Modelling water temperature beneath river ice covers
The water temperature beneath river ice covers has an important influence on the heat flux to the overlying ice cover and on ice melt. Measurements of water temperature beneath the Liard River ice cover showed that prior to spring breakup, the water temperature was always between 0.0 and 0.025 °C, w...
| Published in: | Canadian Journal of Civil Engineering |
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| Main Author: | |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1990
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/l90-006 http://www.nrcresearchpress.com/doi/pdf/10.1139/l90-006 |
| Summary: | The water temperature beneath river ice covers has an important influence on the heat flux to the overlying ice cover and on ice melt. Measurements of water temperature beneath the Liard River ice cover showed that prior to spring breakup, the water temperature was always between 0.0 and 0.025 °C, with important cross-channel and diurnal variations. The lowest temperatures were controlled by the bed heat flux and frictional heating, while variations above these minimum values were explained by changes in solar radiation. Using measurements of these heat fluxes, in conjunction with measurements of ice and bed roughness, water depth and velocity, and slope, a simple method which assumes the similarity between heat and momentum transfer was able to accurately predict water temperatures beneath the ice cover. During breakup when the river had both ice-free and ice-covered sections, water temperatures rose to a few degrees above 0 °C. When this water entered an ice-covered reach, the water temperature declined rapidly to near 0 °C within 10 km. This temperature decay was predicted from measurements of the initial temperature, ice and bed roughness, and water depth. Key words: water temperature, ice, thermal regime, ice melt. |
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