Advertisement

Journal of Atmospheric Chemistry

, Volume 9, Issue 1–3, pp 187–211 | Cite as

Airborne and lidar measurements of aerosol and cloud particles in the troposphere over Alert Canada in April 1986

  • W. R. Leaitch
  • R. M. Hoff
  • J. I. MacPherson
Article

Abstract

As a component of the Canadian Arctic Haze Study, held coincident with the second Arctic Gas and Aerosol Sampling Program (AGASP II), vertical profiles of aerosol size distribution (≥0.17 μm), light scattering parameters and cloud particle concentrations were obtained with an instrumented aircraft and ground-based lidar system during April 1986 at Alert. Northwest Territories. Average aerosol number concentrations range from about 200 cm−3 over the Arctic ice cap to about 100 cm−3 at 6 km. The aerosol size spectrum is virtually free of giant or coarse aerosol particles, and does not vary significantly with altitude. Most of the aerosol volume is concentrated in the 0.17–0.50 μm size range, and the aerosol number concentration is found to be a good surrogate for the SO4= concentration of the Arctic haze aerosol. Comparison of the aircraft and lidar data show that, when iced crystal scattering is excluded, the aerosol light scattering coefficient and the lidar backscattering coefficient are proportional to the Arctic haze aerosol concentration. Ratios of scattering to backscattering, scattering to aerosol number concentration, and backscattering to aerosol number concentration are 15.3 steradians, 1.1×10−13 m2, and 4.8×10−15 m2 sr−1, respectively. Aerosol scattering coefficients calculated from the measured size distributions using Mie scattering agree well with measured values. The calculations indicate the aerosol absorption optical depth over 6 km to range between 0.011 and 0.018. The presence of small numbers of ice crystals (10–20 crystals 1−1 measured) increased light scattering by over a factor of ten.

Key words

aerosol size distribution aerosol particle profiles aerosol scattering Arctic haze ice crystals lidar ozone profiles 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Barrie, L.A., R.M. Hoff, and S. Daggupaty (1981) The influence of mid-latitudinal pollution sources on haze in the Canadian Arctic. Atmos. Environ., 15, 1407–1420.Google Scholar
  2. Barrie, L.A. (1986) Arctic air pollution: an overview of current knowledge. Atmos. Environ., 20, 643–663.Google Scholar
  3. Barrie, L.A., G. denHartog, J.W. Bottenheim, and S. Landsberger (1989) Anthropogenic aerosols and gases in the lower troposphere at Alert Canada in April 1986. J. Atmos. Chem., (this issue).Google Scholar
  4. Bohren, C.F. and D.R. Huffman (1983) Absorption and Scattering of Electromagnetic Radiation by Small Particles, Wiley-Interscience, New York, U.S.A.Google Scholar
  5. 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.Google Scholar
  6. Heintzenberg, J. (1980) Particle size distribution and optical properties of Arctic haze. Tellus, 32, 251–260.Google Scholar
  7. Hoff, R.M., W.R. Leaitch, P. Fellin, and L.A. Barrie (1983) Mass size distribution of chemical constituents of the winter Arctic aerosol. J. Geophys. Res., 88, 10947–10956.Google Scholar
  8. Hoff, R.M. (1988) Vertical studies of Arctic Haze by lidar., J. Appl. Met., 27, 125–139.Google Scholar
  9. Isaac, G.A., W.R. Leaitch, J.W. Strapp, and K.G. Anlauf (1986) Summer aerosol profiles over Algonquin Park, Canada. Atmos. Environ., 20, 157–172.Google Scholar
  10. Joranger, E. and B. Ottar (1984) Air pollution studies in the Norwegian Arctic. Geophys. Res. Lett., 11, 365–368.Google Scholar
  11. Kent, G.S., L.R. Poole, and M.P. McCormick (1986) Characteristics of Arctic Polar stratospheric clouds as measured by airborne lidar. J. Atmos. Sci., 43, 2149–2161.Google Scholar
  12. Leaitch, W.R., J.W. Strapp, G.A. Isaac, and J.G. Hudson (1986) Cloud droplet nucleation and cloud scavenging of aerosol sulphate in polluted atmospheres. Tellus, 38B, 328–344.Google Scholar
  13. McCormick, M.P., H.M. Steele, P. Hamill, T.J.H. Pepin, W.P. Chu, and Y.J. Swissler (1979) Satellite studies of the stratospheric aerosol, Bull. Am. Meteor. Soc., 60, 1038–1046.Google Scholar
  14. Pinnick, R.G. and H.J. Auvermann (1979) Response characteristics of Knollenberg light-scattering aerosol counters. J. Aerosol Sci., 10, 55–74.Google Scholar
  15. Radke, L.F., J.H. Lyons, D.A. Hegg, and P.V. Hobbs (1984) Airborne observations of Arctic aerosols. I: Characteristics of Arctic haze, Geophys. Res. Lett., 11, 393–396.Google Scholar
  16. Rosen, H. and A.D.A. Hansen (1984) Role of combustion-generated carbon particles in the absorption of solar radiation in the Arctic haze. Geophys. Res. Lett., 11, 461–464.Google Scholar
  17. Schnell, R.C. and W.E. Raatz (1984) Vertical and horizontal characteristics of Arctic haze during AGASP: Alaskan Arctic. Geophys. Res. Lett., 11, 369–372.Google Scholar
  18. Shaw, G.E. (1984) Microparticle size spectrum of Arctic haze. Geophys. Res. Lett., 11, 409–412.Google Scholar
  19. Sheridan, P.J. (1988) Characterization of size-segragated particles collected over Alaska and the Canadian High Arctic: AGASP II, flights 204–206. Atmos. Environ., (submitted).Google Scholar
  20. Sheridan, P.J. (1989) Studies of size-segragated particles collected during AGASP II: flights 201–203. J. Atmos. Chem., (this issue).Google Scholar
  21. Tsonis, A.A., W.R. Leaitch, and M.D. Couture (1987) The effect of the calibration of the forward-scattering spectrometer probe on the sizing of cloud droplets. J. Atmos. Oceanic Technol., 4, 518–526.Google Scholar
  22. Waggoner, A.P., R.E. Weiss, N.C. Ahlquist, D.S. Covert, S. Will and R.J. Charlson (1981) Optical characteristics of atmospheric aerosols. Atmos. Environ., 15, 1891–1909.Google Scholar

Copyright information

© Kluwer Academic Publishers 1989

Authors and Affiliations

  • W. R. Leaitch
    • 1
  • R. M. Hoff
    • 1
  • J. I. MacPherson
    • 2
  1. 1.Atmospheric Environment ServiceDownsviewCanada
  2. 2.Flight Research LaboratoryNational Research CouncilOttawaCanada

Personalised recommendations