| Volumes and Issues Contents of Issue 2 |
www.atmos-meas-tech-discuss.net/2/725/2009/
doi:10.5194/amtd-2-725-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Determination of aerosol properties from MAX-DOAS observations of the Ring effect
1Max-Planck-Institute for Chemistry, Mainz, Germany
2Institute for Environmental Physics, University of Heidelberg, Germany
Abstract. The first quantitative comparison of MAX-DOAS observations of the Ring effect with model simulations is presented. It is performed for a large variety of viewing geometries (solar zenith angles: 45° to 90°, elevation angles: 3°, 6°, 10°, 18°, 90°; three different azimuth angles), which allows a comprehensive test of our capabilities to measure and simulate the Ring effect. In addition to the Ring effect, also the observed O4 absorptions (optical densities) and radiances are compared with model simulations. In general good agreement is found for all measured quantities. From several sensitivity studies it is found that for most measurement situations the aerosol optical depth has usually the strongest influence on the observed quantities, but also other aerosol properties like e.g. the vertical distribution have a significant effect. Typically, the qualitative dependence of the Ring effect on aerosol properties is very similar to that of the O4 absorption. This can be understood, since both quantities depend strongly on the light path length in the lower atmosphere. However, in specific cases, the observation of the Ring effect can provide complementary information to that retrieved from the O4 observations. This is e.g. possible for measurements at small relative azimuth angles, from which information on the asymmetry parameter can be derived. Observations at large solar zenith angle allow the retrieval of stratospheric aerosol properties, even in cases with very low aerosol optical depths. In addition, Ring effect observations in zenith direction are rather sensitive to the aerosol optical depth (in contrast to O4 observations), which might allow to retrieve information on aerosol properties from existing zenith UV data sets prior to the MAX-DOAS era.
Discussion Paper (PDF, 1636 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (AMT)
Citation: Wagner, T., Deutschmann, T., and Platt, U.: Determination of aerosol properties from MAX-DOAS observations of the Ring effect, Atmos. Meas. Tech. Discuss., 2, 725-779, doi:10.5194/amtd-2-725-2009, 2009. Bibtex EndNote Reference Manager XML
