edu.ucar.opensky::articles:12254 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T04:09:39.405774 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d72b8zs4 First direct measurements of formaldehyde flux via eddy covariance: Implications for missing in-canopy formaldehyde sources 2011-10-26T00:00:00Z publication https://n2t.org/ark:/85065/d72b8zs4 https://doi.org/10.5194/acp-11-10565-2011 DiGangi, J. author Boyle, E. author Karl, Thomas author Harley, Peter author Turnipseed, Andrew A. author Kim, Saewung author Cantrell, Chris A. author Mauldin, Roy author Zheng, Wengang author Flocke, Frank M. author Hall, Samuel R. author Ullmann, Kirk author Nakashima, Y. author Paul, J. author Wolfe, G. author Desai, A. author Kajii, Y. author Guenther, Alex B. author Keutsch, F. author UCAR/NCAR - Library publisher We report the first observations of formaldehyde (HCHO) flux measured via eddy covariance, as well as HCHO concentrations and gradients, as observed by the Madison Fiber Laser-Induced Fluorescence Instrument during the BEACHON-ROCS 2010 campaign in a rural, Ponderosa Pine forest northwest of Colorado Springs, CO. A median noon upward flux of ~80 μg m⁻² h⁻¹ (~24 pptv m s⁻¹) was observed with a noon range of 37 to 131 μg m⁻² h⁻¹. Enclosure experiments were performed to determine the HCHO branch (3.5 μg m⁻² h⁻¹) and soil (7.3 μg m⁻² h⁻¹) direct emission rates in the canopy. A zero-dimensional canopy box model, used to determine the apportionment of HCHO source and sink contributions to the flux, underpredicted the observed HCHO flux by a factor of 6. Simulated increases in concentrations of species similar to monoterpenes resulted in poor agreement with measurements, while simulated increases in direct HCHO emissions and/or concentrations of species similar to 2-methyl-3-buten-2-ol best improved model/measurement agreement. Given the typical diurnal variability of these BVOC emissions and direct HCHO emissions, this suggests that the source of the missing flux is a process with both a strong temperature and radiation dependence. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 License. None eng geoscientificInformation