Polarization Lidar Studies of Indirect Desert Dust Effects on Clouds

摘要

Atmospheric aerosols derived from major desert dust storms can disperse widely across the globe and affect the Earth's radiation balance both directly (through aerosol scattering and absorption) and indirectly (by changing cloud properties). In this study we report on polarization lidar observations of Asian dust layers transported to the interior of Alaska during the winter/spring of 2004. We show that there ability to efficiently act as ice nuclei affects supercooled water and ice clouds at great transport distances. In particular, a new phenomenon is shown, in which deposition ice nucleation at relatively warm temperatures and slight ice supersaturations produces thin icy-dust clouds with mixed radiative properties.