Design of a CCN Instrument for Airborne Measurement

Patrick Y. Chuang Environmental Engineering Science, California Institute of Technology, Pasadena, California

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Athanasios Nenes Department of Chemical Engineering, California Institute of Technology, Pasadena, California

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James N. Smith Environmental Engineering Science, California Institute of Technology, Pasadena, California

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Richard C. Flagan Department of Chemical Engineering, California Institute of Technology, Pasadena, California

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John H. Seinfeld Department of Chemical Engineering, California Institute of Technology, Pasadena, California

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Abstract

A new instrument for measuring cloud condensation nuclei (CCN) on board small aircraft is described. Small aircraft are attractive mainly because they are less costly, but they require instruments that are designed for minimum weight, volume, and power consumption; that are robust; and that are capable of autonomous operation and making measurements at a frequency appropriate for aircraft speeds. The instrument design combines the streamwise gradient technique previously reported by J. G. Hudson, and the alternating gradient condensation nuclei counter described by W. A. Hoppel et al. Field and laboratory measurements, and modeling studies show that this combination exhibits poor sensitivity for the measurement of CCN spectra; for the climatically important range of critical supersaturations, 0.03%–1%, the measured variable, droplet diameter, varies only by 30%. The ability to resolve CCN spectra using this method is therefore in question. Studies of this instrument in a fixed supersaturation mode show that it can measure CCN at a single supersaturation in the range of 0.1%–2%. Calibration and testing of the instrument in this mode is described. The instrument is capable of making accurate, high-frequency (>0.1 Hz) measurements of CCN at a fixed supersaturation, while satisfying the constraints for small aircraft.

Corresponding author address: John H. Seinfeld, Mail Code 210-41 Caltech, Pasadena, CA 91125.

Email: seinfeld@its.caltech.edu

Abstract

A new instrument for measuring cloud condensation nuclei (CCN) on board small aircraft is described. Small aircraft are attractive mainly because they are less costly, but they require instruments that are designed for minimum weight, volume, and power consumption; that are robust; and that are capable of autonomous operation and making measurements at a frequency appropriate for aircraft speeds. The instrument design combines the streamwise gradient technique previously reported by J. G. Hudson, and the alternating gradient condensation nuclei counter described by W. A. Hoppel et al. Field and laboratory measurements, and modeling studies show that this combination exhibits poor sensitivity for the measurement of CCN spectra; for the climatically important range of critical supersaturations, 0.03%–1%, the measured variable, droplet diameter, varies only by 30%. The ability to resolve CCN spectra using this method is therefore in question. Studies of this instrument in a fixed supersaturation mode show that it can measure CCN at a single supersaturation in the range of 0.1%–2%. Calibration and testing of the instrument in this mode is described. The instrument is capable of making accurate, high-frequency (>0.1 Hz) measurements of CCN at a fixed supersaturation, while satisfying the constraints for small aircraft.

Corresponding author address: John H. Seinfeld, Mail Code 210-41 Caltech, Pasadena, CA 91125.

Email: seinfeld@its.caltech.edu

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  • Alofs, D. J., 1978: Performance of a dual-range cloud nucleus counter. J. Appl. Meteor.,17, 1286–1297.

    • Crossref
    • Export Citation
  • ——, and J. C. Carstens, 1976: Numerical simulation of a widely used cloud nucleus counter. J. Appl. Meteor.,15, 350–354.

    • Crossref
    • Export Citation
  • Berglund, R. N., and B. Y. H. Liu, 1973: Generation of monodisperse aerosol standards. Environ. Sci. Technol.,7, 147–153.

    • Crossref
    • Export Citation
  • Bohren, C. F., and D. R. Huffman, 1983: Absorption and Scattering of Light by Small Particles. Wiley and Sons, 530 pp.

  • Chuang, P. Y., R. J. Charlson, and J. H. Seinfeld, 1997: Kinetic limitations on droplet formation in clouds. Nature,390, 594–596.

    • Crossref
    • Export Citation
  • ——, and Coauthors, 2000: CCN measurements during ACE-2 and their relationship to cloud microphysical properties. Tellus,52B, 843–867.

    • Crossref
    • Export Citation
  • Delene, D. J., T. Deshler, P. Wechsler, and G. A. Vali, 1998: A balloon-borne cloud condensation nuclei counter. J. Geophys. Res.,103, 8927–8934.

