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Title: Energetics and damping of basin-scale internal waves in a strongly stratified lake Authored by: Shimizu, K. and Imberger, J. Abstract:
Energetics and damping of basin-scale internal waves and subsequent near-bottom transport processes in Lake Kinneret were investigated using modal analysis. The theory of modal analysis in a layer-stratified irregular basin was extended to include linear damping, and evolution of the internal waves was extracted by fitting numerically calculated internal waves to spatially distributed thermistor chain data. Once fitting was complete, damping rates of the individual internal waves could be estimated leading to a complete energy budget of all the basin scale waves. The damping rates (e-folding time) of dominant internal waves ranged from one day to two days depending primarily on bottom friction, and the energy input from strong diurnal winds, estimated to be ~3 GJ day-1, was dissipated within a day. The results of the fitting also provided a local estimate of the bottom stress and hence estimates of the spatial variation of the near-bottom transport processes, such as entrainment rate at the top of the bottom boundary layer and mass transfer at the sediment-water interface; most of these spatial variations could be captured with the first few dominant internal wave modes.
Reference: Shimizu, K. and Imberger, J., 2008, Energetics and damping of basin-scale internal waves in a strongly stratified lake, 53(4):1574-1588 Keywords: Kelvin, Poincare, internal waves, damping |
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