El Nino and La Nina - AP Environmental Science
- What is La Niña?
- A climate pattern characterized by cooling of ocean surface waters in the central and eastern Pacific. This occurs when trade winds strengthen, increasing upwelling of cold water.
- Which direction do the trade winds blow during La Niña?
- Trade winds strengthen, blowing east to west. Strong pressure gradient enhances normal easterly trade wind flow.
- What atmospheric pressure pattern is associated with La Niña?
- Increased pressure over the eastern Pacific and decreased pressure over the western Pacific. This pressure pattern strengthens trade winds during La Niña.
- What is the primary indicator used to predict ENSO events?
- Sea surface temperature anomalies in the equatorial Pacific. Temperature changes in specific Pacific regions signal ENSO development.
- Identify the impact of El Niño on sea surface temperatures in the central Pacific.
- Sea surface temperatures increase. Reduced upwelling allows surface waters to warm significantly.
- What is the Southern Oscillation Index (SOI)?
- A measure of the difference in air pressure between Tahiti and Darwin. SOI quantifies atmospheric pressure oscillation across the Pacific.
- Which ENSO phase often leads to increased snow in the Pacific Northwest?
- La Niña. Cooler temperatures and northern jet stream enhance snowfall.
- What happens to the Walker Circulation during El Niño?
- The Walker Circulation weakens or reverses. Reduced pressure gradient disrupts normal atmospheric circulation.
- Which phase of ENSO is typically associated with hurricanes in the Atlantic?
- La Niña. La Niña's cooler waters reduce wind shear that inhibits hurricanes.
- What is El Niño?
- A climate pattern characterized by warming of ocean surface waters in the central and eastern Pacific. This occurs when trade winds weaken, reducing upwelling of cold water.
- Identify the effect of La Niña on winter temperatures in the northern United States.
- Colder than normal winter temperatures. Northward jet stream shift allows Arctic air to penetrate south.
- Identify the typical time interval between El Niño events.
- Every 2 to 7 years. This irregular cycle varies in timing but follows this general pattern.
- What is the effect of La Niña on rainfall in Southern California?
- Decreased rainfall. Northward jet stream diverts storms away from the region.
- What is the effect of El Niño on rainfall in Southern California?
- Increased rainfall. Southward jet stream carries moisture-laden storms to the region.
- What is the typical effect of La Niña on the fisheries of the west coast of South America?
- Improved fish populations due to cooler, nutrient-rich waters. Strong upwelling brings nutrients to surface, supporting fish growth.
- What is the typical duration of a La Niña event?
- 1 to 3 years. La Niña events tend to persist longer than El Niño events.
- Identify the impact of La Niña on sea surface temperatures in the central Pacific.
- Sea surface temperatures decrease. Enhanced upwelling brings cold deep water to the surface.
- What atmospheric pressure pattern is associated with El Niño?
- Decreased pressure over the eastern Pacific and increased pressure over the western Pacific. This pressure pattern creates weakened trade winds during El Niño.
- Identify one economic impact of El Niño.
- Damage to agriculture due to altered weather patterns. Extreme weather events disrupt crop yields and food production.
- What is the Walker Circulation?
- A conceptual model of air flow in the equatorial Pacific associated with trade winds. This circulation drives normal east-to-west surface wind patterns.
- State the impact of El Niño on global weather patterns.
- Increased rainfall in the central and eastern Pacific, droughts in the western Pacific. Warm waters shift eastward, altering global precipitation patterns.
- Which ENSO phase is associated with coral bleaching events?
- El Niño. Warmer waters stress corals, causing them to expel symbiotic algae.
- Which phase of ENSO is typically associated with reduced hurricane activity in the Atlantic?
- El Niño. El Niño increases wind shear that disrupts hurricane formation.
- Identify the term for the entire cycle of El Niño and La Niña events.
- El Niño-Southern Oscillation (ENSO). ENSO encompasses both oceanic and atmospheric components of this cycle.
- Identify one economic impact of La Niña.
- Increased costs for heating due to colder winters. Colder temperatures increase energy demand for space heating.
- Which ENSO phase often results in floods in Australia?
- La Niña. Enhanced Walker Circulation increases moisture transport to Australia.
- What happens to the Walker Circulation during La Niña?
- The Walker Circulation strengthens. Enhanced pressure gradient intensifies normal circulation patterns.
- Identify the effect of El Niño on winter temperatures in the northern United States.
- Warmer than normal winter temperatures. Southward jet stream shift brings warm Pacific air inland.
- Which ENSO phase often results in drought in Australia?
- El Niño. Weakened Walker Circulation reduces moisture transport to Australia.
- Identify the typical effect of El Niño on the fisheries of the west coast of South America.
- Decline in fish populations due to warmer, nutrient-poor waters. Warm water suppresses upwelling of nutrient-rich cold water.
- State the impact of La Niña on global weather patterns.
- Drier conditions in the central and eastern Pacific, wetter conditions in the western Pacific. Cold waters persist in east, maintaining normal precipitation patterns.
- How does La Niña affect the monsoon season in India?
- It typically strengthens the monsoon, leading to wetter conditions. Enhanced Walker Circulation increases moisture transport to India.
- Which ocean is primarily affected by El Niño and La Niña?
- Pacific Ocean. The Pacific spans the equatorial region where ENSO events originate.
- Identify the primary mechanism driving the ENSO cycle.
- Interaction between oceanic and atmospheric processes in the Pacific. Ocean-atmosphere feedback loops create this oscillating climate pattern.
- What is the typical duration of an El Niño event?
- 9 to 12 months. Most El Niño events peak and decay within this timeframe.
- What is the effect of La Niña on the jet stream over North America?
- The jet stream typically shifts northward. Northern shift keeps storm tracks away from southern regions.
- How does El Niño affect the monsoon season in India?
- It typically weakens the monsoon, leading to drier conditions. Altered Walker Circulation reduces moisture transport to India.
- Which direction do the trade winds blow during El Niño?
- Trade winds weaken and may reverse, blowing west to east. Weakened pressure gradient reduces normal easterly trade wind flow.
- What is the effect of El Niño on the jet stream over North America?
- The jet stream typically shifts southward. Southern shift brings storms and rain to southern regions.