SST – Sea Surface Temperature. Walker Circulation - Also known as Walker Cell, discovered by Gilbert Walker, is a conceptual model of the air flow in the tropics in the lower atmosphere (troposphere). Parcel of air follow a closed circulation in the zonal and vertical directions. This circulation is caused by differences in heat distribution between ocean and land. Jet Stream – Jet streams are fast flowing, narrow air currents found in the atmospheres near tropopause (the transition between troposphere and the stratosphere. The major jet streams on earth are westerly winds (flowing west to east). Their path typically have a meandering shape; jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various direction including the opposite direction. Jet streams are caused by a combination of atmospheric heating and the planet’s rotation on its axis. They form near boundaries of adjacent air masses with significant difference in temperature. Thermocline - Depth at which the rate of decrease of temperature with increase of depth is the largest. In general the sea water temperature decreases from the surface to the deepest levels, There exists in most ocean areas (apart from polar and sub-polar oceans) a zone where the rate of decrease of temperature is much larger compared with that above and below, hence the definition. Thermocline can also vary from one year to the next, as in the tropical Pacific where thermocline vertical displacements play a fundamental role during ENSO. In short the separation zone between the mixed-layer or warmer surface water above, much influenced by atmospheric fluxes, and the colder deep ocean. 6 Made by Arvind Tirkey IMAGES IMAGES PROCESS

El Nino Definition : 

El Nino Definition El Nino and La Nina events are defined as periods when the sea surface temperature measured in the region between 5 degrees north and 5 degrees south and between 120 degrees and 170 degrees west varied 0.4 degrees Centrigrade / Celsius from average for six months or more. - By Kevin Trenberth, Bulletin of the American Meteorological Society, December 1997, pages 2771-77. 7 Made by Arvind Tirkey

El Nino – a background : 

El Nino – a background El Nino – originally applied to an annual weak warm ocean current that ran southward along the coast of Peru and Ecuador about Christmas time (hence Nino, Spanish for “the boy Christ-child”) and only subsequently became associated with the unusually large warming that occur every few years and change the local and regional ecology. The coastal warming is associated with a much more extensive anomalous ocean warming near the international date line. It is pacific basinwide phenomenon that forms the link with the anomalous global climate patterns. The atmospheric component tied to El Nino is termed as ‘Southern Oscillation’. Also called as ENSO, short for El Nino – Southern Oscillation. El Nino then corresponds to the warm phase of ENSO. The opposite ‘La Nina’ (“the girl” in Spanish) phase consist of a basinwide cooling of the tropical Pacific and thus the cold phase of ENSO. (Trenberth, 1997) Influenced by countless variables, including variations in Earth’s orbit, the strength of ocean currents, and possible human influences on the environment, no two El Nino or La Nina events are identical. Even within a single event, local conditions can change drastically over just a few days. Worldwide collection of detailed El Nino and La Nina data dates back only 23* years. (Suplee, 1999) Made by Arvind Tirkey 8

Running Hot and Cold : 

Running Hot and Cold 9 Made by Arvind Tirkey Like a giant saucer with liquid sloshing back and forth across it, the Pacific Ocean contains huge masses of contrasting cool and warm water. During the past 50 years their slow cycle has created El Nino conditions 31 percent of the time and La Nina conditions 23 percent of the time.

El Nino Regions : 

El Nino Regions Made by Arvind Tirkey 10

Normal Conditions in the Pacific Ocean : 

Normal Conditions in the Pacific Ocean 11 Made by Arvind Tirkey

Normal Conditions in Pacific Ocean : 

Normal Conditions in Pacific Ocean Weather is so variable that it’s hard to call any situation normal. But in most years climate in the equatorial Pacific is governed by one generally dependable pattern. Sunlight heats the uppermost layer of seawater in the western ocean around Australia and Indonesia, causing huge volumes of hot, moist air to rise thousands of feet and creating a low-pressure system at the ocean’s surface. As the air mass rises and cools, it sheds its water content as rain, contributing to monsoons in the area. After rain, this air is much drier and it heads east, guided by winds in the upper atmosphere, cooling even more and increasing in density as it travels. By the time it reaches the west coast of Americas, it is cold and heavy enough that it starts to sink, creating a high-pressure system near the water’s surface. The air current then flow as trade winds back towards Australia and Indonesia. This giant circulatory loop, moving from west to east in the upper air and from east to west at low latitudes, is called Walker Circulation. (Sir Gilbert Walker, the British scientist who studied the process in the 1920s). Made by Arvind Tirkey 12

