OSA's Digital Library

Applied Optics

Applied Optics


  • Vol. 40, Iss. 15 — May. 20, 2001
  • pp: 2368–2375

Modified Ångström exponent for the characterization of submicrometer aerosols

Norm T. O’Neill, Oleg Dubovik, and Tom F. Eck  »View Author Affiliations

Applied Optics, Vol. 40, Issue 15, pp. 2368-2375 (2001)

View Full Text Article

Enhanced HTML    Acrobat PDF (1414 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



The classical Ångström exponent is an operationally robust optical parameter that contains size information on all optically active aerosols in the field of view of a sunphotometer. Assuming that the optical effects of a typical (radius) size distribution can be approximated by separate submicrometer and supermicrometer components, we show that one can exploit the spectral curvature information in the measured optical depth to permit a direct estimation of a fine-mode (submicrometer) Ångström exponent (α f ) as well as the optical fraction of fine-mode particles (η). Simple expressions that enable the estimation of these parameters are presented and tested by use of simulations and measurements.

© 2001 Optical Society of America

OCIS Codes
(010.1290) Atmospheric and oceanic optics : Atmospheric optics
(280.1100) Remote sensing and sensors : Aerosol detection

Original Manuscript: May 25, 2000
Revised Manuscript: January 11, 2001
Published: May 20, 2001

Norm T. O’Neill, Oleg Dubovik, and Tom F. Eck, "Modified Ångström exponent for the characterization of submicrometer aerosols," Appl. Opt. 40, 2368-2375 (2001)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. A. Ångström, “On the atmospheric transmission of sun radiation and on dust in the air,” Geogr. Ann. Dtsch. 12, 156–166 (1929). [CrossRef]
  2. N. T. O’Neill, T. F. Eck, B. N. Holben, A. Smirnov, O. Dubovik, “Bi-modal size distribution influences on the variation of Angstrom derivatives in spectral and optical depth space,” J. Geophys. Res. (to be published).
  3. J. S. Reid, T. F. Eck, S. A. Christopher, P. V. Hobbs, B. N. Holben, “Use of the Angstrom exponent to estimate the variability of optical and physical properties of aging smoke particles in Brazil,” J. Geophys. Res. 104, 27473–27489 (1999). [CrossRef]
  4. T. F. Eck, B. N. Holben, J. S. Reid, O. Dubovik, A. Smirnov, N. T. O’Neill, “The wavelength dependence of the optical depth of biomass burning, urban, and desert dust aerosols,” J. Geophys. Res. 104, 31333–31350 (1999). [CrossRef]
  5. K. S. Shifrin, “Simple relationships for the Ångström parameter of disperse systems,” Appl. Opt. 34, 4480–4485 (1995). [CrossRef] [PubMed]
  6. N. T. O’Neill, A. Royer, “Extraction of bimodal aerosol-size distribution radii from spectral and angular slope (Angstrom) coefficients,” Appl. Opt. 32, 1642–1645 (1993). [CrossRef] [PubMed]
  7. A. Ångström, “The parameters of atmospheric turbidity,” Tellus 16, 64–75 (1964). [CrossRef]
  8. World Meteorological Organization, “Report of the experts meeting on aerosols and their climatic effects,” (World Meteorological Organization, Geneva, Switzerland, 1983).
  9. E. M. Patterson, D. A. Gillette, “Commonalities in measured size distribution for aerosols having a soil-derived component,” J. Geophys. Res. 82, 2074–2082 (1977). [CrossRef]
  10. E. P. Shettle, R. W. Fenn, “Models for the aerosol of the lower atmosphere and the effects of humidity variations on their optical properties,” Environmental Research Paper 767, (U.S. Air Force Geophysics Laboratory, Hanscom Air Force Base, Mass., 1979).
  11. J. E. Hansen, L. D. Travis, “Light scattering in planetary atmospheres,” Space Sci. Rev. 16, 527–610 (1974). [CrossRef]
  12. L. Remer, Y. J. Kaufman, B. N. Holben, “Interannual variation of ambient aerosol characteristics on the East Coast of the United States,” J. Geophys. Res. D2 104, 2223–2231 (1999). [CrossRef]
  13. H. C. van de Hulst, Light Scattering by Small Particles (Wiley, New York, 1957).
  14. B. N. Holben, T. F. Eck, I. Slutsker, D. Tanre, J. P. Buis, A. Setzer, E. Vermote, J. A. Reagan, Y. Kaufman, T. Nakajima, F. Lavenu, I. Jankowiak, A. Smirnov, “AERONET—a federated instrument network and data archive for aerosol characterization,” Remote Sens. Environ. 66, 1–16 (1998). [CrossRef]
  15. A. Smirnov, B. N. Holben, T. F. Eck, O. Dubovik, I. Slutsker, “Cloud screening and quality control algorithms for the AERONET data base,” Remote Sens. Environ. 73, 337–349 (2000). [CrossRef]
  16. O. Dubovik, M. D. King, “A flexible inversion algorithm for retrieval of aerosol optical properties from sun and sky radiance measurements,” J. Geophys. Res. 105, 20673–20696 (2000). [CrossRef]
  17. B. N. Holben, D. Tanre, A. Smirnov, T. F. Eck, I. Slutsker, N. Abuhassan, W. W. Newcomb, J. Schafer, B. Chatenet, F. Lavenue, Y. J. Kaufman, J. Vande Castle, A. Setzer, B. Markham, D. Clark, R. Frouin, R. Halthore, A. Karnieli, N. T. O’Neill, C. Pietras, R. T. Pinker, K. Voss, G. Zibordi, “An emerging ground-based aerosol climatology: aerosol optical depth from AERONET,” J. Geophys. Res. (to be published).

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited