Energy Balance and Runoff from a Subarctic Snowpack

• Main Authors: Price,Anthony G., Dunne,Thomas, Colbeck,Samuel C.
• Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H
• Format: Text
• Language: English
• Published: 1976
• Subjects: Hydrology; Limnology and Potamology; Snow; Ice and Permafrost; Numerical Mathematics; *HYDROLOGY; *SNOW; *MATHEMATICAL PREDICTION; DENSITY; MEASUREMENT; MODELS; WATER; RADIATIVE TRANSFER; DEPTH; MELTING; FLOW; VEGETATION; DIURNAL VARIATIONS; FORESTS; ARCTIC REGIONS; TUNDRA; *Subarctic snowpack; *Energy balance; Snowpack runoff; Waterflow; *Snowmelting rate; Melting rate; Boreal forest; Field measurement; Labrador; Arctic; Ice; permafrost; Subarctic; Tundra
• Online Access: http://www.dtic.mil/docs/citations/ADA030096; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA030096

In Part I a physically based model was used to predict daily snowmelt on 2000 m sq plots in the Subarctic. The plots had a range of aspects and inclinations in boreal forest and on the tundra. The energy balance, computed for each of the plots, was compensated for differences in radiative and turbulent energy fluxes caused by varied slope geometry and vegetative cover. The turbulent energy fluxes were also corrected for the effects of the stable stratification of the air over the snow surface. The predictions of the model were compared with daily melts derived from runoff measured on the snowmelt plots. The results show that the method is a good predictor of daily amounts of snowmelt, although some uncertainties are introduced by changes in the snow surface during the melt period. In Part II, a physically based model of the movement of water through snowpacks was used to calculate hydrographs generated by diurnal waves of snowmelt on the tundra and in the boreal forest of subarctic Labrador. The model was tested against measured hydrographs from hillside plots that sampled a range of aspect, gradient, length, vegetative cover, and snow depth and density. The model yielded good results, particularly in the prediction of peak runoff rates, though there was a slight overestimate of the lag time. A comparison of predictions against field measurements indicated that, given the ranges over which each of the controls is likely to vary, the two most critical factors controlling the hydrograph are the snow depth and the melt rate, which must be predicted precisely for short intervals of time. Permeability of the snowpack is another important control, but it can be estimated closely from published values. (Author)