Turbulent exchange of CO over a broadleaf-Korean pine forest in Changbai Mountain, northeast China

Abstract

Turbulent exchange of CO₂ was measured continuously via the open-path eddy covariance technique over a broadleaf-Korean pine forest in Changbai Mountain, northeast China. The results show that with near-neutral atmospheric stratification, CO₂ and vertical wind components measured over the forest canopy in the inertial sub-range followed the expected -2/3 power law. The dominant vertical eddy scale was about 100 m. The frequency ranges of eddy contributions to CO₂ fluxes were mostly within 0.01–2.0 Hz. Large eddies with low frequency over the canopy contributed more to CO₂ fluxes than small eddies. The open-path eddy covariance system could satisfy the estimation of turbulent fluxes over the canopy, but the CO₂ fluxes between forest and atmosphere were generally underestimated at night because of the increment non-turbulent processes, suggesting that the CO₂ fluxes estimated under weak turbulence need to be revised correspondingly.

Keywords

broadleaf-Korean pine forest / eddy covariance method / CO₂ flux / turbulent exchange