Refined simple model of stable water isotopic content in central Antarctic precipitation including oxygen 17 fractionation

• Main Authors: A. Ekaykin A., А. Екайкин А.
• Other Authors: The work was carried out with financial support from the Russian Science Foundation, grant 21-17-00246. The author is grateful to the leaders and the staff of the RAE (in particular, Yuri Shibaev and Sergei Zykov) for the logistical support of field research in Antarctica, as well as to the CERL’s staff for isotope measurements of snow samples collected on the Progress-Vostok profile., Работа выполнена при финансовой поддержке Российского научного фонда, грант 21-17-00246. Автор признателен руководству и сотрудникам РАЭ (в частности, Юрию Шибаеву и Сергею Зыкову) за логистическое обеспечение полевых исследований в Антарктиде, а также сотрудникам ЛИКОС за изотопные измерения образцов снега, собранных на профиле Прогресс — Восток.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: IGRAS 2024
• Subjects: precipitation;simple isotope model;stable water isotopes; простая изотопная модель;осадки;стабильные водные изотопы; Antarc*; Antarctic; Antarctica; East Antarctica
• Online Access: https://ice-snow.igras.ru/jour/article/view/1358; https://doi.org/10.31857/S2076673424010013

Modeling the isotopic composition of atmospheric precipitation is an important tool for climatic, paleoclimatic and hydrological studies. This paper presents an improved simple model of the isotopic composition of precipitation in Central Antarctica. It differs from the previous version published by Salamatin et al. (2004) by 1) the included geochemical cycle of oxygen 17 and 2) the possibility of solving the inverse problem (i.e., finding the trajectory parameters that could form the isotopic composition of the precipitation observed at the end of the trajectory). The paper examines in detail the main tuning parameters of the model, among which the most important are the temperature and humidity in the moisture source, the “circulation parameter”, which takes into account the advection of vapor into the moisture source, the condensation temperature and the degree of air supersaturation with moisture in ice clouds. Based on the analysis of data on the isotopic composition (including “excess of oxygen 17”, 17O-xs) of water vapor in the surface layer of the atmosphere over the ocean and surface snow sampled along meridional profiles in East Antarctica, the optimal tuning of the model for calculating the isotopic composition of atmospheric precipitation at the Antarctic Vostok station was performed. In particular, it is shown that the temperature and humidity of the air in the moisture source are +17.4°C and 72%, respectively, and the condensation temperature is –41.3°C. The possibilities of using the model to analyze the isotopic composition of liquid precipitation falling on other continents are discussed. The final part of the paper discusses the limitations of the model. In particular, it is noted that the model does not take into account such processes as the evaporation of precipitation when it falls in arid conditions, mixing of trajectories, the influence of local sources of moisture, as well as the features of isotope fractionation during the evaporation of moisture from the continents. Представлена ...