EMIC Intercomparison Project (EMIP–CO2): comparative analysis of EMIC simulations of climate, and of equilibrium and transient responses to atmospheric CO2 doubling

An intercomparison of eight EMICs (Earth system Models of Intermediate Complexity) is carried out to investigate the variation and scatter in the results of simulating (1) the climate characteristics at the prescribed 280 ppm atmosphere CO2 concentration, and (2) the equilibrium and transient responses to CO2 doubling in the atmosphere. The results of the first part of this intercomparison suggest that EMICs are in reasonable agreement with the present-day observational data. The dispersion of the EMIC results by and large falls within the range of results of General Circulation Models (GCMs), which took part in the Atmospheric Model Intercomparison Project (AMIP) and Coupled Model Intercomparison Project, phase 1 (CMIP1). Probable reasons for the observed discrepancies among the EMIC simulations of climate characteristics are analysed. A scenario with gradual increase in CO2 concentration in the atmosphere (1% per year compounded) during the first 70 years followed by a stabilisation at the 560 ppm level during a period longer than 1,500 years is chosen for the second part of this intercomparison. It appears that the EMIC results for the equilibrium and transient responses to CO2 doubling are within the range of the corresponding results of GCMs, which participated in the atmosphere-slab ocean model intercomparison project and Coupled Model Intercomparison Project, phase 2 (CMIP2). In particular EMICs show similar temperature and precipitation changes with comparable magnitudes and scatter across the models as found in the GCMs. The largest scatter in the simulated response of precipitation to CO2 change occurs in the subtropics. Significant differences also appear in the magnitude of sea ice cover reduction. Each of the EMICs participating in the intercomparison exhibits a reduction of the strength of the thermohaline circulation in the North Atlantic under CO2 doubling, with the maximum decrease occurring between 100 and 300 years after the beginning of the transient experiment. After this transient reduction, whose minimum notably varies from model to model, the strength of the thermohaline circulation increases again in each model, slowly rising back to a new equilibrium.

[1]  T.N.L. Patterson,et al.  Atmospheric radiation: I. Theoretical basis: R. M. Goody: Clarendon Press, Oxford: Oxford University Press, London, 1964. xi + 436 pp. 75s , 1965 .

[2]  B. Saltzman,et al.  A PARAMETERIZATION OF THE LARGE-SCALE TRANSIENT EDDY FLUX OF RELATIVE ANGULAR MOMENTUM , 1968 .

[3]  A. Vernekar.  An Equilibrium Solution for the Axially Symmetric Component of the , 1971 .

[4]  Peter H. Stone,et al.  A Simplified Radiative-Dynamical Model for the Static Stability of Rotating Atmospheres , 1972 .

[5]  Barry Saltzman,et al.  Global equilibrium solutions for the zonally averaged macroclimate , 1972 .

[6]  H. Reuter.  Globalbilanzen von klimaelementen: Kessler A. (1968): Ein Beitrag zur allgemeinen Klimatologie der Erde. Berichte des Instituts für Meteorologie und Klimatologie der TU Hannover, Nr. 3. 141 S. 43 Tab., 27 Abb. , 1973 .

[7]  L. Jenne.  Data Sets for Meteorological Research , 1975 .

[8]  L. Jaeger,et al.  Monatskarten des Niederschlags für die ganze Erde , 1976 .

[9]  L. V. Worthington.  On the North Atlantic Circulation , 1977 .

[10]  Barry Saltzman,et al.  A Survey of Statistical-Dynamical Models of the Terrestrial Climate , 1978 .

[11]  G. Ohring,et al.  Some Experiments with a Zonally Averaged Climate Model , 1978 .

[12]  V. Ramanathan,et al.  Increased atmospheric CO2: Zonal and seasonal estimates of the effect on the radiation energy balance and surface temperature , 1979 .

[13]  Alan Robock,et al.  The seasonal cycle of snow cover, sea ice and surface albedo , 1980 .

[14]  S. Hastenrath.  On Meridional Heat Transports in the World Ocean , 1982 .

[15]  A. Oort,et al.  Global atmospheric circulation statistics, 1958-1973 , 1994 .

[16]  J. Peixoto,et al.  The Atmospheric Branch Of The Hydrological Cycle And Climate , 1983 .

[17]  M. Verbitsky,et al.  A new Earth climate model , 1984, Nature.

[18]  L. Talley.  Meridional Heat Transport in the Pacific Ocean , 1984 .

[19]  Jane Hsiung,et al.  Estimates of Global Oceanic Meridional Heat Transport , 1985 .

[20]  L. Jenne,et al.  Global distribution of total cloud cover and cloud type amounts over land , 1986 .

