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Predicting the severity of spurious “double ITCZ” problem in CMIP5 coupled models from AMIP simulations
Author(s) -
Xiang Baoqiang,
Zhao Ming,
Held Isaac M.,
Golaz JeanChristophe
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl071992
Subject(s) - intertropical convergence zone , coupled model intercomparison project , climatology , northern hemisphere , environmental science , extratropical cyclone , sea surface temperature , atmospheric model , precipitation , atmospheric sciences , climate model , tropics , tropical cyclone , southern hemisphere , spurious relationship , asymmetry , climate change , meteorology , geology , physics , oceanography , machine learning , quantum mechanics , fishery , computer science , biology
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.