03 Apr 2023
 | 03 Apr 2023
Status: this preprint is open for discussion.

Identifying atmospheric processes favouring the formation of bubble free layers in Law Dome ice core, East Antarctica

Lingwei Zhang, Tessa R. Vance, Alexander D. Fraser, Lenneke M. Jong, Sarah S. Thompson, Alison S. Criscitiello, and Nerilie J. Abram

Abstract. Physical features preserved in ice cores may provide unique records about past atmospheric variability. Linking the formation and preservation of these features and the atmospheric processes causing them is key to their interpretation as paleoclimate proxies. We imaged ice cores from Law Dome, East Antarctica using an Intermediate Layer Ice Core Scanner (ILCS) which shows that thin bubble-free layers (BFLs) occur multiple times per year at this site. The origin of these features is unknown. We used a previously developed age-depth scale in conjunction with regional accumulation estimated from atmospheric reanalysis data (ERA5) to estimate the year and month that the BFLs occurred, and then performed seasonal and annual analysis to reduce the overall dating errors. We then investigated measurements of snow surface height from a co-located automatic weather station to determine snow surface features co-occurring with BFLs, as well as their estimated occurrence date. We also used ERA5 to investigate potentially relevant local/regional atmospheric processes (temperature inversions, wind scour, accumulation hiatuses and extreme precipitation) associated with BFL occurrence. Finally, we used a synoptic typing dataset of the southern Indian and southwest Pacific Oceans to investigate the relationship between large scale atmospheric patterns and BFL occurrence. Our results show that BFLs occur (1) primarily in autumn and winter, (2) in conjunction with accumulation hiatuses >4 days, and (3) during synoptic patterns characterised by meridional atmospheric flow related to the episodic blocking and channeling of maritime moisture to the ice core site. Thus, BFLs may act as a seasonal marker (autumn/winter), and may indicate episodic changes in accumulation (such as hiatuses) associated with large-scale circulation. This study provides a pathway to the development of a new proxy for past climate in the Law Dome ice cores; specifically past snowfall conditions relating to synoptic variability over the southern Indian Ocean.

Lingwei Zhang et al.

Status: open (extended)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Lingwei Zhang et al.

Lingwei Zhang et al.


Total article views: 248 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
185 52 11 248 3 3
  • HTML: 185
  • PDF: 52
  • XML: 11
  • Total: 248
  • BibTeX: 3
  • EndNote: 3
Views and downloads (calculated since 03 Apr 2023)
Cumulative views and downloads (calculated since 03 Apr 2023)

Viewed (geographical distribution)

Total article views: 246 (including HTML, PDF, and XML) Thereof 246 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 07 Jun 2023
Short summary
Physical features in ice cores provide unique records of past atmospheric variability. We identified 1–2 mm thick ice layers without bubbles in surface ice cores from Law Dome, East Antarctica occurring on average five times per year. The origin of these bubble free layers is unknown. In this study, we date the bubble free layers and investigate whether they have the potential to record past atmospheric processes and large scale circulation.