1. Please write down the name (and abbreviation) of your snow model or land-surface model with snow component?
INM: Snow model of the Instituto Nacional de Meteorologia
2. Name and address of model developer;
Alberto Fernandez Phone: 341 5819709 fax: 341 5819767 Email: firstname.lastname@example.org Instituto Nacional de Meteorologia Camino de las Moreras, s/n Ciudad Universitaria 28040 Madrid SPAIN
3. Name and address of model user;
4. Please indicate whether your model is developed for application
in understanding snow processes,
in a runoff forecasting model, X
in a weather forecasting model,
in a global climate model (GCM),
or other (please specify)?
5. The first year when the model was used;
6. One paragraph description of your model (e.g. abstract from report or paper);
INM snowmelt model is based on a physical heat balance method. It is an adaptation of the one layer model proposed by Kondo and Yamazaki (1990). As this one, it takes into account both the heat balance at the snow surface and that of the entire snow cover, and it predicts both the snow surface temperature and the freezing depth. As a new contribution, the model predicts also the evolution of the snow's liquid water content including its refreezing. The energy equation is formulated by means of two energy variables: the Liquid Content and the Cold Content. Percolation is an independent process that depends only on mass liquid fraction trough Darcy's law. The model has been validated through field measurements obtained at the instrumented site of Le Col de Porte of the "Centre d'Etudes de la Neige (CEN-Meteo France)" corresponding to the winter seasons of 1988/89, 93/94 and 94/95. The results show that the model correctly represents the evolution and melting of the seasonal snow.
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
cloud cover :
surface pressure :
11. List the state variables (e.g., snow temperature, snow water equivalent, etc) your snow model uses?
snow surface temperature snow water equivalent liquid water content freezing depth
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?
snow saturated hydraulic conductivity 'equivalent' thermal conductivity of the snow Cold Content factor
13. What are the output data?
snow surface temperature snow water equivalent liquid water content freezing depth percolation
14. What computer language does your model use?
15. How many subroutines (or functions) does your snow model have?
9 subroutines. The main one treats the internal evolution.
16. Number of lines of the snow code?
About 300 effective lines
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.
Snowfall and rainfall have to be specified separately
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 model treats the snowpack as a unique layer, but the freezing depth subdivides the snowpack into a dry surface layer and a humid layer
21. What is your snow model time step?
It can be flexible according to input data (e.g. 1 hour)
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
solar zenith angle
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?
They are taken as calibration parameters and once the model calibrated they are 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?
Not represented. The model is not a distributed model
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?
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)?
Percolation (vertical flux of water to the soil) is an independent process that depends only on mass liquid fraction trough Darcy's law
(b). Once snowmelt is generated, how does your model relate it to runoff?
Runoff equals percolation
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?
The model has been validated through field measurements obtained at the instrumented site of Le Col de Porte of the "Centre d'Etudes de la Neige (CEN-Meteo France)" corresponding to the winter seasons of 1988/89, 93/94 and 94/95. They are point measures with one hour step time except daily runoff and albedo.
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?
Direct and statistical comparisons with measurements of snow surface temperature, snow depth and runoff
48. What are the model fitting procedures, if any?
Trial and error with the calibration parameters
49. What are future plans for using/improving the model?
Develop a distributed model (snow-vegetation interaction, areal distribution, topography, ...) Study its possible use in the HIRLAM NWFP model
50. Please provide references relevant to the model description and use.
Essery, R., Martin, E., Douville, H., Fernandez, A. and E. Brun (1998): A comparison of four snow models using observations from an alpine site. Working Paper.
Fernadez, A. (1998): An energy balance model of seasonal snow evolution, Physics and Chemistry of the Earth, 23 (5/6), 661-666.