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Total Categories: 5
The El Niño–Southern Oscillation (ENSO) is primarily characterized by variations in sea surface temperatures and winds across the tropical Atlantic Ocean.
Answer: False
The source indicates ENSO variations occur across the tropical Pacific Ocean, not the Atlantic.
El Niño is the cooling phase of the ENSO cycle, associated with below-average sea surface temperatures in the central and eastern tropical Pacific.
Answer: False
El Niño is characterized by warmer-than-average sea surface temperatures in the tropical Pacific, representing the warming phase of ENSO.
The Southern Oscillation is the oceanic component of ENSO, describing changes in sea surface temperatures.
Answer: False
The Southern Oscillation is the atmospheric component of ENSO, involving pressure variations, while sea surface temperature changes are the oceanic component.
El Niño and La Niña events typically occur every two to seven years and usually last for approximately one year each.
Answer: True
El Niño and La Niña events typically occur every two to seven years and usually last for approximately one year each.
La Niña phases are characterized by cooler-than-average sea surface temperatures in the central and eastern equatorial Pacific and stronger trade winds.
Answer: True
La Niña phases are characterized by cooler-than-average sea surface temperatures in the central and eastern equatorial Pacific and stronger trade winds.
What are the primary components of the El Niño–Southern Oscillation (ENSO)?
Answer: El Niño (warming phase) and La Niña (cooling phase), along with the Southern Oscillation (atmospheric component).
ENSO comprises three main components: El Niño (the warming phase), La Niña (the cooling phase), and the Southern Oscillation (the atmospheric pressure component).
Which phenomenon describes the atmospheric component of ENSO, involving an oscillation in surface air pressure between the eastern and western tropical Pacific?
Answer: The Southern Oscillation
The Southern Oscillation is the atmospheric component of ENSO, characterized by fluctuations in surface air pressure between the eastern and western tropical Pacific.
Which ENSO phase is characterized by near-average sea surface temperatures, precipitation, and wind patterns?
Answer: Neutral phase
The neutral ENSO phase is characterized by near-average sea surface temperatures, precipitation, and wind patterns.
The Bjerknes feedback mechanism describes a negative feedback loop that stabilizes the ENSO cycle by counteracting temperature anomalies.
Answer: False
The Bjerknes feedback mechanism describes a positive feedback loop that reinforces ENSO states, not a negative feedback that stabilizes them.
During an El Niño phase, the Walker circulation strengthens, leading to increased upwelling of cold water in the eastern equatorial Pacific.
Answer: False
During an El Niño phase, the Walker circulation weakens or reverses, and upwelling of cold water decreases.
The 'atmospheric bridge' mechanism explains how ENSO's tropical convection generates Rossby waves that influence distant atmospheric circulation patterns.
Answer: True
The 'atmospheric bridge' mechanism explains how ENSO's tropical convection generates Rossby waves that influence distant atmospheric circulation patterns.
According to the Bjerknes feedback mechanism, what initial condition leads to the reinforcement of an El Niño state?
Answer: Weaker easterly trade winds leading to reduced upwelling and eastward movement of warm water.
Weaker easterly trade winds lead to reduced upwelling and the eastward movement of warm surface water, which are initial conditions that reinforce an El Niño state according to the Bjerknes feedback mechanism.
What is a key characteristic of an El Niño phase regarding atmospheric circulation?
Answer: Weakening or reversal of the Walker circulation.
A key characteristic of an El Niño phase is the weakening or reversal of the Walker circulation.
The 'atmospheric bridge' mechanism connects ENSO's tropical impacts to distant regions by generating what type of waves?
Answer: Rossby waves
The 'atmospheric bridge' mechanism connects ENSO's tropical impacts to distant regions by generating Rossby waves.
What is the 'recharge oscillator' theory proposed to explain regarding ENSO?
Answer: How internal oceanic processes drive the periodical variation of ENSO.
The 'recharge oscillator' theory proposes that internal oceanic processes drive the periodical variation of ENSO.
What is the 'ocean dynamical thermostat' theory related to ENSO?
Answer: A proposed mechanism where oceanic processes might regulate or influence ENSO cycles.
The 'ocean dynamical thermostat' theory is related to ENSO as a proposed mechanism where oceanic processes might regulate or influence ENSO cycles.
The Southern Oscillation Index (SOI) is calculated using the difference in surface air pressure between Tahiti and Darwin, Australia.
Answer: True
The Southern Oscillation Index (SOI) is calculated using the difference in surface air pressure between Tahiti and Darwin, Australia.
ENSO Modoki, or Central Pacific ENSO, features temperature anomalies centered along the South American coastline.
Answer: False
ENSO Modoki features temperature anomalies centered in the central Pacific, not along the South American coastline.
ENSO Costero, also known as Eastern Pacific ENSO, is characterized by temperature anomalies concentrated in the central Pacific Ocean.
Answer: False
ENSO Costero, or Eastern Pacific ENSO, is characterized by temperature anomalies concentrated along the South American coastline, not in the central Pacific.
