The NCEP Climate Forecast System Reanalysis - NOAA National ...

More documents

Recommendations

Info

algorithms to determine whether an area is either snow covered or snow free. IMS data isavailable at 23 km resolution starting February 1997, and at 4 km resolution startingFebruary 2004.7.3 The Land Surface AnalysisThe land surface model (LSM) used in CFSR is the Noah LSM (Ek et al., 2003), whichwas implemented in the NCEP Global Forecast System (GFS) for operational mediumrangeweather forecast in 2005. Within CFSR, Noah is implemented in both the fullycoupledland-atmosphere-ocean model to make the first guess land-atmospheresimulation, and in the semi-coupled CFSR Global Land Data Assimilation System(GLDAS) to perform land surface analysis. The semi-coupled GLDAS is forced with theCFSR atmospheric data assimilation output and observed precipitation. GLDAS interactswith the reanalysis once per day, instead of every time step as in its fully-coupledcounterpart. The NASA Land Information System infrastructure (LIS, Peters-Lidard et al.,2007) is employed to execute CFSR/GLDAS. This semi-coupled GLDAS/LIS has beenconfigured with the identical setup as in the fully-coupled CFS/Noah, including the sameT382 global gaussian grid specification, land-sea mask, terrain height, soil and vegetationclasses, and soil and vegetation parameters.Compared to R1 and R2, this CFSR GLDAS/LIS uses observed global precipitationanalyses as direct forcing to the land surface analysis, rather than the typical reanalysisapproach of using precipitation from the assimilating background atmospheric model(R1), or using observed precipitation to “nudge” soil moisture (R2). The CPC pentadCMAP analysis and daily gauge analysis are used. Considering global gauge distributionand the strength of the satellite-based precipitation analysis, an optimal precipitationforcing is generated by blending the two precipitation analyses with the CFSRbackground 6-hourly GDAS precipitation. The blending function is latitude-dependentthat favors the satellite-based CMAP analysis in the tropics, the gauge analysis in midlatitudes,and the model precipitation in high-latitudes. Moreover, an even heavier- 40 -
weight is assigned to the gauge analysis in regions of dense gauge network, namely,North America, Western Europe, and Australia.Every LSM is characterized by a specific equilibrium land surface climatology. Thatequilibrium can be quite different from model to model. The spin-up time required todrive an LSM to its equilibrium is much longer than for the troposphere. Experimentshave estimated that at least 3 to 5 years might be required to spin-up the 4-layer CFSRNoah land surface states, if initialized with a previous global reanalysis in which adifferent LSM (for instance, the 2-layer Oregon State University OSU/LSM (Pan andMahrt, 1987) in R1/R2) was used. Since the same Noah LSM has been included in theoperational GFS since 2005, the 2-year (2006 and 2007) averaged GFS land surfacestates for each given calendar day of the start dates of the CFSR streams was used as landinitial conditions. An additional 12-month spin-up period was executed prior to theCFSR production.The CFSR GLDAS/LIS is executed once over each 24-hour land surface analysis cycle at0Z model time, instead of 6-hour cycles of the atmospheric analysis GDAS and theoceanic analysis GODAS. The reason is that GLDAS/LIS is anchored to the daily gaugeprecipitation analysis; hence the gain of executing on a 6-hour cycle is limited. The Noahsimulation is made for the past 24 hours using GDAS atmospheric forcing and theblended precipitation forcing. After completion of the 24-hour execution, the simulatedsoil moisture and soil temperature of all four Noah soil layers are inserted into the CFSR0Z restart file (the so called “surface file”) as the land surface initial conditions for thenext CFSR 0Z cycle.The IMS and SNODEP data were used to produce daily analyses of physical snow depthon the model physics grid over land. The data were horizontally interpolated using a“budget” method (Accadia et al. 2003) in order to preserve the total water volume. In thesouthern hemisphere, and globally prior to February 1997, these analyses were createdsolely from the SNODEP data. In the northern hemisphere starting February 1997, acombination of SNODEP and IMS was used. IMS data was introduced because it more- 41 -
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 24 and 25: esolution with 28 sigma layers in t
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: from the sea ice/ocean back to the
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
Page 91 and 92:
Figure 3: Same as in Figure 2, but
Page 93 and 94:
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
Page 118 and 119:
Figure 30: The vertical structure o
Page 120 and 121:
Figure 32: The global number of tem
Page 122 and 123:
Figure 34: The same as Figure 33, b
Page 124 and 125:
Figure 36: Monthly mean Sea ice ext
Page 126 and 127:
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
Page 132 and 133:
Figure 44: Monthly mean hourly surf
Page 134 and 135:
Figure 46: Global mean temperature
Page 136 and 137:
Figure 48: Zonal mean total ozone d
Page 138 and 139:
Figure 50: The subsurface temperatu
Page 140 and 141:
Figure 52: Vertical profiles of the
Page 142 and 143:
Figure 54: Zonal surface velocities
Page 144 and 145:
ProgramPREVENTSACQCACAR_CQCCQCCQCVA
Page 146:
Satellite Starting date Ending Date
show all

The NCEP Climate Forecast System Reanalysis - NOAA National ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?