El Niño and its global effects El Niño can alter weather conditions in many parts of the world. Its effects include: hot weather, droughts, forest and bush fires, heavy rain and subsequent flooding, landslides and many more. El Niño even influences the activity of tropical cyclones. In the tropical Atlantic, the statistical average declines, but it increases off the Pacific coast of Mexico. More severe typhoons occur in the northwest Pacific. And each El Niño is different, with the effects and their intensity varying from one occurrence to the next. El Niño configures global weather and conditions As contrasting configurations of the tropical ocean-atmosphere system, El Niño and La Niña represent a natural climate oscillation with global effects, particularly in tropical and subtropical regions. Accordingly, the occurrence of an El Niño event alters the probability of weather features and weather extremes arising in many regions of the world. Is it possible to predict El Niño or La Niña? Modern dynamic and statistical prediction models are able to predict the probability of an El Niño or La Nina event up to six months in advance with an impressive level of accuracy. However, it is not yet possible to predict the maximum intensity with any degree of accuracy. The long-term effects on other regions can only be roughly predicted because other factors are also in play. Many aspects of the question of how exactly an El Niño event is triggered are still the subject of research. How El Niño impacts our weather Experts believe that the weather phenomenon, El Niño, is very likely to occur this year. What will this mean for global weather? Key Tendency Bushfire and forest fire North Atlantik South America South America Equator North and east Australia South-east Asia, Indonesia New Zealand Ecuador, south Colombia, north Peru Eastern north Pacific North-western USA Southern Africa Horn of Africa India, Pakistan, Bangladesh South-east China Crop yields Heavy precipitation Tropical cyclones Affected Regions Increase Decrease Floods Landslides Asia West East cold, deep water Warm water Thermocline (transition area between cold and warm) South America Arid air Arid air Humid air Humid air Thermocline Thermocline-position in neutral phase Mean sea level Asia West East cold, deep water Warm water South America Mean sea level Thermocline Thermocline-position in neutral phase Asia West East cold, deep water Warm water South America Mean sea level What happens during a neutral phase Normal conditions are referred to as the neutral phase: Strong trade winds from easterly directions push the warm surface water west as far as the coast of Indonesia, while in the process reducing the thickness of the warm equatorial surface layer in the east. Cold, nutrient-rich, deep water is then able to upwell into the surface layer off the coast of South America. The particularly warm water off the coast of Indonesia evaporates. The resulting rising masses of moisture-laden air result in increa- sed precipitation over Indonesia and the neighbouring land areas. Conversely, dry air, accompanied by cloud dispersion, falls over the eastern tropical Pacific and the west coast of South America, producing dry weather conditions there. What happens during an El Niño phase During an El Niño phase, the trade winds weaken substantially, or can even blow in the reverse direction. Warm surface water drifts from Indonesia along an equatorial corridor as far as South America, increasing the thickness of the warm ocean surface layer there. The cold deep water is then no longer able to upwell into the top layer of water. The warm masses of water now evaporate in the eastern tropical Pacific and off the west coast of South America, resulting in heavy rain there. In Indonesia and neighbouring regions, however, the weather tends to be dry. What happens during a La Niña phase The overall pattern is similar to the neutral phase, the only difference being that the trade winds blow more strongly from easterly directions. The thicker layer of warm surface water that has been pushed by wind shear along the equator close to the coast of Indonesia to form the thick end of a wedge results in significantly increased precipitation along the coast of Indonesia and neighbouring regions, while extremely dry weather prevails in the eastern tropical Pacific and on the west coast of South America. Trade winds Arid air Humid air strong trade winds inversed wind direction +0,5°C for more than 5 equated overlapping three-month-averages = El Niño Anomalies in the Pacific mean surface temperature Source: NOAA Center for Weather and Climate Prediction -0,5°C for more than 5 equated overlapping three-month-averages = La Niña 1950 Year Temperature in °C ′60 ′70 ′80 ′90 2000 ′10 ′15 ′05 ′95 ′85 ′75 ′65 ′55 -3 -2 -1 0 1 2 3 Neutral La Niña Threshold El Niño Heat
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
El Niño and its global e�ectsEl Niño can alter weather conditions in many parts of the world. Its e�ects include: hot weather, droughts, forest and bush fires, heavy rain and subsequent flooding, landslides and many more. El Niño even influences the activity of tropical cyclones. In the tropical Atlantic, the statistical average declines, but it increases o� the Pacific coast of Mexico. More severe typhoons occur in the northwest Pacific. And each El Niño is di�erent, with the e�ects and their intensity varying from one occurrence to the next.
