• Ammann, C., , Brunner A. , , Spirig C. , , and Neftel A. , 2006: Technical note: Water vapour concentration and flux measurements with PTR-MS. Atmos. Chem. Phys., 6, 46434651, doi:10.5194/acp-6-4643-2006.

    • Search Google Scholar
    • Export Citation
  • Aubinet, M., and et al. , 1999: Estimates of the annual net carbon and water exchange of forests: The EUROFLUX methodology. Adv. Ecol. Res., 30, 113175, doi:10.1016/S0065-2504(08)60018-5.

    • Search Google Scholar
    • Export Citation
  • Aubinet, M., , Chermanne B. , , Vandenhaute M. , , Longdoz B. , , Yernaux M. , , and Laitat E. , 2001: Long term carbon dioxide exchange above a mixed forest in the Belgian Ardennes. Agric. For. Meteor., 108, 293315, doi:10.1016/S0168-1923(01)00244-1.

    • Search Google Scholar
    • Export Citation
  • Aubinet, M., , Vesala T. , , and Papale D. , Eds., 2012: Eddy Covariance: A Practical Guide to Measurement and Data Analysis. Springer Atmospheric Sciences, Springer, 438 pp.

  • Baldocchi, D., and et al. , 2001: FLUXNET: A new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor, and energy flux densities. Bull. Amer. Meteor. Soc., 82, 24152434, doi:10.1175/1520-0477(2001)082<2415:FANTTS>2.3.CO;2.

    • Search Google Scholar
    • Export Citation
  • Burba, G. G., , McDermitt D. K. , , Grelle A. , , Anderson D. J. , , and Xu L. , 2008: Addressing the influence of instrument surface heat exchange on the measurements of CO2 flux from open-path gas analyzers. Global Change Biol., 14, 18541876, doi:10.1111/j.1365-2486.2008.01606.x.

    • Search Google Scholar
    • Export Citation
  • Burba, G. G., , Mcdermitt D. K. , , Anderson D. J. , , Furtaw M. D. , , and Eckles R. D. , 2010: Novel design of an enclosed CO2 /H2O gas analyser for eddy covariance flux measurements. Tellus, 62B, 743748, doi:10.1111/j.1600-0889.2010.00468.x.

    • Search Google Scholar
    • Export Citation
  • Clement, R., 2004: Mass and energy exchange of a plantation forest in Scotland using micrometeorological methods. Ph.D. dissertation, University of Edinburgh, 416 pp.

  • Clement, R., , Burba G. G. , , Grelle A. , , Anderson D. J. , , and Moncrieff J. B. , 2009: Improved trace gas flux estimation through IRGA sampling optimization. Agric. For. Meteor., 149, 623–638, doi:10.1016/j.agrformet.2008.10.008.

    • Search Google Scholar
    • Export Citation
  • De Ligne, A., , Heinesch B. , , and Aubinet M. , 2010: New transfer functions for correcting turbulent water vapour fluxes. Bound.-Layer Meteor., 137, 205221, doi:10.1007/s10546-010-9525-9.

    • Search Google Scholar
    • Export Citation
  • Eugster, W., , and Senn W. , 1995: A cospectral correction model for measurement of turbulent N2O flux. Bound.-Layer Meteor., 74, 321340, doi:10.1007/BF00712375.

    • Search Google Scholar
    • Export Citation
  • Fisher, L. R., , and Israelachvili J. N. , 1979: Direct experimental verification of the Kelvin equation for capillary condensation. Nature, 277, 548549, doi:10.1038/277548a0.

    • Search Google Scholar
    • Export Citation
  • Foken, T., , and Wichura B. , 1996: Tools for quality assessment of surface-based flux measurements. Agric. For. Meteor., 78, 83105, doi:10.1016/0168-1923(95)02248-1.

