Vertical propagation of lakewide internal waves

Henderson, Stephen M.; Deemer, Bridget R.

doi:10.1029/2011gl050534

Cited by 15 publications

(37 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since wave periods were comparable to the inertial period (17 h), theory suggests that along‐lake flows persisted sufficiently long to be deflected toward the across‐lake direction by Coriolis. Previously, for locations above the BBL, Henderson and Deemer [] found that substantial flow deflection was prevented by across‐lake tilting of isotherms and resulting baroclinic pressure gradients. Next, for locations within the BBL, it will be shown that major deflection was likely also prevented by baroclinic pressure gradients.…”

Section: Overview Of Observationsmentioning

confidence: 97%

“…Velocities in this lake are dominated by fluctuations of a few cm/s, with periods in the range 0.4–1 day. These fluctuations result from a vertically propagating internal seiche, with upward phase propagation, horizontal wavelength about twice the lake length, and vertical wavelength less than the lake depth [ Henderson and Deemer , ]. Outside the BBL, velocities were predominantly directed along the long axis of the narrow lake.…”

Section: Field Site and Instrumentationmentioning

confidence: 99%

“…Outside the BBL, velocities were predominantly directed along the long axis of the narrow lake. The force required to prevent Coriolis from deflecting the along‐lake flows into the across‐lake direction is provided by across‐lake baroclinic pressure gradients (i.e., an approximate across‐lake thermal wind balance is observed [ Henderson and Deemer , ]). Near the center of the lake, where measurements were made, the internal seiche likely resembles a pair of internal Kelvin waves, one propagating along each shore, and both propagating vertically.…”

Section: Field Site and Instrumentationmentioning

confidence: 99%

“…All were followed, after 0.8–2.2 days, by peaks in wave energy flux and boundary layer turbulent production (Figure e). The lag is comparable to the time taken for internal waves to propagate to the lakebed [ Henderson and Deemer , ]. A fourth peak in lakebed production, on day 166, was unexplained by any burst in measured wind stress (Figure ).…”

Section: Energy Balancementioning

confidence: 99%

“…Field observations of seiches have usually been compared with vertically standing models [e.g., LaZerte , ; Münnich et al ., ; Pannard et al ., ], but in a small lake, Henderson and Deemer [] observed vertical seiche propagation. Vertical propagation aside, the waves observed by Henderson and Deemer [] resembled standard seiches: they were likely generated by winds, with a standing‐wave pattern in the horizontal and a horizontal wavelength about twice the lake length. Reexamination of published observations reveals other cases of vertical propagation [e.g., Serra et al ., , Figure ; LaZerte , , Figures and ; Vidal et al ., , Figures and ].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Turbulent production in an internal wave bottom boundary layer maintained by a vertically propagating seiche

Henderson

2016

JGR Oceans

Self Cite

View full text Add to dashboard Cite

Internal seiches, which supply the energy responsible for mixing many lakes, are often modeled as vertically standing waves. However, recent observations of vertical seiche propagation in a small lake are inconsistent with the standard, vertically standing model. To examine the processes responsible for such propagation, drag and turbulent production in the bottom boundary layer of a small lake are related to the energy supplied by a propagating seiche (period 10–24 h). Despite complex and fluctuating stratification, which often inhibited mixing within 0.4 m of the bed, bottom stress was well represented by a simple drag coefficient model (drag coefficient 1.5 × 10−3). The net supply of seiche energy to the boundary layer was estimated by fitting a model for internal wave vertical propagation to velocity profiles measured above the boundary layer (1–4.5 m above lakebed). Fitted reflection coefficients ranged from 0.3 at 1 cycle/d frequency to 0.7 at 2.4 cycles/d (cf. near‐unity coefficients of classical seiche theories). The net supply of seiche energy approximately balanced boundary layer turbulent production. Three of four peaks in production and energy flux occurred 0.8–2.2 days after strong oscillating winds, a delay comparable to the time required for seiche energy to propagate to the lakebed. A model based on the estimated drag coefficient predicted the observed frequency dependence of the seiche reflection coefficient. For flat‐bed regions in narrow lakes, the model predicts that reflection is controlled by the ratio of water velocity to vertical wave propagation speed, with sufficiently large ratios leading to weak reflection, and clear vertical seiche propagation.

