Measurements

To interpret the effects of aerosols and gases on the atmosphere, information on the vertical and horizontal distribution of aerosol particles, their size distributions and concentration of precursor gases is required. Measurements of aerosols and gases at frequent intervals and over vast areas of atmosphere generally involve remote sensing techniques. These techniques depend on the optical properties of the species studied. Optical properties can vary greatly with aerosol size and refractive index. Remote sensing instruments look at light scattering, extinction, depolarization, and reflection. The chemical composition, phase equilibria, surface properties, and photochemical behavior of stratospheric aerosols are not clearly understood or adequately measured by current technologies. Areas are listed which need technology development.