    • Search Google Scholar
    • Export Citation
  • Fratini, G., , Ibrom A. , , Arriga N. , , Burba G. , , and Papale D. , 2012: Relative humidity effects on water vapour fluxes measured with closed-path eddy-covariance systems with short sampling lines. Agric. For. Meteor., 165, 5363, doi:10.1016/j.agrformet.2012.05.018.

    • Search Google Scholar
    • Export Citation
  • Haslwanter, A., , Hammerle A. , , and Wohlfahrt G. , 2009: Open-path vs. closed-path eddy covariance measurements of the net ecosystem carbon dioxide and water vapour exchange: A long-term perspective. Agric. For. Meteor., 149, 291302, doi:10.1016/j.agrformet.2008.08.011.

    • Search Google Scholar
    • Export Citation
  • Ibrom, A., , Dellwik E. , , Flyvbjerg H. , , Jensen N. O. , , and Pilegaard K. , 2007a: Strong low-pass filtering effects on water vapour flux measurements with closed-path eddy correlation systems. Agric. For. Meteor., 147, 140156, doi:10.1016/j.agrformet.2007.07.007.

    • Search Google Scholar
    • Export Citation
  • Ibrom, A., , Dellwik E. , , Larsen S. E. , , and Pilegaard K. , 2007b: On the use of the Webb–Pearman–Leuning theory for closed-path eddy correlation measurements. Tellus, 59B, 937946, doi:10.1111/j.1600-0889.2007.00311.x.

    • Search Google Scholar
    • Export Citation
  • Järvi, L., and et al. , 2009: Comparison of net CO2 fluxes measured with open- and closed-path infrared gas analyzers in an urban complex environment. Boreal Environ. Res., 14, 499514.

    • Search Google Scholar
    • Export Citation
  • Kekäläinen, P., , Voutilainen M. , , Poteri A. , , Höltta P. , , Hautojärvi A. , , and Timonen J. , 2011: Solutions to and validation of matrix-diffusion models. Transp. Porous Media, 87, 125149, doi:10.1007/s11242-010-9672-y.

    • Search Google Scholar
    • Export Citation
  • Lenschow, D. H., , and Raupach M. R. , 1991: The attenuation of fluctuations in scalar concentrations through sampling tubes. J. Geophys. Res., 96, 15 25915 268, doi:10.1029/91JD01437.

    • Search Google Scholar
    • Export Citation
  • Leuning, R., , and Judd M. J. , 1996: The relative merits of open- and closed-path analyzers for measurements of eddy fluxes. Global Change Biol., 2, 241253, doi:10.1111/j.1365-2486.1996.tb00076.x.

    • Search Google Scholar
    • Export Citation
  • Mammarella, I., , Launiainen S. , , Gronholm T. , , Keronen P. , , Pumpanen J. , , Rannik Ü. , , and Vesala T. , 2009: Relative humidity effect on the high-frequency attenuation of water vapor flux measured by a closed-path eddy covariance system. J. Atmos. Oceanic Technol., 26, 18561866, doi:10.1175/2009JTECHA1179.1.

    • Search Google Scholar
    • Export Citation
  • Massman, W. J., 1991: The attenuation of concentration fluctuations in turbulent flow through a tube. J. Geophys. Res., 96, 15 26915 273, doi:10.1029/91JD01514.

    • Search Google Scholar
    • Export Citation
  • Massman, W. J., , and Ibrom A. , 2008: Attenuation of concentration fluctuations of water vapor and other trace gases in turbulent tube flow. Atmos. Chem. Phys., 8, 62456259, doi:10.5194/acp-8-6245-2008.

    • Search Google Scholar
    • Export Citation
  • Mizoguchi, Y., , Miyata A. , , Ohtani Y. , , Hirata R. , , and Yuta S. , 2009: A review of tower flux observation sites in Asia. J. For. Res., 14 (1), 19, doi:10.1007/s10310-008-0101-9.

    • Search Google Scholar
    • Export Citation
  • Nordbo, A., , and Katul G. G. , 2013: A wavelet-based correction method for eddy-covariance high-frequency losses in scalar concentration measurements. Bound.-Layer Meteor., 146, 81–102, doi:10.1007/s10546-012-9759-9.

