UID:
(DE-602)kobvindex_GFZ20190918152020
Format:
ix, 40 Seiten
,
Illustrationen
Series Statement:
CRREL Report 76-27
Content:
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.
Note:
Contents: Abstract Preface Summary Notation Scope of the study Part I. Energy balance computations Introduction The experimental sites Instrumentation Theoretical Radiation heat flow Hr Sensible heat flux Hc and latent heat flux He The application of the heat flow model Results and discussion Conclusions and recommendations Part II. Comparison of water runoff computations and measurements Introduction The runoff model The unsaturated zone The saturated layer The field study Instrumentation of the plots Descriptive hydrology Application of the runoff model The unsaturated zone The saturated zone Discussion and conclusions Comparison of predicted and observed hydrographs Factors affecting results Literature cited
In:
CRREL Report, 76-27
Language:
English
Keywords:
Forschungsbericht
URL:
https://hdl.handle.net/11681/9527
Bookmarklink