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The structure and dynamics of internal waves in Baldeggersee 1
Author(s) -
Lemmin U.
Publication year - 1987
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.1987.32.1.0043
Subject(s) - seiche , internal wave , geology , stratification (seeds) , buoyancy , spectral line , structural basin , spectral analysis , asymmetry , dominance (genetics) , mode (computer interface) , geophysics , physics , mechanics , spectroscopy , seismology , geomorphology , oceanography , chemistry , computer science , biology , operating system , biochemistry , germination , quantum mechanics , seed dormancy , botany , astronomy , dormancy , gene
Analysis of long records of temperature/depth distribution determined at 10‐ or 20‐min intervals at several stations and extending over three stratification seasons, provides a detailed picture of the characteristics, dynamics, and seasonal variation in activity of internal waves in a small lake (Baldeggersee, Switzerland). Wind stress in general was low, with occasional bursts of higher energy. The ensuing, slightly damped internal seiches govern the dynamics of the stratified lake. The vertical structure displays a dominant response of the first vertical mode. Responses in the second vertical mode, hitherto rarely recorded, are also demonstrated with the help of spectral analysis and models. The horizontal structure of the seiches motion displays dominance and persistence of the fundamental basin mode. Spectral analysis also discloses responses of the second and third basin modes. Multiplying of the spectra with the local buoyancy frequency leads to a collapse of all spectra into a narrow band, pointing toward the possibility of a universal spectrum. New light is shed on apparently common examples of waveform asymmetry and on their interpretation. It is concluded that, in this small‐basin, low‐energy example, internal waves provide motions at all levels, but little vertical mixing.