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Title: Exchange between littoral and pelagic waters in a stratified lake due to wind induced motions: Lake Kinneret, Israel Authored by: Marti, C.L. and Imberger, J. Abstract:
We used field data and three-dimensional numerical simulations to investigate the 2 exchange processes between the lake boundaries (littoral) and lake interior (pelagic) due to 3 wind induced motions in Lake Kinneret, Israel. The field data showed large-scale 4 metalimnion oscillations with amplitudes up to 10 m in response to westerly diurnal winds, 5 the existence of a well-defined turbidity intrusion into the metalimnion of the lake and a 6 benthic boundary layer (BBL). The observed vertical and horizontal movements of the 7 turbidity were explained by the vertical and horizontal advection associated with basin-scale 8 wave motions and a residual circulation set up by the basin-scale motions and the wind field. 9 The horizontal advective transport in the metalimnion, associated with the velocities induced 10 by the basin-scale mode-two Poincaré wave, provided the primary control for the exchange 11 between the lake boundaries and lake interior on daily time scales. Detailed comparison of 12 simulation results with both temperature variations from thermistor chains and velocity 13 profiles from portable flux profiles revealed excellent agreement for time scales from hours to 14 days allowing both tools to be used to complement our understanding of the exchange 15 processes. The validated numerical model was used to extract the residual motions that 16 provided the secondary exchange flows, in the various regions of the lake on time scales from 17 days to weeks. The residual motion in the surface layer consisted of a combination of an 18 anticlockwise gyre in the western half of the lake and a weak clockwise gyre along the eastern 19 boundary that were forced by the curl of the wind field. In the metalimnion, residual motions 20 were predominantly forced by the basin scale internal wave motions and an anticlockwise 21 gyre established itself throughout the whole basin. Lastly in the BBL, residual motions 22 consisted of an anticlockwise gyre, but the geographic distribution was patchy. Together these 23 results provide new insight into a proper characterization of the processes underlying the flux 24 paths of water and particles between the lake boundaries and lake interior.
Reference: Marti, C.L. and Imberger, J., 2008, Exchange between littoral and pelagic waters in a stratified lake due to wind induced motions: Lake Kinneret, Israel, 603(1):25-51 Keywords: Kinneret, ELCOM, BBL, benthic boundary layer, internal waves, Kelvin, Poincare |
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