Challenges associated with the climatic interpretation of water stable isotope records from a highly resolved firn core from Adélie Land, coastal Antarctica

The Cryosphere Discussions

Favier, Vincent^2¹  Goursaud, Sentia^1,2²  Masson-Delmotte, Valérie^1³ 

[1]Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany^3

[2]LSCE (UMR CEA-CNRS-UVSQ 8212-IPSL), Gif-sur-Yvette, France^1

[3]Univ. Grenoble Alpes, CNRS, IGE,38000 Grenoble, France^2

DOI  :  10.5194/tc-13-1297-2019

学科分类：地球科学(综合)

来源: Copernicus Publications

【 摘 要 】

A new 21.3 m firn core was drilled in 2015 at a coastal Antarctic high-accumulation site in Adélie Land (66.78 ^∘ S; 139.56 ^∘ E, 602 m a.s.l.), named Terre Adélie 192A (TA192A). The mean isotopic values ( - 19.3 ‰ ± 3.1 ‰ for δ¹⁸O and 5.4 ‰±2.2 ‰ for deuterium excess) are consistent with other coastal Antarctic values. No significant isotope–temperature relationship can be evidenced at any timescale. This rules out a simple interpretation in terms of local temperature. An observed asymmetry in the δ¹⁸O seasonal cycle may be explained by the precipitation of air masses coming from the eastern and western sectors in autumn and winter, recorded in the d -excess signal showing outstanding values in austral spring versus autumn. Significant positive trends are observed in the annual d -excess record and local sea ice extent (135–145 ^∘ E) over the period 1998–2014. However, process studies focusing on resulting isotopic compositions and particularly the deuterium excess– δ¹⁸O relationship, evidenced as a potential fingerprint of moisture origins, as well as the collection of more isotopic measurements in Adélie Land are needed for an accurate interpretation of our signals.

【 授权许可】

CC BY