Particle dispersal due to interplay of motions in the surface layer of a small reservoir

Okely, Patricia; Imberger, Jörg; Shimizu, Kenji

doi:10.4319/lo.2010.55.2.0589

Cited by 8 publications

(6 citation statements)

References 41 publications

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“…Particles were either all located in the same velocity field or interspersed amongst horizontal velocity fields at different depths. As in Okely et al (2010), a particle dispersal rate was calculated from the change in area (A P ) of the polygon formed by the four particles over time:…”

Section: Methodsmentioning

confidence: 99%

Processes affecting horizontal mixing and dispersion in Winam Gulf, Lake Victoria

Okely

Imberger

Antenucci

2010

Limnology & Oceanography

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Several large rivers enter Winam Gulf, a large shallow semi-enclosed embayment of Lake Victoria. Given the vast spatial scale of this embayment (1400 km 2 ), horizontal transport of waterborne material plays a major role in determining its biochemical properties. To identify the dominant hydrodynamic characteristics of this horizontal transport, a combination of field data and three-dimensional numerical modeling were employed to investigate effects due to variable wind forcing, riverine inflows, and interactions with the rest of Lake Victoria including astronomical tides and a complex bathymetry. Currents in the Gulf were oscillatory due to periodic wind and tidal forcing leading to surface seiching, with a residual circulation component. In the western region of the Gulf near the connection with Lake Victoria, substantial vertical and horizontal shear in the currents resulted in efficient horizontal dispersion with rates of up to 160 m 2 s 21 simulated using numerical tracers. In the eastern region, however, rates of horizontal dispersion were reduced to around 12 m 2 s 21 . This spatial variability in hydrodynamic conditions underpins regional differences in ecological properties of Winam Gulf.

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Section: Methodsmentioning

confidence: 99%

Processes affecting horizontal mixing and dispersion in Winam Gulf, Lake Victoria

Okely

Imberger

Antenucci

2010

Limnology & Oceanography

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“…We restricted our study to the particle transport on the top (or bottom) surface of the simplified lake model. While particle transport is three-dimensional in nature, and since it is almost certainly significantly affected by three-dimensional bathymetric irregularities (e.g., Okely et al, 2010; implications given by Wake et al, 2005), vertical motions and the effect of irregular lake boundaries on particle transport are important issues deserving of future study in order to augment the conclusions of this present work.…”

Section: Discussionmentioning

confidence: 89%

Lagrangian transport in a circular lake: effect of nonlinearity and the second vertical mode

Sakai

Redekopp

2011

Nonlin. Processes Geophys.

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Abstract. Effects of the second vertical mode and nonlinearity of the background flow field on the Lagrangian transport of particle clouds are studied by employing a wind-forced linear hydrostatic model and a weakly-nonlinear, weaklynonhydrostatic evolution model. It is confirmed that Kelvin waves primarily advect particles near the basin perimeter in a cyclonic direction, and Poincaré waves primarily advect particles in off-shore (radial) directions in a manner that is oscillatory in time with frequencies near the inertial period. The internal current associated with the second vertical mode is usually far smaller than that associated with the energetically dominant, lowest vertical mode. However, because of the disparately slow eigenspeed of the vertical mode-two Kelvin wave, the resultant particle transport associated with the vertical mode-two flow near the basin perimeter can drive transport that is comparable with that associated with the Kelvin wave of the lowest vertical mode. It is discovered that nonlinear interaction between the Kelvin-Poincaré wave pair can give birth to a solitary-like wave of large amplitude in an offshore region. This new type of wave generates a large current and co-propagates with the Kelvin wave in a cyclonic direction and, eventually, can cause a burst of particle transport in an off-shore direction.

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“…The Estuary Lake and Coastal Ocean Model (ELCOM) was selected for simulating the three-dimensional hydrodynamics in Knewstubb and Natalkuz Lakes. Without site-specific calibration, ELCOM has adequately reproduced the observed baroclinic response to wind in several stratified waterbodies, for example, Lake Tiberias (Hodges et al 2000;Laval et al 2003;Gomez-Giraldo et al 2006), Lake Constance (Appt et al 2004), Lake Biwa (Shimizu et al 2007), and Valle de Bravo Reservoir (Okely et al 2010).…”

Section: Hydrodynamic Modelingmentioning

confidence: 97%

The baroclinic response to wind in a multiarm multibasin reservoir

Imam

Laval

Pieters

et al. 2019

Limnology & Oceanography

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Field data, a three‐dimensional hydrodynamic numerical model, and modal decomposition were used to examine the baroclinic response to wind in two interconnected multiarm lakes, Knewstubb and Natalkuz Lakes (British Columbia, Canada). Similar to lakes of simpler geometry, the first‐vertical first‐horizontal mode (V1H1) of Knewstubb and Natalkuz Lakes was found to be the most energetic mode. This V1H1 dominance is attributed to similarity between the relatively uniform distributions of along‐thalweg wind and surface‐layer flow for the V1H1 mode. Two bathymetric features, the geometric constriction between Knewstubb and Natalkuz Lakes, and changes in thalweg orientation relative to the wind field act to create subbasins in which wind forcing causes local metalimnetic tilts. These subbasin scale tilts deepen the metalimnion at the downwind ends of the subbasins, raise the metalimnion at the upwind ends, and are superimposed on the lake‐wide V1H1 tilt. The metalimnetic tilts in the subbasins are attributed to higher horizontal modes that are equivalent to V1H1 modes of the subbasins. Because the thickness of the metalimnion is significant, the subbasin metalimnetic tilts occur with variations in the metalimnetic thickness along the subbasins; the metalimnion is compressed at the downwind end and expanded at the other end of each subbasin. This variability in thickness leads to metalimnetic intrusions following the relaxation of wind forcing. The findings of this study contribute to characterizing the baroclinic response to wind in lakes of complex bathymetry. In particular, this study helps in understanding the effect of bathymetric features on modal composition of the baroclinic response.

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Particle dispersal due to interplay of motions in the surface layer of a small reservoir

Cited by 8 publications

References 41 publications

Processes affecting horizontal mixing and dispersion in Winam Gulf, Lake Victoria

Processes affecting horizontal mixing and dispersion in Winam Gulf, Lake Victoria

Lagrangian transport in a circular lake: effect of nonlinearity and the second vertical mode

The baroclinic response to wind in a multiarm multibasin reservoir

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