The authors would like to recognize all the scientists and technical staff of the Global Climate and Weather Modeling Branch of EMC for their hard work and dedication to the development of the GFS. We would also like to extend our thanks to the scientists at GFDL for their work in developing the MOM4. George Vandenberghe, Carolyn Pasti, and Julia Zhu are recognized for their critical support in the smooth running of the CFSv2 retrospective forecasts and the operational implementation of the CFSv2. We also thank Ben Kyger, Dan Starosta, Christine Magee, and Becky Cosgrove from the NCEP Central Operations (NCO) for the timely operational implementation of the CFSv2 in March 2011.
Barker, H. W., , R. Pincus, , and J.-J. Morcrette, 2002: The Monte Carlo independent column approximation: Application within large-scale models. Extended Abstracts, GCSS-ARM Workshop on the Representation of Cloud Systems in Large-Scale Models, Kananaskis, AB, Canada, GEWEX, 1–10.
Behringer, D. W., 2007: The Global Ocean Data Assimilation System at NCEP. Preprints, 11th Symp. on Integrated Observing and Assimilation Systems for Atmosphere, Oceans and Land Surface, San Antonio, TX, Amer. Meteor. Soc., 14–18.
Cai, M., , C.-S. Shin, , H. M. van den Dool, , W. Wang, , S. Saha, , and A. Kumar, 2009: The role of long-term trends in seasonal predictions: Implication of global warming in the NCEP CFS. Wea. Forecasting, 24, 965–973.
Chun, H.-Y., , and J.-J. Baik, 1998: Momentum flux by thermally induced internal gravity wave and its approximation for large-scale models. J. Atmos. Sci., 55, 3299–3310.
Clough, S. A., , M. W. Shephard, , E. J. Mlawer, , J. S. Delamere, , M. J. Iacono, , K. Cady-Pereira, , S. Boukabara, , and P. D. Brown, 2005: Atmospheric radiative transfer modeling: A summary of the AER codes. J. Quant. Spectrosc. Radiat. Transfer, 91, 233–244.
Ek, M., , K. E. Mitchell, , Y. Lin, , E. Rogers, , P. Grunmann, , V. Koren, , G. Gayno, , and J. D. Tarpley, 2003: Implementation of Noah land-surface model advances in the NCEP operational mesoscale Eta model. J. Geophys. Res., 108, 8851, doi:10.1029/2002JD003296.
Fan, Y., , and H. van den Dool, 2008: A global monthly land surface air temperature analysis for 1948–present. J. Geophys. Res., 113, D01103, doi:10.1029/2007JD008470.
Hou, Y., , S. Moorthi, , and K. Campana, 2002: Parameterization of Solar Radiation Transfer in the NCEP Models. NCEP Office Note 441, 46 pp. [Available online at http://www.emc.ncep.noaa.gov/officenotes/newernotes/on441.pdf.]
Iacono, M. J., , E. J. Mlawer, , S. A. Clough, , and J.-J. Morcrette, 2000: Impact of an improved longwave radiation model, RRTM, on the energy budget and thermodynamic properties of the NCAR Community Climate Model, CCM3. J. Geophys. Res., 105, 14 873–14 890.
Kanamitsu, M., , W. Ebisuzaki, , J. Woollen, , S. K. Yang, , J. J. Hnilo, , M. Fiorino, , and G. L. Potter, 2002: NCEP–DOE AMIP-II Reanalysis (R-2). Bull. Amer. Meteor. Soc., 83, 1631–1643.
Kirtman, B. P., and Coauthors, 2014: The North American Multi-Model Ensemble (NMME): Phase-1, seasonal-to-interannual prediction; phase-2, toward developing intraseasonal prediction. Bull. Amer. Meteor. Soc., in press.
Kumar, A., , M. Chen, , L. Zhang, , W. Wang, , Y. Xue, , C. Wen, , L. Marx, , and B. Huang, 2012: An analysis of the nonstationarity in the bias of sea surface temperature forecasts for the NCEP Climate Forecast System (CFS) version 2. Mon. Wea. Rev.,140, 3003–3016.
