Aerosol Optics

This new text offers experienced students a comprehensive review of available techniques for the remote sensing of aerosols. These small particles influence both atmospheric visibility and the thermodynamics of the atmosphere. They are also of great importance in any consideration of climate change problems. Aerosols may also be responsible for the loss of harvests, human health problems and ecological disasters. Thus, this detailed study of aerosol properties on a global scale could not be more timely.

Remote Sensing is of paramount importance for Earth Observation to monitor and analyze the Earth’s vital signs. In this Special Issue are reported the latest research results involving active optical remote sensing instruments, both from ground-based to satellite platforms, that are involved in analyzing the vertical and horizontal aerosol and cloud distribution, other than their geometrical, optical and microphysical properties. Those active optical remote sensing techniques are also very useful in determining pollutant dispersion and the dynamics inside the boundary layer. The published studies put in evidence the hidden mechanisms on how pollution from the source is advected transnationally in other countries and the interaction with local meteorology.

The book describes the theoretical fundamentals of atmospheric optics as a science of propagation, transformation and generation of electromagnetic radiation in the atmosphere from ultraviolet to microwave radiation. The main characteristics of the planets of the solar system and their atmospheres are given. The equation of the transfer of radiation in different spectral ranges, absorption of radiation by atmospheric gases and aerosol, molecular, aerosol and other types of nonresonant scattering, atmospheric refraction, reflection of radiation from the surface, and glow of the atmosphere are discussed. Methods of calculating radiation for the solar and thermal range of the spectrum are outlined. Problems of radiation energetics and remote probing of the atmosphere are discussed. 1. Solar system: planets and the Sun 2. Earth's atmosphere 3. Propagation of radiation in atmosphere 4. Molecular absorption in atmosphere 5. Scattering of light in atmosphere 6. Optical properties of underlying surfaces 7. Fundamentals of theory of transfer of natural radiation of atmosphere 8. Main concepts of theory of transfer of solar radiation 9. Radiation energetics of the atmosphereunderlying suface system 10. Radiation as a source of information on optical and physical parameters of planet atmospheres

This book provides the first comprehensive analysis of how aerosols form in the atmosphere through in situ processes as well as via transport from the surface (dust storms, seas spray, biogenic emissions, forest fires etc.). Such an analysis has been followed by the consideration of both observation data (various field observational experiments) and numerical modeling results to assess climate impacts of aerosols bearing in mind that these impacts are the most significant uncertainty in studying natural and anthropogenic causes of climate change.

This textbook aims to be a one stop shop for those interested in aerosols and their impact on the climate system. It starts with some fundamentals on atmospheric aerosols, atmospheric radiation and cloud physics, then goes into techniques used for in-situ and remote sensing measurements of aerosols, data assimilation, and discusses aerosol-radiation interactions, aerosol-cloud interactions and the multiple impacts of aerosols on the climate system. The book aims to engage those interested in aerosols and their impacts on the climate system: graduate and PhD students, but also post-doctorate fellows who are new to the field or would like to broaden their knowledge. The book includes exercises at the end of most chapters. Atmospheric aerosols are small (microscopic) particles in suspension in the atmosphere, which play multiple roles in the climate system. They interact with the energy budget through scattering and absorption of solar and terrestrial radiation. They also serve as cloud condensation and ice nuclei with impacts on the formation, evolution and properties of clouds. Finally aerosols also interact with some biogeochemical cycles. Anthropogenic emissions of aerosols are responsible for a cooling effect that has masked part of the warming due to the increased greenhouse effect since pre-industrial time. Natural aerosols also respond to climate changes as shown by observations of past climates and modelling of the future climate.

The book describes the morphological, physical and chemical properties of aerosols from various natural and anthropogenic sources to help the reader better understand the direct role of aerosol particles in scattering and absorbing short- and long-wave radiation.