Ice nucleation ability of ammonium sulfate aerosol particles internally mixed with secondary organics

Abstract. The abundance of aerosol particles and their ability to catalyze ice nucleation are key parameters correctly understand describe the indirect effect on climate. Cirrus clouds strongly influence Earth's radiative budget, but is highly sensitive formation mechanism, which still poorly understood. Sulfate organics among most abundant components in troposphere have also been found cirrus crystal residuals. Most studies at cloud conditions looked either purely inorganic or organic particles. However, atmosphere mostly as internal mixtures, not yet fully characterized. In this study, we investigated internally mixed composed crystalline ammonium sulfate (AS) secondary material (SOM) temperatures between ?50 ?65 ?C. SOM was generated from ozonolysis ?-pinene. experiments were conducted a large chamber, allowed us simulate various aging processes that may experience during transport atmosphere, like cycling redistribution matter. We AS / dependent particle morphology. Small mass fractions 5 wt %–8 % condensed surface crystals sufficient completely suppress component, suggesting coating evenly distributed seed case, onset increased saturation ratio with respect Sice?1.30 for pure ?1.45 SOM-coated crystals. if such subjected mentioned processes, they show an improved Sice?1.35. suggest change matter might redistribute form partially engulfed structure, where ice-nucleation-active sites no longer masked by coating, morphology layer transform compact porous structure. Our results underline complexity representing models. They demonstrate need further investigate impact atmospheric processing related