Toward a record of Central Pacific El Niño events since 1880

We investigate the various methods currently available for distinguishing between the Central Pacific (CP) El Niño (or “El Niño Modoki”) and the canonical El Niño by considering nine different methods and five sea surface temperature (SST) datasets from 1880 to 2010. This is aimed to demonstrate the variety which exists between different classification methods as well as to help identify years which can be more confidently classified as CP events. Classifying CP El Niños based on the greatest convergence between methods and between SST datasets provides a more robust identification of these events. Analysis of the SST patterns of the CP years identified demonstrates several misclassifications, stressing the importance of not relying solely on indices. After removal, 14 years which are classified the most consistently as CP events include the following: 1885/1886, 1914/1915, 1940/1941, 1958/1959, 1963/1964, 1968/1969, 1977/1978, 1986/1987, 1990/1991, 1991/1992, 1994/1995, 2002/2003, 2003/2004, and 2004/2005. Our findings also indicate the intermittent appearance of CP events throughout the time period investigated, inciting the role of multidecadal natural climate variability in generating CP El Niños.