The US Climate Prediction Center requires sea surface temperatures to be 0.5°C below average for several seasons to declare an El Niño event.
Answer: False
The US Climate Prediction Center requires sea surface temperatures to be 0.5°C above average for several seasons to declare an El Niño event.
The Madden-Julian Oscillation (MJO) is a climate pattern primarily affecting the North Atlantic and is unrelated to ENSO.
Answer: False
The Madden-Julian Oscillation (MJO) primarily affects the tropics and is related to ENSO, not unrelated and confined to the North Atlantic.
The Pacific Decadal Oscillation (PDO) operates on shorter, more frequent cycles than ENSO and primarily influences tropical regions.
Answer: False
The Pacific Decadal Oscillation (PDO) operates on longer, interdecadal timescales and influences mid-latitude regions, unlike ENSO's tropical focus and shorter cycles.
How is the Southern Oscillation Index (SOI) typically calculated?
Answer: By calculating the difference in surface air pressure between Tahiti and Darwin, Australia.
The Southern Oscillation Index (SOI) is typically calculated by measuring the difference in surface air pressure between Tahiti and Darwin, Australia.
ENSO Modoki, or Central Pacific ENSO, differs from the canonical Eastern Pacific ENSO primarily in:
Answer: The geographical center of the sea surface temperature anomalies.
ENSO Modoki differs from canonical Eastern Pacific ENSO primarily in the geographical center of the sea surface temperature anomalies, which are located in the central Pacific rather than the eastern Pacific.
Which country's meteorological agency monitors the Niño 3.4 region, requiring SST anomalies of 0.5°C above average for several seasons to declare ENSO conditions?
Answer: US Climate Prediction Center
The US Climate Prediction Center monitors the Niño 3.4 region and requires sea surface temperature anomalies of 0.5°C above average for several seasons to declare ENSO conditions.
How does the Pacific Decadal Oscillation (PDO) differ from ENSO in terms of timescale?
Answer: PDO operates on longer, irregular interannual-to-interdecadal timescales (decades).
The PDO operates on longer, irregular interannual-to-interdecadal timescales (decades), differing from ENSO's shorter, more frequent cycles.
Which of the following is a characteristic of ENSO Modoki compared to canonical Eastern Pacific ENSO?
Answer: Anomalies are centered in the central Pacific (Niño 3.4 region).
A characteristic of ENSO Modoki compared to canonical Eastern Pacific ENSO is that its anomalies are centered in the central Pacific (Niño 3.4 region).
What is the significance of the 'Niño regions' in ENSO monitoring?
Answer: They are specific regions in the tropical Pacific used to monitor sea surface temperatures for ENSO phase determination.
The significance of the 'Niño regions' in ENSO monitoring is that they are specific areas in the tropical Pacific used to monitor sea surface temperatures for ENSO phase determination.
El Niño events tend to cause short-term cooling of the global average surface temperature.
Answer: False
El Niño events tend to cause short-term spikes in global average surface temperature, not cooling.
El Niño years generally lead to more active hurricane seasons in the Atlantic Ocean due to reduced vertical wind shear.
Answer: False
El Niño years generally lead to less active hurricane seasons in the Atlantic Ocean due to increased vertical wind shear.
Persistent El Niño conditions can severely impact local fishing industries by reducing nutrient-rich upwelling and fish populations.
Answer: True
Persistent El Niño conditions reduce nutrient-rich upwelling, negatively impacting fish populations and fishing industries.
ENSO cycles have been linked to a decreased incidence of mosquito-borne diseases like malaria and dengue fever.
Answer: False
ENSO cycles are linked to an increased incidence of mosquito-borne diseases like malaria and dengue fever due to altered rainfall and temperature patterns.
Strong El Niño phases can lead to prolonged dry periods in tropical forests, potentially causing widespread fires and changes in species composition.
Answer: True
Strong El Niño phases can lead to prolonged dry periods in tropical forests, increasing the risk of fires and altering species composition.
El Niño events are generally associated with above-average rainfall in regions like Indonesia and northern Australia.
Answer: False
El Niño events are generally associated with below-average rainfall in regions like Indonesia and northern Australia.
La Niña typically brings wetter-than-normal conditions to equatorial East Africa, while El Niño causes drier conditions there.
Answer: False
While La Niña brings wetter conditions to southern Africa, El Niño causes drier conditions in equatorial East Africa, contrary to the statement.
During El Niño conditions, Antarctica tends to experience reduced sea ice in the Weddell Sea due to high-pressure anomalies.
Answer: False
During El Niño conditions, Antarctica tends to experience reduced sea ice in the Amundsen and Bellingshausen Seas, not the Weddell Sea.
In Western Asia, La Niña phases are generally associated with increased precipitation during the November-April rainy season.
Answer: False
In Western Asia, El Niño phases are generally associated with increased precipitation, while La Niña phases bring reduced precipitation.
La Niña events in Australia are strongly correlated with reduced rainfall across the continent and warmer temperatures in the south.
Answer: False
La Niña events in Australia are strongly correlated with increased rainfall across the continent, not reduced rainfall.
