Sunlight-driven nitrate loss records Antarctic surface mass balance

Pete Akers (1) , Joël Savarino (1) , Nicolas Caillon (1) , Aymeric Servettaz , Emmanuel Le Meur (1) , Olivier Magand (1) , Jean Martins (1) , Cécile Agosta (2, 3) , Peter Crockford , Kanon Kobayashi , Shohei Hattori , Mark Curran , Tas van Ommen , Lenneke Jong , Jason Roberts

1 UGA - Université Grenoble Alpes
2 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
3 GLACCIOS - Glaces et Continents, Climats et Isotopes Stables

Abstract Standard proxies for reconstructing surface mass balance (SMB) in Antarctic ice cores are often inaccurate or coarsely resolved when applied to more complicated environments away from dome summits. Here, we propose an alternative SMB proxy based on photolytic fractionation of nitrogen isotopes in nitrate observed at 114 sites throughout East Antarctica. Applying this proxy approach to nitrate in a shallow core drilled at a moderate SMB site (Aurora Basin North), we reconstruct 700 years of SMB changes that agree well with changes estimated from ice core density and upstream surface topography. For the under-sampled transition zones between dome summits and the coast, we show that this proxy can provide past and present SMB values that reflect the immediate local environment and are derived independently from existing techniques.

Domaines: Milieux et Changements globaux

Pete Akers, Joël Savarino, Nicolas Caillon, Aymeric Servettaz, Emmanuel Le Meur, et al.. Sunlight-driven nitrate loss records Antarctic surface mass balance. Nature Communications, 2022, 13 (1), pp.4274. ⟨10.1038/s41467-022-31855-7⟩. ⟨hal-03877291⟩