Tracing the Origin and Fate of NO x in the Arctic Atmosphere Using Stable Isotopes in Nitrate

• DOI: 10.1126/science.1161910
• Publication Date: 2008-10-30T20:43:34Z
• Authors: Samuel Morin; Joël Savarino; Markus M. Frey; Nicolas Yan; Slimane Bekki; Jan W. Bottenheim; Jean M. F. Martins
• Keywords: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; 550; Atmosphere; [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere; 13. Climate action; 551; 01 natural sciences; 0105 earth and related environmental sciences

Atmospheric nitrogen oxides (NO x =NO+ NO 2 ) play a pivotal role in the cycling of reactive nitrogen (ultimately deposited as nitrate) and the oxidative capacity of the atmosphere. Combined measurements of nitrogen and oxygen stable isotope ratios of nitrate collected in the Arctic atmosphere were used to infer the origin and fate of NO x and nitrate on a seasonal basis. In spring, photochemically driven emissions of reactive nitrogen from the snowpack into the atmosphere make local oxidation of NO x by bromine oxide the major contributor to the nitrate budget. The comprehensive isotopic composition of nitrate provides strong constraints on the relative importance of the key atmospheric oxidants in the present atmosphere, with the potential for extension into the past using ice cores.