Spatial and temporal variations in surface snow chemistry along a traverse from Dome C toward South Pole in the framework of East Antarctic International Ice Sheet Traverse (EAIIST) project

• Main Authors: Ventisette, Simone, Baldini, Samuele, Artoni, Claudio, Becagli, Silvia, Caiazzo, Laura, Delmonte, Barbara, Frezzotti, Massimo, Nardin, Raffaello, Savarino, Joel, Severi, Mirko, Spolaor, Andrea, Stenni, Barbara, Traversi, Rita
• Format: Text
• Language: English
• Published: 2023
• Subjects: Antarctic; Indian; South Pole; The Antarctic; Antarc*; Ice Sheet; South pole
• Online Access: https://doi.org/10.5194/egusphere-2023-393; https://egusphere.copernicus.org/preprints/2023/egusphere-2023-393/

As part of the “East Antarctic International Ice Sheet Traverse” (EAIIST) project, surface snow and snow pit samples were collected along a traverse from Dome C toward the geographic South Pole during the 2019–2020 Antarctic campaign. Results on spatial distribution of major ions are here reported to understand deposition and post deposition processes in sites with very low snow accumulation rate in the East Antarctic Plateau where megadune and wind crust areas are present. The volcanic signature of Pinatubo eruption (occurred in 1991) was clearly visible in the non-sea salt SO 4 2− stratigraphy from two snow pits (AGO-5 and PALEO) allowing the determination of annual accumulation rates that revealed to be 25.7 and 22.6 mm of water equivalent/year, respectively at the two sites. Moreover, a decreasing trend in accumulation rate as the distance from the Indian Ocean increases was detected. Mineral dust concentration and size show presence of a criptotephra layer in AGO5 and PALEO stratigraphies which is stratigraphically compatible with the deposition of volcanic ash related to the Puyehue-Cordón Caulle explosive eruption occurred in June 2011. The ssNa + fraction, accounting for the 92.5 % of the total Na + , is preserved stably in the snow layers and was chosen as marker of sea spray deposition. Despite the very low accumulation rate in this area, the main deposition process of sea spray aerosol is the wet deposition. Conversely, both biogenic and crustal nssSO 4 2− are dry deposited, the total flux of nssSO 4 2− resulted to be constant in the Antarctic plateau, but the biogenic to crustal ratio increases as distance from Dome C increases. The presence and quantification (by nssCa 2+ ) of a dry deposited crustal source, as the biogenic one, sheds light on the interpretation of nssSO 4 2− biogenic stratigraphy during glacial and interglacial time in Antarctic ice cores. NssCl − represent the fraction of Cl − deposited as HCl and arises from the exchange reactions between chloride in the sea salt aerosol and ...