Slide 13: 

As the trade winds blow westward over the Pacific, they push the warm top layer of the ocean with them, causing the hottest water to pile up around Indonesia, where, because of both wind action and thermal expansion, the sea level is usually about 18 inches [46 centimeters] higher than it is off the west coast of Mexico. All along the eastern Pacific, and especially off Ecuador and Peru, colder subsurface water wells up to replace the sheared-off top layer, bringing up a bevy of nutrients from the deep ocean. That chemical bounty sustains an enormous food web and makes the coastal waters off Peru one of the world’s most prolific fisheries. (Suplee, 1999) Made by Arvind Tirkey 13 Normal Conditions in Pacific Ocean continues…….

Normal Conditions : 

Normal Conditions Trade winds generally maintain a balance between warm western Pacific water and cool water in the eastern Pacific. The sun heats water in the east, but the thermocline, the boundary between warm water and the cold, nutrient-rich water, lies 130 feet below the surface. Storm clouds form above warm surface water in the western Pacific. 14 Made by Arvind Tirkey

El Nino: For reasons still not entirely understood, atmospheric pressure periodically becomes abnormally low near Tahiti. (1) and unusually high over northern Australia (2). With the presence of the high-pressure system, Pacific trade winds that normally flow to the west become weak (3), allowing sun-warmed Pacific surface water to spread eastward. This creates a warm band of water that spans the equatorial pacific (4). Along the Equator, where cloud formation is already heavy due to the convergence of northern and southern trade winds, more clouds than usual develop (5). Drawn south by the lower atmospheric pressure, the subtropical jet stream carries Pacific clouds eastward and increases the frequency of storms in that region (6). Continuing across southern North America, the jet stream (7) shears off the tops of westbound Atlantic storms, decreasing the development of Atlantic hurricanes. : 

El Nino: For reasons still not entirely understood, atmospheric pressure periodically becomes abnormally low near Tahiti. (1) and unusually high over northern Australia (2). With the presence of the high-pressure system, Pacific trade winds that normally flow to the west become weak (3), allowing sun-warmed Pacific surface water to spread eastward. This creates a warm band of water that spans the equatorial pacific (4). Along the Equator, where cloud formation is already heavy due to the convergence of northern and southern trade winds, more clouds than usual develop (5). Drawn south by the lower atmospheric pressure, the subtropical jet stream carries Pacific clouds eastward and increases the frequency of storms in that region (6). Continuing across southern North America, the jet stream (7) shears off the tops of westbound Atlantic storms, decreasing the development of Atlantic hurricanes. Made by Arvind Tirkey 15 Notes & Legend Effects

La Nina: In a reverse of the mechanism that triggers El Nino, atmospheric pressure is abnormally high over Tahiti (1), and low over Australia (2). Westbound trade winds are intense (3), pushing warm surface water farther west than usual (4). The equatorial cloud formation splits (5), separated by the Tahiti high. Similarly split, the subtropical jet stream is weakened (6), allowing Atlantic hurricanes to move westward and gather strength (7). : 

La Nina: In a reverse of the mechanism that triggers El Nino, atmospheric pressure is abnormally high over Tahiti (1), and low over Australia (2). Westbound trade winds are intense (3), pushing warm surface water farther west than usual (4). The equatorial cloud formation splits (5), separated by the Tahiti high. Similarly split, the subtropical jet stream is weakened (6), allowing Atlantic hurricanes to move westward and gather strength (7). Made by Arvind Tirkey 16 Notes & Legend Effects

El Nino : 

El Nino 17 Made by Arvind Tirkey

El Nino – the normal conditions reversed……. : 

El Nino – the normal conditions reversed……. For reasons that scientists still do not comprehend, every few years the trade winds subside or even disappear. The usual air-pressure pattern reverses itself in a phenomenon called the southern oscillation, making barometer readings higher in Australia than they are in the central Pacific. The resulting pattern—known as ENSO, for El Niño/Southern Oscillation—involves only one-fifth of the circumference of the planet. But it transforms weather around the globe. Without the trade winds the top layer of the eastern Pacific does not move west. It stays in place, getting hotter and hotter, swelling as it warms. Eventually it hits the threshold for what meteorologists call deep convection—the point at which the steamy surface air blasts into the upper atmosphere. (In some places during 1997-98, sea levels off South America were 10 inches [25 centimeters] above normal and surface temperatures reached almost 86°F [30°C].) When that happens, water in the upper atmosphere condenses and falls as torrential rain on the west coast of the Americas. (Suplee, 1999) Made by Arvind Tirkey 18