El Niño generally leads to milder winters in Canada and wetter conditions along the US Gulf Coast and Southeast.
Answer: True
El Niño generally leads to milder winters in Canada and wetter conditions along the US Gulf Coast and Southeast.
The Tehuantepecer wind magnitude is typically greater during La Niña years compared to El Niño years.
Answer: False
The Tehuantepecer wind magnitude is typically greater during El Niño years compared to La Niña years.
During El Niño events, Fiji generally experiences wetter-than-normal conditions, increasing the risk of drought.
Answer: False
During El Niño events, Fiji generally experiences drier-than-normal conditions, increasing the risk of drought.
El Niño events disrupt the marine food web around the Galápagos Islands by reducing nutrient-rich upwelling, impacting populations of primary producers and top predators.
Answer: True
El Niño events disrupt the marine food web around the Galápagos Islands by reducing nutrient-rich upwelling, impacting populations of primary producers and top predators.
How does El Niño typically affect tropical cyclone activity in the Atlantic Ocean?
Answer: It decreases activity due to increased vertical wind shear and a drier atmosphere.
El Niño typically decreases tropical cyclone activity in the Atlantic Ocean due to increased vertical wind shear and a drier atmosphere.
What is a significant ecological impact of strong El Niño phases mentioned in the source?
Answer: Prolonged dry periods in tropical forests, leading to fires.
A significant ecological impact of strong El Niño phases is prolonged dry periods in tropical forests, which can lead to widespread fires.
Which region typically experiences below-average rainfall during El Niño events, according to general patterns?
Answer: Indonesia
Indonesia typically experiences below-average rainfall during El Niño events.
How does La Niña typically influence weather patterns in southern Africa?
Answer: It brings wetter-than-normal conditions.
La Niña typically brings wetter-than-normal conditions to southern Africa.
During El Niño conditions, what happens to sea ice extent in the Amundsen and Bellingshausen Seas around Antarctica?
Answer: It decreases due to high-pressure anomalies and increased heat flux.
During El Niño conditions, sea ice extent in the Amundsen and Bellingshausen Seas around Antarctica decreases due to high-pressure anomalies and increased heat flux.
Which of the following is a potential social impact linked to ENSO cycles?
Answer: Increased risk of civil conflicts in affected countries.
Increased risk of civil conflicts in affected countries is a potential social impact linked to ENSO cycles.
What is the primary impact of El Niño on the fishing industry, particularly off the coast of South America?
Answer: Reduced fish populations due to decreased nutrient upwelling.
The primary impact of El Niño on the fishing industry off South America is reduced fish populations due to decreased nutrient upwelling.
How does ENSO influence global average surface temperatures?
Answer: El Niño events cause short-term spikes in global temperature, while La Niña causes short-term cooling.
ENSO influences global average surface temperatures by causing short-term spikes during El Niño events and short-term cooling during La Niña events.
What is the primary impact of El Niño on rainfall in Australia?
Answer: Reduced rainfall across most of the continent.
The primary impact of El Niño on rainfall in Australia is reduced rainfall across most of the continent.
How does ENSO influence the sea surface height (SSH) in the equatorial Pacific?
Answer: El Niño causes a positive SSH anomaly due to thermal expansion of warmer waters.
El Niño influences the sea surface height (SSH) in the equatorial Pacific by causing a positive SSH anomaly due to the thermal expansion of warmer waters.
How does ENSO influence tropical cyclone activity in the Western Pacific basin?
Answer: It shifts the location where tropical cyclones form eastward.
ENSO influences tropical cyclone activity in the Western Pacific basin by shifting the location where tropical cyclones form eastward.
How does ENSO influence rainfall patterns in India?
Answer: El Niño events are often associated with a weakening of the Indian monsoon and increased drought risk.
ENSO influences rainfall patterns in India, with El Niño events often associated with a weakening of the Indian monsoon and increased drought risk.
There is no evidence suggesting that ENSO events have occurred throughout Earth's history prior to the 20th century.
Answer: False
There is evidence suggesting that ENSO events have occurred throughout Earth's history prior to the 20th century.
Climate change is projected by the IPCC AR6 to decrease precipitation variance related to ENSO.
Answer: False
Climate change is projected by the IPCC AR6 to increase, not decrease, precipitation variance related to ENSO.
What historical event might have been influenced by the strong El Niño event between 1789 and 1793 due to poor crop yields in Europe?
Answer: The French Revolution
The strong El Niño event between 1789 and 1793, which caused poor crop yields in Europe, might have influenced the French Revolution.
The term 'El Niño,' meaning 'The Boy' in Spanish, was associated with the Christ Child due to:
Answer: Its timing around Christmas time when noticed by sailors.
The term 'El Niño' was associated with the Christ Child due to its timing around Christmas time when it was first noticed by sailors.
Which statement accurately reflects the potential impact of climate change on ENSO, according to the source?
Answer: Climate change may exacerbate ENSO's effects, potentially increasing the frequency of extreme El Niño events.
Climate change may exacerbate ENSO's effects, potentially increasing the frequency of extreme El Niño events, according to the source.