Clouds and aerosols

The inference of cloud characteristics is based on much less sophisticated approaches than those for determining thermal stmcture and gas abundances. Clouds tend to be quite inhomogeneous compared with gaseous mixtures and require more parameters for adequate definition. Also, the appropriate equation of transfer [Eq. (2.1.40)] is considerably more complex than Eq. (8.2.1), and not nearly as amenable to inversion techniques. Even so, direct techniques are sometimes capable of leading to rather definitive conclusions about cloud and aerosol systems. We illustrate with an example concerning the abundance of the photochemical aerosol in Titan s stratosphere. 

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There is an effort to tighten estimates of how the Earth will respond to climate warming. The sensitivity of new climate models has improved, but to fully understand the Earth s response to climate warming, a better knowledge of clouds and aerosols is needed, as well as improved and more and better records of past climate changes and their drivers. 

Atkinson, R., D. L. Baulch, R. A. Cox, R. F. Hampson, J. A. Kerr, M. J. Rossie, and J. Troe, Evaluated Kinetic and Photochemical Data for Atmospheric Chemistry. Supplement V. IUPAC Subcommittee on Gas Kinetic Data Evaluation for Atmospheric Chemistry, J. Phys. Chem. Ref. Data, 26, 521-1011 (1997). Bordewijk, J. A., H. Slaper, H. A. J. M. Reinen, and E. Schlamann, Total Solar Radiation and the Influence of Clouds and Aerosols on the Biologically Effective UV, Geophys. Res. Lett., 22, 2151-2154 (1995). 

In short, the overall features of the chemistry involved with the massive destruction of ozone and formation of the ozone hole are now reasonably well understood and include as a key component heterogeneous reactions on the surfaces of polar stratospheric clouds and aerosols. However, there remain a number of questions relating to the details of the chemistry, including the microphysics of dehydration and denitrification, the kinetics and photochemistry of some of the C10x and BrOx species, and the nature of PSCs under various conditions. PSCs and aerosols, and their role in halogen and NOx chemistry, are discussed in more detail in the following section. 

The value of 10 is determined by molecular and particulate (cloud and aerosol) scattering, and surface reflection. A small fraction of the molecular scattering is the non-conservative Rotational Raman scattering (RRS) that partially fills the solar Fraunhofer lines in the scattered radiation, creating what is commonly known as the Ring effect [15] As a result, the ratio Iq/F, where F is the extraterrestrial solar flux, contains structure that is correlated with solar Fraunhofer lines. By separating these effects, one can write... 

GOME Global Ozone Monitoring Experiment TRandST Or, NO2, H20 BrO, OCIO, S02, HCHO and clouds and aerosols ESA-ERS-l (1995-present)... 

MERIS Medium Resolution Imaging Spectrometer for Passive Atmospheric Sounding TR H2O, clouds and aerosol ESA-ENVISAT (2001)... 

Guzzi R., E. Cattani, M. Cervino, C. Levoni, F. Torricella, J.P. Burrows and T. Kurosu (1998) GOME cloud and aerosol data products algorithms development. Final Report ESA Contract 11572/95/NL/CN. 

Because multiple scattering, surface reflection, clouds, and aerosols have a significant effect on radiative intensities at photodissociative wavelengths and consequently on the composition of the middle atmosphere (see, e.g., Luther et al, 1978), simplified radiative transfer... 

The literature is absent of studies on atmospheric PH3 oxidation in detail. In PH3 -I- O2 explosions, the radicals PH2 and PO have been detected (Norrish and Older-shaw 1961), and PO has also been found in interstellar clouds. According to Ghnde-mann et al. (2003, 2005a), the final product of PH3 oxidation in air is phosphate ion but nothing is known about the reaction steps. We can only further speculate that the oxidation proceeds in solution and/or interfacial, i.e. in the cloud and aerosol layer and this might explain why PH3 is found in the upper troposphere. As we have largely discussed, it is not the solubility that controls the washout but the interfacial chemistry for low-soluble species. 

Samuelson, R. E. (1985). Clouds and aerosols of Titan s atmosphere. In The Atmospheres of Saturn and Titan, pp. 99-107. European Space Agency SP-241. 

Elshorbany, Y.F. Crutzen, P. Steil, B. Pozzer, A. Tost, H. Lelieveld, J., 2014 Global and Regional Impacts of HONO on the Chemical Composition of Clouds and Aerosols , in Atmospheric Chemistry and Physics, 14 1167— 1184. 

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