Challenges and Prospects for Reducing Coupled Climate Model SST Biases in the Eastern Tropical Atlantic and Pacific Oceans: The U.S. CLIVAR Eastern Tropical Oceans Synthesis Working Group

Well-known problems trouble coupled general circulation models of the eastern Atlantic and Pacific Ocean basins. Model climates are significantly more symmetric about the equator than is observed. Model sea surface temperatures are biased warm south and southeast of the equator, and the atmosphere is too rainy within a band south of the equator. Near-coastal eastern equatorial SSTs are too warm, producing a zonal SST gradient in the Atlantic opposite in sign to that observed. The U.S. Climate Variability and Predictability Program (CLIVAR) Eastern Tropical Ocean Synthesis Working Group (WG) has pursued an updated assessment of coupled model SST biases, focusing on the surface energy balance components, on regional error sources from clouds, deep convection, winds, and ocean eddies; on the sensitivity to model resolution; and on remote impacts. Motivated by the assessment, the WG makes the following recommendations: 1) encourage identification of the specific parameterizations contributing to the biases in individual models, as these can be model dependent; 2) restrict multimodel intercomparisons to specific processes; 3) encourage development of high-resolution coupled models with a concurrent emphasis on parameterization development of finer-scale ocean and atmosphere features, including low clouds; 4) encourage further availability of all surface flux components from buoys, for longer continuous time periods, in persistently cloudy regions; and 5) focus on the eastern basin coastal oceanic upwelling regions, where further opportunities for observational–modeling synergism exist.

[1]  J. Bjerknes,et al.  A possible response of the atmospheric Hadley circulation to equatorial anomalies of ocean temperature , 1966 .

[2]  P. Mazeika.  Thermal Domes in the Eastern Tropical Atlantic OCEAN1 , 1967 .

[3]  J. Bjerknes.  ATMOSPHERIC TELECONNECTIONS FROM THE EQUATORIAL PACIFIC1 , 1969 .

[4]  S. Philander.  The Response of Equatorial Oceans to a Relaxation of the Trade Winds , 1981 .

[5]  S. Hastenrath,et al.  Atmosphere-Ocean Mechanisms of Climate Anomalies in the Angola-Tropical Atlantic Sector , 1983 .

[6]  M. Cane,et al.  A Model El Niñ–Southern Oscillation , 1987 .

[7]  Prashant D. Sardeshmukh,et al.  The Diagnosis of Mechanical Dissipation in the Atmosphere from Large-Scale Balance Requirements , 1992 .

[8]  S. Klein,et al.  The Seasonal Cycle of Low Stratiform Clouds , 1993 .

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

[10]  Brian J. Hoskins,et al.  Monsoons and the dynamics of deserts , 1996 .

[11]  A. Arakawa,et al.  Peruvian stratus clouds and the tropical Pacific circulation , 1996 .

[12]  Christopher W. Fairall,et al.  Direct Covariance Flux Estimates from Mobile Platforms at Sea , 1998 .

[13]  H. Hendon,et al.  Cloud Radiative Forcing of the Low-Latitude Tropospheric Circulation: Linear Calculations , 2000 .

[14]  R. Voss,et al.  STOIC: a study of coupled model climatology and variability in tropical ocean regions , 2002 .

[15]  Akio Arakawa,et al.  CLOUDS AND CLIMATE: A PROBLEM THAT REFUSES TO DIE. Clouds of many , 2022 .

[16]  Robert Cifelli,et al.  EPIC2001 and the Coupled Ocean Atmosphere System of the Tropical East Pacific. , 2004 .

[17]  Pedro M. M. Soares,et al.  Sensitivity of moist convection to environmental humidity , 2004 .

[18]  David L. Williamson,et al.  Evaluating Parameterizations in General Circulation Models: Climate Simulation Meets Weather Prediction , 2004 .

[19]  C. Bretherton,et al.  The Epic 2001 Stratocumulus Study , 2004 .

[20]  A. Arakawa.  The Cumulus Parameterization Problem: Past, Present, and Future , 2004 .

[21]  S. Xie,et al.  Interaction of the Atlantic Equatorial Cold Tongue and the African Monsoon , 2004 .

[22]  Matthew E. Peters,et al.  A Simplified Model of the Walker Circulation with an Interactive Ocean Mixed Layer and Cloud-Radiative Feedbacks , 2005 .

[23]  R. Garreaud,et al.  Dynamics of the Low-Level Jet off the West Coast of Subtropical South America , 2005 .

[24]  D. Dewitt.  Diagnosis of the tropical Atlantic near‐equatorial SST bias in a directly coupled atmosphere‐ocean general circulation model , 2005 .

