Benefits and limitations of the synergistic aerosol retrieval SYNAER

Abstract

Air pollution by solid and liquid aerosol particles suspended in the air is one of the major concerns in developed countries because of potential health impact of increasing numbers of nano-particles in particular from diesel engines (see, e.g., [2002] and [2004]), as well as in developing countries with their high particle concentrations in the air. Furthermore, windblown dust can also act as carrier for long-range transport of diseases, e.g., from the Sahara to the Caribbean or Western Europe [Pohl, 2003], or even around the globe [Prospero et al., 2002]. Also well known in principle are direct (by reflecting light back to space) and several indirect (e.g., by acting as cloud condensation nuclei) climate effects of aerosols, although large uncertainties exist in the exact values of the forcing [IPCC, 2007]. Finally, the highly variable atmospheric aerosol load has a major impact on satellite observations of the Earth’s surface that need to be atmospherically corrected for quantitative analysis and on the solar irradiance which is exploited in solar energy applications (aerosols are the determining factor in clear-sky conditions). In all these cases an estimation of the type of aerosols is required for an accurate quantitative assessment. For example, [2002] point out, that the absorption behavior of particles (mainly soot and minerals) needs to be known in order to assess their total direct and indirect climate effects. This is because strongly absorbing particles can regionally reverse the sign of the aerosol direct forcing from cooling to heating or suppress cloud formation. Therefore, attempts have been made to extend satellite aerosol retrieval beyond observation of the spatial-temporal distribution patterns to estimate the type of aerosols.