[21]  Ann Henderson-Sellers,et al.  Biosphere-atmosphere Transfer Scheme (BATS) for the NCAR Community Climate Model , 1986 .

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

[23]  P. Jones,et al.  Hemispheric surface air temperature variations: Recent trends and an update to 1987 , 1988 .

[24]  Syukuro Manabe,et al.  Two Stable Equilibria of a Coupled Ocean-Atmosphere Model , 1988 .

[25]  R. Chervin,et al.  Global distribution of total cloud cover and cloud type amounts over the ocean , 1988 .

[26]  C. Ropelewski.  Monitoring large-scale cryosphere/atmosphere interactions , 1989 .

[27]  R. Oglesby,et al.  Extending the EBM: the effect of deep ocean temperature on climate with applications to the cretaceous , 1990 .

[28]  B. Barkstrom,et al.  Seasonal variation of cloud radiative forcing derived from the Earth Radiation Budget Experiment , 1990 .

[29]  André Berger,et al.  Simulation of the last glacial cycle by a coupled, sectorially averaged climate—ice sheet model: 1. The climate model , 1991 .

[30]  James W. Hurrell,et al.  Monthly mean global satellite data sets available in CCM history tape format , 1992 .

[31]  S. Schubert,et al.  Monthly means of selected climate variables for 1985 - 1989 , 1992 .

[32]  Thomas F. Stocker,et al.  A Zonally Averaged, Coupled Ocean-Atmosphere Model for Paleoclimate Studies , 1992 .

[33]  L. Harvey.  A two‐dimensional ocean model for long‐term climatic simulations: Stability and coupling to atmospheric and sea ice models , 1992 .

[34]  J. Bongaarts,et al.  Climate Change: The IPCC Scientific Assessment. , 1992 .

[35]  W. Schmitz,et al.  On the North Atlantic Circulation , 1993 .

[36]  W L Gates,et al.  Uncertainties in Carbon Dioxide Radiative Forcing in Atmospheric General Circulation Models , 1993, Science.

[37]  M. England.  Representing the global-scale water masses in ocean general circulation models , 1993 .

[38]  Klaus Hasselmann,et al.  Mean Circulation of the Hamburg LSG OGCM and Its Sensitivity to the Thermohaline Surface Forcing , 1993 .

[39]  K. Trenberth,et al.  The global heat balance: heat transports in the atmosphere and ocean , 1994 .

[40]  R. Dickson,et al.  The production of North Atlantic Deep Water: Sources, rates, and pathways , 1994 .

[41]  Jürgen Holfort.  Großräumige Zirkulation und meridionale Transporte im Südatlantik , 1994 .

[42]  W. Schmitz.  On the interbasin‐scale thermohaline circulation , 1995 .

[43]  Andreas Schiller,et al.  The mean circulation of the Atlantic Ocean north of 30s determined with the adjoint method applied to an ocean general circulation model , 1995 .

[44]  J. Houghton,et al.  Climate change 1995: the science of climate change. , 1996 .

[45]  S. Rahmstorf.  On the freshwater forcing and transport of the Atlantic thermohaline circulation , 1996 .

[46]  Joseph Alcamo,et al.  Global models meet global policy: How can global and regional modellers connect with environmental policy makers? What has hindered them? What has helped? , 1996 .

[47]  R. Reynolds,et al.  The NCEP/NCAR 40-Year Reanalysis Project , 1996, Renewable Energy.

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

[49]  V. Brovkin,et al.  A continuous climate-vegetation classification for use in climate-biosphere studies , 1997 .

[50]  P. Xie,et al.  Global Precipitation: A 17-Year Monthly Analysis Based on Gauge Observations, Satellite Estimates, and Numerical Model Outputs , 1997 .

[51]  A. Cracknell.  The advanced very high resolution radiometer , 1997 .

[52]  Michael E. Mann.  A study of ocean-atmosphere interaction and low-frequency variability of the climate system , 1998 .

[53]  A. Kattenberg,et al.  ECBILT: a dynamic alternative to mixed boundary conditions in ocean models , 1998 .

[54]  Stefan Rahmstorf,et al.  Simulation of modern and glacial climates with a coupled global model of intermediate complexity , 1998, Nature.

[55]  A. Weaver,et al.  Simulated influence of carbon dioxide, orbital forcing and ice sheets on the climate of the Last Glacial Maximum , 1998, Nature.

[56]  S. M. Marlais,et al.  An Overview of the Results of the Atmospheric Model Intercomparison Project (AMIP I) , 1999 .

[57]  W. Rossow,et al.  Advances in understanding clouds from ISCCP , 1999 .

[58]  Syukuro Manabe,et al.  Are two modes of thermohaline circulation stable , 1999 .

