Measurements of ambient aerosol properties

This chapter describes the wide range of instruments and techniques that are used to measure aerosol particle microphysical and optical properties and how such measurements are used to evaluate models. The range of instruments includes those used to measure particle number and mass concentration, size distribution, water uptake, optical properties, chemical composition, black carbon, and interaction with clouds. The chapter also includes a description of how ambient measurements are made at the surface and from airborne platforms, including several regional and global networks of measurements that provide important data for model evaluation. The chapter concludes with a description of several case studies in which in situ aerosol chemical and microphysical properties have been used to evaluate and improve models.