近日，法国巴黎萨克雷大学Mathieu Casado团队报道了大气环流设定的南极洲水同位素-温度关系变率。2026年4月13日出版的《自然—地球科学》杂志发表了这项成果。

水同位素可作为水文过程的示踪剂，也是冰芯中记录的古气候代用指标。同位素信号贯穿整个水文循环过程而获取——包括海洋蒸发、水汽从低纬向高纬输送过程中发生的降水，以及沉积后过程中雪与大气水汽之间的同位素交换。由于这些多重影响，南极冰芯中同位素比值与局地温度之间的关系在不同区域存在差异；并且，在评估空间上的同位素比值与温度关系（例如表层雪）与同一地点时间上的相关性（例如降水）时，会得到不同的关系。

研究组报告了穿越东南极洲的考察途中以及两个固定站点——沿海迪蒙·迪尔维尔站和冰穹C——的水汽同位素组成测量结果。结合雪和汽同位素数据，证明了时间与空间上的同位素-温度关系之所以不同，是因为降水余量分数在时间和空间上的变化方式存在差异。该研究结果支持这样一种转变：从将同位素-温度关系视为具有不同的时间斜率和空间斜率，转向认识到这种关系基于环流动力学与平均气候状态之间已知的依赖性，沿着一个连续谱而变化。通过沿湿等熵输送路径提纯水汽，研究组可以利用对不同气候条件下大尺度水汽输送的物理理解，预测跨越时间或空间的同位素-温度关系。

附：英文原文

Title: Water isotope–temperature relationship variability across Antarctica set by atmospheric circulation

Author: Casado, Mathieu, Bailey, Adriana, Leroy-Dos Santos, Christophe, Fourr, Elise, Favier, Vincent, Agosta, Ccile, Dutrievoz, Niels, Kittel, Christoph, Arnaud, Laurent, Pri, Frdric, Akers, Pete D., Cauquoin, Alexandre, Werner, Martin, Janssen, Leoni, Stenni, Barbara, Dreossi, Giuliano, Spolaor, Andrea, Petteni, Agnese, Savarino, Joel, Landais, Amaelle

Issue&Volume: 2026-04-13

Abstract: Water isotopes serve as tracers of hydrological processes and as proxies for past climates archived in ice cores. The isotopic signal is acquired throughout the hydrological cycle—through evaporation over the oceans, precipitation, which occurs as moisture is transported from lower to higher latitudes, and during post-depositional processes in which isotopic exchange between snow and atmospheric moisture occurs. Owing to these multiple influences, the relationship between isotope ratios in ice and local temperature varies across Antarctica, and distinct relationships are found when evaluating isotope ratios and temperature across space (for example, in surface snow) compared with temporal correlations at the same site (for example, in precipitation). Here we report measurements of water vapour isotopic compositions from a traverse across East Antarctica, as well as at two fixed sites: the coastal station Dumont D’Urville and Dome C on the plateau. Combining snow and vapour isotopic data, we demonstrate that the temporal and spatial isotope–temperature relationships are distinct because of differences in how the rainout fraction varies across time and space. Our findings support a shift from thinking about the isotope–temperature relationship in terms of distinct temporal and spatial slopes to recognizing that the relationship varies along a continuum based on known dependencies between circulation dynamics and mean climate state. By distilling moisture along moist isentropic transport paths, we can predict the isotope–temperature relationship across either time or space using a physical understanding of large-scale moisture transport under different climatic conditions.

DOI: 10.1038/s41561-026-01961-y

Source: https://www.nature.com/articles/s41561-026-01961-y