Publications by authors named "Hannah Beckmann"
Aircraft observations have revealed ubiquitous new particle formation in the tropical upper troposphere over the Amazon and the Atlantic and Pacific oceans. Although the vapours involved remain unknown, recent satellite observations have revealed surprisingly high night-time isoprene mixing ratios of up to 1 part per billion by volume (ppbv) in the tropical upper troposphere. Here, in experiments performed with the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, we report new particle formation initiated by the reaction of hydroxyl radicals with isoprene at upper-tropospheric temperatures of -30 °C and -50 °C.
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- Ammonia emissions in Southeast Asia significantly impact air pollution and the development of the Asian Tropopause Aerosol Layer (ATAL), particularly during summer when the South Asian monsoon is active.
- The study utilizes the EMAC chemistry-climate model to analyze how ammonia influences particle formation, revealing a tenfold increase in particle creation during the day, especially within the monsoon's upper troposphere and lower stratosphere (UTLS).
- Findings indicate that while ammonia enhances cloud condensation nuclei (CCN) concentrations and aerosol optical depth (AOD), its effect on aerosol mass in the ATAL is comparatively limited, suggesting a complex relationship between ammonia, particle growth, and aerosol composition.