Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 2 5 2009 10.5194/amtd-2-2241-2009 http://www.atmos-meas-tech-discuss.net/2/2241/2009/ http://www.atmos-meas-tech-discuss.net/2/2241/2009/amtd-2-2241-2009.html http://www.atmos-meas-tech-discuss.net/2/2241/2009/amtd-2-2241-2009.pdf 2241 2280 2009-09-29 Sources of uncertainty in eddy covariance ozone flux measurements made by dry chemiluminescence fast response analysers J. B. A. Muller jennifer.muller@postgrad.manchester.ac.uk C. J. Percival M. W. Gallagher D. Fowler M. Coyle E. Nemitz School of Earth, Atmospheric and Environmental Sciences, University of Manchester, Simon Building, Brunswick Street, Manchester, M13 9PL, UK Centre for Ecology & Hydrology, Bush Estate, Penicuik, EH26 0QB, UK Eddy covariance ozone flux measurements are the most direct way to estimate ozone removal near the surface. Over vegetated surfaces, high quality ozone fluxes are required to probe the underlying processes for which it is necessary to separate the flux into the components of stomatal and non-stomatal deposition. Detailed knowledge of the processes that control non-stomatal deposition is limited and more accurate ozone flux measurements are needed to quantify this component of the deposited flux. We present a systematic intercomparison study of eddy covariance ozone flux measurements made using two fast response dry chemiluminescence analysers. Ozone deposition was measured over a well characterised managed grassland near Edinburgh, Scotland, during August 2007. A data quality control procedure specific to these analysers is introduced. Absolute ozone fluxes were calculated based on the relative signals of the dry chemiluminescence analysers using three different calibration methods and the results are compared for both analysers. It is shown that the error in the fitted parameters required for the flux calculations provides a substantial source of uncertainty in the fluxes. The choice of the calculation method itself can also constitute an uncertainty in the flux as the calculated fluxes by the three methods do not agree within error at all times. This finding highlights the need for a consistent and rigorous approach for comparable data-sets, such as e.g. in flux networks. Ozone fluxes calculated by one of the methods were then used to compare the two analysers in more detail. This systematic analyser comparison reveals half-hourly flux values differing by up to a factor of two at times with the difference in mean hourly flux ranging from 0 to 23% with an error in the mean daily flux of ±12%. The comparison of analysers shows that the agreement in fluxes is excellent for some days but that there is an underlying uncertainty as a result of variable analyser performance and/or non-linear behaviour of disc sensitivity. Altimir, N., Kolari, P., Tuovinen, J-P., Vesala, T., Bäck, J., Suni, T., Kulmala, M., and Hari, P.: Foliage surface ozone deposition: a role for surface moisture?, Biogeosciences, 3, 209–228, 2006. Ashmore, M. R.: Assessing the future global impacts of ozone on vegetation, Plant Cell Environ., 28, 949–964, 2005. Bassin, S., Calanca, P., Weidinger, T., Gerosa, G., Fuhrer, J.: Modeling seasonal ozone fluxes to grassland and wheat: model improvement, testing, and application, Atmos. Environ., 38, 2349–2359, 2004. Bauer, M. R., Hultman, N. E., Panek, J. A., and Goldstein, A. H.: Ozone deposition to a ponderosa pine plantation in the Sierra Nevada Mountains (CA): A comparison of two different climatic years, J. Geophys. Res., 105(D17), 22123–22136, 2000. Businger, J. A.: Evaluation of the accuracy with which dry deposition can be measured with current micrometeorological techniques, J. Clim. Appl. Meteorol., 25, 1100–1124, 1986. Coyle, M.: The Gaseous Exchange of Ozone at Terrestrial Surfaces: Non-stomatal Deposition to Grassland, PhD thesis, University of Edinburgh, UK, 2005. de Leeuw, F. A. A. M.: Trends in ground level ozone concentrations in the European Union, Environ. Sci. Policy, 3, 189–199, 2000. Derwent, R. G., Simmonds, P. G., Manning, A. J., and Spain, T. G.: Trends over a 20-year period from 1987 to 2007 in surface ozone at the atmospheric research station, Mace Head, Ireland, Atmos. Environ. 41, 9091–9098, 2007. Derwent, R. G., Stevenson, D. S., Doherty, R. M., Collins, W. J., and Sanderson, M. G.: How is surface ozone in Europe linked to Asian and North American NO_x emissions?, Atmos. Environ., 42, 7412–7422, 2008. Emberson, L. D., Wieser, G., and Ashmore, M. R.: Modelling of stomatal conductance and ozone flux of Norway spruce: comparison with field data, Environ. Pollut., 109, 393–402, 2000. Finkelstein, P. L. and Sims, P. F.: Sampling error in eddy correlation flux measurements, J. Geophys. Res., 106(D4), 3503–3509, 2001. Foken, T. and Wichura, B.: Tools for quality assessment of surface based flux measurements, Agr. Forest Meteorol., 78, 83–105, 1996. Fowler, D., Flechard, C., Cape, J. N., Storeton-West, R. L., and Coyle, M.: Measurements of ozone deposition to vegetation quantifying the flux, the stomatal and non-stomatal components, Water Air Soil Poll., 130(1–4), 63–74, 2001. Fuhrer, J.: Ozone risk for crops and pastures in present and future climates, Naturwissenschaften, 96, 173–194, doi:10.1007/s00114-008-0468-7, 2009. Gallagher, M. W., Beswick, K. M., and Coe, H.: Ozone deposition to coastal waters, Q. J. Roy. Meteor. Soc., 127, 539–558, 2001. Gruenhage, L., Haenel, H.