Modeling circulation in lakes: Spatial and temporal variations

Laval, B.; Imberger, Jörg; Hodges, Ben R.; Stocker, Roman

doi:10.4319/lo.2003.48.3.0983

Cited by 167 publications

(135 citation statements)

References 30 publications

Supporting

Mentioning

128

Contrasting

Unclassified

Order By: Relevance

“…The temperature equation is solved simultaneously. Models based on these equations have been shown to compare reasonably well with time series of measured flow properties as well as with the low wave-number part of measured spectra (Laval et al 2003;Rueda et al 2003;Appt et al 2004).…”

Section: The Numerical Modelmentioning

confidence: 85%

Interbasin exchange and mixing in the hypolimnion of a large lake: The role of long internal waves

Umlauf

Lemmin

2005

Limnol. Oceanogr.

View full text Add to dashboard Cite

We conducted a combined field and numerical study of the effects of episodic internal Kelvin-type waves on bottom boundary turbulence and the exchange of a passive tracer between the main basin and the side basin of a large lake (Lake Geneva). High-resolution measurements of the vertical current structure near the entrance of the 25-km-long and 70-m-deep side basin revealed that hypolimnetic current speeds frequently exceed 0.2 m s Ϫ1 , leading to a turbulent bottom boundary layer several meters thick with logarithmic current profiles and to a region of strong shear across the thermocline. The time series and vertical structure of the currents were reproduced by a threedimensional numerical model of the lake. It was demonstrated that, after episodes of strong winds from the northeast and southwest, exchange flows due to internal Kelvin waves were able to temporarily half or double the hypolimnetic volume of the side basin, leading to an irreversible exchange of up to 40% of the hypolimnetic water in the side basin of Lake Geneva within only a few wave cycles. With the help of the numerical model, it was shown that the key mechanisms of exchange are horizontal dispersion by resolved scales and, to a small extent, shear dispersion in the bottom boundary layer. It is suggested that bottom boundary-layer turbulence and the interbasin exchange can explain the structural differences in the oxygen profiles observed in the side basin and the main basin, respectively.

show abstract

Section: The Numerical Modelmentioning

confidence: 85%

Interbasin exchange and mixing in the hypolimnion of a large lake: The role of long internal waves

Umlauf

Lemmin

2005

Limnol. Oceanogr.

View full text Add to dashboard Cite

show abstract

“…Although thermal effects can be important on a seasonal timescale Akitomo et al 2004), recent studies indicate that, for timescales shorter than seasonal, wind stress curl and topographic effects are the major driving forces of gyres (Laval et al 2003(Laval et al , 2005Rueda et al 2005) and the contributions from internal waves are minor (Pan et al 2002). We will limit our focus to winddriven gyres in this paper.…”

mentioning

confidence: 99%

“…A topographic gyre degenerates primarily into topographic waves after the wind ceases (Raudsepp et al 2003) and propagates cyclonically around the basin with the periods and horizontal structure determined primarily by the basin shape and bottom slope (Rhines 1969). In strongly stratified lakes, currents associated with gyres are observed only in the epilimnion, and the geostrophic pressure associated with the circulation induces doming (or depression) of the pycnocline (Endoh et al 1995a;Kumagai et al 1998;Laval et al 2005).…”

mentioning

confidence: 99%

Horizontal structure and excitation of primary motions in a strongly stratified lake

Shimizu

Imberger

Kumagai

2007

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

A modal analysis in the horizontal plane was extended to a layer-stratified basin with irregular bathymetry, and the theory was applied to Lake Biwa to investigate the horizontal structure and excitation of the basin-scale internal waves and gyres. The horizontal structure of the basin-scale internal waves consisted of cyclonic and anticyclonic elliptic cells, each of which appeared to follow the dispersion relationship of Kelvin and Poincaré waves in elliptic basins. The internal waves were preferentially excited depending on the arrangement of the cells and the wind direction, but the spatial distribution of wind stress curl over the lake primarily determined the horizontal structure of the ensuing gyres. Decoupled evolutionary equations for the individual modes provided a good approximation for excitation of the internal waves and early stages of excitation of the gyres before nonlinear effects and damping become significant. The modal decomposition of hydrodynamic simulation results also showed that the primary action of the wind was to excite the internal waves; however, these internal waves were damped within a few days, and the dynamics during calm periods were dominated by the gyres, illustrating the importance of internal waves on mixing and gyres on long-term horizontal transport.

show abstract

“…At the surface boundary, wind stress can be treated as a source, which affects horizontal movements and disturbs stratified water layers (Laval and Imberger 2003). Wind stress on the water surface can be calculated by:…”

Section: Numerical Simulation Modelmentioning

confidence: 99%

3D-modelling of the thermal circumstances of a lake under artificial aeration

et al. 2017

View full text Add to dashboard Cite

A 3D-model was developed to study the effects of hypolimnetic aeration on the temperature profile of a thermally stratified Lake Vesijärvi (southern Finland). Aeration was conducted by pumping epilimnetic water through the thermocline to the hypolimnion without breaking the thermal stratification. The model used time transient equation based on Navier-Stokes equation. The model was fitted to the vertical temperature distribution and environmental parameters (wind, air temperature, and solar radiation) before the onset of aeration, and the model was used to predict the vertical temperature distribution 3 and 15 days after the onset of aeration (1 August and 22 August). The difference between the modelled and observed temperature was on average 0.6°C. The average percentage model error was 4.0% on 1 August and 3.7% on 22 August. In the epilimnion, model accuracy depended on the difference between the observed temperature and boundary conditions. In the hypolimnion, the model residual decreased with increasing depth. On 1 August, the model predicted a homogenous temperature profile in the hypolimnion, while the observed temperature decreased moderately from the thermocline to the bottom. This was because the effect of sediment was not included in the model. On 22 August, the modelled and observed temperatures near the bottom were identical demonstrating that the heat transfer by the aerator masked the effect of sediment and that exclusion of sediment heat from the model does not cause considerable error unless very short-term effects of aeration are studied. In all, the model successfully described the effects of the aerator on the lake's temperature profile. The results confirmed the validity of the applied computational fluid dynamic in artificial aeration; based on the simulated results, the effect of aeration can be predicted.

show abstract

Modeling circulation in lakes: Spatial and temporal variations

Cited by 167 publications

References 30 publications

Interbasin exchange and mixing in the hypolimnion of a large lake: The role of long internal waves

Interbasin exchange and mixing in the hypolimnion of a large lake: The role of long internal waves

Horizontal structure and excitation of primary motions in a strongly stratified lake

3D-modelling of the thermal circumstances of a lake under artificial aeration

Contact Info

Product

Resources

About