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SUMMARY:EESS talk on "An Observation-Based Climatology of Aerosols During 
 Warm and Moist Intrusions into the Arctic"
DTSTART:20251209T121500
DTEND:20251209T124500
DTSTAMP:20260502T050517Z
UID:b38bf059014263ed4865fbe27fb53ca38c0e315db61efe042133ee12
CATEGORIES:Conferences - Seminars
DESCRIPTION:PhD Student Berkay Dönmez\, EPFL Wallis\nAbstract:\n\n\nArct
 ic climate change is more pronounced than in other regions\, manifesting i
 tself through increase in surface temperatures three to four times that of
  the global average\, a phenomenon referred to as Arctic Amplification (AA
 ). Increased heat and moisture transport to the Arctic from lower latitude
 s\, primarily occurring through warm and moist air intrusions\, associated
  with abrupt increased transport of heat and moisture to the polar regions
 \, has been shown to potentially contribute to AA. Recent studies highligh
 t that these events are significant sources of aerosol particles in the Ar
 ctic\, which can significantly influence the local climate by acting as cl
 oud condensation nuclei (CCN) and ice-nucleating particles (INP)\, thereby
  affecting Arctic cloud properties and thus the resulting radiative forcin
 g in the region. However\, the contribution of these short-lived events to
  different aerosol size modes\, CCN and droplet number concentrations rema
 ins unconstrained. In this study\, we use long term aerosol and CCN observ
 ations\, combined with back trajectory analysis and a state-of-the-art clo
 ud droplet parameterization\, to assess the contribution of warm and moist
  intrusion events to CCN variability\, aerosol size distributions\, and cl
 oud droplet number concentrations at five Arctic sites: Zeppelin\, Villum\
 , Tiksi\, Alert\, and Utqiaġvik/Barrow. Our results show that intrusions
  are a major driver of CCN perturbations in the Arctic\, especially in sum
 mer\, when accumulation mode and CCN concentrations increase significantly
  at all sites during warm and moist intrusion events. In winter and spring
 \, however\, the response splits into two distinct regimes: at sites near 
 0° longitude (Zeppelin\, Villum\, and Alert)\, intrusions lead to reduced
  concentrations\, while at sites near 180° longitude (Tiksi and Utqiaġv
 ik/Barrow)\, they result in increased accumulation mode and CCN concentrat
 ions. We attribute these contrasting patterns to the balance between pollu
 tion source influence and wet scavenging along air mass trajectories. The 
 same regimes are also reflected in simulated droplet concentrations: intru
 sions consistently enhance droplet concentrations at Tiksi and Utqiaġvik
 /Barrow year-round\, whereas at Zeppelin\, Villum\, and Alert\, lower drop
 let concentrations in winter and spring indicate more pristine cloud condi
 tions.\n\n\n\n\n\nBiography:\n\n\n\nBerkay is a PhD researcher at EPFL in 
 the Extreme Environments Research Laboratory (EERL) and the Laboratory of 
 Atmospheric Processes and their Impacts (LAPI)\, supervised by J. Schmale 
 and A. Nenes. His work focuses on modeling aerosol–cloud interactions in
  the Arctic. He grew up in Istanbul\, Türkiye\, and earned his BSc and M
 Sc in Meteorological Engineering and Atmospheric Sciences at Istanbul Tech
 nical University.\n\n\n\n\n\n\n 
LOCATION:GC B1 10 https://plan.epfl.ch/?room==GC%20B1%2010 https://epfl.zo
 om.us/j/69011077410
STATUS:CONFIRMED
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