show abstract

Section: Overview Of Observationsmentioning

confidence: 97%

Section: Field Site and Instrumentationmentioning

confidence: 99%

Section: Field Site and Instrumentationmentioning

confidence: 99%

Section: Energy Balancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Turbulent production in an internal wave bottom boundary layer maintained by a vertically propagating seiche

Henderson

2016

JGR Oceans

Self Cite

View full text Add to dashboard Cite

show abstract

Chemical mixing in the bottom boundary layer of a eutrophic reservoir: The effects of internal seiching on nitrogen dynamics

Deemer

Henderson

Harrison

2015

Limnology & Oceanography

Self Cite

View full text Add to dashboard Cite

In lakes and reservoirs, the bottom boundary layer (BBL) mediates chemical fluxes between sediments and the overlying water column. At the internal shoreline, where the thermocline contacts the lakebed, the motions of internal waves can create fluctuating redox conditions and dynamic physical forcing that may support ecologically important reactions such as denitrification. We characterized physical and chemical dynamics within the internal shoreline of a eutrophic reservoir during the spring and early summer of 2012 (18 May to 18 July). An internal seiche was found to generate quasi-periodic fluctuations (periods about 12-24 h) in BBL stratification, temperature, and redox conditions. To examine possible implications for chemical mixing and microbial processing, differences between vertically offset, simultaneous BBL measurements of velocity, temperature, N 2 , and N 2 O were made over 23 h. Vertical differences in BBL temperature, N 2 , and N 2 O formed and collapsed during the wave cycle, with the largest differences occurring following the arrival of an internal bore. Through much of the wave cycle, chemical differences were explained by physical advection and mixing. However, chemical differences measured after bore arrival were not explained by advection, possibly owing to local production of N 2 and N 2 O. These results highlight the dynamic physical environment within the internal shoreline, and the potential of this zone to contribute to system wide denitrification and nitrous oxide production.

show abstract

Effects of riverine inflows on the climatology of a tropical Andean reservoir

Posada-Bedoya

Gómez-Giraldo

Román-Botero

2021

Limnology & Oceanography

View full text Add to dashboard Cite

Field data and numerical modeling were used to investigate the effects of the riverine inflows on the seasonality of the lake mean temperature, thermal structure, and basin‐scale internal waves in a tropical Andean reservoir. Lake temperature and external forcing were measured during contrasting hydrological periods modulated by severe cold (2011–2012) and warm (2015–2016) phases of El Niño–Southern Oscillation (ENSO), a major driver of Andes hydrology. The seasonal heat budget of the reservoir was driven by the competing rates of cooling by the inflow and heating through the surface. As the atmospheric heating rate remained roughly constant, the seasonality of the river inflow heat flux drove the seasonal reservoir temperature. The inflow also intervened on the heat transport within the reservoir and, during dry periods, mixed heat downward from the surface layer and introduced heat at intermediate depths such that a thick metalimnion formed that brought the V2H1 mode into resonance with the diurnal wind forcing. During wet periods, the inflow compressed and cooled the metalimnion, tuning the V1H1 mode to resonate with the diurnal wind. It was also observed that large inflows destroyed temporarily coherent basin‐scale internal wave motions. Because of the dominant role of the inflow on the seasonal reservoir temperature, changes within the reservoir will be more strongly related to changing temperature and volume of the incoming water than atmospheric forcing as in many large natural lakes.

show abstract

Vertical propagation of lakewide internal waves

Cited by 15 publications

References 33 publications

Turbulent production in an internal wave bottom boundary layer maintained by a vertically propagating seiche

Turbulent production in an internal wave bottom boundary layer maintained by a vertically propagating seiche

Chemical mixing in the bottom boundary layer of a eutrophic reservoir: The effects of internal seiching on nitrogen dynamics

Effects of riverine inflows on the climatology of a tropical Andean reservoir

Contact Info

Product

Resources

About