We want to better understand the tropopause region’s role for the climate and for the atmosphere in general. It’s a key region for many processes, but it has not been studied thoroughly enough so far because it’s not as easily accessible as the air near the ground.
I would above all like to find out how new aerosol particles form in the upper troposphere in the tropics and whether they – as condensation and ice nuclei – have a major influence on cloud formation there. I presume that the tropopause region there is the main “birthplace” for most aerosol particles and that these newly formed particles grow and disperse themselves in the atmosphere. We would like to prove this for the first time and identify the chemical substances that lead to particle formation.
The first milestone for my subproject will be a measuring campaign over the Amazonas in Brazil, which will take place in 2022 in the winter. We want to use measurement flights to find out how new aerosol particles form in the tropopause region high above the rainforest.
We wanted to carry out the measuring campaign in Brazil two years ago, but the coronavirus pandemic threw a spanner in the works. We had to cancel the campaign a few weeks before it was due to start. We hope that it will now be possible to complete it in 2022. Moreover, our mass spectrometer and the other measuring equipment must of course also function properly under the difficult conditions in the tropics.
The measurements we have conducted in the CLOUD aerosol measurement chamber at CERN in Geneva over the last years were a key prerequisite. On the basis of these process analyses under laboratory conditions, we assume that the oxidation of terpenes and isoprene, which the Amazon rainforest releases into the air in vast quantities, leads to the formation of the new particles in the upper troposphere. But that is so far just a hypothesis which we would very much like to test.