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Titre du document / Document title

The effect of light extinction on thermal stratification in reservoirs and lakes

Auteur(s) / Author(s)

HOCKING G. C. (1) ; STRASKRABA M. (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Mathematics and Statistics, Division of Science, Murdoch University, Murdoch, Western Australia 6150, AUSTRALIE
(2) Faculty of Biological Sciences, University of Southern Bohemia and Institute of Entomology, Acad. Sci. Czech Republic, Branišovská 31, 37005 České Budějovice, TCHEQUE, REPUBLIQUE

Résumé / Abstract

An examination is made of the effect of light attenuation in the water column on the hydrodynamics and in particular on temperature stratification in reservoirs. Numerical experiments are described which examine the differences in light profile in the water column when the spectral character of the incident radiation and light penetration is and is not taken into account. It was found that the exponential character of light penetration remains but the exponent may be increased by up to 20% in clear waterbodies and less in waterbodies with higher extinction values when I0(λ) and Kd(λ) are incorporated. The error may be higher when the spectral character of the extinction is due to colored organics rather than phytoplankton. The numerical, one dimensional hydrodynamic model DYRESM is used to isolate and examine the influence of changing the light attenuation in the water column in a reservoir, and on its hydrodynamics, when keeping other conditions unchanged. Not surprisingly, the simulations show that when the extinction rate increases, mixing depth decreases markedly, and although the same energy enters the water column, surface temperatures increase slightly while deep temperatures decrease. Some other surprising effects were found and are described. The results presented and comparison of the model results with real-world data indicate that the pronounced dependence of mixing depth on light extinction is a general phenomenon which cannot be ignored.

Revue / Journal Title

International review of hydrobiology    ISSN  1434-2944 

Source / Source

1999, vol. 84, no6, pp. 535-556 (1 p.3/4)

Langue / Language

Anglais

Editeur / Publisher

Wiley-VCH, Weinheim, ALLEMAGNE  (1998) (Revue)

Mots-clés anglais / English Keywords

Thermal stratification

;

Light

;

Luminescence quenching

;

Depth

;

Hydrodynamic model

;

Simulation model

;

Lakes

;

Impoundment

;

Freshwater environment

;

Environmental factor

;

Mots-clés français / French Keywords

Stratification thermique

;

Lumière

;

Extinction luminescence

;

Profondeur

;

Modèle hydrodynamique

;

Modèle simulation

;

Lac

;

Bassin retenue

;

Milieu eau douce

;

Facteur milieu

;

Mots-clés espagnols / Spanish Keywords

Estratificación térmica

;

Luz

;

Extinción luminiscencia

;

Profundidad

;

Modelo hidrodinámico

;

Modelo simulación

;

Lago

;

Presa retención

;

Medio agua dulce

;

Factor medio

;

Localisation / Location

INIST-CNRS, Cote INIST : 1356, 35400008097918.0010

Nº notice refdoc (ud4) : 1202655



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