Session 18B.2 Using the TLS system to improve understanding of atmospheric turbulent processes

Friday, 13 June 2008: 1:45 PM
Aula Magna Höger (Aula Magna)
Florence Bocquet, CIRES/Univ. of Colorado, Boulder, CO; and B. B. Balsley, M. Tjernstrom, and G. Svensson

Presentation PDF (253.1 kB)

Our analyses of the dissipation rate of kinetic energy (ε) as a proxy for turbulence using a custom-built Tethered Lifting System (TLS) are directed towards improving our understanding of atmospheric turbulent processes. This technique could be used over a range of environmental conditions, locations, and spatial and temporal resolutions in hope that insights from such measurements will be incorporated in regional and global climate models.

Measurements of ε in the nocturnal stable boundary layer show values as low as about 10-7 m2 s-3. When compared to tower measurements of turbulence by means of σ w 2, data reveal a good correlation. Our results show that a) even in the most stable boundary layer, a “residual” turbulence is always present, and b) ε observations are useful even at low turbulence levels. Measuring ε with the TLS system also provides identification of the boundary layer type, its height, and dynamical characteristics. Furthermore, depending on environmental conditions, TLS measurements of turbulence are much less sensitive to the averaging timescale than standard tower measurements.

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