[25]  R. Garreaud,et al.  The Low-Level Jet off the West Coast of Subtropical South America: Structure and Variability , 2005 .

[26]  Yukio Masumoto,et al.  Seasonal and Interannual Variations of Oceanic Conditions in the Angola Dome , 2006 .

[27]  Chunzai Wang.  An overlooked feature of tropical climate: Inter‐Pacific‐Atlantic variability , 2006 .

[28]  P. Zuidema,et al.  The Interaction of Clouds and Dry Air in the Eastern Tropical Pacific , 2006 .

[29]  Gokhan Danabasoglu,et al.  Attribution and Impacts of Upper-Ocean Biases in CCSM3 , 2006 .

[30]  R. Murtugudde,et al.  Effect of ocean mesoscale variability on the mean state of tropical Atlantic climate , 2006 .

[31]  A. Sobel,et al.  AGCM Precipitation Biases in the Tropical Atlantic , 2006 .

[32]  Keir Colbo,et al.  The variability and heat budget of the upper ocean under the Chile-Peru stratus , 2007 .

[33]  Zeng‐Zhen Hu,et al.  Evolution of model systematic errors in the Tropical Atlantic Basin from coupled climate hindcasts , 2007 .

[34]  H. Lass,et al.  On the impact of wind curls on coastal currents , 2007 .

[35]  S. Xie,et al.  The Tropical Eastern Pacific Seasonal Cycle: Assessment of Errors and Mechanisms in IPCC AR4 Coupled Ocean–Atmosphere General Circulation Models , 2007 .

[36]  Tim N. Palmer,et al.  Using numerical weather prediction to assess climate models , 2007 .

[37]  Michael,et al.  THE PIRATA PROGRAM , 2008 .

[38]  Zeng‐Zhen Hu,et al.  Low cloud errors over the southeastern Atlantic in the NCEP CFS and their association with lower‐tropospheric stability and air‐sea interaction , 2008 .

[39]  James J. Hack,et al.  A New Sea Surface Temperature and Sea Ice Boundary Dataset for the Community Atmosphere Model , 2008 .

[40]  Dudley B. Chelton,et al.  A Global Climatology of Surface Wind and Wind Stress Fields from Eight Years of QuikSCAT Scatterometer Data , 2008 .

[41]  Fabrice Hernandez,et al.  THE PIRATA PROGRAM History, Accomplishments, and Future Directions * , 2008 .

[42]  C. Thorncroft,et al.  Shallow Meridional Circulations in the Tropical Atmosphere , 2008 .

[43]  S. Xie,et al.  On the origin of equatorial Atlantic biases in coupled general circulation models , 2008 .

[44]  Stephen G. Yeager,et al.  The global climatology of an interannually varying air–sea flux data set , 2009 .

[45]  P. Zuidema,et al.  Stratocumulus Cloud-Top Height Estimates and Their Climatic Implications , 2009 .

[46]  Robert A. Weller,et al.  Accuracy of the IMET Sensor Package in the Subtropics , 2009 .

[47]  D. Chelton,et al.  SST–Wind Interaction in Coastal Upwelling: Oceanic Simulation with Empirical Coupling , 2009 .

[48]  J. Servain,et al.  Extension of PIRATA in the tropical South-East Atlantic: an initial one-year experiment , 2009 .

[49]  C. Bretherton,et al.  The PreVOCA experiment: Modeling the Lower Troposphere in the Southeast Pacific , 2009 .

[50]  G. Kiladis,et al.  Sea Surface Temperature Biases under the Stratus Cloud Deck in the Southeast Pacific Ocean in 19 IPCC AR4 Coupled General Circulation Models , 2010 .

[51]  Frank O. Bryan,et al.  A prototype two-decade fully-coupled fine-resolution CCSM simulation , 2010 .

[52]  C. Mechoso,et al.  Interhemispheric influence of the Atlantic warm pool on the southeastern Pacific. , 2010 .

[53]  S. Nicholson.  A low-level jet along the Benguela coast, an integral part of the Benguela current ecosystem , 2010 .

[54]  G. Kiladis,et al.  Upper-Ocean Processes under the Stratus Cloud Deck in the Southeast Pacific Ocean , 2010 .

[55]  Uang,et al.  The NCEP Climate Forecast System Reanalysis , 2010 .

[56]  P. Zuidema,et al.  Surface Flux Observations on the Southeastern Tropical Pacific Ocean and Attribution of SST Errors in Coupled Ocean–Atmosphere Models , 2010 .

[57]  S. Moorthi,et al.  Simulation of low clouds in the Southeast Pacific by the NCEP GFS: sensitivity to vertical mixing , 2010 .