-D., and Jaeger, H.-J.: The exchange of ozone between vegetation and atmosphere: micrometeorological measurement techniques and models, Environ. Pollut., 109, 373–392, 2000. Guesten, H. and Heinrich, G.: On-line measurements of ozone surface fluxes: Part 1 Methodology and Instrumentation, Atmos. Environ., 30, 897–909, 1995. Guesten, H., Heinrich, G., Schmidt, R. W. H., and Schurath, U.: A novel ozone sensor for direct eddy covariance measurements, J. Atmos. Chem., 14, 73–84, 1992. Hodgeson, J. A., Krost, K. J., O'Keeffe, A. E., Stevens, R. K.: Chemiluminescent measurement of atmospheric ozone: Response characteristics and operating variables, Anal. Chem., 42, 1796–1802, 1970. Jaeggi, M. and Fuhrer, J.: Oxygen and carbon isotopic signatures reveal a long-term effect of free-air ozone enrichment on leaf conductance in semi-natural grassland, Atmos. Environ., 41, 8811–8817, 2007. Jenkin, M. E.: Trends in ozone concentration distributions in the UK since 1990: local, regional and global influences, Atmos. Environ., 42, 5434–5445, 2008. Keronen, P., Reissell, A., Rannik, U., Pohja, T., Siivola, E., Hiltunen, V., Hari, P., Kulmala, M., and Vesala, T.: Ozone flux measurements over a Scots pine forest using eddy covariance method: performance evaluation and comparison with flux-profile method, Boreal Environ. Res., 8, 425–443, 2003. Laisk, A., Kull, O., and Moldau, H.: Ozone concentration in leaf intercellular air spaces is close to zero, Plant Physiol., 90, 1163–1167, 1989. Lee, X., Massman, W., Law, B. (Eds): Handbook of Micrometeorology: A Guide for Surface Flux Measurements and Analysis, Kluwer Academic Publisher, Dordrecht, The Netherlands, 2004. Massman, W.J.: A review of the molecular diffusivities of H₂O, CO₂, CH₄, CO, O₃, SO₂, NH₃, N₂O, NO and NO₂ in air, O₂ and N₂ at STP, Atmos. Environ., 32, 1111–1127, 1998. Mckendry, I. G, Steyn, D.G., O'Kane, S., Zawar-Reza, P., and Heuff, D.: Lower tropospheric ozone measurements by light aircraft equipped with chemiluminescent sonde, J. Atmos. Ocean. Tech., 15, 136–143, 1998. Milford, C., Theobald, M. R., Nemitz, E., and Sutton, M. A.: Dynamics of ammonia exchange in response to cutting and fertilising in an intensively-managed grassland, Water Soil Air Poll. Focus, 1, 167–176, 2001. Moldau, H. and Bichele, I.: Plasmalemma protection by the apoplast as assessed from above-zero ozone concentrations in leaf intercellular air spaces, Planta, 214, 484–487, 2002. NEGTAP: Transboundary Air Pollution: Acidification, Eutrophication and Ground-Level Ozone in the UK, a report by the National Expert Group on Transboundary Air Pollution (NEGTAP) for UK Department for Environment, Food and Rural Affairs and devolved administrations, available at: http://www.uk-pollutantdeposition.ceh.ac.uk/, 2001. Pearson Jr., R.: Measuring ambient ozone with high sensitivity and bandwidth, Rev. Sci. Instrum., 61, 907–916, 1990. Royal Society: Ground-level ozone in the 21st century: future trends, impacts and policy implications, Science Policy Report of the Royal Society, London, UK, online available at: http://royalsociety.org/, 2008. Rummel, U., Ammann, C., Kirkman, G. A., Moura, M. L. A., Foken, T., Andreae, M. O., and Meixner, F. X.: Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia, Atmos. Chem. Phys., 7, 5415–5435, 2007. Schurath, U., Speuser, W., and Schmidt, R.: Principle and application of a fast sensor for atmospheric ozone, Fresen. J. Anal. Chem., 340, 544–547, 1991. Seinfeld, J. H. and Pandis, S. N.: Atmospheric Chemistry and Physics: from air pollution to climate change, John Wiley, New York, USA, 1326 pp., 1998. Speuser, W., Sahand, S., and Schurath, U.: A novel fast-response chemiluminescence sonde for routine soundings of stratospheric ozone up to 1.5 mbar, in: Ozone in the Atmosphere, edited by: Bojkov, R. D. and Fabian, P., A. Deepak Publishing, Hampton Virginia, USA, 747–750, 1989. Stull, R. B.: An Introduction to Boundary Layer Meteorology, Kluwer Academic Publishers, Dordrecht, The Netherlands, 666 pp., 1988. Tuovinen, J.-P., Ashmore, M. R., Emberson, L. D., and Simpson, D.: Testing and improving the EMEP ozone deposition module, Atmos. Environ., 38, 2373–2385, 2004. Tuovinen, J.-P., Aurela, M., and Laurila, T.: Resistances to ozone deposition to a flark fen in the northern aapa mire zone, J. Geophys. Res., 103(D14), 16953–16966, 1998. Weather: Weather Log, 62 (\refeq10), online available at: www.interscience.wiley.com/weather, 2007. Weinheimer, A. J.: Chemical Methods: Chemiluminescence, Chemical Amplification, Electrochemistry and Derivatization, in: Analytical Techniques for Atmospheric Measurement, edited by: Heard, D. E., Blackwell Publishing Ltd, Oxford, 311–360, 2006. Wohlfahrt, G., Hoertnagel, L., Hammerle, A., Graus, M., and Hansel, A.: Measuring eddy covariance fluxes of ozone with a slow-response analyser, Atmos. Environ., 43, 4579–4576, 2009.