Radiative Effects of Dust - Mineral Dust: A Key Player in the Earth System - page 263

Chapter 11
Radiative Effects of Dust

Eleanor J. Highwood and Claire L. Ryder

Abstract Dust is a major component of atmospheric aerosols, and aerosols in
general are a major uncertainty in predicting climate change. Aerosols are crucial
too in cloud formation processes and therefore in the hydrologic cycle. As a first
step to understanding and quantifying the impact of dust on weather and climate,
we must be able to characterise the impact of dust on radiative transfer processes in
the atmosphere. In this chapter we consider the impact of dust on the reflection and
absorption of both long-wave and short-wave radiation and illustrate the sensitivity
of this effect to the size and composition of dust particles. We also consider the
impact of dust on satellite retrievals of aerosol and other quantities.

Keywords Optical properties ￿ Single-scattering albedo ￿ Radiative effect ￿
Satellite retrievals ￿ Radiation ￿ Scattering ￿ Refractive index ￿ Particle size ￿
Extinction ￿ Visibility ￿ Dust models

11.1 Introduction

Dust affects weather and climate in two main ways - via modifying the capture or
redirection of radiation by the atmosphere and by modification of cloud properties
(see Chap. 12 ) . Dust also deposits nutrients to oceanic and terrestrial ecosystems,
which affects the global carbon cycle (see Chap. 14 ) . This chapter will address the
so-called “direct” impact of dust on radiation in both the short- and long-wave parts
of the radiation spectrum. The interaction of dust with radiation also has impacts for
satellite retrievals of surface temperature and other quantities, and this will also be
discussed briefly in this chapter.