Effects of spatial wind inhomogeneity and turbulence anisotropy on circulation in an elongated basin: A simplified analytical solution

Toffolon, Marco; Rizzi, Giuliano

doi:10.1016/j.advwatres.2009.08.001

Cited by 13 publications

(11 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Turbulent transport of momentum in lakes is expected to occur at a much larger rate in the horizontal direction, possibly affecting the general circulation [ Toffolon and Rizzi , ]. This turbulence anisotropy is partly due to the effect of the relative shallowness of these water bodies, and partly due to the effect of stratification, which is not examined in this work.…”

Section: Results For the Homogeneous Wind Casementioning

confidence: 99%

“…in a valley surrounded by a complex orography with peaks reaching 1988 m a.s.l. Therefore the local orographic features channel the wind to certain directions [Laiti et al, 2014;Giovannini et al, 2015] and, together with vegetation canopy or anthropogenic structures, affect the wind distribution [Laval et al, 2003;Rueda et al, 2005], resulting in peculiar lake circulations [Podsetchine and Schernewski, 1999;Rubbert and K€ ongeter, 2005;Toffolon and Rizzi, 2009].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Large eddy simulation (LES) of wind‐driven circulation in a peri‐alpine lake: Detection of turbulent structures and implications of a complex surrounding orography

Santo

Toffolon

Zanier³

et al. 2017

JGR Oceans

Self Cite

View full text Add to dashboard Cite

We investigate wind‐driven circulation in a peri‐alpine lake (Lake Ledro ‐ Italy) using LES‐COAST. Lake Ledro is interesting because its own dimensions are suited for LES and it is surrounded by complex orography, affecting wind distribution. We consider the winter condition when stratification is nearly absent. Two types of time‐varying wind stress are used: spatially homogeneous and spatially inhomogeneous respectively. The analysis of the eddy viscosities shows substantial differences with respect to the ocean case characterized by absence of coastal boundaries and homogeneous, steady wind. The quantities exhibit a noticeable inhomogeneous behavior: the horizontal eddy viscosity is larger in the water body far from the boundaries, whereas the vertical one is larger close to the lateral boundaries due to the presence of a boundary layer. The energetic bottom boundary layer, typically occurring in lakes, is not present. This because of the intrinsic unsteadiness of the thermal wind blowing over the lake and due to the absence of large amplitude internal waves, the latter present only in case of stable stratification. In the inhomogeneous wind case, up‐welling and down‐welling areas are not confined along the shoreline only, but are also generated in the water body due to substantial horizontal velocity divergence, and turbulent mixing, quantified by eddy viscosities, TKE and its dissipation rate, appears enhanced with respect to the homogeneous wind case. Finally, downwelling/upwelling areas along the windward/leeward coastline respectively were observed, whose quantitative estimation may give explanation for the bloom of cyanobacteria at the lake surface observed in winter.

show abstract

Section: Results For the Homogeneous Wind Casementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Large eddy simulation (LES) of wind‐driven circulation in a peri‐alpine lake: Detection of turbulent structures and implications of a complex surrounding orography

Santo

Toffolon

Zanier³

et al. 2017

JGR Oceans

Self Cite

View full text Add to dashboard Cite

show abstract

“…In a simple approach, the geographic location and morphometry can be considered the passive components and the meteorological factors the active component. Often, however, it is a combination of those two to affect a lake as the shape of a basin and surrounding terrain modify wind 1956, 1957, 1962-1967, 1969, 1978, 1979, 1986, 1987 patterns (Wüest & Lorke, 2003;Toffolon & Rizzi, 2009), and large lakes create even a regional microclimate with specific temperature and precipitation regimes (Daly, 2006). The type and trophic status of lakes that affects heat distribution by modifying optical properties of water, has an intermediate position between active and passive components.…”

Section: Discussionmentioning

confidence: 99%

Morphometry and trophic state modify the thermal response of lakes to meteorological forcing

Nõges

Ghiani

et al. 2011

Hydrobiologia

View full text Add to dashboard Cite

We hypothesised that (i) a summer heat wave would increase the thermal stability of lakes and (ii) the size and trophic state differences would modify the lakes' responses to heating. Within 2 years, 2008 and 2009, we studied the thermal and optical regimes of two adjacent stratified lakes in northern Italy, the oligo-mesotrophic Lake Monate (2.5 km 2 , max. depth 34 m) and the eutrophic Lake Varese (14.8 km 2 , 26 m). After the cold winter 2008-2009, a heat wave starting in May turned the whole year 2009 the second hottest after 2003. The particular sequence of meteorological events resulted in extreme vertical temperature gradients and unusually high thermal stability of both lakes. All calculated thermal parameters showed the highest values in 2009 while also the values for 2008 exceeded considerably those published for these lakes in the past. Due to the large wind exposed surface, wind mixing was supposedly the dominating mechanism of heat transfer in the shallower eutrophic Lake Varese where, due to low water transparency, large amount of solar energy trapped in the upper layers markedly increased the thermal stability. In the deeper and more transparent Lake Monate, the deeper penetrating solar irradiance contributed to better energy dissipation within the water column and smaller interannual differences in thermal stability.

show abstract

“…For small and very shallow lakes, as the Superior Lake of Mantua, the Coriolis effect is negligible (Fenocchi, 2015). In small basins placed in lowland regions, meteorological differences across the lake surface (Rueda et al, 2009) and disturbances by the surrounding topography (Toffolon and Rizzi, 2009) are not present. The wind stress curl then reduces to the asymptotic stress growth along the fetch triggered by the 2 -3 orders of magnitude drop of the aerodynamic roughness at the land-water interface and to its subsequent rise because of wave formation (Charnock, 1955).…”

Section: Wind Stressmentioning

confidence: 99%

Hydrodynamic modelling and characterisation of a shallow fluvial lake: a study on the Superior Lake of Mantua

Fenocchi

Sibilla

2016

J Limnol

View full text Add to dashboard Cite

show abstract

Effects of spatial wind inhomogeneity and turbulence anisotropy on circulation in an elongated basin: A simplified analytical solution

Cited by 13 publications

References 41 publications

Large eddy simulation (LES) of wind‐driven circulation in a peri‐alpine lake: Detection of turbulent structures and implications of a complex surrounding orography

Large eddy simulation (LES) of wind‐driven circulation in a peri‐alpine lake: Detection of turbulent structures and implications of a complex surrounding orography

Morphometry and trophic state modify the thermal response of lakes to meteorological forcing

Hydrodynamic modelling and characterisation of a shallow fluvial lake: a study on the Superior Lake of Mantua

Contact Info

Product

Resources

About