at Google ScholarTitle data
Ruppert, Johannes ; Thomas, Christoph ; Foken, Thomas:
Scalar similarity for relaxed Eddy accumulation methods.
In: Boundary-Layer Meteorology.
Vol. 120
(2006)
Issue 1
.
- pp. 39-63.
ISSN 1573-1472
DOI: https://doi.org/10.1007/s10546-005-9043-3
Abstract in another language
The relaxed eddy accumulation (REA) method allows the measurement of trace gas fluxes when no fast sensors are available for eddy covariance measurements. The flux parameterisation used in REA is based on the assumption of scalar similarity, i. e. similarity of the turbulent exchange of two scalar quantities. In this study changes in scalar similarity between carbon dioxide, sonic temperatureand water vapour were assessed using scalar correlation coefficients and spectral analysis. The infuence on REA measurements was assessed by simulation. The evaluation is based on data recorded during experiments over grassland, irrigated cotton plantation and spruce forest. Scalar similarity between carbon dioxide, sonic temperature and water vapour showed a distinct diurnal pattern and change within the day. Poor scalar similarity was found to be linked to dissimilarities in the energy contained in the low frequency part of the turbulent spectra (< 0.01 Hz).The simulations of REA showed signifcant change in b-factors throughout the diurnal course. The b-factor is part of the REA parameterisation scheme and describes a relation between the concentration diverence and the flux of a trace gas. The diurnal course of b-factors for carbon dioxide, sonic temperature and water vapour matched well. Relative °ux errors induced in REA by varying scalar similarity were generally below +/-10 %. Systematic underestimation of the flux of up to -40% was found for the use of REA applying a hyperbolic deadband (HREA).This underestimation was addressed to poor scalar similarity between the scalar of interest and the scalar used as proxy for the deadband definition.
Further data
| Item Type: | Article in a journal |
|---|---|
| Refereed: | Yes |
| Additional notes: | BAYCEER33801 |
| Institutions of the University: | Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Professor Micrometeorology Research Institutions > Research Centres > Bayreuth Center of Ecology and Environmental Research- BayCEER Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Professor Micrometeorology > Professor Micrometeorology - Univ.-Prof. Dr. Christoph K. Thomas Faculties Faculties > Faculty of Biology, Chemistry and Earth Sciences Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences Research Institutions Research Institutions > Research Centres |
| Result of work at the UBT: | No |
| DDC Subjects: | 500 Science |
| Date Deposited: | 24 Apr 2015 11:56 |
| Last Modified: | 16 Jan 2020 08:36 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/11449 |