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esolution with 28 sigma layers in the vertical with the top layer near 3 hPa. Since then theNCEP global forecast system (GFS) atmospheric model (AM) has undergone many majorrevisions and improvements. The current operational CFS (Saha et al., 2006) is based uponthe GFS AM of 2003. Changes included in the operational CFS, after R1, are to theboundary layer vertical diffusion (Hong and Pan 1996), simplified Arakawa-Schubertcumulus convection (Pan and Wu, 1995; Hong and Pan 1998) with cumulus momentummixing and orographic gravity wave drag (Kim and Arakawa 1995, Alpert et al. 1988,1996). The land surface model used in the CFS is based on the two-layer Oregon StateUniversity (OSU) land model (Pan and Mahrt, 1987). In addition, the cloud condensate is aprognostic variable (Moorthi et al. 2001) with a simple cloud microphysicsparameterization (Zhao and Carr 1997, Sundqvist et al., 1989). Both large-scalecondensation and detrainment of cloud water from cumulus convection provide source forcloud condensate. The fractional cloud cover used in the radiation calculation isdiagnostically determined by the predicted cloud condensate based on the approach of Xuand Randall (1996). The CFS also has ozone as a prognostic variable with a simpleparameterization for ozone production and destruction based on ten day meanclimatological data supplied by NASA/GSFC. The shortwave (SW) radiation isparameterized following the NASA approach (Chou et al., 1998, Hou et al., 1996, 2002)and the longwave (LW) radiation following GFDL (Fels and Schwarzkopf, 1975;Schwarzkopf and Fels, 1991). Both radiation parameterizations use random cloud overlapwith shortwave being called every hour and longwave every three hours. This version ofGFS AM produced realistic moisture prediction, which may have contributed to a betterdepiction of no-rain areas and much improved tropical and hurricane track prediction.Subsequent improvements to the GFS AM include fast and accurate LW radiationparameterization based on Rapid Radiative Transfer Model (RRTM) developed atAtmospheric and Environmental Research Inc. (AER, Mlawer et al., 1997). It is alsocoupled to a four-layer Noah land-surface model (Ek et al., 2003). In addition to gravitywavedrag, the model now includes a parameterization of mountain blocking (Alpert, 2004)- 24 -
following the subgrid-scale orographic drag parameterization by Lott and Miller (1997). Atwo-layer sea-ice model (Wu et al., 2005) is also part of the current operational GFS AMand the model now uses the Earth System Modeling Framework (ESMF) base moderncomputer algorithms (Collins et al., 2005). Update of the ozone production and destructionterms is done by using the monthly mean data provided by NRL (McCormack et al., 2006).The horizontal resolution is T382 with 64 hybrid vertical layers with the top layer ~ 0.2 hPa.The vertical structure of the model levels for the 28 sigma layer model (left panels) used inR1 and the 64 layer sigma-pressure hybrid model (right panels) used in the GFS/CFSR isshown in Figure 30 as a cross section at 90E, and as a cross section across North America at40N in Figure 31. The top panels in both figures are plotted as a function of pressure toemphasize the resolution in the troposphere. In the bottom panels, the vertical axis islog(pressure) to emphasize the stratosphere. It can be seen that the new vertical structureadds more resolution in the stratosphere and does not have the topography signature above100 hPa.The version of GFS AM used in the CFSR has additional changes. It now uses enthalpy(CpT) as a prognostic variable in place of virtual temperature (Akmaev and Juang, 2008,Juang 2009) with a generalized hybrid vertical coordinate with sigma-pressure option. Thevertical discretization is based on the generalized hybrid vertical coordinate (Juang, 2005). Italso uses RRTM shortwave radiation with maximum random cloud overlap (Iacono et al.,2000; Clough et al., 2005) and a simple modification of shallow convection/vertical eddydiffusion parameterizations that helps in improving marine stratus prediction off the westcoasts of continents. In the following, some details on some of the newer features of themodel are provided.3.2.1 Upgrades to Radiation ParameterizationThe new LW and SW radiation parameterizations are modified GCM versions(v2.3g_LW and v2.3g_SW) of the Rapid Radiative Transfer Model (RRTM) (hereafterreferred to as RRTMG-LW and RRTMG_SW) adapted from AER Inc. (e.g. Mlawer et al.,1997; Iacono et al., 2000; Clough et al., 2005). In the CFSR implementation we invoke both- 25 -
