Stable isotopic composition in snowpack along the traverse from a coastal location to Dome A (East Antarctica): Results from observations and numerical modeling

• Published in: Polar Science
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2020
• Subjects: Water stable isotopes; Isotope-temperature relationship; MCIM; Moisture source diagnosis; Transportation path; Antarctic; East Antarctica; Antarc*; Antarctica; ice core; Ice Sheet; Polar Science
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=16017; http://id.nii.ac.jp/1291/00015905/

Stable isotopic composition (δ18O and δD) in Antarctic snow/ice cores serves as the proxy of past temperature. However, the accuracy of temperature reconstruction is largely dependent on the relationship between water isotopes and local temperature (δ-T) derived from present conditions. Thus, it is crucial to quantitatively understand the spatial δ-T relationship and the influencing factors of δ18O and δD in surface snow besides temperature. In this work, we characterized the spatial and temporal variation of stable isotopes in surface snow using a comprehensive assessment of observations and simulations on the traverse from the coast to Dome A, the summit of East Antarctica ice sheet. The δ18O and δD from surface snow and snow pit samples show an insignificant variation at interannual scale, possibly suggesting that interannual changes in controlling factors are not remarkable during the investigation period. Along the traverse, the spatial δ18O-T slope is 0.91‰·oC−1 based on averages of δ18O measurements for snow pits and annual mean temperature at the sampling site. Results from the mixed cloud isotope model (MCIM) suggest that the effects of evaporative conditions and transportation paths of moisture on water isotopes for specific sites are insignificant. Therefore, it is more important to consider other effects on water isotopes (e.g. post-depositional processes) when interpreting ice core records, particularly in interior Antarctica.