El Niño configures global weather and conditionsAs contrasting configurations of the tropical ocean-atmosphere system, El Niño and La Niña represent a natural climate oscillation with global e�ects, particularly in tropical and subtropical regions. Accordingly, the occurrence of an El Niño event alters the probability of weather features and weather extremes arising in many regions of the world.
Is it possible to predict El Niño or La Niña?Modern dynamic and statistical prediction models are able to predict the probability of an El Niño or La Nina event up to six months in advance with an impressive level of accuracy. However, it is not yet possible to predict the maximum intensity with any degree of accuracy. The long-term e�ects on other regions can only be roughly predicted because other factors are also in play. Many aspects of the question of how exactly an El Niño event is triggered are still the subject of research.
How El Niño impacts our weatherExperts believe that the weather phenomenon, El Niño, is very likely to occur this year. What will this mean for global weather?
Key
Tendency
Bushfire and forest fire
North Atlantik
SouthAmerica
South America
Equator
North and east Australia
South-east Asia, Indonesia
New Zealand
Ecuador, south Colombia, north Peru
Eastern north Pacific
North-western USA
Southern Africa
Horn of Africa
India, Pakistan, Bangladesh
South-east China
Crop yields
Heavy precipitation
Tropical cyclones A�ected Regions
Increase Decrease
Floods Landslides
Asia
West East
cold, deepwater
Warm water
Thermocline(transition area between cold and warm)
SouthAmerica
Arid air
Arid air
Humid air
Humidair
ThermoclineThermocline-positionin neutral phase
Mean sea level
Asia
West East
cold, deepwater
Warm water
SouthAmerica
Mean sea level
ThermoclineThermocline-positionin neutral phase
Asia
West East
cold, deepwater
Warm water
SouthAmerica
Mean sea level
What happens during a neutral phaseNormal conditions are referred to as the neutral phase: Strong trade winds from easterly directions push the warm surface water west as far as the coast of Indonesia, while in the process reducing the thickness of the warm equatorial surface layer in the east. Cold, nutrient-rich, deep water is then able to upwell into the surface layer o� the coast of South America. The particularly warm water o� the coast of Indonesia evaporates. The resulting rising masses of moisture-laden air result in increa-sed precipitation over Indonesia and the neighbouring land areas. Conversely, dry air, accompanied by cloud dispersion, falls over the eastern tropical Pacific and the west coast of South America, producing dry weather conditions there.
What happens during an El Niño phaseDuring an El Niño phase, the trade winds weaken substantially, or can even blow in the reverse direction. Warm surface water drifts from Indonesia along an equatorial corridor as far as South America, increasing the thickness of the warm ocean surface layer there. The cold deep water is then no longer able to upwell into the top layer of water. The warm masses of water now evaporate in the eastern tropical Pacific and o� the west coast of South America, resulting in heavy rain there. In Indonesia and neighbouring regions, however, the weather tends to be dry.
What happens during a La Niña phaseThe overall pattern is similar to the neutral phase, the only di�erence being that the trade winds blow more strongly from easterly directions. The thicker layer of warm surface water that has been pushed by wind shear along the equator close to the coast of Indonesia to form the thick end of a wedge results in significantly increased precipitation along the coast of Indonesia and neighbouring regions, while extremely dry weather prevails in the eastern tropical Pacific and on the west coast of South America.
Trade winds
Arid airHumid air strong trade winds
inversed wind direction
+0,5°C for more than 5 equated overlapping three-month-averages = El Niño
Anomalies in the Pacific mean surface temperatureSource: NOAA Center for Weather and Climate Prediction
-0,5°C for more than 5 equated overlapping three-month-averages = La Niña
1950Year
Temperature in °C
′60 ′70 ′80 ′90 2000 ′10 ′15′05′95′85′75′65′55-3
-2
-1
0
1
2
3
Neutral La Niña ThresholdEl Niño
Heat
Related Documents
