An optimized estimate of glacial melt from the Ross Ice Shelf using noble gases, stable isotopes, and CFC transient tracers
An optimized estimate of glacial melt from the Ross Ice Shelf using noble gases, stable isotopes, and CFC transient tracers
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使用稀有气体、稳定同位素和 CFC 瞬态示踪剂对罗斯冰架冰川融化进行优化估计
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发表时间：
2009
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通讯作者：
S. Jacobs
中科院分区：
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作者：
B. Loose;P. Schlosser;W. Smethie;S. Jacobs
[1]氦和氖的同位素和水的H218 O/H216 O比率被证明是浮冰架下和冰架前沿冰川冰融化的替代物。与其他环境来源相比，它们在冰川融水中的高浓度使其成为研究冰川融水从其起源到海洋内部的路径的理想示踪剂。我们结合联合收割机惰性气体和稳定同位素的温度，盐度和溶解氧的测量从三个巡航（沿着罗斯冰架在1993-1994年和1999-2000年的南方夏季和罗斯海在2000-2001年），并使用最佳的多参数分析计算水的质量浓度，包括冰川融水。罗斯冰架前端的融水分布从西经180°向东延伸，1994年和2000年在西经165°附近发现最高浓度。1994年、2000年和2001年罗斯海西部冰架前缘的平均融水浓度分别为2.0 ± 0.33‰、2.2 ± 0.36‰和0.25 ± 0.1‰。水的质量浓度是用来纠正偏差的CFC年龄，介绍了与CFC-自由沃茨混合，通过比较CFC年龄与渡越时间分布曲线显示的效果。水在冰架空腔内的停留时间，使用CFC和平均融水浓度，意味着基础融化速率为33-50 km 3 a−1。
[1] Isotopes of helium and neon and the H218O/H216O ratio of water are proven proxies for melt from glacial ice beneath floating ice shelves and at ice shelf fronts. Their high concentrations in glacial meltwater, compared to other environmental sources, make them ideal tracers for studies of the pathways of glacial meltwater from its origins into the ocean interior. We combine noble gas and stable isotopes with temperature, salinity, and dissolved oxygen measurements from three cruises (along the Ross Ice Shelf during the austral summers of 1993–1994 and 1999–2000 and to the Ross Sea in 2000–2001) and use optimal multiparameter analysis to compute the water mass concentration, including glacial meltwater. The distribution of meltwater at the front of the Ross Ice Shelf extended east from 180°W, with the highest concentrations found near 165°W in both 1994 and 2000. The mean meltwater concentration at the ice shelf front was 2.0 ± 0.33‰ in 1994, 2.2 ± 0.36‰ in 2000, and 0.25 ± 0.1‰ in the western Ross Sea in 2001. Water mass concentrations are used to correct for bias in the CFC age, introduced by mixing with CFC-free waters, an effect revealed by comparing CFC age with transit time distribution curves. The water residence time within the ice shelf cavity, using CFCs and the mean meltwater concentration, implies a basal melt rate of 33–50 km3 a−1.