Relaxed Eddy Accumulation System for Size-Resolved Aerosol Particle Flux Measurements

Anca Gaman Department of Physical Sciences, University of Helsinki, Helsinki, Finland

Search for other papers by Anca Gaman in
Current site
Google Scholar
PubMed
Close
,
Üllar Rannik Department of Physical Sciences, University of Helsinki, Helsinki, Finland

Search for other papers by Üllar Rannik in
Current site
Google Scholar
PubMed
Close
,
Pasi Aalto Department of Physical Sciences, University of Helsinki, Helsinki, Finland

Search for other papers by Pasi Aalto in
Current site
Google Scholar
PubMed
Close
,
Toivo Pohja Hyytiälä Forestry Field Station, University of Helsinki, Helsinki, Finland

Search for other papers by Toivo Pohja in
Current site
Google Scholar
PubMed
Close
,
Erkki Siivola Hyytiälä Forestry Field Station, University of Helsinki, Helsinki, Finland

Search for other papers by Erkki Siivola in
Current site
Google Scholar
PubMed
Close
,
Markku Kulmala Department of Physical Sciences, University of Helsinki, Helsinki, Finland

Search for other papers by Markku Kulmala in
Current site
Google Scholar
PubMed
Close
, and
Timo Vesala Department of Physical Sciences, University of Helsinki, Helsinki, Finland

Search for other papers by Timo Vesala in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

A novel relaxed eddy accumulation (REA) system for aerosol particle flux measurement has been developed and tested. The system consisted of a fast-response sonic anemometer, a flow system, and software for operating the valves and the concentration analysis system. The prototype was used during September–October 2001 at the SMEAR II station of the University of Helsinki. The REA system was operated with a varying threshold for valve switching determined by the running mean standard deviation of the vertical wind speed. Such a varying threshold made the flux proportionality coefficient β independent of observation conditions. Using temperature as a tracer, β was determined to be 0.392 ± 0.002. The system was validated by comparing the carbon dioxide fluxes estimated by REA with the ones measured by the eddy covariance technique. The system was used subsequently for flux measurements of 50-nm aerosol particles and deposition velocity estimation. Observed deposition velocities over a pine forest during the autumn season were on the average 0.43 ± 0.06 (standard error) cm s−1, which is higher than the earlier model estimates for forest canopies. Deposition velocity was dependent on the turbulence level and stability. To the authors' knowledge, no direct experimental data of deposition velocities on this size range is available in the literature.

Corresponding author address: Dr. Üllar Rannik, Department of Physical Sciences, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki, Finland. Email: ullar.rannik@helsinki.fi

Abstract

A novel relaxed eddy accumulation (REA) system for aerosol particle flux measurement has been developed and tested. The system consisted of a fast-response sonic anemometer, a flow system, and software for operating the valves and the concentration analysis system. The prototype was used during September–October 2001 at the SMEAR II station of the University of Helsinki. The REA system was operated with a varying threshold for valve switching determined by the running mean standard deviation of the vertical wind speed. Such a varying threshold made the flux proportionality coefficient β independent of observation conditions. Using temperature as a tracer, β was determined to be 0.392 ± 0.002. The system was validated by comparing the carbon dioxide fluxes estimated by REA with the ones measured by the eddy covariance technique. The system was used subsequently for flux measurements of 50-nm aerosol particles and deposition velocity estimation. Observed deposition velocities over a pine forest during the autumn season were on the average 0.43 ± 0.06 (standard error) cm s−1, which is higher than the earlier model estimates for forest canopies. Deposition velocity was dependent on the turbulence level and stability. To the authors' knowledge, no direct experimental data of deposition velocities on this size range is available in the literature.

Corresponding author address: Dr. Üllar Rannik, Department of Physical Sciences, University of Helsinki, P.O. Box 64, FIN-00014 Helsinki, Finland. Email: ullar.rannik@helsinki.fi

Save
  • Anderson, S. M., Delany A. C. , Fehsenfeld F. C. , Goldan P. D. , Kolb C. E. , Ridley B. A. , and Steele L. P. , 1989: Status of chemical sensors for flux measurements. Global Tropospheric Chemistry, D. H. Lenschow and B. B. Hicks, NCAR, 47–68.