    • Search Google Scholar
    • Export Citation
  • Nordbo, A., , Launiainen S. , , Mammarella I. , , Leppäranta M. , , Huotari J. , , Ojala A. , , and Vesala T. , 2011: Long-term energy flux measurements and energy balance over a small boreal lake using eddy covariance technique. J. Geophys. Res., 116, D02119, doi:10.1029/2010JD014542.

    • Search Google Scholar
    • Export Citation
  • Nordbo, A., , Järvi L. , , Haapanala S. , , Wood C. R. , , and Vesala T. , 2012a: Fraction of natural area as main predictor of net CO2 emissions from cities. Geophys. Res. Lett.,39, L20802, doi:10.1029/2012GL053087.

  • Nordbo, A., , Järvi L. , , and Vesala T. , 2012b: Revised eddy covariance flux calculation methodologies—Effect on urban energy balance. Tellus, 64B, 18184, doi:10.3402/tellusb.v64i0.18184.

    • Search Google Scholar
    • Export Citation
  • Nordbo, A., , Järvi L. , , Haapanala S. , , Moilanen J. , , and Vesala T. , 2013a: Intra-city variation in urban morphology and turbulence structure in Helsinki, Finland. Bound.-Layer Meteor.,146, 469–496, doi:10.1007/s10546-012-9773-y.

  • Nordbo, A., , Kekäläinen P. , , Siivola E. , R. Lehto, Vesala T. , , and Timonen J. , 2013b: Tube transport of water vapor with condensation and desorption. Appl. Phys. Lett.,102, 194101, doi:10.1063/1.4804639.

  • Rannik, Ü., 1998: On the surface layer similarity at a complex forest site. J. Geophys. Res., 103, 86858697, doi:10.1029/98JD00086.

  • Runkle, B. R. K., , Wille C. , , Gažovic M. , , and Kutzbach L. , 2012: Attenuation correction procedures for water vapour fluxes from closed-path eddy-covariance systems. Bound.-Layer Meteor., 142, 401423, doi:10.1007/s10546-011-9689-y.

    • Search Google Scholar
    • Export Citation
  • Su, H. B., , Schmid H. P. , , Grimmond C. S. B. , , Vogel C. S. , , and Oliphant A. J. , 2004: Spectral characteristics and correction of long-term eddy-covariance measurements over two mixed hardwood forests in non-flat terrain. Bound.-Layer Meteor., 110, 213253, doi:10.1023/A:1026099523505.

    • Search Google Scholar
    • Export Citation
  • Taylor, G., 1953: Dispersion of soluble matter in solvent flowing slowly through a tube. Proc. Roy. Soc. London, 219A, 186203, doi:10.1098/rspa.1953.0139.

    • Search Google Scholar
    • Export Citation
  • Taylor, G., 1954: The dispersion of matter in turbulent flow through a pipe. Proc. Roy. Soc. London, 223A, 446468, doi:10.1098/rspa.1954.0130.

    • Search Google Scholar
    • Export Citation
  • Thomson, W., 1871: On the equilibrium of vapour at a curved surface of liquid. Philos. Mag., 42, 448452, doi:10.1080/14786447108640606.

    • Search Google Scholar
    • Export Citation
  • Valentini, R., and et al. , 2000: Respiration as the main determinant of carbon balance in European forests. Nature, 404, 861865, doi:10.1038/35009084.

    • Search Google Scholar
    • Export Citation
  • Vesala, T., and et al. , 2005: Effect of thinning on surface fluxes in a boreal forest. Global Biogeochem. Cycles, 19, GB2001, doi:10.1029/2004GB002316.

    • Search Google Scholar
    • Export Citation
  • Webb, E. K., , Pearman G. I. , , and Leuning R. , 1980: Correction of flux measurements for density effects due to heat and water vapor transfer. Quart. J. Roy. Meteor. Soc., 106, 85100, doi:10.1002/qj.49710644707.

