DESCRIPTION

r.snow given the temperature (temp) [°C], the radiation (RAD) [W/(m^2*t)], the rain (rain) [mm/t], the initial snowpack water content (in_snow) [mm] and the initial snowpack energy content (in_energy) [Kcal/m^2] calculates the snowpack water equivalent (out_snow) [mm], the snowpack energy content (out_energy) [Kcal/m^2], and the snowmelt (out_snowmelt) [mm/t] at the end of the timestep t.

This algorithm has been developed following the SHE model approach with some modification.

For more details on the algorithms see the references.

OPTIONS

The program will run non-interactively if the user specifies program arguments settings on the command line using the following form:
r.snow temp=name RAD=name rain=name in_snow=name in_energy=name out_snow=name out_energy=name out_snowmelt=name

Alternatively, the user can simply type r.snow on the command line and the program will ask for parameter values settings interactively, using the standard GRASS parser interface.

Parameters:

temp=name
Input: temperature raster map [°C]. Required.
RAD=name
Input: global radiation raster map [W/(m^2*t)]. Required.
rain =name
Input: rainfall raster map [mm/t]. Required.
in_snow =name
Input: initial snowpack water content raster map [mm]. Required.
in_energy =name
Input: initial snowpack energy content raster map [Kcal/m^2]. Required.
out_snow =name
Output: final snowpack water content raster map [mm]. Required.
out_energy =name
Output: final snowpack energy content raster map [Kcal/m^2]. Required.
out_snowmelt =name
Output: snowmelt raster map [mm/t]. Required.

NOTES

The algorithm basically estimates the needed energy to maintain the snowpack in a solid phase (in a zero snowmelt hypothesis). If the available energy is enough to melt part of the snowpack then the snow is melted and the enrgy is depleted, otherwise no melting occurs the enrgy remain available in the snowpack for further step.

SEE ALSO

AUTHORS

Original version of program: The HydroFOSS project, 2006, IST-SUPSI. (http://istgis.ist.supsi.ch:8001/geomatica/index.php?id=1)
Massimiliano Cannata, Istituto Scienze della Terra - Scuola Universitaria Professionale della Svizzera Italiana
Maria A. Brovelli, Politecnico di Milano - Polo regionale di Como

Contact: Massimiliano Cannata

REFERENCES

Cannata M., 2006. A GIS embedded approach for Free & Open Source Hydrological Modelling. PhD dissertation in Geodesy and Geomatic engineering, Politecnico di Milano.

Abbott, M. et al., 1986a, An introduction to the European Hydrological System – Système Hydrologique Européen, SHE; 1. History and philosophy of a physically based distributed modeling system, Journal of Hydrology, Vol. 87, 45-59.

Abbott, M. et al., 1986b, Physically based distributed modelling of an upland catchment using the Système Hydrologique Européen, Journal of Hydrology, Vol. 87, 79-102.

Tarboton, D. G. and C. H. Luce, 1996. Utah Energy Balance Snow Accumulation and Melt Model (UEB): Computer model technical description and user's guide, Utah Water Research Laboratory and USDA Forest Service Intermountain Research Station.

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