24 Aug 2023
 | 24 Aug 2023
Status: this preprint is open for discussion.

Control of the temperature signal in Antarctic proxies by snowfall dynamics

Aymeric P. M. Servettaz, Cécile Agosta, Christoph Kittel, and Anaïs J. Orsi

Abstract. Antarctica, the coldest and driest continent, is home to the largest ice sheet, whose mass is predominantly recharged by snowfall. A common feature of polar regions is the warming associated with snowfall, as moist oceanic air and cloud cover increase the surface temperature. Consequently, snow accumulated onto the ice sheet is deposited under unusually warm conditions. Here we use a polar-oriented regional atmospheric model to study the statistical difference between average and snowfall-weighted temperatures. During snowfall, the warm anomaly scales with snowfall amount, with strongest sensitivity at low accumulation sites. Heavier snowfall in winter contributes to cool the annual snowfall-weighted temperature, but this effect is overwritten by the event-scale warming associated with precipitating atmospheric systems, which particularly contrast with the extremely cold conditions in winter. Consequently, the seasonal range of snowfall-weighted temperature is reduced by 20 %. On the other hand, annual snowfall-weighted temperature shows 80 % more interannual variability than annual temperature, due to irregularity of snowfall occurrence and their associated temperature anomaly. Disturbance in apparent annual temperature cycle and interannual variability have important consequences for the interpretation of water isotopes in precipitation, which are deposited with snowfall and commonly used for paleo-temperature reconstructions from ice cores.

Aymeric P. M. Servettaz et al.

Status: open (until 05 Oct 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1903', Anonymous Referee #1, 30 Aug 2023 reply
  • RC2: 'Review of Servettaz et al. for TC (egusphere-2023-1903)', Anonymous Referee #2, 29 Sep 2023 reply
  • RC3: 'Comment on egusphere-2023-1903', Anonymous Referee #3, 29 Sep 2023 reply

Aymeric P. M. Servettaz et al.

Aymeric P. M. Servettaz et al.


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Short summary
It has been previously observed in polar region that the atmospheric temperature is warmer during precipitation events. Here, we use a regional atmospheric model to quantify the temperature changes associated with the snowfall events in the entire Antarctic continent. We show that more intense snowfall statistically corresponds to warmer temperature anomaly compared to seasonal average, with largest anomalies in winter. This bias may affect water isotopes in ice cores, deposited during snowfall.