The CEIP-ADVEX Campaigns: An Experimental Approach to Measure Advective CO2 Fluxes and Their Impact on NEE at Three European FLUXNET Forest Sites

HR: 11:50h
AN: B32B-07 [Abstracts]
TI: The CEIP-ADVEX Campaigns: An Experimental Approach to Measure Advective CO2 Fluxes and Their Impact on NEE at Three European FLUXNET Forest Sites
AU: * Feigenwinter, C
EM: feigenwinter@metinform.ch
AF: Faculté Universitaire des Sciences Agronomiques de Gembloux, Unité de Physique des Biosystèmes, Av. de la Faculté 8, Gembloux, 5030, Belgium
AU: * Feigenwinter, C
EM: feigenwinter@metinform.ch
AF: University of Basel, Institute of Meteorology, Climatology and Remote Sensing, Klingelbergstr. 27, Basel, 4056, Switzerland
AU: Bernhofer, C
AF: TU Dresden, Department of Meteorology, Helmholtzstr. 10, Dresden, 01069, Germany
AU: Eichelmann, U
AF: TU Dresden, Department of Meteorology, Helmholtzstr. 10, Dresden, 01069, Germany
AU: Heinesch, B
AF: Faculté Universitaire des Sciences Agronomiques de Gembloux, Unité de Physique des Biosystèmes, Av. de la Faculté 8, Gembloux, 5030, Belgium
AU: Hertel, M
AF: Max Planck Institute for Biogeochemistry, Hans-Knoell Str. 10, Jena, 07745, Germany
AU: Janous, D
AF: Institute of System Biology and Ecology, Porici 3b, Brno, 60300, Czech Republic
AU: Kolle, O
AF: Max Planck Institute for Biogeochemistry, Hans-Knoell Str. 10, Jena, 07745, Germany
AU: Lagergren, F
AF: University of Lund, Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362, Sweden
AU: Lindroth, A
AF: University of Lund, Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362, Sweden
AU: Minerbi, S
AF: Autonomous Province of Bolzano, Forest Service, Brennerstr. 6, Bolzano, 39100, Italy
AU: Moderow, U
AF: TU Dresden, Department of Meteorology, Helmholtzstr. 10, Dresden, 01069, Germany
AU: Moelder, M
AF: University of Lund, Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362, Sweden
AU: Montagnani, L
AF: Autonomous Province of Bolzano, Forest Service, Brennerstr. 6, Bolzano, 39100, Italy
AU: Queck, R
AF: TU Dresden, Department of Meteorology, Helmholtzstr. 10, Dresden, 01069, Germany
AU: Rebmann, C
AF: Max Planck Institute for Biogeochemistry, Hans-Knoell Str. 10, Jena, 07745, Germany
AU: Vestin, P
AF: University of Lund, Physical Geography and Ecosystems Analysis, Solvegatan 12, Lund, 22362, Sweden
AU: Yernaux, M
AF: Faculté Universitaire des Sciences Agronomiques de Gembloux, Unité de Physique des Biosystèmes, Av. de la Faculté 8, Gembloux, 5030, Belgium
AU: Zeri, M
AF: Max Planck Institute for Biogeochemistry, Hans-Knoell Str. 10, Jena, 07745, Germany
AU: Ziegler, W
AF: Max Planck Institute for Biogeochemistry, Hans-Knoell Str. 10, Jena, 07745, Germany
AU: Aubinet, M
AF: Faculté Universitaire des Sciences Agronomiques de Gembloux, Unité de Physique des Biosystèmes, Av. de la Faculté 8, Gembloux, 5030, Belgium
AB: This study presents mean characteristics of the advective CO₂ fluxes in a first site-to-site comparison and evaluates the main problems for future investigation of advection mechanisms. Extensive field measurements have been performed at three European FLUXNET forest sites with different topography (Renon/Ritten, Italian Alps, Italy; Wetzstein, Thuringia, Germany; Norunda, Uppland, Sweden) to evaluate the relevant terms of the carbon balance by measuring CO₂ concentrations and the wind field in a 3D multi-tower cube setup [1]. The same experimental setup (geometry and instrumentation) and the same methodology for the calculation of the advective fluxes were applied to all the three experiments in order to provide a reliable base for a comprehensive site to site comparison. We present mean diurnal/nocturnal courses of all relevant terms of the carbon balance equation, i.e. turbulent flux, storage change and horizontal and vertical advection. It is shown that all sites are affected by advection in different ways and strength. The size of the averaged non-turbulent advective fluxes was of the same order of magnitude as the turbulent flux measured by eddy-covariance technique, but with considerable scatter. This implies that it is not advisable to use directly measured quantities of the non-turbulent advective fluxes for the estimation of net ecosystem exchange (NEE) on e.g. a hourly basis, though there may be useful information for a better understanding of the steering mechanisms of advection in this noisy data. Nevertheless, situations with and without advection were closely related to local or synoptic meteorological conditions and the topography of the respective site. Thus, it is possible to separate advection affected NEE estimates from fluxes which are representative of the source term. The main goal of ongoing analysis of the ADVEX data set is the development of a robust correction scheme for advection, based on a more detailed site specific analysis of single events for the identification of the relevant processes. [1] Feigenwinter, C., Bernhofer, C., Eichelmann, U., Heinesch, B., Hertel, M., Janous, D., Kolle, O., Lagergren, F., Lindroth, A., Minerbi, S., Moderow, U., Moelder, M., Montagnani, L., Queck, R., Rebmann, C., Vestin, P., Yernaux, M., Zeri, M., Ziegler, W. and Aubinet, M., 2007, Comparison of horizontal and vertical advective CO₂ fluxes at three forest sites. Agric. Forest Meteorol., in press
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0428 Carbon cycling (4806)
DE: 0439 Ecosystems, structure and dynamics (4815)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting