Natural variability of the central Pacific El Nino event on multi-centennial timescales

There is an evidence of the increasing intensity as well as occurrence frequency of the so-called central Pacific (CP) El Nino events since the 1990s. We examine whether such an increase in the frequency of CP El Nino may be a manifestation of natural climate variability. A control simulation of the Kiel Climate Model, run for 4200 years with the present values of greenhouse gases, exhibit large variations of the occurrence frequency of the CP El Nino versus the eastern Pacific (EP) El Nino. A model simulates to some extent changes in the occurrence ratio of CP and EP El Nino in comparison with the observations. Therefore, we can not exclude the possibility that an increasing of occurrence frequency of CP El Nino during recent decades in the observation could be a part of natural variability in the tropical climate system. Citation: Yeh, S.-W., B. P. Kirtman, J.-S. Kug, W. Park, and M. Latif (2011), Natural variability of the central Pacific El Nino event on multi-centennial timescales, Geophys. Res. Lett., 38, L02704, doi: 10.1029/2010GL045886.