Deposition of atmospheric nitrous acid on alkaline snow surfaces

Beine, H. J.; Amoroso, Antonio; Esposito, Giulio; Sparapani, R.; Ianniello, A.; Georgiadis, T.; Nardino, M.; Bonasoni, Paolo; Cristofanelli, Paolo; Dominé, Florent

doi:10.1029/2005gl022589

Cited by 42 publications

(38 citation statements)

References 24 publications

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“…From the table we can infer no nitrous acid emission on alkaline snow surfaces, which is consistent with the field measurements of Beine et al (2005).…”

Section: Model Sensitivity Analysissupporting

confidence: 78%

1-D Air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

Liao

Tan

2008

Atmos. Chem. Phys.

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Abstract.A 1-D air-snowpack model of HONO has been developed and constrained by observed chemistry and meteorology data. The 1-D model includes molecular diffusion and mechanical dispersion, windpumping in snow, gas phase to quasi-liquid layer phase HONO transfer and quasi-liquid layer nitrate and interstitial air HONO photolysis. Photolysis of nitrate is important as a dominant HONO source inside the snowpack, however, the observed HONO emission from the snowpack was triggered mainly by the equilibrium between quasi liquid layer nitrite and firn air HONO deep down the snow surface (i.e. 30 cm below snow surface). The high concentration of HONO in the firn air is subsequently transported above the snowpack by diffusion and windpumping. The model uncertainties come mainly from lack of measurements and the interpretation of the QLL properties based on the bulk snow measurements. One critical factor is the ionic strength of QLL nitrite, which is estimated here by the bulk snow pH, nitrite concentration, and QLL to bulk snow volume ratio.

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“…From the table we can infer no nitrous acid emission on alkaline snow surfaces, which is consistent with the field measurements of Beine et al (2005).…”

Section: Model Sensitivity Analysissupporting

confidence: 78%

1-D Air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

Liao

Tan

2008

Atmos. Chem. Phys.

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“…It has been proposed that the HONO flux out of or into the snowpack depends on the pH value of the snow [17,36]. Our model calculations indicate that the pH value of the QLL does not impact the formation rate of HONO in the snow: the formation is always negligible due to the small NO 2 − concentrations obtained in the model calculations.…”

Section: Hono Production In the Surface Snowpackmentioning

confidence: 48%

“…We can compare this destruction rate with observed deposition fluxes of HONO to snow surfaces. For example, a HONO flux of up to 120 nmol m −2 h −1 was observed in the Apennine mountains in Italy in spring [36]. This value corresponds to a HONO flux of 2.0 × 10 13 molecules m −2 s −1 .…”

Section: Hono Production In the Surface Snowpackmentioning

confidence: 87%

“…Emissions of nitrogen oxides (NO x = NO + NO 2 ) from the surface snow under the influence of solar radiation have been reported from several Arctic [2,4,11,12], Antarctic [5][6][7]15], as well as a mid-latitude sites [3]. Nitrous acid (HONO) has also been found to be released from the surface snow at non-marine polar sites [8,11,16], although HONO fluxes from alkaline snow seem to be negligible or even directed to the snow [17,36]. These emissions are driven by the strongly enhanced concentrations of the reactive nitrogen compounds in the interstitial air of the surface snow compared to ambient concentrations [9,14,16].…”

Section: Introductionmentioning

confidence: 99%

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A mechanism for the photochemical transformation of nitrate in snow

Jacobi

Hilker

2007

Journal of Photochemistry and Photobiology A: Chemistry

110

150

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Photochemical reactions of trace compounds in snow have important implications for the composition of the atmospheric boundary layer in snow-covered regions and for the interpretation of concentration profiles in snow and ice regarding the composition of the past atmosphere. One of the prominent reactions is the photolysis of nitrate, which leads to the formation of OH radicals in the snow and to the release of reactive nitrogen compounds, like nitrogen oxides (NO and NO 2 ) and nitrous acid (HONO) to the atmosphere. We performed photolysis experiments using artificial snow, containing variable initial concentrations of nitrate and nitrite, to investigate the reaction mechanism responsible for the formation of the reactive nitrogen compounds. Increasing the initial nitrite concentrations resulted in the formation of significant amounts of nitrate in the snow. A possible precursor of nitrate is NO 2 , which can be transformed into nitrate either by the attack of a hydroxy radical or the hydrolysis of the dimer (N 2 O 4 ). A mechanism for the transformation of the nitrogen-containing compounds in snow was developed, assuming that all reactions took place in a quasi-liquid layer (QLL) at the surface of the ice crystals. The unknown photolysis rates of nitrate and nitrite and the rates of NO and NO 2 transfer from the snow to the gas phase, respectively, were adjusted to give an optimum fit of the calculated time series of nitrate, nitrite, and gas phase NO x with respect to the experimental data. Best agreement was obtained with a ∼25 times faster photolysis rate of nitrite compared to nitrate. The formation of NO 2 is probably the dominant channel for the nitrate photolysis. We used the reaction mechanism further to investigate the release of NO x and HONO under natural conditions. We found that NO x emissions are by far dominated by the release of NO 2 . The release of HONO to the gas phase depends on the pH of the snow and the HONO transfer rate to the gas phase. However, due to the small amounts of nitrite produced under natural conditions, the formation of HONO in the QLL is probably negligible. We suggest that observed emissions of HONO from the surface snow are dominated by the heterogeneous formation of HONO in the firn air. The reaction of NO 2 on the surfaces of the ice crystals is the most likely HONO source to the gas phase.

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“…There are only a few attempts to measure atmospheric nitrous acid (HONO) fluxes, mostly derived from the gradient method (e.g., Harrison and Kitto, 1994;Neftel et al, 1996;Honrath et al, 2002;Stutz et al, 2002;Beine et al, 2005Beine et al, , 2006. To our knowledge, there are very limited HONO flux measurements using the REA method Zhou et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

A relaxed eddy accumulation system for measuring vertical fluxes of nitrous acid

et al. 2011

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Abstract.A relaxed eddy accumulation (REA) system combined with a nitrous acid (HONO) analyzer was developed to measure atmospheric HONO vertical fluxes. The system consists of three major components: (1) a fast-response sonic anemometer measuring both vertical wind velocity and air temperature, (2) a fast-response controlling unit separating air motions into updraft and downdraft samplers by the sign of vertical wind velocity, and (3) a highly sensitive HONO analyzer based on aqueous long path absorption photometry that measures HONO concentrations in the updrafts and downdrafts. A dynamic velocity threshold (±0.5σ w , where σ w is a standard deviation of the vertical wind velocity) was used for valve switching determined by the running means and standard deviations of the vertical wind velocity. Using measured temperature as a tracer and the average values from two field deployments, the flux proportionality coefficient, β, was determined to be 0.42 ± 0.02, in good agreement with the theoretical estimation. The REA system was deployed in two ground-based field studies. In the California Research at the Nexus of Air Quality and Climate Change (CalNex) study in Bakersfield, California in summer 2010, measured HONO fluxes appeared to be upward during the day and were close to zero at night. The upward HONO flux was highly correlated to the product of NO 2 and solar radiation. During the Biosphere Effects on Aerosols and Photochemistry Ex-

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Deposition of atmospheric nitrous acid on alkaline snow surfaces

Cited by 42 publications

References 24 publications

1-D Air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

1-D Air-snowpack modeling of atmospheric nitrous acid at South Pole during ANTCI 2003

A mechanism for the photochemical transformation of nitrate in snow

A relaxed eddy accumulation system for measuring vertical fluxes of nitrous acid

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