El Nino / Warming : 

El Nino / Warming As eastrly trade winds decrease, warm water in the western Pacific flows eastward. This layer, typically 500 feet deep, flows over cooler, nutrient-rich water and blocks its normal upwelling along North and South America. Sea life there can suffer from lack of food. (also an environmental effect of El Nino) Air gains heat and moisture from the warm ocean surface and rises, forming storm clouds in the central Pacific. 19 Made by Arvind Tirkey

La Nina : 

La Nina Made by Arvind Tirkey 20

La Nina – the abnormal cooling……. : 

La Nina – the abnormal cooling……. In La Niña years the easterly winds from the Americas are stronger than usual. That drives more than the normal amount of warm sea-surface water westward, in turn causing larger than normal volumes of deep, chilly water to rise to the surface and producing a “cold tongue” that extends 3,000 miles [4,800 kilometers] along the Equator from Ecuador to Samoa. With so much warm water flowing toward Asia, the Pacific’s mighty heat engine remains firmly anchored in the west, causing heavier monsoon rains in India, higher than average precipitation in Australia, and wetter than normal conditions as far west as southern Africa. The huge air masses and cloud banks associated with the hot zone also change the path of the jet streams, which move high-altitude air from west to east across the ocean. Made by Arvind Tirkey 21

La Nina / Cooling : 

La Nina / Cooling Pushed westward by strong trade winds, warm surface water flows toward Asia. Colder deep-sea water upwells to the surface along the Americas. Nutrients become more plentiful, and evaporation decreases, reducing storm cloud formation and rain in the region. (also an environmental effect of La Nina) Storm clouds in the western Pacific intensify, gaining moisture from warm surface waters. 22 Made by Arvind Tirkey

ENSO Climatic effects……. El Nino : 

Atmospheric pressure periodically becomes abnormally low near Tahiti and unusually high over northern Australia. Pacific winds that normally flow to the west becomes weak due to the presence of high pressure system around northern Australia due to which, sun warmed Pacific surface water spreads eastward creating a warm band of water that spans the equatorial Pacific. Along the Equator, normally there is heavy formation of clouds due to convergence of northern and southern trade winds, but due to El Nino, more clouds than usual develop causing more rainfall than usual in Tahiti or Nino 3.4 region. The subtropical jet stream carries Pacific clouds eastward and increases the frequency of storms in that region (storms in California, Arizona & coastal Mexico). As the Jet stream cut off the tops of Atlantic storms, it decrease the development of Atlantic hurricanes. One study indicates that El Niño also generally reduces tornadoes in the southern Plains states. Less rain than normal Vietnam, Cambodia, Malaysia, Indonesia, Brunei, Singapore, Philippines Papua New Guinea & northern parts of Australia. North-eastern part of South America – Guyana, Surinam, French Guyana & north-eastern parts of Brazil. South-eastern part of Africa – Malawi, Mozambique, Swaziland, Botswana, Zambia, Madagascar and eastern parts of Angola & Democratic Rep. of Congo. (with warmer than normal temperature). More rain than normal Central Africa – Ethiopia, Kenya, Uganda, southern Sudan, Central Africa Republic, Cameroon, Rep. of Congo, Rwanda, Democratic Rep. of Congo and Tanzania. North-west South America - Colombia, Ecuador, North Peru & north-west Brazil. Central South America – Uruguay, Praguay & southern Brazil. Southern USA and Northern Mexico. (with cooler than normal temperature). Warmer than normal Japan, North Korea, South Korea & South-east Australia (New South Wales, Victoria & South Australia). North west part of North America (Alaska, North-west Canada) & North east part of North America (north-east Canada) & South eastern Brazil in South America. Made by Arvind Tirkey 23 ENSO Climatic effects……. El Nino MAP

ENSO Climatic effects……. La Nina : 

