• 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
  • Arking, A., 1991: The radiative effects of clouds and their impact on climate. Bull. Amer. Meteor. Soc.,72, 795–813.

    • 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
  • ——, and M. Spowart, 1990: Evaluation of the Forward Scattering Spectrometer Probe. Part III: Time response and laser inhomogeneity limitations. J. Atmos. Oceanic Technol.,7, 666–672.

    • Crossref
    • Export Citation
  • ——, W. Strapp, and J. 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
  • 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
  • ——, and L. Amodei, 1989: Coincidence and dead-time corrections for particle counters. Part I: A general mathematical formalism. J. Atmos. Oceanic Technol.,6, 575–584.

    • Crossref
    • Export Citation
  • ——, D. Baumgardner, and B. Baker, 1994: A review and discussion of processing algorithms for FSSP concentration measurements. J. Atmos. Oceanic Technol.,11, 1409–1414.

    • Crossref
    • Export Citation
  • Cederfelt, S.-I., and Coauthors, 1997: Field validation of the droplet aerosol analyzer. Atmos. Environ.,31, 2657–2670.

    • Crossref
    • Export Citation
  • 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
  • Charlson, R. J., and J. Heintzenberg, 1995: Aerosol Forcing of Climate. Vol. 19, Dahlem Workshop Reports, Environmental Science Research Report, John Wiley and Sons, 416 pp.

  • Choularton, T. W., I. E. Consterdine, B. A. Gardiner, M. J. Gay, M. K. Hill, J. Latham, and M. 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
  • Cooper, W. A., 1988: Effects of coincidence on measurements with a Forward Scattering Spectrometer Probe. J. Atmos. Oceanic Technol.,5, 823–832.

    • Crossref
    • Export Citation
  • Dandin, P., C. Pontikis, and E. Hicks, 1997: Sensitivity of a GCM to changes in the droplet effective radius parameterization. Geophys. Res. Lett.,24, 437–440.

    • 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
  • Fuzzi, S., and Coauthors, 1998: Overview of the Po Valley fog experiment (CHEMDROP). Contrib. Atmos. Phys.,71, 3–19.

  • Gerber, H. E., 1984: Liquid water content of fogs and hazes from visible light scattering. J. Climate Appl. Meteor.,3, 1247–1252.

    • Crossref
    • Export Citation
  • ——, 1991: Direct measurement of suspended particulate volume concentration and far-infrared extinction coefficient with a laser-diffraction instrument. Appl. Opt.,30, 4824–4831.

    • Crossref
    • Export Citation
  • ——, 1996: Microphysics of marine stratocumulus clouds with two drizzle modes. J. Atmos. Sci.,53, 1649–1662.

    • Crossref
    • Export Citation
  • ——, B. G. Arends, and A. S. Ackerman, 1994: New microphysics sensor for aircraft use. Atmos. Res.,31, 235–252.

    • Crossref
    • Export Citation
  • Hovenac, E. A., and J. A. Lock, 1993: Calibration of the Forward Scattering Spectrometer Probe: Modeling scattering from a multimode laser beam. J. Atmos. Oceanic Technol.,10, 518–525.

  • Kim, Y. J., and J. F. Boatman, 1990: Corrections for the effects of particle trajectory and beam intensity profile on the size spectra of atmospheric aerosols measured with a Forward Scattering Spectrometer Probe. J. Atmos. Oceanic Technol.,7, 673–680.

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

    • Crossref
    • Export Citation
  • Laj, P., S. Fuzzi, and Coauthors, 1998: The size dependent composition of fog drops. Contrib. Atmos. Phys., in press.

  • Lawson, R. P., and R. H. Cormack, 1995: Theoretical design and preliminary tests of two new particle spectrometers for cloud microphysical research. Atmos. Res.,35, 315–348.

    • Crossref
    • Export Citation
  • ——, and A. M. Blyth, 1998: A comparison of optical measurements of liquid water content and drop size distribution in adiabatic regions of Florida cumuli. Atmos. Res., in press.

