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Horizontal transport and dispersion in the surface layer of a medium‐sized lake
Author(s) -
Stocker Roman,
Imberger Jörg
Publication year - 2003
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.2003.48.3.0971
Subject(s) - drifter , internal wave , dispersion (optics) , vorticity , mechanics , kinematics , geology , shear (geology) , physics , lagrangian , optics , classical mechanics , vortex , petrology , mathematical physics
Lagrangian GPS drifter experiments, carried out in the surface layer of stratified Lake Kinneret (Israel), are presented. Differential kinematic properties and Lagrangian statistics were calculated and used to estimate the dominant mechanisms for horizontal dispersion. On time scales smaller than a few internal wave periods, internal waves lead to strong divergence and convergence events, causing instantaneous apparent horizontal growth rates that were larger, by up to an order of magnitude, than the actual mean dispersion coefficient. It is shown that the internal wave field modulated the vorticity field so as to satisfy conservation of potential vorticity. On time scales larger than a few internal wave periods, unbounded horizontal shear dispersion was of the same order as the actual mean observed dispersion coefficient (K xy = 17.1 m 2 s −1 ), while vertical shear dispersion was negligible.