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ClNO 2 Yields From Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of the Current Parameterization
Author(s) -
McDuffie Erin E.,
Fibiger Dorothy L.,
Dubé William P.,
Lopez Hilfiker Felipe,
Lee Ben H.,
Jaeglé Lyatt,
Guo Hongyu,
Weber Rodney J.,
Reeves J. Michael,
Weinheimer Andrew J.,
Schroder Jason C.,
CampuzanoJost Pedro,
Jimenez Jose L.,
Dibb Jack E.,
Veres Patrick,
Ebben Carlena,
Sparks Tamara L.,
Wooldridge Paul J.,
Cohen Ronald C.,
Campos Teresa,
Hall Samuel R.,
Ullmann Kirk,
Roberts James M.,
Thornton Joel A.,
Brown Steven S.
Publication year - 2018
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1029/2018jd029358
Subject(s) - chemistry , box model , aerosol , aqueous solution , parameterized complexity , chloride , meteorology , organic chemistry , mathematics , physics , combinatorics
Nitryl chloride (ClNO 2 ) plays an important role in the budget and distribution of tropospheric oxidants, halogens, and reactive nitrogen species. ClNO 2 is formed from the heterogeneous uptake and reaction of dinitrogen pentoxide (N 2 O 5 ) on chloride‐containing aerosol, with a production yield, ϕ (ClNO 2 ), defined as the moles of ClNO 2 produced relative to N 2 O 5 lost. The ϕ (ClNO 2 ) has been increasingly incorporated into 3‐D chemical models where it is parameterized based on laboratory‐derived kinetics and currently accepted aqueous‐phase formation mechanism. This parameterization models ϕ (ClNO 2 ) as a function of the aerosol chloride to water molar ratio. Box model simulations of night flights during the 2015 Wintertime INvestigation of Transport, Emissions, and Reactivity (WINTER) aircraft campaign derived 3,425 individual ϕ (ClNO 2 ) values with a median of 0.138 and range of 0.003 to 1. Comparison of the box model median to those predicted by two other field‐based ϕ (ClNO 2 ) derivation methods agreed within a factor of 1.3, within the uncertainties of each method. In contrast, the box model median was 75–84% lower than predictions from the laboratory‐based parameterization (i.e., [parameterization − box model]/parameterization). An evaluation of factors influencing this difference reveals a positive dependence of ϕ (ClNO 2 ) on aerosol water, opposite to the currently parameterized trend. Additional factors may include aqueous‐phase competition reactions for the nitronium ion intermediate and/or direct ClNO 2 loss mechanisms. Further laboratory studies of ClNO 2 formation and the impacts of aerosol water, sulfate, organics, and ClNO 2 aqueous‐phase reactions are required to elucidate and quantify these processes on ambient aerosol, critical for the development of a robust ϕ (ClNO 2 ) parameterization.