NCEP/NCAR Reanalysis Sigma Level Data - Monthly Means

Monthly means and statistics computed from the 4-times daily data.

SOURCE: Data Support Section Dataset ds090.0
	From the 'grbsanl' file. T62 gaussian grid.

FORMAT: CCM2 History Tape (Feb 1979 - Nov 1996)
          netCDF (Dec 1996 - current)

GRID:   Global - T63 Gaussian (192 x 96)

LEVELS: (28 Sigma levels)
	.9950,.9821,.9644,.9425,.9159,.8838,.8458,.8014,.7508,.6943,
	.6329,.5681,.5017,.4357,.3720,.3125,.2582,.2101,.1682,.1326,
	.1028,.0782,.0580,.0418,.0288,.0183,.0101,.0027

FIELDS: Description                     Name    Units   Levels
        ---------------------------------------------------------
	Zonal Wind Component		U	m/s	all 
	Meridional Wind Component	V	m/s	all
	Relative Vorticity		VOR	1/s	all
	Relative Divergence		DIV	1/s	all
	Temperature			T	K	all
	Specific Humidity		Q	kg/kg	all - though values above 0.1682 do not appear to be reliable
	Relative Humidity		RH	percent	all - though values above 0.1682 do not appear to be reliable
        Vertical Pressure Velocity      OMEGA   Pa/s    all
        Geopotential Height             ZA      m       all
	Surface Pressure		PS	Pa	surface
	Sea Level Pressure		SLP	Pa	surface
	Surface Geopotential		PHIS	m^2/s^2	surface
	Horizonal Wind Speed		VMAG	m/s	all
	Specific Kinetic Energy		KE	J/kg	all

      Tendencies: 
	of Zonal Wind Component		DU	m/s/s	all 
	of Meridional Wind Component	DV	m/s/s	all
	of Temperature			DT	K/s	all
	of Specific Humidity		DQ	kg/kg/s	all - though values above 0.1682 do not appear to be reliable
	of Surface Pressure		DPS	Pa/s	surface
	
      Variances and Covariances:
			U,U		UUP
			V,V		VVP
			OMEGA,OMEGA	WWP
			T,T		TTP
			Q,Q		QQP
			PS,PS		PSP
			VOR,VOR		VORP
			DIV,DIV		DIVP
			ZA,ZA		ZZP
			SLP,SLP		SLPP
			RH,RH		RHP

			U,T		UTP
			V,T		VTP
			U,Q		UQP
			V,Q		VQP
			U,ZA		UZP
			V,ZA		VZP
			U,V		UVP
			U,VOR		UVORP
			V,VOR		VVORP
			U,OMEGA		UWP
			V,OMEGA		VWP
			OMEGA,Q		WQP
			OMEGA,T		WTP
			OMEGA,ZA	WZP


SPECIAL NOTE:  Beginning December 1996 the data files also include
     variances and covariances for each time of day (00z, 06z, 12z,
     and 18z) in addition to the total variances and covariances.

TIMES:  One mean per month.

MSS Directory: /CA/NMC/SIGMA/
               /CA/NMC/SIGMA/UPDATE/

Filename: T63yymmM  where yy=year, mm=month
	One month per volume
	e.g. T638501M for January 1985. 
        Newer netCDF files (from Dec 1996++) include a ".nc"
          file tag and a four-digit year (e.g. T63199812M.nc)

Current holdings: February 1979 - December 2007

Update(Sept 2004) Monthly mean NCEP Reanalysis sigma level data 
        from March 1997 through December 2001 has been rerun and is 
	now available in netCDF format. 
        These files can be retrieved from the MSS directory: 
         /CA/NMC/SIGMA/UPDATE/. 
        Filenames follow the convention(s) above.

Update(December 2004) 2002 Data has been processed and is
        available from the MSS directory:
         /CA/NMC/SIGMA/UPDATE/.

Update(February 2005) 2003 Data has been processed and is
        available from the MSS directory:
         /CA/NMC/SIGMA/UPDATE/.
                                                                                
Update(September 2005) 2004 Data has been processed and is
        available from the MSS directory:
         /CA/NMC/SIGMA/UPDATE/.

Update(April 2006) 2005 Data has been processed and is
        available from the MSS directory:
         /CA/NMC/SIGMA/UPDATE/.
                   
Update(October 2007) 2006 Data has been processed and is
        available from the MSS directory:
         /CA/NMC/SIGMA/UPDATE/.    

Update(August 2008) 2007 Data has been processed and is
        available from the MSS directory:
         /CA/NMC/SIGMA/UPDATE/.

Related Software:

• Code to convert CCM format to NetCDF (ccm2nc)

Other Products Related to this Dataset:

• Daily Data

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