Thermally driven cross-shore flows in stratified lakes
| Quand ? |
Le 24/06/2025, de 11:00 à 12:00 |
|---|---|
| Où ? | MGN1 107 |
| Participants |
Damien Bouffard |
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The sloping boundaries of stratified aquatic systems, such as lakes, are crucial environmental dynamic zones. While the role of sloping boundaries as energy dissipation hotspots is well established, their contribution to triggering large-scale motions has received less attention. I will focus on the development of thermally driven cross-shore flows on sloping boundaries under weak wind conditions. I will specifically examine ‘thermal siphons’ (TS), a dynamical process that occurs when local free convection transforms into a horizontal circulation over sloping boundaries. Thermal siphons result from bathymetrically induced temperature (i.e. density) gradients when a lake experiences a uniform surface buoyancy flux, also known as differential cooling or heating. In the most common case of differential cooling of waters above the temperature of maximum density, TS lead to an overturning circulation characterised by a downslope density current and a surface return flow within a convective environment.