ENSO Climatic effects……. La Nina Atmospheric pressure periodically becomes abnormally high over Tahiti and low over Australia. West bound trade winds from north & south America side become more intense as there is low pressure in Australian side pushing the warm surface water further west than usual. The Equatorial cloud formation splits due to the Tahiti high pressure. Similarly due to low pressure over Australia, the subtropical jet stream gets weakened, allowing Atlantic hurricanes to move west-word with more strength. (hurricanes in Florida, Alabama, Mississipi, Louisiana etc.) Less rain than normal Central Africa Republic, Rwanda, Uganda & Kenya. Southern parts of USA (Georgia, Alabama, Mississipi, Louisiana & Texas). (with warmer than normal temperature). Colombia, Ecuador & North Peru (with cooler than normal temperature). More rain than normal Vietnam, Cambodia, Malaysia, Indonesia, Brunei, Singapore, Philippines Papua New Guinea & northern parts of Australia. North eastern parts of South America (Guyana, Surinam, French Guyana & north east Brazil). South eastern parts of Africa (South Africa, Mozambique, Zimbabwe, Botswana, Malawi & Madagascar. (with cooler than normal temperature). Cooler than normal Western Africa (Western Sahara, Mauritania, Senegal, Gambia, Sierra Leone, Liberia, Ivory Coast, Ghana Burkina Faso, Mali, Niger, Algeria, Togo & Benin). Japan, North Korea & South Korea. North west part of North America (Alaska, North-west Canada, western USA) & South eastern Brazil in South America Made by Arvind Tirkey 24 MAP

ENSO Environmental effects……. : 

ENSO Environmental effects……. El Nino environmental effects discussed earlier. Normally the cool Humboldt Current, flows north along the west coast of South America. It is part of the anti-clockwise flow of the South Pacific gyre, a circular current on the ocean’s surface. As the wind and current push sea water away from the coast, upwelling occurs, which allows cool, deep, nutrient-rich waters to rise to the sunlit zones. This, in turn, creates a food-rich marine environment that includes penguins and sea lions, and productive fishing grounds. But due to El Nino, occasionally this the pattern was broken, the upwelling stops and is overridden by warm tropical waters from the central Pacific. This causes great loss of marine life and changes conditions from dry and desert-like to stormy and humid. In 1982, this condition reached as far north as California and as far south as Antarctica. La Nina environmental effects discussed earlier. Floodings Due to El Nino, after every four to seven years, the rainfall arrives after a pool of hot sea water (the size of Canada) appears off the west coast of Americas. This creates conditions for storms which pour vast amount of precipitation onto Peru’s normally arid northwestern coast. In 1998, the Piura River near a small hamlet Chato Chico in Peru flooded due to weeks of incessant rain. The swirling torrent was first knee-deep and soon chest high. The runoff from the floods poured into the coastal Sechura Desert and created the second largest lake in Peru. Draught/Forest Fires Indonesia and surrounding regions suffered months of drought. Forest fires burned furiously in Sumatra, Borneo, and Malaysia, forcing drivers to use their headlights at noon. The haze traveled thousands of miles to the west into the ordinarily sparkling air of the Maldive Islands, limiting visibility to half a mile [0.8 kilometer] at times. The result, as seen in the 1997 round of fires, is one of the world's great environmental disasters. The land burned in Indonesia during that dry season has so far been estimated at 8,000 square miles, roughly the size of New Jersey. (This assessment will almost certainly grow; after the last great Indonesian drought, in 1982-83, it took experts three years to determine that 12,000 square miles had been torched.). The 1997 drought, Indonesia's most severe in 50 years, (which was largely the result of El Niño), land clearing license by the government, burning down trees by plantation operators and slash-n-burn by the tribals (Dayak) & farmers had created favorable conditions for severe forest fire and aggravated the situation. (Simons, 1998) Made by Arvind Tirkey 25

ENSO Environmental effects continues……. : 