Page 2 and 3: ABSTRACTThe NCEP Climate Forecast S
Page 4 and 5: 1. IntroductionThe first reanalysis
Page 6 and 7: In this paper we only discuss globa
Page 8 and 9: the reanalysis was halted to addres
Page 10 and 11: online archive of data for reanalys
Page 12 and 13: density MESONET data is included in
Page 14 and 15: The 1B datasets were calibrated usi
Page 16 and 17: MetOp is Europe's first polar-orbit
Page 20 and 21: The third GSI feature enabled in th
Page 22 and 23: the hydrostatic assumption. Soon af
Page 26 and 27: SW and LW radiations at one-hour in
Page 28 and 29: SST data. The other uses AVHRR and
Page 30 and 31: y Gent and McWilliams (1990; see al
Page 32 and 33: from the Global Temperature-Salinit
Page 34 and 35: through the end of the data set in
Page 36 and 37: The passive microwave weather filte
Page 39 and 40: from the sea ice/ocean back to the
Page 41 and 42: weight is assigned to the gauge ana
Page 43 and 44: Stream 6: 1 Jan 1994 to 31 Mar 1999
Page 45 and 46: in the mid 1990’s, the period whe
Page 47: e due to a change over the oceans (
Page 52 and 53: In Figure 49, we show the temporal
Page 54 and 55: distributed in time and space. Desp
Page 56 and 57: forecast model at a lower resolutio
Page 58 and 59: Appendix A: AcronymsAER Atmospheric
Page 60 and 61: ONPCMDIPIRATAPROFLRQBOQuikSCATR1R2R
Page 62 and 63: TMP2M 2m air temperature 24 / 473TM
Page 64 and 65: Appendix C: The Data AccessTo addre
Page 66 and 67: Figure 26 shows the global total bi
Page 68 and 69: Argo Science Team, 2001: The global
Page 70 and 71: Compo, G.P., J.S. Whitaker, and P.D
Page 72 and 73: ozone Mapping and Profiler Suite (O
Page 75 and 76:
Global Forecast System. Manuscript
Page 77 and 78:
and climate models. Atmos. Chem. Ph
Page 79 and 80:
performance Earth system modeling w
Page 81 and 82:
with mesoscale numerical weather pr
Page 83 and 84:
experiments using SSM/I wind speed
Page 85 and 86:
Figure 21: Same as Figure 2, but fo
Page 87 and 88:
Figure 45: The fit of 6-hour foreca
Page 89 and 90:
Figure 1: Diagram illustrating CFSR
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Figure 3: Same as in Figure 2, but
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Page 95 and 96:
Page 97 and 98:
Page 99 and 100:
Page 101 and 102:
Page 103 and 104:
Figure 15: Radiance instruments on
Page 105 and 106:
Figure 17: Same as in Figure 16, bu
Page 107 and 108:
Figure 19: Global average Tb first
Page 109 and 110:
Figure 21: Same as in Figure 16, bu
Page 111:
Figure 23: Comparisons of the SSU b
Page 114 and 115:
Figure 26: The global total bias fo
Page 116 and 117:
Figure 28: The yearly total of trop
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Figure 30: The vertical structure o
Page 120 and 121:
Figure 32: The global number of tem
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Figure 34: The same as Figure 33, b
Page 124 and 125:
Figure 36: Monthly mean Sea ice ext
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Figure 38: 2-meter volumetric soil
Page 128 and 129:
Figure 40: Schematic of the executi
Page 130 and 131:
Figure 42: Yearly averaged Southern
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Figure 44: Monthly mean hourly surf
Page 134 and 135:
Figure 46: Global mean temperature
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Figure 48: Zonal mean total ozone d
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Figure 50: The subsurface temperatu
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Figure 52: Vertical profiles of the
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Figure 54: Zonal surface velocities
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ProgramPREVENTSACQCACAR_CQCCQCCQCVA
Page 146:
Satellite Starting date Ending Date
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