Comparison of dissipation of turbulent kinetic energy determined from shear and temperature microstructure
A total of 826 temperature and shear microstructure profiles, measured during 12 days during March 1996 in Lake NeuchÔtel (Switzerland), are used to compare estimates of turbulent kinetic energy dissipation, determined by the Batchelor (ÁT; temperature) and the shear (ÁS; shear) methods. Positioned horizontally 35 m apart, the two different profiles were raised through the nearly homogeneous surface boundary layer. The collected time series covered two different atmospheric forcings, including calm (almost equal to 1 m s -1) and windy (> 10 m s -1) periods, as well as periods of thermally-induced convection kg(-1). The comparison of the 72'674 pairs of dissipation estimates, determined from 25 cm long vertical profile segments, reveals excellent agreement for the bulk of the estimates, with deviations smaller than a factor of 2. In a relatively small subset, collected under strong heating, deviations of up to a factor of 6 occur in 1-4 m depth. These deviations are, however, just about within the 95% confidence limits of the bootstrap distribution. Under low turbulence, the ÁT method tends to provide slightly larger dissipation, whereas for high wind-induced turbulence the ÁS method gives larger dissipation.
Bibliographic Reference: Article: Journal of Marine Systems, Vol. 21 (1999) pp. 67-84
Availability: Journal of Marine Systems
Record Number: 200012143 / Last updated on: 2000-08-10
Original language: en
Available languages: en