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Modeling of Hcho and Chocho at a Semi-rural Site in Southern China During the Pride-prd2006 Campaign : Volume 13, Issue 12 (17/12/2013)

By Li, X.

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Book Id: WPLBN0003996602
Format Type: PDF Article :
File Size: Pages 42
Reproduction Date: 2015

Title: Modeling of Hcho and Chocho at a Semi-rural Site in Southern China During the Pride-prd2006 Campaign : Volume 13, Issue 12 (17/12/2013)  
Author: Li, X.
Volume: Vol. 13, Issue 12
Language: English
Subject: Science, Atmospheric, Chemistry
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Historic
Publication Date:
2013
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

Description
Description: Institut für Energie- und Klimaforschung Troposphäre (IEK-8), Forschungszentrum Jülich, Jülich, Germany. HCHO and CHOCHO are important trace gases in the atmosphere, serving as tracers of VOCs oxidations. In the past decade, high concentrations of HCHO and CHOCHO have been observed for the Pearl River Delta (PRD) region in southern China. In this study, we performed box model simulations of HCHO and CHOCHO at a semi-rural site in PRD, focusing on understanding their sources and sinks and factors influencing the CHOCHO to HCHO ratio (RGF). The model was constrained by the simultaneous measurements of trace gases and radicals. Isoprene oxidation by OH radicals is the major pathway forming HCHO, followed by degradations of alkenes, aromatics, and alkanes. The production of CHOCHO is dominated by isoprene and aromatic degradation; contributions from other NMHCs are of minor importance. The modeled RGF shows a complex dependence on the VOCs composition, OH and NOx levels, and atmospheric physical processes, which suggest the necessity of careful treatment of RGF as an indicator of anthropogenic or biogenic emissions. Compared to the measurement results, the model predicts significant higher HCHO and CHOCHO concentrations. Sensitivity studies suggest that this discrepancy is to a large extent (>70%) due to the missing consideration of fresh emissions, vertical transport of precursor VOCs, and uptake of HCHO and CHOCHO by aerosols in the model. Insufficient treatments of dry deposition of HCHO and CHOCHO and of vertical dilution of all species in the model account for the rest 30% discrepancy. Our study indicates that, in addition to chemical mechanisms, atmospheric physical processes (e.g., transport, dilution, deposition) have to be well considered for a box model predicting HCHO and CHOCHO concentrations.

Summary
Modeling of HCHO and CHOCHO at a semi-rural site in southern China during the PRIDE-PRD2006 campaign

Excerpt
Choi, W., Faloona, I. C., Bouvier-Brown, N. C., McKay, M., Goldstein, A. H., Mao, J., Brune, W. H., LaFranchi, B. W., Cohen, R. C., Wolfe, G. M., Thornton, J. A., Sonnenfroh, D. M., and Millet, D. B.: Observations of elevated formaldehyde over a forest canopy suggest missing sources from rapid oxidation of arboreal hydrocarbons, Atmos. Chem. Phys., 10, 8761–8781, doi:10.5194/acp-10-8761-2010, 2010.; DiGangi, J. P., Boyle, E. S., Karl, T., Harley, P., Turnipseed, A., Kim, S., Cantrell, C., Maudlin III, R. L., Zheng, W., Flocke, F., Hall, S. R., Ullmann, K., Nakashima, Y., Paul, J. B., Wolfe, G. M., Desai, A. R., Kajii, Y., Guenther, A., and Keutsch, F. N.: First direct measurements of formaldehyde flux via eddy covariance: implications for missing in-canopy formaldehyde sources, Atmos. Chem. Phys., 11, 10565–10578, doi:10.5194/acp-11-10565-2011, 2011.; DiGangi, J. P., Henry, S. B., Kammrath, A., Boyle, E. S., Kaser, L., Schnitzhofer, R., Graus, M., Turnipseed, A., Park, J-H., Weber, R. J., Hornbrook, R. S., Cantrell, C. A., Maudlin III, R. L., Kim, S., Nakashima, Y., Wolfe, G. M., Kajii, Y., Apel, E.C., Goldstein, A. H., Guenther, A., Karl, T., Hansel, A., and Keutsch, F. N.: Observations of glyoxal and formaldehyde as metrics for the anthropogenic impact on rural photochemistry, Atmos. Chem. Phys., 12, 9529–9543, doi:10.5194/acp-12-9529-2012, 2012.; Finlayson-Pitts, B. J. and Pitts, J. N.: Chemistry of the Upper and Lower Atmosphere – Theory, Experiments and Applications, 1st edn., Academic Press, San Diego, 2000.; Fortems-Cheiney, A., Chevallier, F., Pison, I., Bousquet, P., Saunois, M., Szopa, S., Cressot, C., Kurosu, T. P., Chance, K., and Fried, A.: The formaldehyde budget as seen by a global-scale multi-constraint and multi-species inversion system, Atmos. Chem. Phys., 12, 6699–6721, doi:10.5194/acp-12-6699-2012, 2012.; Fried, A., Crawford, J., Olson, J., Walega, J., Potter, W., Wert, B., Jordan, C., Anderson, B., Shetter, R., Lefer, B., Blake, D., Blake, N., Meinardi, S., Heikes, B., O'Sullivan, D., Snow, J., Fuelberg, H., Kiley, C. M., Sandholm, S., Tan, D., Sachse, G., Singh, H., Faloona, I., Harward, C. N., and Carmichael, G. R.: Airborne tunable diode laser measurements of formaldehyde during TRACE-P: distributions and box model comparisons, J. Geophys. Res., 108, 8798, doi:10.1029/2003jd003451, 2003a.; Fried, A., Wang, Y., Cantrell, C., Wert, B., Walega, J., Ridley, B., Atlas, E., Shetter, R., Lefer, B., Coffey, M. T., Hannigan, J., Blake, D., Blake, N., Meinardi, S., Talbot, B., Dibb, J., Scheuer, E., Wingenter, O., Snow, J., Heikes, B., and Ehhalt, D.: T}unable diode laser measurements of formaldehyde during the {TOPSE 2000 study: distributions, trends, and model comparisons, J. Geophys. Res., 108, D4, 8365, doi:10.1029/2002jd002208, 2003b.; Fu, T.-M., Jacob, D. J., Wittrock, F., Burrows, J. P., Vrekoussis, M., and Henze, D. K.: Global budgets of atmospheric glyoxal and methylglyoxal, and implications for formation of secondary organic aerosols, J. Geophys. Res., 113, D15303, doi:10.1029/2007JD009505, 2008.; Garcia, A. R., Volkamer, R., Molina, L. T., Molina, M. J., Samuelson, J., Mellqvist, J., Galle, B., Herndon, S. C., and Kolb, C. E.: Separation of emitted and photochemical formaldehyde in Mexico City using a statistical analysis and a new pair of gas-phase tracers, Atmos. Chem. Phys., 6, 4545–4557, doi:10.5194/acp-6-4545-2006, 2006.; Fried, A., Cantrell, C., Olson, J., Crawford, J. H., Weibring

 

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