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**CFS Retrospective Forecasts :**

**Time Series of Monthly Means Data**

**in the EMC/NCEP CFS public server**

**Catherine Thiaw and Suranjana Saha**

Environmental Modeling Center, NCEP/NWS/NOAA

Email for all correspondence : <cfs@noaa.gov>

Revised: September 27, 2006

Monthly mean time series of many commonly used variables from the
retrospective forecasts of the NCEP Climate Forecast System (Saha et al,
2005) have been archived to the EMC CFS public server in GRIB format.
These include forecast monthly means of all 15 members initialized in
each calendar month of the year, covering a period of 24 years from
1981-2004. They also include an ensemble mean of the 15 members, and the
verifying observations (from Reanalysis-2 and GODAS, as well as
Xie-Arkin for precipitation). The forecast lead is zero to 8 months.

[Where to find the time series of monthly mean data ?]{.underline}

The time series for each variable can be accessed by 2 methods :

-   by an **anonymous ftp login into cfs.ncep.noaa.gov, then go to the
    /pub/cfs/monthly directory**

-   by downloading the data from a web browser :
    [http://cfs.ncep.noaa.gov/cfs/monthly](http://nomad6.ncep.noaa.gov/cfs/monthly)

**IMPORTANT** : An update of the 2004 data for all 15 initial states per
month is available. The data is in the same format with "2004" specified
in the name of the files:

variable.mxx.month.2004.data

variable.ensm.month.2004.data

variable.obs.month.2004.data

***Please be advised that we will not be providing any more
retrospective forecasts beyond 2005. For maintaining a continuing
history of the CFS, please start downloading the two operational CFS
forecasts for your archives as soon as possible***

**[References]{.underline}**

S. Saha, S. Nadiga, C. Thiaw, J. Wang, W. Wang, Q. Zhang, H. M. van den
Dool, H.-L. Pan, S. Moorthi, D. Behringer, D. Stokes, M. Pena, S. Lord,
G. White, W. Ebisuzaki, P. Peng, P. Xie , 2006 : The NCEP Climate
Forecast System. Journal of Climate, Vol. 19, No. 15, pages 3483-3517.

*THIS DATA IS NOT CALIBRATED (BIAS CORRECTED) IN ANYWAY. IT IS STRONGLY
RECOMMENDED THAT USERS PERFORM SOME CALIBRATION ON THE FORECAST DATA
BEFORE USING IT IN A PREDICTIVE ENVIRONMENT.*

[List of variables saved in monthly mean time series
format:]{.underline}

  ------------------------- --------------------- -----------------------
  144 x 73 (2.5 degrees)    192 x 94 (T62         180 x 139 (2x1 degree)
                            Gaussian Grid)        

  **z1000**: geopotential   **bcld** : boundary   **sst**: sea surface
  at 1000 hPa               layer cloud           temperature

  **z850**: geopotential at **ccld**: convective  **slh**: sea level
  850 hPa                   cloud                 height

  **z700**: geopotential at **lcld**: low level   **dt2.5c**: depth of
  700 hPa                   cloud                 the 2.5C isotherm in
                                                  the ocean

  **z500**: geopotential at **hcld**: high level  **dt5c**: depth of the
  500 hPa                   cloud                 5C isotherm in the
                                                  ocean

  **z200**: geopotential at **mcld**: middle      **dt2.5c**: depth of
  200 hPa                   level cloud           the 2.5C isotherm in
                                                  the ocean

  **tmp850**: temperature   **tcld**: total cloud **dt5c**: depth of the
  at 850 hPa                                      5C isotherm in the
                                                  ocean

  **tmp500**: temperature   **cprat**: convective **dt10c**: depth of the
  at 500 hPa                precipitation. rate   10C isotherm in the
                                                  ocean

  **tmp200**: temperature   **dlwsfc**: downward  **dt15c**: depth of the
  at 200 hPa                long wave radiation   15C isotherm in the
                            at the surface        ocean

  **wnd850**: zonal and     **dswsfc**: downward  **dt20c**: depth of the
  meridional winds at 850   short wave radiation  20C isotherm in the
  hPa                       at the surface        ocean

