Spatial distribution of 17O-excess in surface snow along a traverse from Zhongshan station to Dome A, East Antarctica
Spatial distribution of 17O-excess in surface snow along a traverse from Zhongshan station to Dome A, East Antarctica
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东南极中山站至Dome A横断面地表积雪17O超标的空间分布
DOI：
10.1016/j.epsl.2015.01.014
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发表时间：
2015-03-15
影响因子：
5.3
通讯作者：
Falourd, Sonia
中科院分区：
文献类型：
--
作者：
Pang, Hongxi;Hou, Shugui;Falourd, Sonia
温度对水氧同位素组成的影响是一个悬而未决的问题，限制了南极冰芯水同位素剖面的解释。主要的局限性来自缺乏O-17-过量的测量，特别是对偏远地区的特点是低温和积累率。在这项研究中，我们提出了新的O-17-过量测量的表面雪沿着东南极横贯，从沿海中山站南极冰盖的最高点在圆顶A。O-17过量数据在内陆显著减少，纬度梯度为-1.33 +/- 0.41/meg/degree，海拔梯度为-0.48 +/- 0.17/meg/100 m，温度梯度为0.35 +/- 0.11/meg/degree C。使用瑞利模型进行的理论计算将这种内陆减少归因于在低温下过饱和条件下从蒸汽到冰的冷凝过程中发生的动力学同位素分馏。然而，大的异质性的O-17-过剩在南极降水不能只解释在冷凝温度和/或相对湿度的影响，在水汽源区。(C)2015 Elsevier B. V.版权所有。
The influence of temperature on the triple isotopic composition of oxygen in water is still an open question and limits the interpretation of water isotopic profiles in Antarctic ice cores. The main limitation arises from the lack of O-17-excess measurements in surface snow and especially for remote regions characterized by low temperature and accumulation rate. In this study, we present new O-17-excess measurements of surface snow along an East Antarctic traverse, from the coastal Zhongshan station to the highest point of the Antarctic ice sheet at Dome A. The O-17-excess data significantly decrease inland, with a latitudinal gradient of -1.33 +/- 0.41 per meg/degree, an altitudinal gradient of -0.48 +/- 0.17 per meg/100 m, and a temperature gradient of 0.35 +/- 0.11 per meg/degrees C. Theoretical calculations performed using a Rayleigh model attribute this inland decrease to kinetic isotopic fractionation occurring during condensation from vapor to ice under supersaturation conditions at low temperatures. However, large heterogeneity of O-17-excess in Antarctic precipitation cannot only be explained by temperature at condensation and/or influences of relative humidity in the moisture source region. (C) 2015 Elsevier B.V. All rights reserved.