[58]  J. Slingo,et al.  Upper-ocean heat budget and ocean eddy transport in the south-east Pacific in a high-resolution coupled model , 2010 .

[59]  G. Allen,et al.  Large-scale and synoptic meteorology in the south-east Pacific during the observations campaign VOCALS-REx in austral Spring 2008 , 2011 .

[60]  Y. Masumoto,et al.  Tropical Atlantic biases and their relation to surface wind stress and terrestrial precipitation , 2012, Climate Dynamics.

[61]  Nils Wedi,et al.  Simulating the diurnal cycle of rainfall in global climate models: resolution versus parameterization , 2012, Climate Dynamics.

[62]  A. Arakawa,et al.  Toward unification of the multiscale modeling of the atmosphere , 2011 .

[63]  James C. McWilliams,et al.  Heat balance and eddies in the Peru-Chile current system , 2012, Climate Dynamics.

[64]  T. Jung.  Diagnosing remote origins of forecast error: relaxation versus 4D‐Var data‐assimilation experiments , 2011 .

[65]  M. Mcphaden,et al.  TropFlux: air-sea fluxes for the global tropical oceans—description and evaluation , 2012, Climate Dynamics.

[66]  G. Danabasoglu,et al.  The Community Climate System Model Version 4 , 2011 .

[67]  M. Latif,et al.  On the Tropical Atlantic SST warm bias in the Kiel Climate Model , 2011 .

[68]  R. Saravanan,et al.  An investigation of tropical Atlantic bias in a high-resolution coupled regional climate model , 2011, Climate Dynamics.

[69]  Robert Pincus,et al.  Exposing Global Cloud Biases in the Community Atmosphere Model (CAM) Using Satellite Observations and Their Corresponding Instrument Simulators , 2012 .

[70]  A. Genio.  Representing the Sensitivity of Convective Cloud Systems to Tropospheric Humidity in General Circulation Models , 2012 .

[71]  S. Bates,et al.  The CCSM4 Ocean Component , 2012 .

[72]  M. Mcphaden,et al.  TropFlux wind stresses over the tropical oceans: evaluation and comparison with other products , 2013, Climate Dynamics.

[73]  David L. Williamson,et al.  Southeast Pacific Stratocumulus in the Community Atmosphere Model , 2012 .

[74]  Chidong Zhang,et al.  Possible Root Causes of Surface Westerly Biases over the Equatorial Atlantic in Global Climate Models , 2012 .

[75]  Y. Masumoto,et al.  Equatorial Atlantic variability and its relation to mean state biases in CMIP5 , 2012, Climate Dynamics.

[76]  Masahiro Watanabe,et al.  The Transpose-AMIP II Experiment and Its Application to the Understanding of Southern Ocean Cloud Biases in Climate Models , 2012 .

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

[78]  Frank O. Bryan,et al.  Impact of ocean model resolution on CCSM climate simulations , 2012, Climate Dynamics.

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

[80]  S. Klein,et al.  Are climate model simulations of clouds improving? An evaluation using the ISCCP simulator , 2012 .

[81]  P. Chang,et al.  Oceanic origin of southeast tropical Atlantic biases , 2014, Climate Dynamics.

[82]  Sarah M. Kang,et al.  Contrasting the tropical responses to zonally asymmetric extratropical and tropical thermal forcing , 2013, Climate Dynamics.

[83]  J. McWilliams,et al.  Mesoscale Eddy Buoyancy Flux and Eddy-Induced Circulation in Eastern Boundary Currents , 2013 .

[84]  S. Bony,et al.  On the Correspondence between Mean Forecast Errors and Climate Errors in CMIP5 Models , 2013 .

[85]  Axel Lauer,et al.  Simulating Clouds with Global Climate Models: A Comparison of CMIP5 Results with CMIP3 and Satellite Data , 2013 .

[86]  T. Toniazzo,et al.  Development of warm SST errors in the southern tropical Atlantic in CMIP5 decadal hindcasts , 2014, Climate Dynamics.

[87]  Andrew Gettelman,et al.  Microphysical process rates and global aerosol–cloud interactions , 2013 .

[88]  Jean-Luc Redelsperger,et al.  The Present and Future of the West African Monsoon: A Process-Oriented Assessment of CMIP5 Simulations along the AMMA Transect , 2013 .

[89]  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.

[90]  N. Loeb,et al.  Surface Irradiances Consistent With CERES-Derived Top-of-Atmosphere Shortwave and Longwave Irradiances , 2013 .

[91]  J. Farrar,et al.  Structure and surface properties of eddies in the southeast Pacific Ocean , 2013 .

