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

  Tohoku Snow Cover Model with Multi-layer (TSCMM)

2. Name and address of model developer;

  YAMAZAKI Takeshi
  Geophysical Institute,
  Tohoku University
  Aza-Aoba, Aramaki,
  Aoba-ku, Sendai, 980-8578, JAPAN
  TEL +81-22-217-5781,  FAX +81-22-217-7758

3. Name and address of model user;

Same as Q2

4. Please indicate whether your model is developed for application

   in understanding snow processes,    X
   in a runoff forecasting model,        
   in a weather forecasting model,         
   in a global climate model (GCM),     
   or other (please specify)?          X
      (estimating energy exchange between the atmosphere and ground)

5. The first year when the model was used;


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

A one-dimensional model has been developed to simulate time series of snow cover in mainly intense cold regions. This model can calculate the profile of snow temperature, density and liquid water content using meteorological data as input. The model structure is simple having snow layers with same thickness; the treatment of liquid water flow and albedo is very simple. Effective temperature gradient is introduced to consider depth hoar, which is frequently observed in intense cold regions. Using this parameter, we can incorporate the change of thermal conductivity and compactive viscosity coefficient by depth hoar formation. Moreover, the ratio of snow amount to rain amount is given as a function of wet-bulb temperature.

7. Please specify any known application range or restrictions;

8. What are the development data needs;

9. What are the operational data needs?

incident solar and atmospheric radiation, air temperature, wind speed, specific humidity, preciptation

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 
   downwelling shortwave radiation : X
   downwelling longwave  radiation : X
   cloud cover                     :  
   surface pressure                :   

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

vertical profile of snow temperature, density, liquid water content

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?

  bulk coefficients for sensible and latent heat,
  maximum water content,
  maximum and minimum albedo

13. What are the output data?

  vertical profile of snow temperature, density, liquid water content
  snow depth, water equivalent
  Snow character
  sensible and latent heat fluxes

14. What computer language does your model use?


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


16. Number of lines of the snow code?


17. What is the recommended hardware?

PC or work-station

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

  s: rate of snow
  s=1-0.5exp(-2.2(1.1-Tw)**1.3) for Tw<1.1 C
  s=0.5exp(-2.2(Tw-1.1)**1.3)   for Tw>1.1 C
  Tw: wet-bulb temp.
  Ta: air temp.
  e: vapor pressure

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


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

the thickness is 2cm number of layers depends on snow depth

21. What is your snow model time step?

200 sec

22. Does your model snow albedo allow its

    spectral differences    (visible vs. near-IR)?
    directional differences (direct  vs. diffuse)?

23. Is your model snow albedo a function of

      snow age                 X (depends on air temperature)
      grain size                
      solar zenith angle         
      snow depth?               

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


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


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


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


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

No, however, depth hoar is considered.

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


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


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


32. How is areal snow distribution treated?

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


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?

No (possible)

35. Does the snow-vegetation interaction account for

 different vegetation types     (grass vs. forest),            
 different vegetation heights   (short vs. tall),             
 different vegetation densities (small vs. large LAI),       
 different vegetation coverages (sparse vs. dense vegetation)?   

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

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

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

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?

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

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

42. How is frozen soil treated in your model?

43. Has your snow model been tested with the field data?


If so, what data? (areas)

what are their temporal and spatial scales?

routine data in Japan at several points,

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


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?


46. Please list any other previous applications.

47. Please specify verification criteria, if any?

  snow depth, water equivalent
  snow pit observations

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

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

  connecting to vegetation and soil models
  adapting GAME(GEWEX Asian Monsoon Experiment) data

50. Please provide references relevant to the model description and use.

Yamazaki, T. 1998: A multi-layer heat balance model of snow cover. --simulations in Siberia and plans--, Research Report of IHAS No.4, Proceedings of Second International Workshop on Energy and Water Cycle in GAME-Siberia, pp. 161--168.

-- Last updated Fri Oct 8 12:47:54 MST 1999 by Zong-Liang Yang.
For questions and comments, please contact Zong-Liang Yang