Complex picture for likelihood of ENSO-driven flood hazard

• Published in: Nature communications Vol. 8; no. 1; p. 14796
• Main Authors: Emerton, R., Cloke, H. L., Stephens, E. M., Zsoter, E., Woolnough, S. J., Pappenberger, F.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.03.2017; Nature Publishing Group; Nature Portfolio
• Subjects: 20th century; 704/106/242; 704/242; 704/4111; Climate; Datasets; El Nino; Humanities and Social Sciences; Hydrology; multidisciplinary; Ocean currents; Precipitation; Probability; Rain; River networks; Science; Science (multidisciplinary); Weather forecasting; United Kingdom > UK
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms14796

El Niño and La Niña events, the extremes of ENSO climate variability, influence river flow and flooding at the global scale. Estimates of the historical probability of extreme (high or low) precipitation are used to provide vital information on the likelihood of adverse impacts during extreme ENSO events. However, the nonlinearity between precipitation and flood magnitude motivates the need for estimation of historical probabilities using analysis of hydrological data sets. Here, this analysis is undertaken using the ERA-20CM-R river flow reconstruction for the twentieth century. Our results show that the likelihood of increased or decreased flood hazard during ENSO events is much more complex than is often perceived and reported; probabilities vary greatly across the globe, with large uncertainties inherent in the data and clear differences when comparing the hydrological analysis to precipitation. El Niño and La Niña (ENSO) events influence global river flow and are often used as an early indicator of potential flooding. Here, the authors show that the probability of ENSO-driven flood hazard is more complex than is often perceived, and highlight the importance of considering hydrological response.