[92]  B. Stevens,et al.  The Atlantic ITCZ bias in CMIP5 models , 2015, Climate Dynamics.

[93]  Patrick Heimbach,et al.  North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part I: Mean states , 2014 .

[94]  P. Chang,et al.  Tropical Atlantic variability and coupled model climate biases: results from the Tropical Atlantic Climate Experiment (TACE) , 2014, Climate Dynamics.

[95]  M. Satoh,et al.  Intermodel variances of subtropical stratocumulus environments simulated in CMIP5 models , 2014 .

[96]  C. Bretherton,et al.  Global and regional modeling of clouds and aerosols in the marine boundary layer during VOCALS: the VOCA intercomparison , 2014 .

[97]  Ingo Richter,et al.  What controls equatorial Atlantic winds in boreal spring? , 2014, Climate Dynamics.

[98]  S. Bony,et al.  The diurnal cycle of marine cloud feedback in climate models , 2015, Climate Dynamics.

[99]  B. Stevens,et al.  Simulating the role of subtropical stratocumulus clouds in driving Pacific climate variability , 2014 .

[100]  J. Farrar,et al.  Heat and salinity budgets at the Stratus mooring in the southeast Pacific , 2014 .

[101]  Daniel Klocke,et al.  A comparison of two numerical weather prediction methods for diagnosing fast‐physics errors in climate models , 2014 .

[102]  E. Guilyardi,et al.  A systematic approach to identify the sources of tropical SST errors in coupled models using the adjustment of initialised experiments , 2014, Climate Dynamics.

[103]  S. Bony,et al.  Influence of low‐cloud radiative effects on tropical circulation and precipitation , 2014 .

[104]  Taotao Qian,et al.  Stratocumulus Clouds in Southeastern Pacific Simulated by Eight CMIP5–CFMIP Global Climate Models , 2014 .

[105]  B. Santer,et al.  Statistical significance of climate sensitivity predictors obtained by data mining , 2014 .

[106]  M. Iredell,et al.  The NCEP Climate Forecast System Version 2 , 2014 .

[107]  C. Bretherton,et al.  Ocean–Cloud–Atmosphere–Land Interactions in the Southeastern Pacific: The VOCALS Program , 2014 .

[108]  P. Chang,et al.  Diagnosing southeast tropical Atlantic SST and ocean circulation biases in the CMIP5 ensemble , 2014, Climate Dynamics.

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

[110]  B. Blanke,et al.  Short‐term upwelling events at the western African coast related to synoptic atmospheric structures as derived from satellite observations , 2014 .

[111]  Unexpected impacts of the Tropical Pacific array on reanalysis surface meteorology and heat fluxes , 2014 .

[112]  B. Kirtman,et al.  Contributions of the atmosphere–land and ocean–sea ice model components to the tropical Atlantic SST bias in CESM1 , 2015 .

[113]  Hannah M. Christensen,et al.  Does the ECMWF IFS convection parameterization with stochastic physics correctly reproduce relationships between convection and the large-scale state? , 2015 .

[114]  Shian-Jiann Lin,et al.  Simulation and Prediction of Category 4 and 5 Hurricanes in the High-Resolution GFDL HiFLOR Coupled Climate Model , 2015 .

[115]  R. Weller.  Variability and Trends in Surface Meteorology and Air–Sea Fluxes at a Site off Northern Chile , 2015 .

[116]  I. Richter.  Climate model biases in the eastern tropical oceans: causes, impacts and ways forward , 2015 .

[117]  W. Large,et al.  The Benguela upwelling system: Quantifying the sensitivity to resolution and coastal wind representation in a global climate model , 2015 .

[118]  I. Sandu,et al.  Observed and modeled patterns of covariability between low‐level cloudiness and the structure of the trade‐wind layer , 2015 .

[119]  B. Stevens,et al.  The influence of cloud feedbacks on equatorial Atlantic variability , 2015 .

[120]  Vincent E. Larson,et al.  Regional Assessments of Low Clouds against Large-Scale Stability in CAM5 and CAM-CLUBB Using MODIS and ERA-Interim Reanalysis Data , 2015 .

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

[122]  C. Chuang,et al.  An improved hindcast approach for evaluation and diagnosis of physical processes in global climate models , 2015 .

[123]  K. Emanuel,et al.  Hurricanes and Climate: The U.S. CLIVAR Working Group on Hurricanes , 2015 .

[124]  P. Formenti,et al.  Smoke and Clouds above the Southeast Atlantic: Upcoming Field Campaigns Probe Absorbing Aerosol’s Impact on Climate , 2016 .