Relation of the double‐ITCZ bias to the atmospheric energy budget in climate models

We examine how tropical zonal mean precipitation biases in current climate models relate to the atmospheric energy budget. Both hemispherically symmetric and antisymmetric tropical precipitation biases contribute to the well-known double-Intertropical Convergence Zone (ITCZ) bias; however, they have distinct signatures in the energy budget. Hemispherically symmetric biases in tropical precipitation are proportional to biases in the equatorial net energy input; hemispherically antisymmetric biases are proportional to the atmospheric energy transport across the equator. Both relations can be understood within the framework of recently developed theories. Atmospheric net energy input biases in the deep tropics shape both the symmetric and antisymmetric components of the double-ITCZ bias. Potential causes of these energetic biases and their variation across climate models are discussed.

[1]  J. Janowiak,et al.  The Version 2 Global Precipitation Climatology Project (GPCP) Monthly Precipitation Analysis (1979-Present) , 2003 .

[2]  T. Schneider,et al.  The Equatorial Energy Balance, ITCZ Position, and Double-ITCZ Bifurcations , 2016 .

[3]  B. Tian.  Spread of model climate sensitivity linked to double‐Intertropical Convergence Zone bias , 2015 .

[4]  M. Holland,et al.  Trends in Arctic sea ice extent from CMIP5, CMIP3 and observations , 2012 .

[5]  David R. Doelling,et al.  Toward Optimal Closure of the Earth's Top-of-Atmosphere Radiation Budget , 2009 .

[6]  Richard A. Wood,et al.  Global Climatic Impacts of a Collapse of the Atlantic Thermohaline Circulation , 2002 .

[7]  S. Xie,et al.  Origins of tropical‐wide SST biases in CMIP multi‐model ensembles , 2012 .

[8]  C. Bitz,et al.  Influence of high latitude ice cover on the marine Intertropical Convergence Zone , 2005 .

[9]  S. Solomon.  The Physical Science Basis : Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change , 2007 .

[10]  Graeme Stephens,et al.  Southern Ocean albedo, inter-hemispheric energy transports and the double ITCZ: global impacts of biases in a coupled model , 2017, Climate Dynamics.

[11]  Sarah M. Kang,et al.  The Response of the ITCZ to Extratropical Thermal Forcing: Idealized Slab-Ocean Experiments with a GCM , 2008 .

[12]  J. Marshall,et al.  The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone , 2013, Climate Dynamics.

[13]  Veronika Eyring,et al.  Evaluation of Climate Models. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change , 2013 .

[14]  B. Barkstrom,et al.  Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment , 1996 .

[15]  Minghua Zhang,et al.  Double ITCZ in Coupled Ocean‐Atmosphere Models: From CMIP3 to CMIP5 , 2015 .

[16]  Phillip A. Arkin,et al.  Analyses of Global Monthly Precipitation Using Gauge Observations, Satellite Estimates, and Numerical Model Predictions , 1996 .

[17]  K. Trenberth.  Using Atmospheric Budgets as a Constraint on Surface Fluxes , 1997 .

[18]  Karen L. Smith,et al.  How Well Do the CMIP5 Models Simulate the Antarctic Atmospheric Energy Budget , 2015 .

[19]  J. Chiang,et al.  Extratropical Cooling, Interhemispheric Thermal Gradients, and Tropical Climate Change , 2012 .

[20]  J. Thepaut,et al.  The ERA‐Interim reanalysis: configuration and performance of the data assimilation system , 2011 .

[21]  C. Mechoso,et al.  A global perspective on CMIP5 climate model biases , 2014 .

[22]  T. Schneider,et al.  Energetic Constraints on the Position of the Intertropical Convergence Zone , 2013 .

[23]  G. Vecchi,et al.  Simulated Climate and Climate Change in the GFDL CM2.5 High-Resolution Coupled Climate Model , 2012 .

[24]  S. Xie,et al.  Tropical Biases in CMIP5 Multimodel Ensemble: The Excessive Equatorial Pacific Cold Tongue and Double ITCZ Problems* , 2014 .

[25]  Jialin Lin,et al.  The Double-ITCZ Problem in IPCC AR4 Coupled GCMs: Ocean–Atmosphere Feedback Analysis , 2007 .

[26]  Tapio Schneider,et al.  Migrations and dynamics of the intertropical convergence zone , 2014, Nature.

[27]  Kevin E. Trenberth,et al.  The Annual Cycle of the Energy Budget. Part II: Meridional Structures and Poleward Transports , 2008 .

[28]  A. Sobel,et al.  The Eastern Pacific ITCZ during the Boreal Spring , 2005 .

[29]  R. Stouffer,et al.  Response of the ITCZ to Northern Hemisphere cooling , 2006 .

[30]  Yan Du,et al.  Climate Model Errors over the South Indian Ocean Thermocline Dome and Their Effect on the Basin Mode of Interannual Variability , 2015 .

[31]  R. Abernathey,et al.  Phase Speed Cross Spectra of Eddy Heat Fluxes in the Eastern Pacific , 2015 .

[32]  Tim Li,et al.  Why the ITCZ is mostly north of the equator , 1996 .

[33]  K. Trenberth,et al.  The atmospheric energy budget and implications for surface fluxes and ocean heat transports , 2001 .

[34]  Yen-Ting Hwang,et al.  Link between the double-Intertropical Convergence Zone problem and cloud biases over the Southern Ocean , 2013, Proceedings of the National Academy of Sciences.

[35]  T. Shinoda,et al.  The Equatorial Pacific Cold Tongue Simulated by IPCC AR4 Coupled GCMs: Upper Ocean Heat Budget and Feedback Analysis , 2012 .

[36]  K. Trenberth,et al.  Tracking Earth’s Energy: From El Niño to Global Warming , 2012, Surveys in Geophysics.

[37]  T. Schneider,et al.  Seasonal and Interannual Variations of the Energy Flux Equator and ITCZ. Part I: Zonally Averaged ITCZ Position , 2016 .

[38]  J. Kay,et al.  Global Climate Impacts of Fixing the Southern Ocean Shortwave Radiation Bias in the Community Earth System Model (CESM) , 2016 .

[39]  M. Latif,et al.  The Seasonal Cycle over the Tropical Pacific in Coupled Ocean Atmosphere General Circulation Models , 1995 .

[40]  S. Bony,et al.  The radiative impact of clouds on the shift of the Intertropical Convergence Zone , 2014 .

[41]  D. Lawrence,et al.  A new synoptic scale resolving global climate simulation using the Community Earth System Model , 2014 .

[42]  J. Marshall,et al.  The Relationship between ITCZ Location and Cross-Equatorial Atmospheric Heat Transport: From the Seasonal Cycle to the Last Glacial Maximum , 2012 .

[43]  S. Bony,et al.  The ‘too few, too bright’ tropical low‐cloud problem in CMIP5 models , 2012 .