Ice-nucleating properties of uncoated and coated mineral dust particles
Authors
Gourihar Kulkarni — Pacific Northwest National Laboratory
Cassandra Sanders — Pacific Northwest National Laboratory
Xiaohong Liu — Texas A&M University
Category
Aerosol Properties
Description
Mineral dust particles contribute to a major component of global aerosol fraction, and substantial evidence indicates that dust particles are most effective ice nuclei (IN). However, the ice-nucleating ability of mineral dust particles could be altered if they are coated with soluble materials such as sulfates. We report ice nucleation laboratory experiments showing that IN properties of coated dust particles depend upon the mineralogy of the dust particles.The ice nucleation ability of uncoated and coated dust particles was investigated at three temperatures: -25°C, -30°C, and -35°C. Particles were size-selected and coated with sulfuric acid, and coating thickness was estimated by measuring the hygroscopicity properties of dust-coated particles. Only coated Arizona test dust particles showed suppression of IN ability; the ice-nucleating ability of other particles such as illite, kaolinite, montomorillonite, and quartz was not altered. This suggests mineralogical compositions dictate the chemical reactions with sulfuric acid that affect the ice nucleating abilities. Results and conclusions with atmospheric implications will be presented.