Estimating the storage term in eddy covariance measurements: the ICOS methodology
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| Authors: | L. Montagnani1,2, T. Grünwald3, A. Kowalski4,5, I. Mammarella6, L. Merbold7,8, S. Metzger9,10, P. Sedlák11,12, L. Siebicke13 1Faculty of Science and Technology, Free University of Bolzano, Piazza Università 1, 39100 Bolzano, Italy 2Forest Services, Autonomous Province of Bolzano, Via Brennero 6, 39100 Bolzano, Italy 3Technical University Dresden, Institute of Hydrology and Meteorology, Tharandt, Germany 4Department of Applied Physics of the University of Granada, Granada, 18071, Spain 5Andalusian Centre for Environmental Research (CEAMA-IISTA), Granada, 18071, Spain 6Department of Physics, University of Helsinki, Helsinki, P.O. Box 68, 00014, Finland 7Mazingira Centre, International Livestock Research Institute (ILRI), P.O. Box 30709, 00100, Nairobi, Kenya 8Department of Environmental System Sciences, Institute of Agricultural Sciences, ETH Zurich, Universitaetsstrasse 2, 8092 Zurich, Switzerland 9National Ecological Observatory Network, Battelle, 1685 38th Street, CO 80301 Boulder, USA 10Department of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, 1225 West Dayton Street, Madison, WI 53706, USA 11Institute of Atmospheric Physics CAS, Bocni II 1401, 14131 Praha 4, Czech Republic 12Department of Matter and Energy Fluxes, Global Change Research Institute, CAS, Bělidla 986/4a, 603 00 Brno, Czech Republic 13University of Goettingen, Bioclimatology, Büsgenweg 2, 37077 Göttingen, Germany |
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| Abstract : | In eddy covariance measurements, the storage flux represents the variation in time of the dry molar fraction of a given gas in the control volume representative of turbulent flux. Depending on the time scale considered, and on the height above ground of the measurements, it can either be a major component of the overall net ecosystem exchange or nearly negligible. Instrumental configuration and computational procedures must be optimized to measure this change at the time step used for the turbulent flux measurement. Three different configurations are suitable within the Integrated Carbon Observation System infrastructure for the storage flux determination: separate sampling, subsequent sampling and mixed sampling. These configurations have their own advantages and disadvantages, and must be carefully selected based on the specific features of the considered station. In this paper, guidelines about number and distribution of vertical and horizontal sampling points are given. Details about suitable instruments, sampling devices, and computational procedures for the quantification of the storage flux of different GHG gases are also provided. |
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| Keywords : | ICOS, protocol, storage flux, eddy covariance, greenhouse gases | ||||||||||
| Language : | English | ||||||||||