Observations of rapid photochemical destruction of ozone in snowpack interstitial air

Peterson, Matt A.; Honrath, R. E.

doi:10.1029/2000gl012129

Cited by 76 publications

(70 citation statements)

References 24 publications

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“…At night and during shading experiments (NO ? NO 2 ) mixing ratios dropped markedly, with nighttime values at 150-200 pptv (Peterson and Honrath 2001;Jacobi et al 2004). In a similar experiment at South Pole, (NO ?…”

Section: Resultsmentioning

confidence: 71%

Fluxes and chemistry of nitrogen oxides in the Niwot Ridge, Colorado, snowpack

et al. 2009

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The effect of snow cover on surfaceatmosphere exchanges of nitrogen oxides (nitrogen oxide (NO) ? nitrogen dioxide (NO 2 ); note, here 'NO 2 ' is used as surrogate for a series of oxidized nitrogen gases that were detected by the used monitor in this analysis mode) was investigated at the high elevation, subalpine (3,340 m asl) Soddie site, at Niwot Ridge, Colorado. Vertical (NO ? NO 2 ) concentration gradient measurements in interstitial air in the deep (up to *2.5 m) snowpack were conducted with an automated sampling and analysis system that allowed for continuous observations throughout the snow-covered season. These measurements revealed sustained, highly elevated (NO ? NO 2 ) mixing ratios inside the snow. Nitrogen oxide concentrations were highest at the bottom of the snowpack, reaching levels of up to 15 ppbv during mid-winter. Decreasing mixing ratios with increasing distance from the soilsnow interface were indicative of an upwards flux of NO from the soil through the snowpack, and out of the snow into the atmosphere, and imply that biogeochemical processes in the subnival soil are the predominant NO source. Nitrogen dioxide reached maximum levels of *3 ppbv in the upper layers of the snowpack, i.e., *20-40 cm below the surface. This behavior suggests that a significant fraction of NO is converted to NO 2 during its diffusive transport through the snowpack. Ozone showed the opposite behavior, with rapidly declining levels below the snow surface. The mirroring of vertical profiles of ozone and the NO 2 /(NO ? NO 2 ) ratio suggest that titration of ozone by NO in the snowpack contributes to the ozone reaction in the snow and to the ozone surface deposition flux. However, this surface efflux of (NO ? NO 2 ) can only account for a minor fraction of ozone deposition flux over snow that has been reported at other mid-latitude sites. Neither (NO ? NO 2 ) nor ozone levels in the interstitial air showed a clear dependence on incident solar irradiance, much in contrast to observations in polar snow. Comparisons with findings from polar snow studies reveal a much different (NO ? NO 2 ) and ozone snow chemistry in this alpine environment. Snowpack concentration gradients and diffusion theory were applied to estimate an average, wintertime (NO ? NO 2 ) flux of 0.005-0.008 nmol m -2 s -1 , which is of similar magnitude as reported (NO ? NO 2 ) fluxes

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Section: Resultsmentioning

confidence: 71%

Fluxes and chemistry of nitrogen oxides in the Niwot Ridge, Colorado, snowpack

et al. 2009

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“…These authors hypothesized that ozone may be temporarily stored in the snow base. However, subsequent research with many weeks of measurements of ozone in interstitial air at Summit, (Peterson and Honrath, 2001;Helmig et al, 2006b), South Pole (Helmig, 2003, unpublished results) and at Niwot Ridge, Rocky Mountains, Colorado (Bocquet et al, 2006a) have all revealed significantly lower ozone mixing ratios in the snowpack than above the surface, which would contradict this theory. These contrasting observations can not be conclusively evaluated with the current understanding of ozone-snowpack interaction.…”

Section: Ozone Uptake To Snowmentioning

confidence: 83%

“…In a study at Summit, Greenland, Peterson and Honrath (2001) measured diurnal cycles of UV radiation, NO x and ozone in interstitial air (the air between snow grains in the snowpack; also referred to as firn air) at 30 cm depth and compared those measurements with data from above the surface. Ozone and NO x in firn air exhibited diurnal cycles with amplitudes of ∼10 ppbv and ∼350 pptv, respectively, and ozone and NO x were anti-correlated and directly determined by solar irradiance.…”

Section: Ozone Uptake To Snowmentioning

confidence: 99%

The role of ozone atmosphere-snow gas exchange on polar, boundary-layer tropospheric ozone – a review and sensitivity analysis

et al. 2007

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Abstract. Recent research on snowpack processes and atmosphere-snow gas exchange has demonstrated that chemical and physical interactions between the snowpack and the overlaying atmosphere have a substantial impact on the composition of the lower troposphere. These observations also imply that ozone deposition to the snowpack possibly depends on parameters including the quantity and composition of deposited trace gases, solar irradiance, snow temperature and the substrate below the snowpack. Current literature spans a remarkably wide range of ozone deposition velocities (v dO3 ); several studies even reported positive ozone fluxes out of the snow. Overall, published values range from ∼-3

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“…Increase of ozone level under the wind at Summit, Greenland In recent years it has been discovered [29] that ozone is present in the interstitial air of the polar snowpack at levels comparable with those in ambient air. At Summit, up to 90 % of ambient ozone levels were observed at a depth of up to 1 m. [30] According to Helmig et al [30] photochemical destruction is the dominant mechanism for ozone loss at Summit, and maximum loss is in the near surface layer, where ozone depletion follows both the diurnal and seasonal cycle in solar radiation.…”

Section: Unknown Sources Of Oh Formationmentioning

confidence: 99%

Possible contribution of triboelectricity to snow - air interactions

Tkachenko¹,

Kozachkov²

2012

Environ. Chem.

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Environmental context. Polar near-surface snow can act as a chemical reactor that alters the composition and chemistry of snow and the overlying air. Although the mechanisms and driving forces of these reactions have long been debated, triboelectrification (production of electrostatic charges by friction) of snow by wind has not yet been considered as a factor. It is proposed that in polar regions, triboelectrification could significantly influence the composition and chemistry of snow.Abstract. Reactions that proceed in polar snow cover may significantly affect the chemistry of the overlying atmosphere, but mechanisms and driving forces of these reactions are still under discussion. The proposed hypothesis attempts to explain some experimental data that cannot be fully understood (e.g. the effect of wind on OH radicals, ozone and persistent organic pollutants levels) by taking into account the influence of electrical phenomena on the snow surface. We assumed that a combination of such factors as low humidity, high wind speed and low temperatures makes the influence of triboelectrification of snow significant for polar areas, where purity and the depth of snow cover prevent fast charge dissipation. The major points of the hypothesis are: (1) when the electric field reaches a value sufficient for the onset of corona discharge, various free radical processes are initiated resulting in changes in the concentrations of ozone, OH radical, nitrate, etc., and the decomposition of pollutant molecules; (2) the high electric field can stimulate transport of ions (such as bromide and nitrate) from the condensed phase to the gas phase; and (3) the ageing of charged snow can increase its electrical potential.

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Observations of rapid photochemical destruction of ozone in snowpack interstitial air

Cited by 76 publications

References 24 publications

Fluxes and chemistry of nitrogen oxides in the Niwot Ridge, Colorado, snowpack

Fluxes and chemistry of nitrogen oxides in the Niwot Ridge, Colorado, snowpack

The role of ozone atmosphere-snow gas exchange on polar, boundary-layer tropospheric ozone – a review and sensitivity analysis

Possible contribution of triboelectricity to snow - air interactions

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