SIOS Access Project Completed
By Stefania Gilardoni
Aerosol particles affect how clouds interact with solar radiation and impact climate. The ability of aerosol particles to define cloud properties depends on their mixing state, i.e. how different chemical species mix up to compose a single particle. Within MIST-CA2 we collected aerosol particles throughout the year at the Zeppelin Observatory to investigate the chemical composition of single particles and to understand the mixing state of hydrophilic (i.e. soluble in water) and hydrophobic (i.e. poorly soluble in water) aerosol components. The Zeppelin observatory is often within clouds and it is the ideal place to collect particles that participated to cloud formation.
The device for aerosol collection was installed in March 2021 and sampling covered the period in June 2021 – July 2022. Figure 2 shows the sampling device together with some examples of collected samples.
To characterize aerosol mixing state we measure how X-Ray radiation is absorbed by the aerosol particles by STXM-NEXAFS. Since different chemical species absorb X-Ray in different ways, we can draw a map for each particle showing the distribution of the different chemical components. Figure 3 shows the maps of each single particle analysed in two samples reporting in green organic molecules, in red soot, and in light-blue inorganic molecules.
We will continue analysing the collected samples to increase the statistical significance of the observations.
