Biological and Environmental Research - Earth and Environmental System Sciences
Earth and Environmental System Modeling
30 November 2016

Initialized Decadal Prediction for Transition to Positive Phase of the Interdecadal Pacific Oscillation


The negative phase of the Interdecadal Pacific Oscillation (IPO), a dominant mode of multi-decadal variability of sea surface temperatures (SSTs) in the tropical Pacific, contributed to the reduced rate of global surface temperature warming in the early 2000s.  A proposed mechanism for IPO multidecadal variability indicates that the build-up of upper ocean heat content in the off-equatorial western tropical Pacific in the 1980s and 1990s could provide conditions for an El Niño/Southern Oscillation (ENSO) event to trigger a transition of tropical Pacific SSTs to the opposite IPO phase.  


A decadal prediction initialized in 2013 shows that the Niño3.4 SSTs have qualitatively tracked the observations through 2015 with a small El Niño in 2014, and a larger El Niño event in 2015.  


The year 3-7 average prediction (2015-2020) from the 2013 initial state shows a transition to the positive phase of the IPO from the previous negative phase, and a resumption of larger rates of global warming consistent with a positive IPO phase.

Gerald Meehl
National Center for Atmospheric Research (NCAR)