Examine the oceanic circulation and climatological impacts of the El Niño-Southern Oscillation phenomenon: Statement I: During an El Niño event, trade winds weaken or reverse direction, causing warm surface waters to pile up along the western coast of South America and suppressing coastal upwelling. Statement II: This atmospheric-oceanic coupling typically leads to enhanced monsoon rainfall and drought conditions across the western Pacific and Indian subcontinents. Which of the following is correct?

💡 Solution & Explanation

Both statements accurately describe the physical anomalies associated with El Niño phases in the equatorial Pacific. Weakening easterly trade winds disrupt normal Walker circulation, allowing warm equatorial pools to migrate eastward toward Peru, shutting down nutrient-rich cold upwelling currents. Simultaneously, shifts in atmospheric pressure cells suppress convection over northern Australia and South Asia, frequently triggering deficient monsoonal rainfall in India. ENSO cycles represent major drivers of global inter-annual climate variability.