1. Please write down the name (and abbreviation) of your snow model or land-surface model with snow component?

energy and mass budget model, implemented in standard version of ECHAM

2. Name and address of model developer;

   Duemenil, Lydia
   Max-Planck-Institute fuer Meteorologie
   Bundesstrasse 55
   D-20146 Hamburg, Germany
   loth@dkrz.de

3. Name and address of model user;

all users of ECHAM physics

4. Please indicate whether your model is developed for application

   in understanding snow processes,   
   in a runoff forecasting model,	 
   in a weather forecasting model,   
   in a global climate model (GCM),    X
   or other (please specify)?          X 
      and regional climate model

5. The first year when the model was used;

1988

6. One paragraph description of your model (e.g. abstract from report or paper);

energy and mass budget model of a snow cover with one separate snow layer,
state-of-the-art model for atmospheric climate models

7. Please specify any known application range or restrictions;

8. What are the development data needs;

9. What are the operational data needs?

atmospheric data, initial soil data

10. Please indicate with an "x" for those meteorological variables used to DRIVE your snow model?

   precipitation                   : X
   air temperature                 : X
   wind speed                      : X
   wind direction                  :   
   humidity                        : X (dew point temperature)
   downwelling shortwave radiation : (estimated) 
   downwelling longwave  radiation : (estimated)
   cloud cover                     : X
   surface pressure                : X 

11. List the state variables (e.g., snow temperature, snow water equivalent, etc) your snow model uses?

       snow albedo, snow surface temperature, mean snow temperature
       snow water equivalent

12. List the measurable/adjustable parameters (e.g., snow surface aerodynamic roughness, maximum albedo at visible wavelength, etc, excluding initial conditions) your snow model uses?

cf. 11

13. What are the output data?

cf. 11

14. What computer language does your model use?

FORTRAN

15. How many subroutines (or functions) does your snow model have?

1

16. Number of lines of the snow code?

17. What is the recommended hardware?

cray

18. How does your model determine the form of precipitation (i.e., snowfall and rainfall)? Please give the formulation.

19. Is your snow model one dimensional or multi-dimensional? Please specify.

energy and mass budget model for each grid point (global)

20. If one dimensional, how many layers are there in your snow model? Please specify layering structure.

1 layer

21. What is your snow model time step?

    not fixed
    according to atmospheric model (standard ECHAM T42: 24 min.)
    or according to input data (1 h to 3h)

22. Does your model snow albedo allow its

    spectral differences    (visible vs. near-IR)? no
    directional differences (direct  vs. diffuse)? no

23. Is your model snow albedo a function of

      snow age                  
      grain size                
      solar zenith angle       
      pollution                 
      snow depth?              X

24. Does your snow model explicitly treat liquid water retention and percolation within the snowpack?

No.

25. Does your snow model account for changes in the hydraulic and thermal properties of snow due to meltwater refreezing?

No.

26. Is snow density in your snow model changing with time or fixed?

Fixed.

27. Is heat capacity and conductivity in your snow model changing with time or fixed?

Both fixed.

28. Does your snow model simulate vapor transfer in the snowpack?

No.

29. Does your snow model account for the heat transfer between the bottom of the snowpack and the underlying soil?

YES

30. In snow energy balance, does your model consider heat convected by rain or falling snow?

No.

31. Does your snow model include snow drifting and redistribution by wind (or avalanche)? If so, how?

No

32. How is areal snow distribution treated?

in the ECHAM versions: estimating the fraction of snow coverage of grid-cell area as function of snow water equivalent (critical value)

33. Does your snow model account for sub-grid (or sub-watershed) effects of topography? If so, how is temperature distributed?

No.

how is precipitation (spatial, elevation and corrections) distributed?

how is solar radiation distributed?

how is wind distributed?

how are other meteorological variables distributed?

34. Does your snow model consider snow-vegetation interaction?

YES.

35. Does the snow-vegetation interaction account for

 different vegetation types     (grass vs. forest), 
  --forest vs. non-forest for radiation (for the ECHAM versions)
 different vegetation heights   (short vs. tall),              
 different vegetation densities (small vs. large LAI),        
 different vegetation coverages (sparse vs. dense vegetation)? 
  --indirectly for heat fluxes (for the ECHAM versions)

36. Are snow interception, drip and melt on canopy surface allowed in your model?

No.

37. How is the upper limit of the canopy interception determined?

38. In the presence of vegetation, how is snow surface albedo altered?

separately for snow-covered forest and snow over bare soil

39. In the presence of vegetation, how is snow surface roughness altered?

40. In the presence of forest, does your snow model allow spatial variability of snow depth and water equivalent on forest floor?

indirectly due to the parameterization of albedo and the turbulent fluxes

41(a). How does your model deliver snowmelt to the soil system (e.g. affecting soil moisture)?

soil moisture and runoff

(b). Once snowmelt is generated, how does your model relate it to runoff?

ECHAM runoff scheme

42. How is frozen soil treated in your model?

no water infitration in soil at temperatures below the freezing point

43. Has your snow model been tested with the field data? If so, what data? (areas)

what are their temporal and spatial scales?

global snow depth climatology

44. Has your snow model been used together with remote sensing data as input?

No.

If so, how?

45. If your snow model is coupled with a numerical weather forecasting model or climate model, has the model snow product been compared with satellite data? If so, what satellite data were used?

Yes. SMMR.

46. Please list any other previous applications.

47. Please specify verification criteria, if any?

snow depth, snow water equivalent, surface albedo.

48. What are the model fitting procedures, if any?

49. What are future plans for using/improving the model?

50. Please provide references relevant to the model description and use.
Verification of ECHAM standard version:

Foster, J.; G. Liston, R. Koster., R. Essery, H. Behr, L. Dümenil, D. Verseghy, S. Thompson, D. Pollard and J. Cohen, 1996: "Snow Cover and Mass Intercomparisons of General Circulation Models and Remotely Sensed Data", J Clim., 9(2), 409-426.
Description of ECHAM standard version and verification of the global climate model ECHAM:

Roeckner, E.; K. Arpe, L. Bengtsson, M. Christoph, M. Claussen, L. Dümenil, M. Esch, M. Giorgetta, U. Schlese, U. Schulzweida, 1996: "The atmospheric circulation model ECHAM-4: Model description and simulation of present-day climate", MPI-Rep. 218, MPI für Meteorologie, Hamburg, 90 pp.