Tropospheric aerosols

Krotkov, N. A., P. K. Bhartia, J. R. Herman, V. Fioletov, and J. Kerr, Satellite Estimation of Spectral Surface UV Irradiance in the Presence of Tropospheric Aerosols. 1. Cloud-Free Case, J. Geophys. Res., 103, 8779-8793 (1998). 

Transport on Free Tropospheric Aerosols over the Central USA in Springtime, Geophys. Res. Lett., 25, 1367-1370 (1998). 

Much more relevant to the aqueous phase in clouds and fogs in the atmosphere is the catalyzed oxidation of S(IV) by 02. Both Fe3+ and Mn2+ catalyze the oxidation and as described in Chapter 9, both are common constituents of tropospheric aerosols even in remote... 

Based on numerous size distributions measured in air, various categories of tropospheric aerosols have been proposed. Table 9.2, for example, shows a typical set of categories and some of their associated characteristics. However, these should be taken merely as examples rather than as fixed categories since many aerosols will display characteristics of more than one category. 

TABLE 9.2 Some Typical Tropospheric Aerosols and Their Associated Properties"... 

Figure 9.45 shows the structures of a few of the other organics found in tropospheric aerosols and be-... 

Hegg, D., T. Larson, and P.-F. Yuen, A Theoretical Study of the Effect of Relative Humidity on Light Scattering by Tropospheric Aerosols, J. Geophys. Res., 98, 18435-18439 (1993). 

Mishchenko, M. I., A. A. Lacis, B. E. Carlson, and L. D. Travis, Nonsphericity of Dust-Like Tropospheric Aerosols Implications for Aerosol Remote Sensing and Climate Modeling, Geophys. Res. Lett, 22, 1077-1080(1995). 

Anderson, J. R P. R. Buseck, and T. L. Patterson, Characterization of the Bermuda Tropospheric Aerosol by Combined Individual-Particle and Bulk-Aerosol Analysis, Atmos. Environ., 30, 319-338 (1996). 

TOMS is also a satellite-based method based on a similar approach to that of SBUV, in which the earth s albedo is measured at several wavelengths around 300 nm. Unlike SBUV, vertical distributions of 03 are not derived using TOMS, but it provides better horizontal resolution (Ziernke et al., 1998). TOMS has also been used to measure tropospheric aerosols using the wavelength dependence of UV reflectivity at wavelengths that are not absorbed by 03 (e.g., Hsu et al., 1996 Herman et al., 1997 Torres et al., 1998). 

In addition, as seen in Fig. 13.9, changes in tropospheric composition can also impact the results. For example, the trend in total ozone over 20 years measured in Belgium was -1.38 + 0.50% per decade but after correcting for changes in tropospheric S02, no significant trend in ozone could be discerned (De Muer and De Backer, 1992). There is also a concern regarding the effects of trends in tropospheric aerosols on the derived trends in 03. 

Pilinis, C., and X. Li, Particle Shape and Internal Inhomogeneity Effects on the Optical Properties of Tropospheric Aerosols of Relevance to Climate Forcing, J. Geophys. Res., 103, 3789-3800 (1998). 

Raes, F., Entrainment of Free Tropospheric Aerosols as a Regulating Mechanism for Cloud Condensation Nuclei in the Remote Marine Boundary Layer, J. Geophys. Res., 100, 2893-2903 (1995). 

Pollack, J. B., and J. N. Cuzzi, 1980. Scattering by nonspherical particles of size comparable to a wavelength a new semi-empirical theory and its application to tropospheric aerosols, J. Atmos. Sci., 37, 868-881. 

It is concluded tentatively from these preliminary 210Bi/210Pb ratio data that tropospheric aerosols have a much shorter atmospheric residence time than is generally appreciated. If so, both natural aerosols and radioactive fallout observed at tropospheric levels will not be well mixed zonally but for the most part will be deposited within a few... 

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