Eddy covariance relaxed

Kddy covariance, eddy accitnuilafion, relaxed eddy accumulation Surface flux (sensor above canopy) or flux profile (sensor within canopy) Steady, horizontally uniform X = 1 km, T = 30 min... 

The vertical concentration profiles of biogenic VOCs in a forest canopy were measured, and there were major differences in VOC emission between daytime and nighttime [70,71]. The canopy fluxes of isoprenoids above the Norway spruce forest were determined by GC and PTR-MS with relaxed eddy accumulation (REA) method [72], In the use of REA, samples were analyzed at two different reservoirs, which depended on the direction of the vertical wind w ( up-draught reservoir in case of w > 0 and down-draught reservoir in case of w < 0). Subsequently, the diurnal variation of biogenic VOCs was measured at 12 m (in the treetop) and at 24 m (above the canopy) [73], By using PTR-MS coupled with the eddy covariance technique and GC-flame ionization detector (FID) with a REA system, the mixing ratios and fluxes of total monoterpenes, from a ponderosa pine plantation [74] and from Scots pine... 

Lee et al. used PTR-MS and eddy covariance methods to determine mixing ratios and fluxes of total monoterpenes above a ponderosa pine plantation [34], The results from these studies were compared to those obtained using GC-FID and a relaxed eddy accumulation system. It was found that the daytime measurements resulted in values that agreed well with each other. However, at night PTR-MS detected additional reactive terpenes which... 

EC = Eddy covariance DEC = disjunct eddy covariance vDEC = virtual disjunct eddy covariance REA = relaxed eddy accumulation EM = enclosure method CBL = conveaive boundary layer budgeting MEG = mixed layer gradient MLV = mixed layer variance. 

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