The Dominant Role of Brewer-Dobson Circulation on 17O-Excess Variations in Snow Pits at Dome A, Antarctica

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Pang, Hongxi, Zhang, Peng, Wu, Shuangye, Jouzel, Jean, Steen-Larsen, Hans Christian, Liu, Ke, Zhang, Wangbin, Yu, Jinhai, An, Chunlei, Chen, Deliang, Hou, Shugui
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2022
• Subjects: Antarctic; East Antarctica; The Antarctic; Antarc*; Antarctica; Ice Sheet
• Online Access: https://hdl.handle.net/11250/3026578; https://doi.org/10.1029/2022JD036559

Recent studies have suggested that water isotopologues in snow pits from remote East Antarctica can be influenced by the input of stratospheric water, which has anomalously high 17O-excess values. However, it remains unclear whether the 17O-excess records preserved in snow and ice from this region can be used to reconstruct stratosphere-troposphere exchange (STE). In this study, we present high-resolution 17O-excess records from two snow pits at Dome A, the highest point of the Antarctic ice sheet. The 17O-excess records show a significant positive correlation with the strength of the Brewer-Dobson circulation (BDC), the hemispheric-scale troposphere-stratosphere overturn circulation. Stronger BDC leads to more stratospheric water input over Antarctica and higher 17O-excess, and vice versa. In addition, the 17O-excess records also have a significant positive correlation with the Southern Annular Mode (SAM) index, because SAM modulates Antarctic precipitation, which has a dilution effect on the stratospheric water input. The 17O-excess records do not show significant correlations with local temperature and relative humidity in the moisture source region. These results suggest the dominant effect of BDC on 17O-excess and indicate the potential for using 17O-excess records in ice cores from remote sites in East Antarctica for reconstructing long-term variations of STE, and understanding their mechanisms and climate effects. publishedVersion