11 Jul 2023
 | 11 Jul 2023
Status: this preprint is currently under review for the journal TC.

A model framework on atmosphere-snow water vapor exchange and the associated isotope effects at Dome Argus, Antarctica: part I the diurnal changes

Tianming Ma, Zhuang Jiang, Minghu Ding, Yuansheng Li, Wenqian Zhang, and Lei Geng

Abstract. Ice-core water isotopes contain valuable information on past climate changes. However, such information can be altered by post-depositional processing after snow deposition. Atmosphere-snow water vapor exchange is one of such processes, but its influence remains poorly constrained. Here we constructed a box model to quantify the atmosphere-snow water vapor exchange fluxes and the associated isotope effects at sites with low snow accumulation rate where the effects of atmosphere-snow water vapor exchange are suspected to be large. The model reproduced the observed diurnal variations of δ18O, δD, and d-excess in water vapor at Dome C, East Antarctica. According to the same model framework, we found that under summer clear-sky conditions atmosphere-snow water vapor exchange at Dome A can cause diurnal variations in atmospheric water vapor δ18O and δD by 8.2±0.3 ‰ and 54.4±1.2 ‰, with corresponding diurnal variations in surface snow δ18O and δD by 0.11±0.01 ‰ and 0.62±0.01 ‰, respectively. The modeled results under summer cloudy conditions display similar patterns to those under clear-sky conditions but with smaller magnitudes of diurnal variations. After 24-hour simulation, snow water isotopes were enriched under both cloudy and clear-sky conditions. Under winter conditions at Dome A, the model indicates there are no diurnal cycles in atmospheric and surface snow water isotopes can be caused by atmosphere-snow vapor exchange, but the model predicts more or less depletions in snow δ18O and δD in the period of 24-hour simulation, opposite to the results under summer conditions. If the modeled snow isotope enrichments in summer and depletions in winter represent general situations at Dome C, this likely suggests the air-snow vapor exchange tends to enlarge snow water isotope seasonality, but the annual net effect would be small due to the offsetting of effects in summer and winter. This remains to be explored in the future.

Tianming Ma et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on tc-2023-76', Mathieu Casado, 07 Sep 2023
  • RC2: 'Comment on tc-2023-76', Anonymous Referee #2, 08 Sep 2023

Tianming Ma et al.

Tianming Ma et al.


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Short summary
We constructed a box model to evaluate the isotope effects of atmosphere-snow water vapor exchange at Dome A, Antarctica. The results show a clear and invisible diurnal cycle in surface snow isotopes under summer and winter conditions, respectively. After a 24-hour period, the model predicts a depletion in snow δ18O and δD under winter conditions, opposite to those in summer. The results suggest that annually atmosphere-snow water vapor exchange causes little isotope changes at the study site.