Snow chemistry across Antarctica

Un updated compilation of published and new data of major ion (Ca, Cl, K, Mg, Na, NO3, SO4) and methylsulfonate (MS) concentrations in snow from 520 Antarctic sites is provided by the national ITASE (International Trans-Antarctic Scientific Expedition) programmes of Australia, Brazil, China, Germany, Italy, Japan, Korea, New Zealand, Norway, United Kingdom, the United States, and the national Antarctic programme of Finland. The comparison shows that snow chemistry concentrations vary by up to four orders of magnitude across Antarctica and exhibit distinct geographical patterns. The Antarctic-wide comparison of glaciochemical records provides a unique opportunity to improve our understanding of the fundamental factors that ultimately control the chemistry of snow or ice samples. This paper aims to initiate data compilation and administration in order to provide a framework for facilitation of antarctic-wide snow chemistry discussions across all ITASE nations and other contributing groups. The data are made available through the ITASE web page (http://www2.umaine.edu/itase/content/syngroups/snowchem.html) and will be updated with new data as they are provided. In addition, recommendations for future research efforts are summarized

Insight Into Radio-Isotope 129I Deposition in Fresh Snow at aRemote Glacier Basin of Northeast Tibetan Plateau, China

We present data of 129I deposition in fresh snow in the Laohugou glacier basin, northeast Tibetan Plateau, in summer 2016 and 2017, and trace its source and elevational distribution in the troposphere. Our results show that the 129I/127I atomic ratios in the fresh snow on the glacier surface are about 2 orders of magnitude larger than those in the Antarctic fresh snow and 4 orders the prenuclear level, indicating a predominantly anthropogenic source of the 129I in the mountain glacier environment of northeast Tibetan Plateau. The 129I level in the Laohugou glacier basin is 1–2 orders of magnitude lower than at representative European locations, and not significantly higher than that observed at other sites in Asia. The 129I/127I atomic ratio and 129I level show clear increases with elevation from 4,300 to 5,100 m above sea level. The 129I in the Laohugou glacier basin is probably deposited from the upper troposphere where there exists a local maximum of 129I. A conceptual model for interpretation of the observed 129I concentration and profile in Laohugou is provided. Thus, this work is of importance in providing a more complete view on the transport, dispersion, and removal of 129I in the atmosphere