[59]  Stefan Rahmstorf,et al.  Long-Term Global Warming Scenarios Computed with an Efficient Coupled Climate Model , 1999 .

[60]  Henry D. Jacoby,et al.  Integrated Global System Model for Climate Policy Assessment: Feedbacks and Sensitivity Studies , 1999 .

[61]  Victor Brovkin,et al.  CLIMBER-2: a climate system model of intermediate complexity. Part II: model sensitivity , 2001 .

[62]  G. Meehl,et al.  The seasonal cycle in coupled ocean-atmosphere general circulation models , 2000 .

[63]  L. Mysak,et al.  A Simple Coupled Atmosphere–Ocean–Sea Ice–Land Surface Model for Climate and Paleoclimate Studies* , 2000 .

[64]  Victor Brovkin,et al.  CLIMBER-2: a climate system model of intermediate complexity. Part I: model description and performance for present climate , 2000 .

[65]  Carl Wunsch,et al.  Improved estimates of global ocean circulation, heat transport and mixing from hydrographic data , 2000, Nature.

[66]  R. Betts,et al.  Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model , 2000, Nature.

[67]  G. Boer,et al.  CMIP1 evaluation and intercomparison of coupled climate models , 2001 .

[68]  Stabilization of thermohaline circulation by wind-driven and vertical diffusive salt transport , 2001 .

[69]  Marika M. Holland,et al.  The UVic earth system climate model: Model description, climatology, and applications to past, present and future climates , 2001, Data, Models and Analysis.

[70]  A two‐phase response of the Southern Ocean to an increase in greenhouse gas concentrations , 2001 .

[71]  H. Goosse,et al.  Decadal variability in high northern latitudes as simulated by an intermediate-complexity climate model , 2001, Annals of Glaciology.

[72]  Leon D. Rotstayn,et al.  Climate feedbacks in a general circulation model incorporating prognostic clouds , 2001 .

[73]  Andrei P. Sokolov,et al.  An efficient climate model with a 3D ocean and statistical–dynamical atmosphere* , 2002 .

[74]  A. Eliseev,et al.  Dependence of Permafrost Conditions on Global Warming: Comparison of Models, Scenarios, and Paleoclimatic Reconstructions , 2002 .

[75]  A. Weaver,et al.  Forcing of the deep ocean circulation in simulations of the Last Glacial Maximum , 2002 .

[76]  A. Eliseev,et al.  Estimation of Global and Regional Climate Changes during the 19th-21st Centuries on the Basis of the IAP RAS Model with Consideration for Anthropogenic Forcing , 2002 .

[77]  L. Mysak,et al.  Simulation of the last glacial inception and rapid ice sheet growth in the McGill Paleoclimate Model , 2002 .

[78]  T. Fichefet,et al.  Modeling the effect of freshwater pulses on the early Holocene climate: the influence of high-frequency climate variability , 2002 .

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

[80]  T. Fichefet,et al.  Climate evolution during the Holocene: a study with an Earth system model of intermediate complexity , 2002 .

[81]  Frank Lunkeit,et al.  Earth system models of intermediate complexity: closing the gap in the spectrum of climate system models , 2002 .

[82]  Seong-Joong Kim,et al.  A coupled climate model simulation of the Last Glacial Maximum, Part 1: transient multi-decadal response , 2002 .

[83]  Katrin J. Meissner,et al.  The role of land surface dynamics in glacial inception: a study with the UVic Earth System Model , 2003 .

[84]  K. Taylor,et al.  An overview of results from the Coupled Model Intercomparison Project , 2003 .

[85]  Paul E. Robbins,et al.  Data-Based Meridional Overturning Streamfunctions for the Global Ocean , 2003 .

[86]  H. Damon Matthews,et al.  Radiative forcing of climate by historical land cover change , 2003 .

[87]  Amplitude-Phase Characteristics of the Annual Cycle of Surface Air Temperature in the Northern Hemisphere , 2003 .

[88]  W. Rossow,et al.  International satellite cloud climatology project (ISCCP): cd documentation , 2003 .

[89]  A. Weaver,et al.  Sensitivity of the inorganic ocean carbon cycle to future climate warming in the UVic coupled model , 2004 .

[90]  Stefan Rahmstorf,et al.  Dynamic sea level changes following changes in the thermohaline circulation , 2005 .

[91]  Climate Changes and Their Assessment Based on the IAP RAS Global Model Simulations , 2005 .

[92]  S. Rahmstorf,et al.  The earth system model of intermediate complexity CLIMBER-3α. Part I: description and performance for present-day conditions , 2005 .

[93]  T. Haar,et al.  Climatology of radiation budget measurements from satellites , 2007 .