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The seasonal evolution of high vertical鈥搈ode internal waves in a deep reservoir

The causal mechanism and seasonal evolution of the internal wave field in a deep, warm, monomictic reservoir are examined through the analysis of field observations and numerical techniques. The study period extends from the onset of thermal stratification in the spring until midsummer in 2005. During this time, wind forcing was periodic, with a period of 24 h (typical of land鈥搒ea breezes), and the thermal structure in the lake was characterized by the presence of a shallow surface layer overlying a thick metalimnion, typical of small to medium sized reservoirs with deep outtakes. Basin-scale internal seiches of high vertical mode (ranging from mode V3 to V5) were observed in the metalimnion. The structure of the dominant modes of oscillation changed as stratification evolved on seasonal timescales, but in all cases, their periods were close to that of the local wind forcing (i.e., 24 h), suggesting a resonant response. Nonresonant oscillatory modes of type V1 and V2 became dominant after large frontal events, which disrupted the diurnal periodicity of the wind forcing

漏 Limnology and Oceanography, 2007, vol. 52, n煤m. 6, p. 2656-2667

Association for the Sciences of Limnology and Oceanography (ASLO)

Author: Vidal Hurtado, Javier
Rueda, Francisco J.
Casamitjana, Xavier
Date: 2007
Abstract: The causal mechanism and seasonal evolution of the internal wave field in a deep, warm, monomictic reservoir are examined through the analysis of field observations and numerical techniques. The study period extends from the onset of thermal stratification in the spring until midsummer in 2005. During this time, wind forcing was periodic, with a period of 24 h (typical of land鈥搒ea breezes), and the thermal structure in the lake was characterized by the presence of a shallow surface layer overlying a thick metalimnion, typical of small to medium sized reservoirs with deep outtakes. Basin-scale internal seiches of high vertical mode (ranging from mode V3 to V5) were observed in the metalimnion. The structure of the dominant modes of oscillation changed as stratification evolved on seasonal timescales, but in all cases, their periods were close to that of the local wind forcing (i.e., 24 h), suggesting a resonant response. Nonresonant oscillatory modes of type V1 and V2 became dominant after large frontal events, which disrupted the diurnal periodicity of the wind forcing
Format: application/pdf
ISSN: 0024-3590 (versi贸 paper)
1939-5590 (versi贸 electr貌nica)
Document access: http://hdl.handle.net/10256/9718
Language: eng
Publisher: Association for the Sciences of Limnology and Oceanography (ASLO)
Collection: Reproducci贸 digital del document publicat a: http://dx.doi.org/10.4319/lo.2007.52.6.2656
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Is part of: 漏 Limnology and Oceanography, 2007, vol. 52, n煤m. 6, p. 2656-2667
Rights: Tots els drets reservats
Subject: Hidrodin脿mica
Hydrodynamics
Ones -- Models matem脿tics
Waves -- Mathematical models
Title: The seasonal evolution of high vertical鈥搈ode internal waves in a deep reservoir
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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