An evaluation of ENSO dynamics in CMIP simulations in the framework of the recharge oscillator model

Asha Vijayeta, Dietmar Dommenget

Research output: Contribution to journalArticleResearchpeer-review

12 Citations (Scopus)

Abstract

The CMIP model simulations show wide spread uncertainties in ENSO statistics and dynamics. In this study, we use the concept of the linear recharge oscillator (ReOsc) model to diagnose the ENSO-dynamics in CMIP3 and CMIP5 model simulations. The ReOsc model parameters allow us to quantify SST and thermocline damping, SST coupling to thermocline and vice-versa, sensitivity to wind stress and heat flux forcings and separate atmospheric from oceanic processes. Our results show that the ENSO-dynamics and their diversity within the CMIP ensemble can be well represented with the linear recharge oscillator model diagnostics. We also illustrate that the ENSO dynamics show larger biases relative to observations and spread within the models than simple large-scale statistics such as SST standard deviation would suggest. The CMIP models underestimate the atmospheric positive and negative feedbacks, they have compensating atmospheric and oceanic errors, the thermocline damping is too strong and stochastic noise forcings in models is too weak. The CMIP5 models show only marginal improvements relative to CMIP3. The results suggest that models can still be significantly improved and our analysis gives directions to what needs to be improved.

Original languageEnglish
Pages (from-to)1753-1771
Number of pages19
JournalClimate Dynamics
Volume51
Issue number5-6
DOIs
Publication statusPublished - 1 Sep 2018

Keywords

  • CGCM
  • Climate feedbacks
  • CMIP simulations
  • Coupled general circulation models
  • El Nino dynamics
  • El Nino southern oscillation
  • ENSO
  • ENSO dyanmics
  • Model evaluation
  • Ocean and atmospheric dynamics
  • Recharge oscillator model

Cite this