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Data assimilation method for control analysis: Climate Forecast System Reanalysis (CFSR)
Resolution of model used to generate Control Analysis: T384/L64 for hindcast and T574/L64 for real-time forecasts after 2011
Ensemble initial perturbation strategy: Add a small perturbation into atmospheric, oceanic and land analysis at each cycle
Horizontal and vertical resolution of perturbations:  3D, all levels and variables
Perturbations in +/- pairs: Yes, there is one +/- pair

 

 

Initialization of land surface:

 

 1. What is the land surface model (LSM) and version used in the forecast model, and what are the current/relevant references for the model? 4-layer Noah Land surface model 2.7.1 (Ek et al. 2003)

      Are there any significant changes/deviations in the operational version of the LSM from the documentation of the LSM? No.

 

 2. How is soil moisture initialized in the forecasts? (climatology / realistic / other) Realistic: From CFSR (Saha et al. 2010) and associated GLDAS land surface analysis (Meng et al. 2012).

     Is there horizontal and/or vertical interpolation of initialization data onto the forecast model grid? If so, please give original data resolution(s). Yes. From the CFSR analysis resolution (T382) to the CFSv2 (T126) resolution.

     Does the LSM differentiate between liquid and ice content of the soil? If so, how are each initialized? Yes. The Noah LSM defines two soil moisture state variables, liquid and ice (liquid + ice = total soil moisture). The amounts of liquid  and ice within the soil layers are determined by soil temperature and the net thermal energy transition within each of the 4 soil layers.

            If all model soil layers are not initialized in the same way or from the same source, please describe. All model soil layers are initialized in the same way of the Noah LSM driven GLDAS land analysis.

 

3. How is snow initialized in the forecasts? (climatology / realistic / other) Realistic: From the CFSR snow analysis using IMS (Interactive Multisensor Snow and Ice Mapping System) and Air Force Weather Agency (AFWA) SNODEP (Snow depth) analysis.

           Is there horizontal and/or vertical interpolation of data onto the forecast model grid? If so, please give original data resolution(s) Horizontal interpolation. From the CFSR analysis resolution (T382) to the CFSv2 (T126) resolution.

          Are snow mass, snow depth or both initialized? What about snow age, albedo, or other snow properties? Yes, both snow mass and snow depth are initialized. The Noah LSM defines two snow state variables, water equivalent snow mass (SWE) and actual snow depth. Snow depth is determined by SWE and snow age (days of snow pack on the ground). Albedo is calculated from the background albedo, snow albedo, and snow cover fraction.

 

4. How is soil temperature initialized in the forecasts? (climatology / realistic / other) Realistic: From CFSR (Saha et al. 2010) and associated GLDAS land surface analysis.

    Is the soil temperature initialized consistently with soil moisture (frozen soil water where soil temperature ≤0°C) and snow cover (top layer soil temperature ≤0°C under snow)? Yes, some coherency checks are done in the GLDAS

 

Is there horizontal and/or vertical interpolation of data onto the forecast model grid? If so, please give original data resolution(s) Horizontal interpolation. From the CFSR analysis resolution (T382) to the CFSv2 (T126) resolution.

 

 If all model soil layers are not initialized in the same way or from the same source, please describe. All model soil layers are initialized in the same way of the Noah LSM driven GLDAS land analysis.

 

5. How are time-varying vegetation properties represented in the LSM? Is phenology predicted by the LSM? If so, how is it initialized? Phenology is not predicted by the Noah LSM. It is represented in the Noah LSM via monthly climatology of green vegetation fraction derived from AVHRR data (Gutman and Ignatov, 1998).

 

6. What is the source of soil properties (texture, porosity, conductivity, etc.) used by the LSM? Soil texture is defined following Zobler (1986). Porosity, soil conductivity and other soil properties are prescribed as soil texture dependent empirical parameters.

 

7. If the initialization of the LSM for re-forecasts deviates from the procedure for forecasts, please describe the differences. The initialization procedure is in the same way.

 

 



4. Model Uncertainties perturbations:

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Number of years covered: 1999-2010
Produced on the fly or fix re-forecasts? Fix
Frequency:   Everyday; 4 runs/day
Ensemble size: 1 member
Initial conditions: CFSR
Is the model physics and resolution  the same as for the real-time forecasts: Yes
If not, what are the differences: NA
Is the ensemble generation the same as for real-time forecasts? CFSR analysis for each cycle
If not, what are the differences: NA


 8. References:

 

Ek, M. B., K. E. Mitchell, Y. Lin, E. Rogers, P. Grunmann, V. Koren, G. Gayno, and J. D. Tarplay, 2003: Implementation of Noah land surface model advances in the National Centers for Environmental Prediction operational mesoscale Eta model. J. Geophys. Res., 108, 8851, doi:10.1029/2002JD003296.

Meng, J., et al., 2012: The land surface analysis in the NCEP Climate Forecast System Reanalysis. J. Hydrometeor., 13, 1621–1630, doi:10.1175/JHM-D-11-090.1.

Gutman, G., and A. Ignatov. 1998. “The Derivation of the Green Vegetation Fraction from NOAA/AVHRR Data for Use in Numerical Weather Prediction Models.” International Journal of Remote Sensing 19 (8): 1533–1543. doi:10.1080/014311698215333.


Comprehensive description of the model physics:

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Saha, S. and Coauthors, 2014: The NCEP Climate Forecast System Version 2 J. Climate, 27, 2185–2208. doi: http://dx.doi.org/10.1175/JCLI-D-12-00823.1

 

http://www.ral.ucar.edu/research/land/technology/lsm/noah/Noah_LSM_USERGUIDE_2.7.1.pdf

Zobler, L. 1986. A World Soil File for Global Climate Modelling. NASA Technical Memorandum 87802. NASA Goddard Institute for Space Studies, New York, New York, U.S.A.

9. Configuration  in the S2S archiving

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  • Step 0 is not available for all surface  instantaneous fields, except for mean sea level pressure (msl)
  • Step 0-24 (day 1) not available for all daily-mean fields except 2-metre dewpoint temperature, total cloud cover and Convective available Potential Energy (CAPE)
  • For some re-forecast dates, only the 00Z runs could be recovered, which means that the control, ensemble members 1, 2 and 3 are identical and correspond tot he 00Z run. 
    The list of affected dates is:

    19990101,

    19991110 -- 19991012,

    20001110 -- 20001119,

    20011110 -- 20011119,

    19990210 -- 19990221,

    20000210 -- 20000221,

    20010210 -- 20010221.