Possible contribution of triboelectricity to snow - air interactions

Abstract

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.

Comments on 'Possible contribution of triboelectricity to snow - air interactions'

“…This behaviour might be in agreement with some hypotheses presented by Tkachenko and Kozachkov as they propose that O 3 production by the triboelectrical effect would be most pronounced at sites characterised by a thick, glacial snowpack, low humidity, periodic high wind speeds, and low temperatures [1] ; all conditions that are typical for Summit.…”

“…Heterogeneous and quasi-liquid layer chemistry has been postulated to play a role in accounting for the discrepancies. The Tkachenko and Kozachkov [1] article is therefore a timely presentation of new ideas for further elucidating snowpack chemical mechanisms. In the following discussion we present recent data relevant to testing hypothesis proposed by Tkachenko and Kozachkov.…”

“…In the following discussion we present recent data relevant to testing hypothesis proposed by Tkachenko and Kozachkov. [1] Some of the hypotheses presented in this paper build upon data from measurements of ozone (O 3 ) in interstitial air of the deep, glacial snowpack at Summit, Greenland, that were presented in our previous work.[2] These experiments reported on positive O 3 atmosphere-snowpack gradients, i.e. depleted O 3 within the snowpack, and their dynamical behaviour dependent on environmental conditions.…”

Comment on ‘Possible contribution of triboelectricity to snow - air interactions'

“…Tkachenko and Kozachkov [1] discuss how the unique weather conditions in wind-swept snowy areas, e.g. Antarctica, can favour electrical phenomena in the lowermost atmosphere.…”

Radical views on snow chemistry

“…This is certainly the case for the Concept article by Tkachenko and Kozachkov appearing in this issue of Environmental Chemistry. [1] The paper entitled 'Possible contribution of triboelectricity to snow-air interactions' presents the view that snow-air interactions and the resultant electrification of snow can play a significant role in snow chemistry processes. In this way, Tkachenko and Kozachkov hope to better explain some important polar chemical phenomena such as ozone depletion events and their relationship to the natural release of brominated compounds.…”