From Coastal Megacities to the tropical UTLS: Iodine and Ion induced Particle Formation
Rainer Volkamer,
ANYL faculty, CU Boulder

"The tropical upper troposphere and lower stratosphere (UTLS) is a unique yet understudied atmospheric environment. The combination of higher flux of ion inducing cosmic radiation and lower temperatures makes ion-induced nucleation a more significant source of particles in the UTLS than in the lower troposphere. The Volkamer group develops advanced instrumentation (optical and mass spectrometric) to measure small molecules, condensable vapors and ambient ions that are relevant to particle formation, public health and climate discussions. We seek to better quantify and understand the interconnections between marine ecosystem, aerosols and their control on atmospheric chemistry. We also study the changing oxidative chemistry in coastal Megacities using research aircraft and satellites. Examples from recent field and laboratory experiments are discussed that aim to develop a molecular level understanding of the fundamental processes that affect a) new particle formation from iodine, and b) apply high-resolution mass spectrometry on high-flying aircraft to sample ambient ions in the UTLS. Opportunities for graduate research exist to 1) conduct and analyze field measurements using research aircraft (i.e., TI3GER-2022, CUPiDS-2023 projects), 2) laboratory experiments of particle formation (incl. at CLOUD/CERN) and multiphase chemistry, and 3) develop instrumentation to exploit synergies between optical spectroscopy and mass spectrometry."