ENSO Environmental effects continues……. An estimated 20 million people were treated in the 1997 fires for illnesses such as asthma, bronchitis, emphysema, and eye, skin, and cardiovascular diseases; a passenger plane crashed in poor visibility over Sumatra, killing 234; ships collided in the Strait of Malacca, killing dozens. Pollution cost regional economies billions in aborted tourist plans, canceled airline flights, lost workdays, medical bills, and ruined crops. Wildlife has suffered too. Every day orangutans fleeing the smoke ambled, disoriented, into a conservation reserve near Pangkalanbuun; they were weakened by infections and respiratory ailments. (Simons, 1998) Disease Connection With both El Nino and La Nina, climate extremes become more intense, so droughts are more severe and floods are more frequent. Drought leads to famine and disease associated with malnutrition. Flooding promotes the increase of waterborne diseases such as cholera and typhoid. Prolonged wet periods are also favorable for the breeding of insects that carry diseases such as malaria and encephalitis. After the 1982-83 El Nino caused heavy rain and flooding in Ecuador, Peru and Bolivia, the mosquitoes multiplied and there were major outbreaks of malaria. La Nina can also cause unusual wet periods. The 1973-73 La Nina caused an especially wet summer in southern Africa and contributed to an epidemic of West Nile fever there. The same year wet conditions in Brazil resulted in an outbreak of encephalitis in which sixty-one people died. In the spring of 1993 a flu like disease – Hantavirus appeared in rural areas of United States (where Arizona, New Mexico, Utah and Colorado meet). But the real reason behind the spread of Hantavirus was El Nino. El Nino conditions in the previous spring had brought unusually heavy rain to the desert, promoting heavy growth of desert plants. Small rodents called deer mice feasted on the abundant food and multiplied. Ordinarily, predators such as owls and snakes keep the number of deer mice under control. But a six-year drought that preceded the heavy rain had reduced their numbers and allowed the deer mouse population to grow unchecked. The people became exposed to the virus when they touched deer mice droppings or breathed contaminated dust. The outbreak quickly subsided as the desert climate returned to normal, food became scarce, and the deer mice population returned to normal. (Arnold, 2005) In 1998, the Piura River near a small hamlet Chato Chico in Peru flooded due to weeks of incessant rain. In other areas water simply pooled. The mosquitoes that thrived in these places caused rampant malaria—some 30,000 cases in the Piura region alone, three times the average for its 1.5 million residents. (Suplee, 1999) Made by Arvind Tirkey 26

ENSO Economic effects……. : 

ENSO Economic effects……. Economic Benefits Agriculture: Weather and climate patterns of the past help scientists predict the future. With the help of predictions by National Weather Service Climate Analysis Center and National Oceanic and Atmospheric Administration (NOAA) it is easy to predict general climate conditions as many as twelve to eighteen months in advance and in some cases to forecast El Ninos. These predictions are helping people to better manage agriculture, water supplies, fisheries, and other resources that are affected by the weather. One country that has benefited from El Nino forecasts is Peru. Each year since 1983 the Peruvian government has used information about winds and water temperatures in the Pacific to make predictions for the upcoming rainy season. Farmers are told to expect one of four possibilities: near-normal conditions, a weak El Nino with a slightly wetter than normal growing season, a full blown El Nino with flooding, or cooler-than-normal ocean temperatures with a higher-than-normal chance of drought. They then use this information to decide what combination of their two major crops, rice and cotton, they should plant. Rice does well in wet conditions, whereas cotton, which has a deeper root system, can tolerate drier weather. By adjusting conditions, the farmers can improve their harvests. Other countries that have used El Nino predictions to manage agriculture are Australia, Brazil, Ethiopia and India. (Arnold, 2005) Due to early predictions by NOAA in 1997, allowed many farmers and fishermen of Peru to make the best of El Niño’s effects. Grass grew on land that is usually barren, and farmers raised cattle. Rice and beans could be planted in areas normally too dry to support them; fishermen were able to plan for shrimp harvests in coastal waters, generally too cold for the shellfish. Fisheries: Heavy rain in areas offshore Peru reduces the salinity of the coastal seas, where deepwater upwelling has already declined or stopped. Marine life that customarily thrives off Ecuador and Peru, including economically essential anchovy populations, heads south in search of cooler, richer waters—to the great benefit of fishermen in Chile. Off North America exotic warm-water species suddenly appear farther north benefiting USA states of California, Washington and Alaska. (Suplee, 1999) Made by Arvind Tirkey 27

ENSO Economic effects continues……. : 

