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

2. Name and address of model developer;

Dr. Diana Verseghy

3. Name and address of model user;

4. Please indicate whether your model is developed for application

5. The first year when the model was used;

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

A land surface scheme incorporating three soil layers, a snow layer, and a vegetation canopy with physically-based calculations of heat and moisture transfers at the surface and across layer boundaries. Snow is treated as a variable depth fourth ‘soil’ layer and snow-covered and snow-free areas are treated separately. Canopy snow processes (interception, sublimation, and melt) are also treated in CLASS. The energy balance equation is solved iteratively for the surface temperature and the surface infiltration rate is calculated using a simplified theoretical analysis which allows for surface ponding and runoff.

7. Please specify any known application range or restrictions;

8. What are the development data needs?

9. What are the operational data needs?

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 (or net longwave)

cloud cover :

surface pressure :

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

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?

??

13. What are the output data?

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?

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.

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

Please specify layering structure.

21. What is your snow model time step?

22. Does your model snow albedo allow its

spectral differences (visible vs. near-IR)? Yes

directional differences (direct vs. diffuse)? No

23. Is your model snow albedo a function of

snow age Yes

grain size

solar zenith angle Yes

pollution

snow depth? Yes

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?

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? No

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?

35. Does the snow-vegetation interaction account for

different vegetation types (grass vs. forest), Yes

different vegetation heights (short vs. tall), Yes

different vegetation densities (small vs. large LAI), Yes

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?

Ice fraction changes thermal properties…

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

Is so, what data? Col de Porte and Goose Bay

what are their temporal and spatial scales? Daily snow depth, weekly swe

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?

Bias, rmse (monthly snow depth and swe)

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

None

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

Further validation as part of SNOWMIP comparison study.

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

Verseghy, D.L., 1991: CLASS - A Canadian land surface scheme for GCMs. I. Soil Model. Intl. J. Climatology, 11, 111-133.

Foster, J., G. Liston, R. Koster, R. Essery, H. Behr, L. Dumenil, D. Verseghy, S. Thompson, D. Pollard, J. Cohen, 1996: Snow cover and snow mass intercomparisons of general circulation models and remotely sensed datasets, J. Clim., 9, 409-426.