Modeling of the processing and removal of trace gas and aerosol species by Arctic radiation fogs and comparison with measurements

Authors

M H. Bergin, Carnegie Mellon UniversityFollow
S N. Pandis, Carnegie Mellon University
C Davidson, Carnegie Mellon University
J L. Jaffrezo, Domaine Universitaire, Grenoble, FrancFollow
Jack E. Dibb, University of New HampshireFollow
A G. Russell, Carnegie Mellon University
H D. Kuhns, Carnegie Mellon UniversityFollow

Abstract

A Lagrangian radiation fog model is applied to a fog event at Summit, Greenland. The model simulates the formation and dissipation of fog. Included in the model are detailed gas and aqueous phase chemistry, and deposition of chemical species with fog droplets. Model predictions of the gas phase concentrations of H₂O₂, HCOOH, SO₂, and HNO₃ as well as the fog fluxes of S(VI), N(V), H₂O₂, and water are compared with measurements. The predicted fluxes of S(VI), N(V), H₂O₂, and fog water generally agree with measured values. Model results show that heterogeneous SO₂ oxidation contributes to approximately 40% of the flux of S(VI) for the modeled fog event, with the other 60% coming from preexisting sulfate aerosol. The deposition of N(V) with fog includes contributions from HNO₃ and NO₂ initially present in the air mass. HNO₃ directly partitions into the aqueous phase to create N(V), and NO₂ forms N(V) through reaction with OH and the nighttime chemistry set of reactions which involves N₂O₅ and water vapor. PAN contributes to N(V) by gas phase decomposition to NO₂, and also by direct aqueous phase decomposition. The quantitative contributions from each path are uncertain since direct measurements of PAN and NO₂ are not available for the fog event. The relative contributions are discussed based on realistic ranges of atmospheric concentrations. Model results suggest that in addition to the aqueous phase partitioning of the initial HNO₃ present in the air mass, the gas phase decomposition of PAN and subsequent reactions of NO₂ with OH as well as nighttime nitrate chemistry may play significant roles in depositing N(V) with fog. If a quasi-liquid layer exists on snow crystals, it is possible that the reactions taking place in fog droplets also occur to some extent in clouds as well as at the snow surface.

Department

Earth Sciences, Earth Systems Research Center

Publication Date

6-20-1996

Journal Title

Journal of Geophysical Research: Atmospheres

Publisher

Wiley

Digital Object Identifier (DOI)

10.1029/96JD00340

Document Type

Article

Recommended Citation

Bergin, M. H., S. N. Pandis, C. I. Davidson, J.-L. Jaffrezo, J. E. Dibb, A. G. Russell, and H. D. Kuhns (1996), Modeling of the processing and removal of trace gas and aerosol species by Arctic radiation fogs and comparison with measurements, J. Geophys. Res., 101(D9), 14465–14478, doi:10.1029/96JD00340.

Rights

Copyright 1996 by the American Geophysical Union.