D28: Internal seiche mixing study - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D28: Internal seiche mixing study
FP5_Contract No.: EVK1-CT1999-00004
Version: 1.2
Date: 24.08.2004
File: D28.doc
Page 92 of 92
al., 1998). These waves and their breaking play a role in the production and redistribution
of currents and stratification as well as mixing (Thorpe and Jiang, 1998). From our
studies it appears that short progressive internal waves are often produced in the passage
of non-linear internal seiches (Thorpe et al., 1996).
The measured characteristics of the velocity time series (namely the non-linear wave) in
the case of a strong wind event could be reproduced. In addition, the good agreement
of the measured and computed structure of the temperature profile suggest that the
turbulence model yields reasonable turbulent diffusivities.
6.3 LAKE CONSTANCE (BODENSEE)
The method of calculating the eigen-periods of free internal oscillations in a two-layermodel
also permits a relatively simple evaluation of the influence of the stratification on
the eigen-periods. But also the variation of the structure with respect to the stratification
is calculated at the same time and provides the characteristical differences, which result
from strong or diminishing influence of the earth´s rotation via varying stratification.
The application of the eigen-value method should be calculated for other lakes in order
permit the comparison and evaluation of the lake-specific characteristics
6.4 LOCH LOMOND
In order to obtain a clearer picture of the kind of temperature fluctuations occurring in
the upper water column in Loch Lomond the thermistor recordings from both north and
mid basin locations were analysed statistically for the period of 8 th August and 18 th
September 2002. Frequency analysis provides a few conspicuous periods ranging between
about 5 hours and 24 hours.