Wednesday, 11 July 2018
Regency A/B/C (Hyatt Regency Vancouver)
Al2O3 and Fe2O3 particles have been observed not only in the surroundings of the industrial area but also in the natural atmospheric environment. These two kinds of aerosols can influence aerosol-cloud interaction. Physico-chemical properties of Al2O3 and Fe2O3 particles, such as size distribution, cloud condensation nuclei (CCN) and ice nuclei (IN) abilities, were investigated by using CCN counter, MRI dynamic cloud chamber, continuous flow diffusion chamber-type IN counter (CFDC-type INC) and several aerosol instruments in this study. The results indicated that their hygroscopicity (κ-value) were around 0.01-0.03, which are comparable to that of surrogates of mineral dust particles, and smaller than typical κ-values of atmospheric aerosols. On the other hand, based on ice nucleation active surface site (INAS) density, these materials may act as good ice nuclei via immersion freezing mode. Al2O3 and Fe2O3 particles continuously nucleated ice crystals at -14°C and colder temperatures and at -20°C and colder temperatures, respectively, in cloud simulation experiments. While in CFDC-type INC experiments, only Al2O3 seemed to act as good IN below -25 °C. Al2O3 seemed to have better IN ability than Fe2O3 and its INAS values as a function of temperature were relatively close to those of illite particles which are better surrogates of natural atmospheric dust and have been well investigated so far.
- Indicates paper has been withdrawn from meeting
- Indicates an Award Winner