Abstract
AbstractStable isotope ratios (δ18O and δD) in Antarctic snow and ice are basic proxy indices of climate in ice core studies. The relation between the ratios has important indicative significance for moisture sources. In general, the fractionation characteristics of the two isotopes vary with different meteorological and topographical conditions. This paper presents the spatial and temporal distribution of meteoric water line (MWL) slopes along a traverse from the Zhongshan Station (ZSS) to Dome A in East Antarctica. It is found that the slopes decrease with the increasing distance inland from the coast and the lowest slope occurred at Dome A, where the long-range transported moisture dominates and clear sky snowing have an influence. The slopes in different layers of the snowpack showed a decreasing trend with depth and this is attributed to the fractionation during the interstitial sublimation and re-condensation processes of the water vapor. Frost flower development on the interior plateau surface can greatly alter the depth evolution of the MWL slope. The coastal snow pits also go through the post-depositional smoothing effect, but their influences are not so significant as the inland regions.
Highlights
Stable isotope records of snow and ice cores in Antarctica were widely used to infer past local temperature variations and moisture origin (Dansgaard, 1964; Landais and others, 2008; Steen-Larsen and others, 2011; Xiao and others, 2013)
The general decreasing trend of the meteoric water line (MWL) slopes in three sections may be caused by the increasing distance from the source regions and intensified fractionation effects (Masson-Delmotte and others, 2008; Xiao and others, 2013; Pang and others, 2015, 2019)
Three spatial sections were divided along the traverse, the low slope existed at the interior section and high values at the coastal region, the intermediate section showed large variations implying that complex mechanisms were involved in the fractionation processes and more efforts are needed in the future
Summary
Stable isotope records of snow and ice cores in Antarctica were widely used to infer past local temperature variations and moisture origin (Dansgaard, 1964; Landais and others, 2008; Steen-Larsen and others, 2011; Xiao and others, 2013). A lower mean MWL slope (7.75) was detected on Antarctica ice sheet (Masson-Delmotte and others, 2008) and showed great spatial variations (Xiao and others, 2013; Li and others, 2016).
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