Lin, H., , G. Brunet, , and J. Derome, 2008: Forecast skill of the Madden–Julian oscillation in two Canadian atmospheric models. Mon. Wea. Rev., 136, 4130–4149.
Mitchell, K. E., , H. Wei, , S. Lu, , G. Gayno, and J. Meng, 2005: NCEP implements major upgrade to its medium-range global forecast system, including land-surface component. GEWEX Newsletter, No. 15 (4), International GEWEX Project Office, Silver Spring, MD, 8–9.
Mlawer, E. J., , S. J. Taubman, , P. D. Brown, , M. J. Iacono, and S. A. Clough, 1997: Radiative transfer for inhomogeneous atmosphere: RRTM, a validated correlated-k model for the longwave. J. Geophys. Res.,102 (D14), 16 663–16 683.
Moorthi, S., , R. Sun, , H. Xia, , and C. R. Mechoso, 2010: Southeast Pacific low-cloud simulation in the NCEP GFS: Role of vertical mixing and shallow convection. NCEP Office Note 463, 28 pp. [Available online at http://www.emc.ncep.noaa.gov/officenotes/FullTOC.html#2000.]
Penland, C., , and S. Saha, 2006: El Niño in the Climate Forecast System: T62 vs T126. Proc. 30th Climate Diagnostics and Prediction Workshop, State College, PA, NOAA, P1.3. [Available online at http://www.cpc.ncep.noaa.gov/products/outreach/proceedings/cdw30_proceedings/P1.3.pdf.]
Pincus, R., , H. W. Barker, , and J.-J. Morcrette, 2003: A fast, flexible, approximate technique for computing radiative transfer in inhomogeneous cloud fields. J. Geophys. Res., 108, 4376, doi:10.1029/2002JD003322.
Reynolds, R. W., , N. A. Raynor, , T. M. Smith, , D. C. Stokes, , and W. Wang, 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15, 1609–1625.
Reynolds, R. W., , T. M. Smith, , C. Liu, , D. B. Chelton, , K. S. Casey, , and M. G. Schlax, 2007: Daily high-resolution blended analyses for sea surface temperature. J. Climate, 20, 5473–5496.
Sato, M., , J. E. Hansen, , M. P. McCormick, , and J. B. Pollack, 1993: Stratospheric aerosol optical depths, 1850–1990. J. Geophys. Res., 98, 22 987–22 994.
Sun, R., , S. Moorthi, , and C. R. Mechoso, 2010: Simulation of low clouds in the southeast Pacific by the NCEP GFS: Sensitivity to vertical mixing. Atmos. Chem. Phys., 10, 12 261–12 272.
Van den Dool, H. M., cited 2011: Reconstruction of the solar constant back to 1750. [Available online at http://www.cpc.ncep.noaa.gov/products/people/wd51hd/vddoolpubs/solar_reconstruction.doc.]
Vitart, F., , S. Woolnough, , M. A. Balmaseda, , and A. M. Tompkins, 2007: Monthly forecast of the Madden–Julian oscillation using a coupled GCM. Mon. Wea. Rev.,135, 2700–2715.
Wheeler, M., , and H. H. Hendon, 2004: An all-season real-time multivariate MJO index: Development of an index for monitoring and prediction. Mon. Wea. Rev., 132, 1917–1932.
Zhang, Q., , and H. van den Dool, 2012: Relative merit of model improvement versus availability of retrospective forecasts: The case of Climate Forecast System MJO prediction. Wea. Forecasting,27, 1045–1051.
This paper describes the CFS reanalysis data from 1979–2010 and the CFSv2 retrospective data from 1982–2010. However, both datasets are being updated in real-time operations at NCEP.
CO2 is not increased during a particular hindcast, but through the initial conditions; for example, hindcasts for 2010 are run at much higher CO2 (which is maintained throughout the forecast) than for hindcasts in 1982. In CFSv1, a single CO2 value valid in 1988 was used for all years.
We should point out that what we call the International Multimodel Ensembles (IMME) has its counterpart called Eurosip in Europe. CFSv2 has been included as a member in the Eurosip ensemble, which consists of the European Centre for Medium-Range Weather Forecasts (ECMWF), Met Office (UKMO), and Météo France.