Which of the following best describes the phenomenon of El Niño in the context of global climate?
Show answer & explanation
Correct answer: A
Explanation
Solution: The correct answer is Periodic warming of sea surface in central and eastern Pacific.
Explanation:
☛ El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO) climate cycle.
☛ It involves the periodic warming of sea surface temperatures across the central and east-central equatorial Pacific Ocean.
☛ Under normal conditions, trade winds blow from east to west across the tropical Pacific; during El Niño, these trade winds weaken or even reverse direction.
☛ As a result, warm equatorial water surges eastward toward the coast of South America (near Peru and Ecuador), disrupting marine upwelling and global weather patterns.
☛ In Spanish, El Niño translates to 'The Little Boy' or 'Christ Child', so named by Peruvian fishermen because the phenomenon typically peaks around Christmas.
☛ In India, El Niño events are frequently linked to the suppression and weakening of the Southwest Monsoon, leading to drought-like conditions.
Extra Exam-Relevant Facts:
☛ La Niña: Represents the cold phase of the ENSO cycle, characterized by unusually cold ocean temperatures in the equatorial Pacific, which generally favors a strong Indian monsoon.
☛ Walker Circulation: An east-west atmospheric circulation cell across the equatorial Pacific driven by ocean temperature and atmospheric pressure gradients.
☛ Southern Oscillation: The atmospheric counterpart of El Niño, involving sea-level pressure fluctuations between the eastern tropical Pacific (measured at Tahiti) and western tropical Pacific (measured at Darwin, Australia).
Important One-Liners for Upcoming Exams:
☛ What does the Spanish term 'El Niño' literally translate to? → 'The Little Boy' or 'Christ Child'
☛ Which cold ocean current along the South American coast is temporarily replaced by warm water during El Niño? → Humboldt Current (Peru Current)
☛ What is the atmospheric component of the El Niño phenomenon called? → Southern Oscillation
☛ What is the cooler counterpart phase of El Niño called? → La Niña
☛ Which index is calculated from the air pressure difference between Tahiti and Darwin? → Southern Oscillation Index (SOI)