EC-Earth V2.2: description and validation of a new seamless earth system prediction model

EC-Earth, a new Earth system model based on the operational seasonal forecast system of the European Centre for Medium-Range Weather Forecasts (ECMWF), is presented. The performance of version 2.2 (V2.2) of the model is compared to observations, reanalysis data and other coupled atmosphere–ocean-sea ice models. The large-scale physical characteristics of the atmosphere, ocean and sea ice are well simulated. When compared to other coupled models with similar complexity, the model performs well in simulating tropospheric fields and dynamic variables, and performs less in simulating surface temperature and fluxes. The surface temperatures are too cold, with the exception of the Southern Ocean region and parts of the Northern Hemisphere extratropics. The main patterns of interannual climate variability are well represented. Experiments with enhanced CO2 concentrations show well-known responses of Arctic amplification, land-sea contrasts, tropospheric warming and stratospheric cooling. The global climate sensitivity of the current version of EC-Earth is slightly less than 1 K/(W m−2). An intensification of the hydrological cycle is found and strong regional changes in precipitation, affecting monsoon characteristics. The results show that a coupled model based on an operational seasonal prediction system can be used for climate studies, supporting emerging seamless prediction strategies.

[1]  P. Gent,et al.  Isopycnal mixing in ocean circulation models , 1990 .

[2]  A. K. Betts,et al.  O ine validation of the ERA 40 surface scheme , 2000 .

[3]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[4]  W. Hibler.  A Dynamic Thermodynamic Sea Ice Model , 1979 .

[5]  Fei-Fei Jin,et al.  An Equatorial Ocean Recharge Paradigm for ENSO. Part I: Conceptual Model , 1997 .

[6]  A. Sterl,et al.  EC-Earth A Seamless earth-System Prediction Approach in Action , 2010 .

[7]  Elizabeth C. Kent,et al.  Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century , 2003 .

[8]  Martin Köhler,et al.  Advances in simulating atmospheric variability with the ECMWF model: From synoptic to decadal time‐scales , 2008 .

[9]  H. V. D. Dool,et al.  A global monthly land surface air temperature analysis for 1948-present , 2008 .

[10]  Kelly Elder,et al.  An Improved Snow Scheme for the ECMWF Land Surface Model: Description and Offline Validation , 2010 .

[11]  James W. Hurrell,et al.  The North Atlantic Oscillation: Climatic Significance and Environmental Impact , 2003 .

[12]  G. J. van Oldenborgh,et al.  Large-scale atmospheric circulation biases and changes in global climate model simulations and their importance for climate change in Central Europe , 2006 .

[13]  Peter Bergamaschi,et al.  The global chemistry transport model TM5: description and evaluation of the tropospheric chemistry version 3.0 , 2010 .

[14]  G. P. Kyle,et al.  Global and regional evolution of short-lived radiatively-active gases and aerosols in the Representative Concentration Pathways , 2011 .

[15]  A dampened land use change climate response towards the tropics , 2011 .

[16]  T. Reichler,et al.  How Well Do Coupled Models Simulate Today's Climate? , 2008 .

[17]  Wilco Hazeleger,et al.  Arctic winter warming amplified by the thermal inversion and consequent low infrared cooling to space , 2011 .

[18]  Antonio J. Busalacchi,et al.  The Tropical Ocean‐Global Atmosphere observing system: A decade of progress , 1998 .

[19]  B. Soden,et al.  Robust Responses of the Hydrological Cycle to Global Warming , 2006 .

[20]  J. Wallace,et al.  Teleconnections in the Geopotential Height Field during the Northern Hemisphere Winter , 1981 .

[21]  William E. Johns,et al.  Temporal Variability of the Atlantic Meridional Overturning Circulation at 26.5°N , 2007, Science.

[22]  David C. Douglas,et al.  Fluctuating Arctic Sea Ice Thickness Changes Estimated by an In Situ Learned and Empirically Forced Neural Network Model , 2008 .

[23]  M. Maqueda,et al.  Sensitivity of a global sea ice model to the treatment of ice thermodynamics and dynamics , 1997 .

[24]  Philippe Gaspar,et al.  A simple eddy kinetic energy model for simulations of the oceanic vertical mixing: Tests at Station Papa and long-term upper ocean study site , 1990 .