    • Search Google Scholar
    • Export Citation
  • Aubinet, M., and Coauthors, 2000: Estimates of the annual net carbon and water exchange of European forests: The EUROFLUX methodology. Adv. Ecol. Res, 30 , 113175.

    • Search Google Scholar
    • Export Citation
  • Baker, J. M., 1992: A field test of flux measurement by conditional sampling. Agric. For. Meteor, 62 , 3152.

  • Baker, J. M., 2000: Conditional sampling revisited. Agric. For. Meteor, 104 , 5965.

  • Baker, J. M., Norman J. M. , and Bland W. L. , 1992: Field scale application of flux measurement by conditional sampling. Agric. For. Meteor, 62 , 3152.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Baron, P. A., and Willeke K. , 2001: Aerosol Measurement: Principles, Techniques, and Applications. John Wiley and Sons, 1131 pp.

  • Beverland, I. J., Milne R. , Boissard C. , O'Neill D. H. , Moncrieff J. B. , and Hewitt C. N. , 1996: Measurement of carbon dioxide and hydrocarbon fluxes from a Sitka spruce forest using micrometeorological techniques. J. Geophys. Res, 101 , 2280722815.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bowling, D. R., Turnipseed A. A. , Delany A. C. , Baldocchi D. D. , Greenberg J. P. , and Monson R. K. , 1998: The use of relaxed eddy accumulation to measure biosphere–atmosphere exchange of isoprene and other biological trace gases. Oecologia, 116 , 306315.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brockmann, J. E., 1993: Sampling and transport of aerosols. Aerosol Measurement: Principles, Techniques, and Applications, P. A. Baron and K. Willeke, Eds., John Wiley and Sons, 143–195.

    • Search Google Scholar
    • Export Citation
  • Businger, J. A., and Oncley S. P. , 1990: Flux measurement with conditional sampling. J. Atmos. Oceanic Technol, 7 , 34935.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Buzorius, G., Rannik Ü , Mäkelä J. , Vesala T. , and Kulmala M. , 1998: Vertical aerosol particle fluxes measured by eddy covariance technique using condensational particle counter. J. Aerosol Sci, 29 , 157171.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Buzorius, G., Rannik Ü , Mäkelä J. , Keronen P. , Vesala T. , and Kulmala M. , 2000: Vertical aerosol fluxes measured by the eddy covariance method and deposition of nucleation mode particles above a Scots pine forest in southern Finland. J. Geophys. Res, 105 , 1990519916.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Buzorius, G., Rannik Ü , Nilsson D. , and Kulmala M. , 2001: Vertical fluxes and micrometeorology during aerosol particle formation events. Tellus, 53B , 394405.

    • Search Google Scholar
    • Export Citation
  • Christensen, C. S., Hummelshøj P. , Jensen N. O. , Larsen B. , Lohse C. , Pilegaard K. , and Skov H. , 2000: Determination of the terpene flux from orange species and Norway spruce by relaxed eddy accumulation. Atmos. Environ, 34 , 30573067.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Desjardins, R. L., 1977: Description and evaluation of a sensible heat flux detector. Bound.-Layer Meteor, 11 , 147154.

  • Duan, B., Fairall C. W. , and Thomson D. W. , 1988: Eddy covariance measurements of the dry deposition of particles in wintertime. J. Appl. Meteor, 27 , 642652.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gallager, M. W., Beswick K. M. , Duyzer J. , Westrate H. , Choularton T. W. , and Hummelshøj P. , 1997: Measurements of aerosol fluxes to Speulder forest using a micrometeorological technique. Atmos. Environ, 31 , 359373.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gallager, M. W., Clayborough R. , Beswick K. M. , Hewitt C. N. , Owen S. , Moncrieff J. , and Pilegaard K. , 2000: Assessment of a relaxed eddy accumulation for measurements of fluxes of biogenic volatile organic compounds: Study over arable crops and mature beech forest. Atmos. Environ, 34 , 28872899.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Guenther, A., and Coauthors, 1996: Isoprene fluxes measured by enclosure, relaxed eddy accumulation, surface layer gradient, mixed layer gradient, and mixed layer mass balance techniques. J. Geophys. Res, 101 , 1855518567.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Jokinen, V., and Mäkelä J. M. , 1997: Closed-loop arrangement with critical orifice for DMA sheath/excess flow system. J. Aerosol Sci, 28 , 643648.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kaimal, J. C., and Finnigan J. J. , 1994: Atmospheric Boundary Layer Flows: Their Structure and Measurement. Oxford University Press, 289 pp.