    • Crossref
    • Export Citation
  • Fitzgerald, J. W., C. F. Rogers, and J. G. Hudson, 1981: Review of isothermal haze chamber performance. J. Rech. Atmos.,15, 333–346.

  • Fukuta, N., and V. K. Saxena, 1979: A horizontal thermal gradient cloud condensation nucleus spectrometer. J. Appl. Meteor.,18, 1352–1362.

    • Crossref
    • Export Citation
  • Gosman, A. D., and A. Ideriah, 1976: TEACH-2E. Tech. Rep. FM-83-2, University of California, Berkeley, Berkeley, CA.

  • Hindmarsh, A. C., 1983: ODEPACK: A Systemized Collection of ODE Solvers. North-Holland.

  • Hoppel, W. A., S. Twomey, and T. A. Wojciechowski, 1979: A segmented thermal diffusion chamber for continuous measurements of CN. J. Aerosol Sci.,10, 369–373.

  • Hudson, J. G., 1989: An instantaneous CCN spectrometer. J. Atmos. Oceanic Technol.,6, 1055–1065.

    • Crossref
    • Export Citation
  • ——, and P. Squires, 1976: An improved continuous flow diffusion cloud chamber. J. Appl. Meteor.,15, 776–782.

    • Crossref
    • Export Citation
  • ——, and A. D. Clarke, 1992: Aerosol and cloud condensation nuclei measurements in the Kuwait plume. J. Geophys. Res.,97, 14 533–14 536.

  • ——, and G. Svensson, 1995: Cloud microphysical relationships in California marine stratus. J. Appl. Meteor.,34, 2655–2666.

    • Crossref
    • Export Citation
  • ——, Y. Xie, and S. S. Yum, 1998: Vertical distributions of cloud condensation nuclei spectra over the summertime Southern Ocean. J. Geophys. Res.,103, 16 609–16 624.

  • IPCC, 1996: Climate Change 1995: The Science of Climate Change. Cambridge University Press, 572 pp.

  • Jiusto, J. E., R. E. Ruskin, and A. Gagin, 1981: CCN comparisons of static diffusion chambers. J. Rech. Atmos.,15, 291–302.

  • Kandlikar, M., and G. Ramachandran, 1999: Inverse methods for analysing aerosol spectrometer measurements: A critical review. J. Aerosol Sci.,30, 413–437.

    • Crossref
    • Export Citation
  • Laktionov, A. G., 1972: A constant-temperature method of determining the concentrations of cloud condensation nuclei. Atmos. Oceanic Phys.,8, 672–677.

  • Lala, G. G., and J. E. Jiusto, 1977: An automatic light scattering CCN counter. J. Appl. Meteor.,16, 413–418.

    • Crossref
    • Export Citation
  • Leaitch, R., and W. J. Megaw, 1982: The diffusion tube: A cloud condensation nucleus counter for use below 0.3% supersaturation. J. Aerosol Sci.,13, 297–319.

  • Patankar, S. V., 1980: Numerical Heat Transfer and Fluid Flow. McGraw-Hill, 197 pp.

  • Raes and Coauthors, 2000: The second Aerosol Characterization Experiment (ACE-2): General overview and main results. Tellus,52B, 111–125.

    • Crossref
    • Export Citation
  • Seinfeld, J. H., and S. N. Pandis, 1998: Atmospheric Chemistry and Physics: From Air Pollution to Climate Change. Wiley and Sons, 1326 pp.

    • Crossref
    • Export Citation
  • Shulman, M. L., M. C. Jacobson, R. J. Charlson, R. E. Synovec, and T. E. Young, 1996: Dissolution behavior and surface tension effects of organic compounds in nucleating cloud droplets. Geophys. Res. Lett.,23, 277–280.

    • Crossref
    • Export Citation
  • Sinnarwalla, A. M., and D. J. Alofs, 1973: A cloud nucleus counter with long available growth time. J. Appl. Meteor.,12, 831–835.

    • Crossref
    • Export Citation
  • Twomey, S., 1963: Measurements of natural cloud nuclei. J. Rech. Atmos.,1, 101–105.

  • ——, 1977: The influence of pollution on the shortwave albedo of clouds. J. Atmos. Sci.,34, 149–152.

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