Ocean circulation and El Nino/La Nina
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All 12 Flashcards — Ocean circulation and El Nino/La Nina
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Question
Define an ocean current.
Answer
A continuous, directed flow of seawater (e.g. the warm Gulf Stream, the cold Humboldt Current).
Question
Define a gyre.
Answer
A large, roughly circular system of surface currents driven by winds and the Coriolis effect (clockwise in the northern hemisphere).
Question
What is the thermohaline conveyor belt?
Answer
The slow, global deep-ocean circulation driven by differences in **temperature** (thermo) and **salinity** (haline).
Question
Define upwelling.
Answer
Cold, **nutrient-rich** deep water rising to the surface (e.g. off Peru), feeding plankton and large fisheries.
Question
What is El Nino?
Answer
The warm ENSO phase: trade winds weaken, warm water spreads east, and upwelling off South America is **suppressed**.
Question
What is La Nina?
Answer
The cold ENSO phase: trade winds strengthen, the eastern Pacific **cools**, and upwelling **intensifies**.
Question
El Nino vs La Nina in one line?
Answer
El Nino = eastern Pacific warms + upwelling off Peru collapses; La Nina = eastern Pacific cools + upwelling strengthens.
Question
Why does El Nino hurt Peru's fishery?
Answer
Warm water shuts down the Humboldt upwelling, so nutrients fall, anchovy stocks collapse, and fishing income drops.
Question
Give one benefit of El Nino.
Answer
Fewer Atlantic hurricanes (more wind shear), so the US Gulf and Caribbean coasts suffer fewer tropical storms.
Question
Give one harm of La Nina.
Answer
Heavy rain and flooding in eastern Australia/SE Asia, and worse drought and wildfire in California.
Question
How do you find a range on an ENSO graph?
Answer
Subtract the lowest reading from the highest reading (e.g. +2.25 - (-1.50) = 3.75), then quote the units.
Question
What does a top [10] Examine answer need?
Answer
A developed benefit AND harm in different regions, named places, a weighing of which outweighs, and a balanced judgement.
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Full study notes for Ocean circulation and El Nino/La Nina
Topic 8.1 hub
Ocean-atmosphere interactions
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