Deployment and Evaluation of a System for Ground-Based Measurement of Cloud Liquid Water Turbulent Fluxes

Andrew S. Kowalski College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon

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Peter M. Anthoni College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon

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Richard J. Vong College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon

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Anthony C. Delany Atmospheric Technology Division, National Center for Atmospheric Research, Boulder, Colorado

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Gordon D. Maclean Atmospheric Technology Division, National Center for Atmospheric Research, Boulder, Colorado

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Abstract

Direct interception of windblown cloud water by forests has been dubbed “occult deposition” because it represents a hydrological input that is hidden from rain gauges. Eddy correlation studies of this phenomenon have estimated cloud water fluxes to vegetation yet have lacked estimates of error bounds. This paper presents an evaluation of instrumental and methodological errors for cloud liquid water fluxes to put such eddy correlation measurements in context. Procedures for data acquisition, processing (including correction factors), and calibration testing of the particulate volume monitor (PVM) and forward-scattering spectrometer probe (FSSP) are detailed. Nearly 200 h of in-cloud data are analyzed for intercomparison of these instruments. Three methods of coordinate system rotation are investigated; the flux shows little sensitivity to the method used, and the difference between fluxes at different stations is even less sensitive to this choice. Side-by-side intercomparison of two PVMs and one FSSP leads to error bounds of 0.01–0.035 g m−3 on half-hour mean cloud liquid water content (relative to typical values of 0.35 g m−3) and 2–3.5 mg m−2 s−1 on the surface-normal liquid water flux (typical magnitude of 7 mg m−2 s−1 for these data), depending on which instruments are compared.

Corresponding author address: Andrew S. Kowalski, College of Oceanic and Atmospheric Sciences, Oregon State University, Oceanography Admin. Bldg. 104, Corvallis, OR 97331-5503.

Email: andyk@ats.orst.edu

Abstract

Direct interception of windblown cloud water by forests has been dubbed “occult deposition” because it represents a hydrological input that is hidden from rain gauges. Eddy correlation studies of this phenomenon have estimated cloud water fluxes to vegetation yet have lacked estimates of error bounds. This paper presents an evaluation of instrumental and methodological errors for cloud liquid water fluxes to put such eddy correlation measurements in context. Procedures for data acquisition, processing (including correction factors), and calibration testing of the particulate volume monitor (PVM) and forward-scattering spectrometer probe (FSSP) are detailed. Nearly 200 h of in-cloud data are analyzed for intercomparison of these instruments. Three methods of coordinate system rotation are investigated; the flux shows little sensitivity to the method used, and the difference between fluxes at different stations is even less sensitive to this choice. Side-by-side intercomparison of two PVMs and one FSSP leads to error bounds of 0.01–0.035 g m−3 on half-hour mean cloud liquid water content (relative to typical values of 0.35 g m−3) and 2–3.5 mg m−2 s−1 on the surface-normal liquid water flux (typical magnitude of 7 mg m−2 s−1 for these data), depending on which instruments are compared.

Corresponding author address: Andrew S. Kowalski, College of Oceanic and Atmospheric Sciences, Oregon State University, Oceanography Admin. Bldg. 104, Corvallis, OR 97331-5503.

Email: andyk@ats.orst.edu

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  • Arends, B. G., G. P. A. Kos, W. Wobrock, D. Schell, K. J. Noone, S. Fuzzi, and S. Pahl, 1992: Comparison of techniques for measurements of fog liquid water content. Tellus,44B, 604–611.

    • Crossref
    • Export Citation
  • Baumgardner, D., 1983: An analysis and comparison of five water droplet measuring instruments. J. Climate Appl. Meteor.,22, 891–910.

    • Crossref
    • Export Citation
  • ———, W. Strapp, and J. E. Dye, 1985: Evaluation of the forward scattering spectrometer probe. Part II: Corrections for coincidence and dead-time losses. J. Atmos. Oceanic Technol.,2, 626–632.

    • Crossref
    • Export Citation
  • Beswick, K. M., K. Hargreaves, M. W. Gallagher, T. W. Choularton, and D. Fowler, 1991: Size-resolved measurements of cloud droplet deposition velocity to a forest canopy using an eddy correlation technique. Quart. J. Roy. Meteor. Soc.,117, 623–645.

    • Crossref
    • Export Citation
  • Blackman, R. B., and J. W. Tukey, 1958: The Measurement of Power Spectra. Dover, 178 pp.

  • Brenguier, J. L., 1989: Coincidence and dead-time corrections for particle counters. Part II: High concentration measurements with an FSSP. J. Atmos. Oceanic Technol.,6, 585–598.

    • Crossref
    • Export Citation
  • Businger, J. A., and A. C. Delany, 1990: Chemical sensor resolution required for measuring surface fluxes by three common micrometeorological techniques. J. Atmos. Chem.,10, 399–410.

  • Cerni, T. A., 1983: Determination of the size and concentration of cloud drops with an FSSP. J. Climate Appl. Meteor.,22, 1346–1355.

    • Crossref
    • Export Citation
  • Choularton, T. W., D. Consterdine, I. Gardner, B. Gay, M. Hill, J. Latham, and I. Stromberg, 1986: Field studies of the optical and microphysical characteristics of clouds enveloping Great Dun Fell. Quart. J. Roy. Meteor. Soc.,112, 131–148.

