Analysis of an Ice Fog Episode in Fairbanks, Alaska during Winter 2022 - INSU - Institut national des sciences de l'Univers Accéder directement au contenu
Communication Dans Un Congrès Année : 2023

Analysis of an Ice Fog Episode in Fairbanks, Alaska during Winter 2022

Résumé

Fairbanks, Alaska is often impacted by wintertime pollution events where concentrations of fine particulate matter ≤ 2.5 μm (PM2.5) reach 50 μg m-3 and exceed the Environmental Protection Agency (EPA) 24-hour standard of 35 μg m-3 due to the burning of wood, oil, gasoline, and coal coupled with poor dispersion caused by low wind speeds and temperature inversions. A small but important number of these particles may act as ice nucleating particles (INPs) by facilitating the formation of ice from supercooled droplets, which is crucial for cloud/fog formation. Wintertime episodes of ice fog can occur when the surface temperature is < -15°C. Ice fog can cause poor visibility, which is a significant issue for aviation and transportation. With many communities in Interior Alaska depending on air travel for transportation of people and supplies due to being isolated from highways, ice fog events have the ability to cut off communities from air travel for weeks at a time. The role of INPs in ice fog formation is poorly understood with only three studies from the 1960s-70s evaluating sources of INPs in ice fog. The Alaskan Layered Pollution and Chemical Analysis (ALPACA) field campaign involved deployment of a wide suite of atmospheric measurements in winter 2022 (17 January - 25 February) to better understand atmospheric chemical mechanisms in cold and dark conditions. We report on measurements of particulate metal composition, particle size, trace gas composition, and INPs during a week-long ice fog period (29 January - 3 February). Preliminary results indicate increases in the abundance of trace gases and PM2.5 during the ice fog period; correlated with low temperatures and a strong surface inversion. We performed an Empirical Orthogonal Function (EOF) analysis on the PM10 atmospheric metal composition data. This analysis demonstrated patterns of variability between aluminum (Al), sulfur (S), potassium (K), and calcium (Ca) which is indicative of the presence of dust. Preliminary results also show lower INP concentrations and activation temperatures during the ice fog period, suggesting that the fog had activated particles via ice nucleation.
Fichier non déposé

Dates et versions

insu-04216349 , version 1 (24-09-2023)

Identifiants

  • HAL Id : insu-04216349 , version 1

Citer

Emily Rose Lill, Meeta Cesler‐maloney, Paul J Demott, Russell J. Perkins, Ezra J T Levin, et al.. Analysis of an Ice Fog Episode in Fairbanks, Alaska during Winter 2022. AMS 2023 - 103rd Annual Meeting, Jan 2023, Denver (Colorado), United States. ⟨insu-04216349⟩
66 Consultations
0 Téléchargements

Partager

Gmail Facebook X LinkedIn More