    • Search Google Scholar
    • Export Citation
  • White, F. M., 1994: Fluid Mechanics. 3rd ed. McGraw-Hill, Inc., 736 pp.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 25 25 3
PDF Downloads 11 11 4

Sorption-Caused Attenuation and Delay of Water Vapor Signals in Eddy-Covariance Sampling Tubes and Filters

View More View Less
  • 1 Department of Physics, University of Helsinki, Helsinki, Finland
  • | 2 Department of Chemistry, University of Helsinki, Helsinki, Finland
  • | 3 Department of Physics, University of Helsinki, Helsinki, Finland
  • | 4 Department of Physics, and Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland, and Information Technologies, Mechanics and Optics University, Saint Petersburg, Russia
  • | 5 Department of Physics, University of Helsinki, Helsinki, Finland
© Get Permissions
Restricted access

Abstract

Adsorption and desorption (together called sorption) processes in sampling tubes and filters of eddy-covariance stations cause attenuation and delay of water vapor signals, leading to an underestimation of water vapor fluxes by tens of percent. The aim of this work was (i) to quantify the effects on sorption in filters and tubes of humidity, flow rate, and dirtiness and (ii) to test a recently introduced sorption model that facilitates correction of fluxes. Laboratory measurements on the transport of water vapor pulses through tubes and filters were carried out, and eddy-covariance field measurements were also used.

In the laboratory measurements, the effects of sorption processes were evident, and filters caused a similar attenuation and delay of the signal as tubes. Filters could have a larger impact than a long tube, whereas the flow rate had a much smaller impact on the flux loss than the sorption processes (Reynolds numbers 2120–3360). The sorption model represented well the water vapor pulses in a wide range of conditions. As for the field measurements, the transfer function (TF) derived from the sorption model represented well the observations. Fitting parameters were found to depend strongly on the relative humidity and correlate with the signal delay. Having a more complex shape, TF of the sorption model represented much better the measured TFs than, for example, a Lorentzian or adjusted Gaussian TF, leading on average to a 4% unit difference in the flux corrections. Use of this more complex TF is recommended and its implementation is assisted by the codes provided in .

Corresponding author address: Ivan Mammarella, Department of Physics, University of Helsinki, Erik Palménin Aukio 1, P.O. Box 48, Helsinki 00041, Finland. E-mail: ivan.mammarella@helsinki.fi

Abstract

Adsorption and desorption (together called sorption) processes in sampling tubes and filters of eddy-covariance stations cause attenuation and delay of water vapor signals, leading to an underestimation of water vapor fluxes by tens of percent. The aim of this work was (i) to quantify the effects on sorption in filters and tubes of humidity, flow rate, and dirtiness and (ii) to test a recently introduced sorption model that facilitates correction of fluxes. Laboratory measurements on the transport of water vapor pulses through tubes and filters were carried out, and eddy-covariance field measurements were also used.

In the laboratory measurements, the effects of sorption processes were evident, and filters caused a similar attenuation and delay of the signal as tubes. Filters could have a larger impact than a long tube, whereas the flow rate had a much smaller impact on the flux loss than the sorption processes (Reynolds numbers 2120–3360). The sorption model represented well the water vapor pulses in a wide range of conditions. As for the field measurements, the transfer function (TF) derived from the sorption model represented well the observations. Fitting parameters were found to depend strongly on the relative humidity and correlate with the signal delay. Having a more complex shape, TF of the sorption model represented much better the measured TFs than, for example, a Lorentzian or adjusted Gaussian TF, leading on average to a 4% unit difference in the flux corrections. Use of this more complex TF is recommended and its implementation is assisted by the codes provided in .

Corresponding author address: Ivan Mammarella, Department of Physics, University of Helsinki, Erik Palménin Aukio 1, P.O. Box 48, Helsinki 00041, Finland. E-mail: ivan.mammarella@helsinki.fi
Save