    • Crossref
    • Export Citation
  • Dabberdt, W. F., and T. W. Schlatter, 1996: Research opportunities from emerging atmospheric observing and modeling capabilities. Bull. Amer. Meteor. Soc.,77, 305–323.

    • Crossref
    • Export Citation
  • ———, D. Lenschow, T. Horst, P. Zimmerman, S. Oncley, and A. C. Delany, 1993: Atmospheric surface exchange measurements. Science,260, 1472–1480.

    • Crossref
    • Export Citation
  • Dye, J. E., and D. Baumgardner, 1984: Evaluation of the forward scattering spectrometer probe. Part I: Electronic and optical studies. J. Atmos. Oceanic Technol.,1, 329–344.

    • Crossref
    • Export Citation
  • Fairall, C. W., 1994: Interpretation of eddy correlation measurements of particulate deposition and aerosol flux. Atmos. Environ.,18, 1329–1337.

    • Crossref
    • Export Citation
  • Fuzzi, S., 1994: The Kleiner Feldberg cloud experiment 1990: Introduction. J. Atmos. Chem.,19, 1–2.

    • Crossref
    • Export Citation
  • ———, and Coauthors, 1992: The Po Valley Fog Experiment 1989: An overview. Tellus,44B, 448–468.

  • Gerber, H., 1991: Direct measurement of suspended particulate volume concentration and far infrared extinction coefficient with a laser diffraction instrument. Appl. Opt.,30, 4824.

    • Crossref
    • Export Citation
  • Heintzenberg, J., 1992: The Po Valley Fog Experiment 1989: What have we learned, where do we go from here? Tellus,44B, 443–447.

    • Crossref
    • Export Citation
  • Højstrup, J., 1993: A statistical data screening procedure. Meas. Sci. Technol.,4, 153–157.

    • Crossref
    • Export Citation
  • Kaimal, J. C., J. E. Gaynor, H. A. Zimmerman, and G. A. Zimmerman, 1990: Minimizing flow distortion errors in a sonic anemometer. Bound.-Layer Meteor.,53, 103–115.

    • Crossref
    • Export Citation
  • Knollenberg, R. G., 1981: Techniques for probing cloud microstructure. Clouds, Their Formation, Optical Properties, and Effects, P. V. Hobbs and A. Deepak, Eds., Academic, 15–91.

    • Crossref
    • Export Citation
  • Lovett, G. M., and J. D. Kinsman, 1990: Atmospheric pollutant deposition to high-elevation ecosystems. Atmos. Environ.,24A, 2767–2786.

    • Crossref
    • Export Citation
  • McMillen, R. T., 1988: An eddy correlation technique with extended applicability to non-simple terrain. Bound.-Layer Meteor.,43, 231–245.

    • Crossref
    • Export Citation
  • Miller, E. K., A. Friedland, E. Arons, V. A. Mohnen, J. Battle, J. A. Panek, J. Kadlecek, and A. H. Johnson, 1993: Atmospheric deposition to forests along an elevational gradient at Whiteface Mountain, NY, USA. Atmos. Environ.,27A, 2121–2136.

    • Crossref
    • Export Citation
  • Rogers, R. R., and M. K. Yau, 1989: A Short Course in Cloud Physics, Pergammon, 293 pp.

  • Schuepp, P. H., M. Y. Leclerc, J. I. MacPherson, and R. L. Desjardins, 1990: Footprint prediction of scalar fluxes from analytical solutions of the diffusion equation. Bound.-Layer Meteor.,50, 355–373.

    • Crossref
    • Export Citation
  • Valente, R. J., R. K. A. M. Mallant, S. E. McLaren, R. S. Schemenauer, and R. E. Stogner, 1989: Field intercomparison of ground-based cloud physics instruments at Whitetop Mountain, Virginia. J. Atmos. Oceanic Technol.,6, 396–406.

    • Crossref
    • Export Citation
  • Vong, R. J., and A. S. Kowalski, 1995: Eddy correlation measurements of size-dependent cloud droplet turbulent fluxes to complex terrain. Tellus,47B, 331–352.

    • Crossref
    • Export Citation
  • ———, H. C. Hansson, H. B. Ross, D. S. Covert, and R. J. Charlson, 1988: Northeastern Pacific sub-micrometer aerosol and rainwater composition: A multivariate analysis. J. Geophys. Res.,93(D2), 1625–1637.

    • Crossref
    • Export Citation
  • Wesely, M. L, 1970: Eddy correlation measurements in the atmospheric surface layer over agricultural crops. Ph.D. dissertation, University of Wisconsin—Madison, 102 pp.

  • Wyngaard, J. C., 1981: The effects of probe-induced flow distortion on atmospheric turbulence measurements. J. Appl. Meteor.,20, 784–794.

    • Crossref
    • Export Citation
  • ———, and S. F. Zhang, 1985: Transducer shadow effects on turbulence spectra measured by sonic anemometers. J. Atmos. Oceanic Technol.,2, 548–558.

    • Crossref
    • Export Citation
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