Which of the following statements CORRECTLY defines Southern Oscillations?
Show answer & explanation
Correct answer: A
Explanation
Answer: There is a periodic change in pressure conditions within the Pacific and Indian Oceans.
Explanation:
The Southern Oscillation is a periodic fluctuation in atmospheric pressure occurring in the tropical Pacific Ocean. Typically, when high pressure prevails in the southeastern Pacific Ocean, low pressure exists in the tropical eastern Indian Ocean. However, in certain years, this pressure pattern reverses. This reversal in pressure is termed the 'Southern Oscillation.' It is directly linked to the El Niño phenomenon; consequently, the two are collectively referred to as ENSO (El Niño–Southern Oscillation). This process influences global climate, and specifically, the intensity of the Indian monsoon. To quantify this pressure differential, the pressure difference between Tahiti (in the Pacific Ocean) and Darwin (Australia/Indian Ocean) is frequently calculated.
Additional Points:
El Niño: This refers to the phenomenon involving the temporary development of a warm ocean current near the coast of Peru, displacing the usual cold current.
ITCZ: This is the region near the equator where trade winds converge; its shifting is responsible for the onset of the monsoon.
Jet Stream: These are high-velocity winds flowing in the upper atmosphere, which facilitate the arrival of Western Disturbances over the Indian subcontinent.
Potential Exam Questions and Answers:
Question: With which oceanic phenomenon is the Southern Oscillation primarily associated?
Answer: El Niño.
Question: If the pressure difference between Tahiti and Darwin is negative, what impact will this have on the Indian monsoon?
Answer: The monsoon is likely to be weaker or below normal.