Wolter, K., and M. S. Timlin, 1998: Measuring the strength of ENSO events: How does 1997/98 rank? Weather, 53, 315-324.


The 1997/98 El Niño event has been hailed as the "El Niño of the century", pushing 1982/83 from its throne. Is this claim valid? How do we determine the strength of El Niño and La Niña events? This paper addresses these issues by comparing the temporal evolution of different El Niño Southern Oscillation (ENSO) indices for both events. The Multivariate ENSO Index (MEI) is favoured over conventional indices, since it combines the significant features of all observed surface fields in the tropical Pacific. Based on MEI data until May 1998, the current event is placed a close second both for its peak value and for the duration of front-runner status.