The El Nino-Southern Oscillation and Global Precipitation

Our understanding of the relationship between the El Nino-Southern Oscillation (ENSO) phenomenon and global precipitation is reviewed from the early works of Sir Gilbert Walker to the latest research frontiers. ENSO is defined by large-scale changes in the sea surface temperature and sea-level pressure patterns of the Pacific Ocean. Rainfall follows the low (high) pressure (temperature) anomalies and subsequently impacts the global atmospheric circulation. ENSO contributes to global precipitation anomalies through teleconnections -changes in the Walker and Hadley circulations, oceanic Kelvin and Rossby waves, 'atmospheric bridge' mechanisms, and atmospheric Rossby wave trains -as observed with long-term in situ measurements and recent satellite-based analyses. Finally, some outstanding research questions are discussed. Is precipitation a useful predictor for ENSO? How does ENSO affect the probability density function of precipitation around the globe? What is the impact of global warming on the ENSO-precipitation relationship?