Predicting the severity of spurious “double ITCZ” problem in CMIP5 coupled models from AMIP simulations

Baoqiang Xiang, Ming Zhao, Isaac M. Held, Jean Christophe Golaz

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


The severity of the double Intertropical Convergence Zone (DI) problem in climate models can be measured by a tropical precipitation asymmetry index (PAI), indicating whether tropical precipitation favors the Northern Hemisphere or the Southern Hemisphere. Examination of 19 Coupled Model Intercomparison Project phase 5 models reveals that the PAI is tightly linked to the tropical sea surface temperature (SST) bias. As one of the factors determining the SST bias, the asymmetry of tropical net surface heat flux in Atmospheric Model Intercomparison Project (AMIP) simulations is identified as a skillful predictor of the PAI change from an AMIP to a coupled simulation, with an intermodel correlation of 0.90. Using tropical top-of-atmosphere (TOA) fluxes, the correlations are lower but still strong. However, the extratropical asymmetries of surface and TOA fluxes in AMIP simulations cannot serve as useful predictors of the PAI change. This study suggests that the largest source of the DI bias is from the tropics and from atmospheric models.

Original languageEnglish (US)
Pages (from-to)1520-1527
Number of pages8
JournalGeophysical Research Letters
Issue number3
StatePublished - Feb 16 2017
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geophysics
  • General Earth and Planetary Sciences


  • CMIP5
  • SST bias
  • double ITCZ
  • precipitation asymmetry index
  • surface heat flux bias


Dive into the research topics of 'Predicting the severity of spurious “double ITCZ” problem in CMIP5 coupled models from AMIP simulations'. Together they form a unique fingerprint.

Cite this