  **wnd700**: zonal and     **gflux**: ground     **dt25c**: depth of the
  meridional winds at 700   heat flux             25C isotherm in the
  hPa                                             ocean

  **wnd60**0: zonal and     **hpbl**: height of   **dt28c**: depth of the
  meridional winds at 600   the planetary         28C isotherm in the
  hPa                       boundary layer        ocean

  **wnd500**: zonal and     **tmax**: maximum     **oceansild**: ocean
  meridional winds at 500   temperature at        surface isothermal
  hPa                       2meters               layer depth

  **wnd200**: zonal and     **tmin**: minimum     **oceanmld**: ocean
  meridional winds at 200   temperature at        mixed layer depth
  hPa                       2meters               

  **sfvp850**: stream       **pevpr**: potential  **oceanheat**: ocean
  function and velocity     evaporation rate      heat content
  potential at 850 hPa                            

  **sfvp200**: stream       **pwat**:             **oceantchp**: ocean
  function and velocity     precipitable water    tropical cyclone heat
  potential at 200 hPa                            potential

  **vw500**: vertical       **watr**: ground      
  velocity at 500 hPa       water runoff          

  **mslp**: mean seal level **shtfl**: sensible   
  pressure                  heat flux             

  **qbo.month**: zonal wind **weasd**: snow depth 
  at 100,70,50,30,20 and 10                       
  hPa, where month is                             
  jan,feb,mar..,etc.                              

                            **soilw**: soil       
                            moisture (2-layers)   

                            **soilt**: soil       
                            temperature           
                            (2-layers)            

                            **spfh2m**: specific  
                            humidity at 2meters   

                            **ps**: surface       
                            pressure              

                            **tmp2m**:            
                            temperature at        
                            2meters               

                            **tmpsfc**: surface   
                            temperature           

                            **prate**: total      
                            precipitation rate    

                            **ulwtop**: upward    
                            long wave radiation   
                            at the top of the atm 

                            **ulwsfc**: upward    
                            long wave radiation   
                            at the surface        

                            **uswtop**: upward    
                            short wave radiation  
                            at the top of the atm 

                            **uswsfc**: upward    
                            short wave radiation  
                            at the surface        

                            **wnd10m**: zonal and 
                            meridional wind at    
                            10meters              

                            **wndstr**: zonal and 
                            meridional wind       
                            stress at the surface 

                            **lhtfl**: latent     
                            heat flux             
  ------------------------- --------------------- -----------------------

[How to read the monthly mean data :]{.underline}

Each **variable** (example: z500) is a subdirectory containing files in
the following format:

variable.mxx.month.data

variable.ensm.month.data

variable.obs.month.data

where xx represents the 15 members forecast: 01, 02, 03, 09, 10, 11, 12,
13, 14, 15 and month is the month when the forecast is made (zero lead)

Example of *members for Sep 1990* :

m01-m05 : 9 - 13 Aug 1990

m06-m10 : 19 - 23 Aug 1990

m11-m12 : 30 - 31 Aug 1990 (last 2 days of the previous month)

m13-m15 : 1 - 3 Sep 1990

ensm : Ensemble mean of all 15 members

obs : Reanalysis-2 for pgb and flx files; Xie-Arkin for total
precipitation

and GODAS for sst and slh.

Example for *geopotential time series at 500 hPa :*

In the server : /pub/cfs/monthly/z500.cfs.data.tar

Contains 17 sets of files for each calendar month (total of 204 files)

*Example for September* :

1\. z500.m01.sep.cfs.data : member 1

2\. z500.m02.sep.cfs.data : member 2

3-14. z500.m..... : etc., etc.

15\. z500.m15.sep.cfs.data : member 15

16\. z500.ensm.sep.cfs.data : ensemble mean

17\. z500.obs.sep.data : Reanalysis-2

Each file contains all 23 Septembers (1981-2003) at all leads (0-8).

Lead 0 refers to the forecast monthly mean of September itself.

Lead 1 refers to the forecast monthly mean of October, and so on.

The entire tar file, or any of its individual members may be accessed.