[25]  Andrew P. Morse,et al.  DEVELOPMENT OF A EUROPEAN MULTIMODEL ENSEMBLE SYSTEM FOR SEASONAL-TO-INTERANNUAL PREDICTION (DEMETER) , 2004 .

[26]  D. Stephenson,et al.  The North Atlantic Oscillation in coupled climate models: a CMIP1 evaluation , 2003 .

[27]  Jonathan M. Gregory,et al.  Mechanisms for the land/sea warming contrast exhibited by simulations of climate change , 2008 .

[28]  A. Sterl,et al.  The ERA‐40 re‐analysis , 2005 .

[29]  Veronika Eyring,et al.  A Summary of the CMIP5 Experiment Design , 2010 .

[30]  Johannes Quaas,et al.  Model intercomparison of indirect aerosol effects , 2006 .

[31]  Jonathan M. Gregory,et al.  A new method for diagnosing radiative forcing and climate sensitivity , 2004 .

[32]  G. Madec.  NEMO ocean engine , 2008 .

[33]  M. Holland,et al.  Polar amplification of climate change in coupled models , 2003 .

[34]  Reto Knutti,et al.  The equilibrium sensitivity of the Earth's temperature to radiation changes , 2008 .

[35]  M. Rodwell,et al.  Toward Seamless Prediction: Calibration of Climate Change Projections Using Seasonal Forecasts , 2008 .

[36]  R. Haarsma,et al.  Drier Mediterranean soils due to greenhouse warming bring easterly winds over summertime central Europe , 2009 .

[37]  A. Semtner.  A MODEL FOR THE THERMODYNAMIC GROWTH OF SEA ICE IN NUMERICAL INVESTIGATIONS OF CLIMATE , 1975 .

[38]  S. Zalesak.  Fully multidimensional flux-corrected transport algorithms for fluids , 1979 .

[39]  K. Trenberth,et al.  Estimates of Meridional Atmosphere and Ocean Heat Transports , 2001 .

[40]  J. Wallace,et al.  Annular Modes in the Extratropical Circulation. Part I: Month-to-Month Variability* , 2000 .

[41]  G. Shutts,et al.  Stochastic parametrization of multiscale processes using a dual-grid approach , 2008, Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[42]  P. A. Arkin,et al.  Global monthly precipitation: A 7-year analysis using gauge observations, satellite estimates and model predictions , 1996 .

[43]  Balaji Rajagopalan,et al.  Analyses of global sea surface temperature 1856–1991 , 1998 .

[44]  B. Hurk,et al.  A Revised Hydrology for the ECMWF Model: Verification from Field Site to Terrestrial Water Storage and Impact in the Integrated Forecast System , 2009 .

[45]  J. Houghton,et al.  Climate change 2001 : the scientific basis , 2001 .

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

[47]  John F. B. Mitchell,et al.  THE WCRP CMIP3 Multimodel Dataset: A New Era in Climate Change Research , 2007 .

[48]  U. Lohmann,et al.  What governs the spread in shortwave forcings in the transient IPCC AR4 models? , 2009 .

[49]  Timothy P. Boyer,et al.  World ocean atlas 2001 : objective analyses, data statistics, and figures : CD-ROM documentation , 2002 .

[50]  K. Trenberth,et al.  Earth's annual global mean energy budget , 1997 .

[51]  M. Winton.  Surface Albedo Feedback Estimates for the AR4 Climate Models , 2006 .

[52]  James W. Hurrell,et al.  The North Atlantic Oscillation: Climate Significance and Environmental Impact , 2003 .

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

[54]  J. Wallace,et al.  ENSO-like Interdecadal Variability: 1900–93 , 1997 .

[55]  R. Haarsma,et al.  Sensitivity of tropical Atlantic climate to mixing in a coupled ocean–atmosphere model , 2005 .

[56]  J. David Neelin,et al.  ENSO theory , 1998 .

[57]  M. Webb,et al.  Quantification of modelling uncertainties in a large ensemble of climate change simulations , 2004, Nature.

[58]  B. Hurk,et al.  The Torne-Kalix PILPS 2(e) experiment as a test bed for modifications to the ECMWF land surface scheme , 2003 .

[59]  W. Hazeleger,et al.  Global surface cooling: The atmospheric fast feedback response to a collapse of the thermohaline circulation , 2009 .