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Modeling the diurnal mixed layer
Author(s) -
Spigel Robert H.,
Imberger Jorg,
Rayner Kenneth N.
Publication year - 1986
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1986.31.3.0533
Subject(s) - mixed layer , kinetic energy , advection , energetics , mechanics , turbulence kinetic energy , turbulence , atmospheric sciences , momentum (technical analysis) , meteorology , environmental science , physics , thermodynamics , classical mechanics , finance , economics
The numerical model presented here is based on the one‐dimensional equations for momentum,heat, salt, and turbulent kinetic energy integrated over the diurnal mixed layer. Two noteworthyfeatures are the inclusion of the energetics of billowing due to Kelvin‐Helmholtz instability at thebase of the mixed layer, and a closure hypothesis which retains average mixed‐layer turbulentkinetic energy as an explicit variable, rather than assuming it to be a fixed proportion of externalenergy input. The importance of both these features is illustrated in the application of the modelto the data for 1 day which included several mixing processes: a fairly calm morning with uninterruptedsolar heating, followed by rapid mixed‐layer deepening during a strong afternoon seabreeze, and finally a relatively cool night with little wind. The data contain rapidly changingmeteorological inputs as well as evidence of strong billow formation and collapse and thus providean ideal test of the importance of both billow energetics and the temporal effects in the turbulentkinetic energy budget. The model does not account for processes occurring below the mixed layernor for the effects of horizontal advection. Within these constraints, model results agree well withmeasured temperatures and represent an improvement over the results of a slab model withoutbillow energetics.