Surprisingly small HONO emissions from snow surfaces at Browning Pass, Antarctica

• Main Authors: Beine, HJ, Amoroso, A, Domine, F, King, Martin, Nardino, M, Ianniello, A, France, JL
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2006
• Subjects: South-Pole; Boundary-Layer; Uv-Radiation; Sea-Ice; Nitrate; Iscat 2000; Nitrogen-Dioxide; Hydrogen-Peroxide; Photolysis; Fluxes; Faculty of Science\Earth Sciences; Research Groups and Centres\Earth Sciences\Ancient and Modern Earth Systems; Research Groups and Centres\Earth Sciences\Geochemistry; Browning; Browning Pass; South Pole; Antarc*; Antarctica; Sea ice; South pole
• Online Access: https://repository.royalholloway.ac.uk/items/3eca6ff1-1748-44a9-fabb-93a97461cda7/8/

Measured Fluxes of nitrous acid at Browning Pass, Antarctica were very low, despite conditions that are generally understood as favorable for HONO emissions, including: acidic snow surfaces, an abundance of NO3- anions in the snow surface, and abundant UV light for NO3- photolysis. Photochemical modeling suggests noon time HONO fluxes of 5-10 nmol m(-2) h(-1); the measured fluxes, however, were close to zero throughout the campaign. The location and state of NO3- in snow is crucial to its reactivity. The analysis of soluble mineral ions in snow reveals that the NO3- ion is probably present in aged snows as NaNO3. This is peculiar to our study site, and we suggest that this may affect the photochemical reactivity of NO3-, by preventing the release of products, or providing a reactive medium for newly formed HONO. In fresh snow, the NO3- ion is probably present as dissolved or adsorbed HNO3 and yet, no HONO emissions were observed. We speculate that HONO formation from NO3- photolysis may involve electron transfer reactions of NO2 from photosensitized organics and that fresh snows at our site had insufficient concentrations of adequate organic compounds to favor this reaction.