  • Personne, P., J. L. Brenguier, J. P. Pinty, and Y. Pointin, 1982: Comparative study and calibration of sensors for the measurement of the liquid water content of clouds with small droplets. J. Appl. Meteor.,21, 189–196.

    • Crossref
    • Export Citation
  • Pinnick, R. G., D. M. Garvey, and L. D. Duncan, 1981: Calibration of Knollenberg FSSP light-scattering counters for measurement of cloud droplets. J. Appl. Meteor.,20, 1049–1057.

    • Crossref
    • Export Citation
  • Raschke, E., 1993: Radiation-cloud-climate interaction. Energy and Water Cycles in the Climate System, E. Raschke and D. Jacob, Eds., NATO ASI Series, Vol. 15, Springer, 69–93.

    • Crossref
    • Export Citation
  • Slingo, A., 1990: Sensitivity of the earth’s radiation budget to changes in low clouds. Nature,343, 49–51.

    • Crossref
    • Export Citation
  • Stephens, G. L., 1994: Dirty clouds and global cooling. Nature,370, 420–421.

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

    • Crossref
    • Export Citation
  • Wendisch, M., A. Keil, and A. V. Korolev, 1996: FSSP characterization with monodisperse water droplets. J. Atmos. Oceanic Technol.,13, 1152–1165.

    • Crossref
    • Export Citation
  • Wendisch, M., and Coauthors, 1998: Drop size distribution and LWC in Po Valley fog. Contrib. Atmos. Phys.,71, 87–100.

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A Quantitative Comparison of Ground-Based FSSP and PVM Measurements

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  • 1 Physics Department, Institute for Tropospheric Research, Leipzig, Germany
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Abstract

Cloud microphysical measurements of two ground-based field campaigns are analyzed in order to compare Particle Volume Monitor (PVM) measurements and Forward Scattering Spectrometer Probe (FSSP)-derived integrated quantities (mainly liquid water content LWC) for different types of drop size distributions. It is shown that in case of size distributions containing mostly small drops with diameters D < 25 μm the PVM and FSSP measurements agree if respective data corrections (activity and changing VAR, Mie curve adjustment, and wind ramming) are applied to the FSSP raw data. Therefore, it is concluded that both PVM and FSSP are excellent microphysical sensors in continental, stratiform, or cumuliform clouds with mostly small drops. However, if low concentrations of large drops (D > 25 μm) are present in the drop size distribution, which considerably increases LWC, discrepancies between PVM and FSSP measurements are established. The most likely explanation for the differences is that the sensitivity of the PVM decreases for low drop concentrations.

Corresponding author address: Dr. Manfred Wendisch, Institute for Tropospheric Research, Permoserstr. 15, 04303 Leipzig, Germany.

Email: wendisch@tropos.de

Abstract

Cloud microphysical measurements of two ground-based field campaigns are analyzed in order to compare Particle Volume Monitor (PVM) measurements and Forward Scattering Spectrometer Probe (FSSP)-derived integrated quantities (mainly liquid water content LWC) for different types of drop size distributions. It is shown that in case of size distributions containing mostly small drops with diameters D < 25 μm the PVM and FSSP measurements agree if respective data corrections (activity and changing VAR, Mie curve adjustment, and wind ramming) are applied to the FSSP raw data. Therefore, it is concluded that both PVM and FSSP are excellent microphysical sensors in continental, stratiform, or cumuliform clouds with mostly small drops. However, if low concentrations of large drops (D > 25 μm) are present in the drop size distribution, which considerably increases LWC, discrepancies between PVM and FSSP measurements are established. The most likely explanation for the differences is that the sensitivity of the PVM decreases for low drop concentrations.

Corresponding author address: Dr. Manfred Wendisch, Institute for Tropospheric Research, Permoserstr. 15, 04303 Leipzig, Germany.

Email: wendisch@tropos.de

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