The study of a forced delayed oscillator ENSO model suggests that the intensity of ENSO can be suppressed significantly by an external periodic forcing due to the nonlinear mechanism of frequency entrainment. This suppression of ENSO is most effective for ENSOs in the regime of unstable self-exciting oscillation and for forcing of frequencies close to that of ENSO. In particular, an annual cycl...

We examine the impact of El Niño–Southern Oscillation (ENSO) on surface ozone abundance observed over the continental United States (U.S.) during 1993–2013. The monthly ozone decreases (increases) during El Niño (La Niña) years with amplitude up to 1.8 ppb per standard deviation of Niño 3.4 index. The largest ENSO influences occur over two southern U.S. regions during fall when the ENSO develop...

The impact of Indo-Pacific climate feedback on the dynamics of El Niño–Southern Oscillation (ENSO) is investigated using an ensemble set of Indian Ocean decoupling experiments (DCPL), utilizing a millennial integration of a coupled climatemodel. It is found that eliminating air–sea interactions over the IndianOcean results in various degrees of ENSO amplification across DCPL simulations, with a...

The variability of the hydroclimate over mainland Southeast Asia is strongly influenced by the El Niño– Southern Oscillation (ENSO), which has been linked to severe droughts and floods that profoundly influence human societies and ecosystems alike. Although the significance of ENSO is well understood, there are still limitations in the understanding of its effects on hydroclimate, particularly ...

Surface observations and subsurface ocean assimilation datasets are examined to contrast two distinct types of El Niño–Southern Oscillation (ENSO) in the tropical Pacific: an eastern-Pacific (EP) type and a central-Pacific (CP) type. An analysis method combining empirical orthogonal function (EOF) analysis and linear regression is used to separate these two types. Correlation and composite anal...

It is vital to understand how the El Niño–Southern Oscillation (ENSO) has responded to past changes in natural and anthropogenic forcings, in order to better understand and predict its response to future greenhouse warming. To date, however, the instrumental record is too brief to fully characterize natural ENSO variability, while large discrepancies exist amongst paleo-proxy reconstructions of...

The El Niño-Southern Oscillation (ENSO) drives large changes in global climate patterns from year to year, yet its sensitivity to continued anthropogenic greenhouse forcing is uncertain. We analyzed fossil coral reconstructions of ENSO spanning the past 7000 years from the Northern Line Islands, located in the center of action for ENSO. The corals document highly variable ENSO activity, with no...

Low precipitation enhances transmission of influenza viruses, which cause seasonal epidemics during the winter in northern and southern hemispheres. El Niño southern oscillation (ENSO) which modulates global precipitation is a multicomponent signal that is composed of sub-annual to multi-decadal oscillations. The dynamics of oscillatory components of ENSO and influenza are characterized, and ca...