ENSO Economic effects continues……. Economic Benefits Polar Jet Stream saving money: During El Nino in North America, the jet streams that travel 5 to 8 miles [8 to 13 kilometers] above Earth’s surface shift dramatically. The polar jet stream tends to stay farther north over Canada than usual; as a result, less cold air moves into the upper United States. In fact, northern-tier states saved an estimated five billion dollars in heating costs during the 1997-98 El Niño. The potential uses of advance information are almost limitless: Governments and industries around the world can make planning for El Niño and La Niña pay off. For example, Kenyan coffee growers find their product in greater demand when droughts affect coffee harvests in Brazil and Indonesia. Palm oil production in the Philippines typically declines during El Niño, as does the squid catch off the California coast. Countries that anticipate these developments can fill the gaps and prosper. Economic Loss The giant El Niño of 1997-98 had deranged weather patterns around the world, killed an estimated 2,100 people, and caused at least 33 billion [U.S.] dollars in property damage. In the U.S. mudslides and flash floods flattened communities from California to Mississippi, storms pounded the Gulf Coast, and tornadoes ripped Florida. By the time the debris settled and the collective misery was tallied, the devastation had in some respects exceeded even that of the El Niño of 1982-83, which killed 2,000 worldwide and caused about 13 billion dollars in damage. (Suplee, 1999) Just in USA, El Nino caused real economic losses such as storm damage or crop losses. These are losses that can't be prevented or reduced by a better forecast or mitigation. For example, on average, El Ninos resulted in agricultural losses approaching $2 billion, or nearly 1-2 percent of total crop output. In the 1997-98 El Nino, property losses were estimated at nearly $2.6 billion. (Spacedaily) During an El Niño event, the southeast trade winds weaken and so does the amount upwelling in the eastern Pacific. The deeper thermocline means that any upwelling that does occur is unable to tap into the rich nutrients found in deeper waters. Consequently, warm nutrient-poor water predominates the region and a decrease in the fish population is observed. A reduction of the fish population reduces the amount of fishmeal produced and exported (by local industry) to other countries for feeding poultry and livestock. If the world's fishmeal supply decreases, more expensive alternative feed sources must be used, resulting in an increase in poultry prices worldwide. (University of Illinois) Made by Arvind Tirkey 28

Economic ImpactsofEl Nino(1982-83) (NOAA) : 

Economic ImpactsofEl Nino(1982-83) (NOAA) Made by Arvind Tirkey 29

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Walker Circulation : 

Walker Circulation Made by Arvind Tirkey 32 BACK

Jet Stream : 

Jet Stream Made by Arvind Tirkey 33 BACK

El Nino Notes: Sea-surface temperature, intertropical convergence zone, and jet stream information is based on data from December 1997. Land temperature and precipitation anomalies show areas that are consistently affected from December through February during El Nino events. : 

El Nino Notes: Sea-surface temperature, intertropical convergence zone, and jet stream information is based on data from December 1997. Land temperature and precipitation anomalies show areas that are consistently affected from December through February during El Nino events. Made by Arvind Tirkey 34 Back

La Nina Notes: Sea-surface temperature, intertropical convergence zone, and jet stream information is based on data from December 1988. Land temperature and precipitation anomalies show areas that are consistently affected from December through February during La Nina events. : 

La Nina Notes: Sea-surface temperature, intertropical convergence zone, and jet stream information is based on data from December 1988. Land temperature and precipitation anomalies show areas that are consistently affected from December through February during La Nina events. Made by Arvind Tirkey 35 Back

References: : 

References: Book Arnold, Caroline. El Nino: Stormy Weather for People and Wildlife. 1st ed. Australia: Sandpiper, 2005. 34-45. Print. Journal Article Trenberth, Kevin E. "The Definition of El Nino." Bulletin of the American Meteorological Society. Dec (1997): 2771. Print. Magazine Article Suplee, Curt. "El Niño/La Niña Nature’s Vicious Cycle." National Geographic Magazine Mar 1999: 81-83. Print. Simons, Lewis M. “Indonesia’s Plague of Fire." National Geographic Magazine Aug 1998. Print Web Document "The Economic Impacts Of An El Nino." Spacedaily. Space Media Network, Web. 27 Dec 2009. <http://www.spacedaily.com/news/pacific-02g.html>. "Economic Consequences of El Niño and the influence on prices worldwide." WW2010. Department of Atmospheric Sciences, University of Illinois, Web. 27 Dec 2009. <http://ww2010.atmos.uiuc.edu/%28Gl%29/guides/mtr/eln/econ.rxml>. Image sources http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/nino_regions.shtml http://www.pmel.noaa.gov/tao/elnino/nino_normal.html http://upload.wikimedia.org/wikipedia/en/6/68/LaNina.png http://www.bom.gov.au/lam/climate/levelthree/analclim/imagesm/fig4.gif http://en.wikipedia.org/wiki/Jet_stream http://www.nationalgeographic.com/elnino/photopop2.html http://ngm.nationalgeographic.com/2008/11/indonesia-fires/yamashita-photography http://www.pmel.noaa.gov/tao/elnino/report/figure22.html Notes * The actual article in the year 1999 states that - data dates back only 13 years. so from 1999 till the year 2009, it is 23years. Made by Arvind Tirkey 36 BACK

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