    • Search Google Scholar
    • Export Citation
  • Katul, G., Finkelstein P. L. , Clark J. F. , and Ellestad T. G. , 1996: An investigation of the conditional sampling methods used to estimate fluxes of active, reactive, and passive scalars. J. Appl. Meteor, 35 , 18351845.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kulmala, M., 2001: Overview of the international project on biogenic aerosol formation in the boreal forest (BIOFOR). Tellus, 53B , 324343.

    • Search Google Scholar
    • Export Citation
  • Lenchow, D. H., Mann J. , and Kristensen L. , 1994: How long is long enough when measuring fluxes and other turbulence statistics? J. Atmos. Oceanic Technol, 11 , 661673.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Milne, R., Mennim A. , and Hargreaves K. , 2001: The evaluation of the β coefficient in the relaxed eddy accumulation method in terms of fourth-order moments. Bound.-Layer Meteor, 101 , 359373.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Oncley, S. P., Delany A. C. , Horst T. W. , and Tans P. P. , 1993: Verification of flux measurement using relaxed eddy accumulation. Atmos. Environ, 27A , 24172426.

    • Search Google Scholar
    • Export Citation
  • Pattey, E., Desjarduins R. L. , and Rochette P. , 1993: Accuracy of the relaxed eddy accumulation technique. Bound.-Layer Meteor, 66 , 341355.

  • Peters, K., and Eiden E. , 1992: Modelling of the dry deposition velocity of aerosol particles to a spruce forest. Atmos. Environ, 26A , 25552564.

    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, 1998: On the surface layer similarity at a complex forest site. J. Geophys. Res, 103 , 86858697.

  • Rannik, Ü, and Vesala T. , 1999: Autoregressive filtering versus linear detrending in estimation of fluxes by the eddy covariance method. Bound.-Layer Meteor, 91 , 259280.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, Petäjä T. , Buzorius G. , Aalto P. , Vesala T. , and Kulmala M. , 2001: Deposition velocities of nucleation mode particles into a Scots pine forest. Environ. Chem. Phys, 22 , 97102.

    • Search Google Scholar
    • Export Citation
  • Rannik, Ü, Markkanen T. , Raittila J. , Hari P. , and Vesala T. , 2003: Turbulence statistics inside and over forest: Influence on footprint prediction. Bound.-Layer Meteor, 109 , 163189.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schery, S. D., Wasiolek P. T. , Nemetz B. M. , and Yarger F. D. , 1998: Relaxed eddy accumulation for flux measurement of nanometer-size particles. Aerosol Sci. Technol, 28 , 159172.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Valentini, R., Greco S. , Seufert G. , Bertin N. , Ciccioli P. , Cecinato A. , Brancaleoni E. , and Erattoni M. , 1997: Fluxes of biogenic VOC from Mediterranean vegetation by trap enrichment relaxed eddy accumulation. Atmos. Environ, 31 , 229238.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Vesala, T., and Coauthors, 1998: Long-term field measurements of atmosphere–surface interactions in boreal forest combining forest ecology, micrometeorology, aerosol physics and atmospheric chemistry. Trends Heat, Mass Momentum Transfer, 4 , 1735.

    • Search Google Scholar
    • Export Citation
  • Wesley, M. L., Cook D. R. , and Hart R. L. , 1983: Fluxes of gases and particles above a decidous forest in wintertime. Bound.-Layer Meteor, 27 , 237255.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wesley, M. L., Cook D. R. , and Hart R. L. , 1985: Measurements and parameterizations of particulate sulphur dry deposition over grass. J. Geophys. Res, 90 , 21312143.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Winklmayr, W., Reischl G. P. , Linder A. O. , and Berner A. , 1991: A new electromobility spectrometer for the measurement of aerosol size distributions in the size range 1 to 1000 nm. J. Aerosol. Sci, 22 , 289296.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wyngaard, J. C., and Moeng C. H. , 1992: Parameterizing turbulent diffusion through the joint probability density. Bound.-Layer Meteor, 60 , 113.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 871 364 115
PDF Downloads 374 111 23