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ADVEX, the CarboEurope-IP advection campaigns: Overview paper, Norunda nights C. Feigenwinter 1,7 and the ADVEX teams 1,2,3,4,5,6 1 Gembloux Agricultural University, Physique des Bio-systèmes, Gembloux, Belgium (FUSAGx)
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ADVEX, the CarboEurope-IP advection campaigns: Overview paper, Norunda nights C. Feigenwinter1,7 and the ADVEX teams1,2,3,4,5,6 1 Gembloux Agricultural University, Physique des Bio-systèmes, Gembloux, Belgium (FUSAGx) 2 TU Dresden, Institute of Hydrology and Meteorology, Department of Meteorology, Dresden, Germany (TUD) 3 Max Planck Institute for Biogeochemistry, Jena, Germany (MPI-BGC) 4 University of Lund, Physical Geography and Ecosystems Analysis, Lund, Sweden (LUND) 5 Autonomous Province of Bolzano, Forest Service, Agency of Environment, Bolzano, Italy (APB) 6 Institute of System Biology and Ecology, Laboratory of Plants Ecological Physiology, Brno, Czech Republic (ILE) 7 University of Basel, Institute of Meteorology, Climatology and Remote Sensing, Basel, Switzerland (MCR)
Current state of the ADVEX overview paper uncorrected proof availabledoi:10.1016/j.agrformet.2007.08.013corrected proof available online soon…
ADVEX overview paper summary: advection and flow direction at night
Hotspot Norunda : two independent measurements show same phenomenon (tower B)
Hotspot Norunda : comparison with Renon and Wetzstein Nights with large site specific vertical CO2 gradients 360…537 ppm 360…395 ppm 360…425 ppm
Hotspot Norunda : high CO2 concentrations (420 ppm) up to 100 m
Hotspot Norunda : unrealistic high values for horizontal advection
Hotspot Norunda : impacts on components of NEE EC-flux: Occasional high positive fluxes during the night (up to 10 mmol m-2 s-1) despite low u* values. Storage: large variability of the storage flux, but in the average the common picture for forests with CO2 accumulation during the night and sudden „flush out“ after sunrise Vertical advection: temporal differences in sign between towers probably related to incomplete tilt correction algorithms (planar fit). Temporarily large fluxes but nightly average is often close to zero. Horizontal advection: extremely large (unrealistic) fluxes caused by large horizontal gradients in crown space.
Hotspot Norunda : in canopy turbulence increases when top canopy turbulence is low