Mineral quartz concentration measurements of mixed mineral dust/urban haze pollution plumes over Korea with multiwavelength aerosol Raman-quartz lidar

Abstract

We present a case study of a concentration measurement of mineral quartz immersed in East Asian urban pollution. We use a novel lidar measurement technique that uses signals from Raman scattering from quartz at ultraviolet (360 nm) wavelength. The particle-extinction-related ngstrm exponent (wavelength pair 355/532 nm) varies around 0.7±0.2 , the lidar ratio is 50-55 sr at 532 nm. The numbers indicate that the pollution plume likely consisted of a mixture of mineral dust with urban haze. Dust concentrations vary between 8-11 g/cm 3. We determined Raman quartz concentrations from measurements simultaneously carried out at 546 nm, which allows us to measure for the first time the Raman-quartz-related ngstrm exponent of mineral dust. Values are 3-4, whereas we expect a theoretical value of 4. It is unclear if the lower values follow from retrieval uncertainties or if they are linked to the internal structure of the quartz grains. © 2010 by the American Geophysical Union.