Numerical studies of the 4-day oscillation in Lake Champlain
| Autor: | Kenneth Hunkins, James H. Saylor, Patricia L. Manley, T. O. Manley |
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| Rok vydání: | 1998 |
| Předmět: |
Atmospheric Science
Water mass Baroclinity Soil Science Aquatic Science Oceanography Physics::Geophysics Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Bathymetry Dispersion (water waves) Geomorphology Physics::Atmospheric and Oceanic Physics Earth-Surface Processes Water Science and Technology Shore geography geography.geographical_feature_category Ecology Paleontology Forestry Waves and shallow water Geophysics Space and Planetary Science Upwelling Thermocline Geology |
| Zdroj: | Journal of Geophysical Research: Oceans. 103:18425-18436 |
| ISSN: | 0148-0227 |
| Popis: | The summer thermocline of Lake Champlain, which is found at depths of 20-30 m, oscillates with typical vertical amplitudes of 20-40 m and periods of ∼4 days. Fluctuations at the ends of the lake are opposite in phase and accompanied in the central lake by strong shears across the thermocline. Thcsc arc basin-wide baroclinic disturbances which are forced by wind. A numerical, one-dimensional, two-laycr, shallow-water model incorporating nonlinear and frictional effects in a rectangular basin forced by wind was first tested with idealized wind impulses. The results do not resemble the observed thermocline motion. However, when this simple model is forced with wind data from a nearby shore site, there is rcasonable agreement between the model results and observed long-period thermocline motions in Lake Champlain. Dispersion effects appear to be negligible hcre. This contrasts with othcr long, narrow lakes whcre dispersion effects are important and internal surges are followed by wave trains resembling the soliton solutions of the Korteweg-deVries equation. A possiblc explanation for the different regime in Lake Champlain may be found in its unique bathymetry with sloping bottom at the ends and numerous embayments on the sides that provide traps to collect wind-driven warm water and then release it slowly during recovery of cquilibrium, prevcnting the formation of steep fronts and soliton wave trains. |
| Databáze: | OpenAIRE |
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