O’Neill, Norm T.Dubovik, OlegEck, Thomas2024-04-292024-04-292001-05-20O’Neill, Norm T., Oleg Dubovik, and Tom F. Eck. “Modified Ångström Exponent for the Characterization of Submicrometer Aerosols.” Applied Optics 40, no. 15 (May 20, 2001): 2368–75. https://doi.org/10.1364/AO.40.002368.https://doi.org/10.1364/AO.40.002368http://hdl.handle.net/11603/33563The 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 (αբ) 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.8 pagesen-USThis work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.Public Domainhttps://creativecommons.org/publicdomain/mark/1.0/AerosolsCurvatureNear infraredOptical computingPoint cloudsRefractive indexText