Lidar measurements of atmospheric aerosol as a function of relative humidity

Hänel and Frankenberger have related the extinction coefficient and standard visibility to the relative humidity. It has been assumed that these relations also apply to the backscatter coefficient. Lidar measurements of atmospheric backscatter have confirmed that the assumption is reasonable and provide a means of distinguishing between air masses with different aerosol contents.Notation _k extinction coefficient of sample - V_k volume of sample - N_k number of particles in sample - r_j equivalent radius of particle - K_j extinction efficiency factor for particle - r_k characteristic radius of particle in sample - K_k characteristic extinction efficiency factor - S_k total extinction efficiency factor - f relative humidity - solid angle - _k() scattering coefficient at angle - _j^* scattering phase shift parameter of particle - m_j complex refractive index of particle - wavelength - Q ratio of particle cross-section areas [4] - exponent in Kasten's relation - R ratio of backscatter coefficients