Observationally constrained surface mass balance of Larsen C ice shelf, Antarctica
Observationally constrained surface mass balance of Larsen C ice shelf, Antarctica
复制标题
南极洲拉森 C 冰架观测约束的表面质量平衡
DOI：
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
N. Gourmelen
中科院分区：
文献类型：
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作者：
P. K. Munneke;D. McGrath;B. Medley;A. Luckman;S. Bevan;B. Kulessa;D. Jansen;A. Booth;P. Smeets;B. Hubbard;D. Ashmore;M. Broeke;Heïdi Sevestre;K. Steffen;A. Shepherd;N. Gourmelen
抽象的。南极拉森C冰架（LCIS）的表面质量平衡（SMB），由于缺乏现场观测的约束。结合几种地球物理技术，我们重建的空间和时间模式的SMB在LCIS。连续时间序列的积雪高度（2.5-6年）在五个地点允许多年的季节性和年度SMB的估计超过LCIS。SMB的年际变化和空间变化都很大：在北部，SMB为0.40 ± 0.06至0.41 ± 0.04 m w.e. year−1，而在更南部，SMB高达0.50 ± 0.05 m w.e. year−1。2009年的一次机载雷达调查显示，冬季积雪平均厚度为0.34米，证实了南北之间的这种差异。66° S以北，0.40 m w.e.南纬68°。对几次实地活动的探地雷达进行分析，可以对中小企业的空间变化进行更长期的观察：在整个大陆架收集的雷达图中，观察到25-44 m以下的水当量冰和雪的特别强烈且相干的反射层。我们认为，这个地平线是同步形成的冰架。结合积雪高度观测、地面和机载雷达以及区域气候模式的SMB输出，得到LCIS上SMB的网格估计。这证实了SMB从北向南增加，叠加了SMB向西增加的梯度，在西部由焚风引起的升华调制。以前的观测结果表明，向西，我们归因于空间格局的融化，refreezing和致密化，而不是SMB的积雪空气含量的强烈下降。
Abstract. The surface mass balance (SMB) of the Larsen C ice shelf (LCIS), Antarctica, is poorly constrained due to a dearth of in situ observations. Combining several geophysical techniques, we reconstruct spatial and temporal patterns of SMB over the LCIS. Continuous time series of snow height (2.5–6 years) at five locations allow for multi-year estimates of seasonal and annual SMB over the LCIS. There is high interannual variability in SMB as well as spatial variability: in the north, SMB is 0.40 ± 0.06 to 0.41 ± 0.04 m w.e. year−1, while farther south, SMB is up to 0.50 ± 0.05 m w.e. year−1. This difference between north and south is corroborated by winter snow accumulation derived from an airborne radar survey from 2009, which showed an average snow thickness of 0.34 m w.e. north of 66° S, and 0.40 m w.e. south of 68° S. Analysis of ground-penetrating radar from several field campaigns allows for a longer-term perspective of spatial variations in SMB: a particularly strong and coherent reflection horizon below 25–44 m of water-equivalent ice and firn is observed in radargrams collected across the shelf. We propose that this horizon was formed synchronously across the ice shelf. Combining snow height observations, ground and airborne radar, and SMB output from a regional climate model yields a gridded estimate of SMB over the LCIS. It confirms that SMB increases from north to south, overprinted by a gradient of increasing SMB to the west, modulated in the west by fohn-induced sublimation. Previous observations show a strong decrease in firn air content toward the west, which we attribute to spatial patterns of melt, refreezing, and densification rather than SMB.
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DOI：
10.1002/2016jf004047
发表时间：
2017-05
期刊：
Journal of Geophysical Research: Earth Surface
影响因子：
--
作者：
D. Ashmore;B. Hubbard;A. Luckman;B. Kulessa;S. Bevan;A. Booth;P. K. Munneke;M. O’Leary;Heïdi Seve
通讯作者：
D. Ashmore;B. Hubbard;A. Luckman;B. Kulessa;S. Bevan;A. Booth;P. K. Munneke;M. O’Leary;Heïdi Seve
影响因子：
1.6
作者：
Luckman, Adrian;Elvidge, Andrew;Barrand, Nicholas E.
通讯作者：
Barrand, Nicholas E.
影响因子：
5.2
作者：
Luckman, A.;Jansen, D.;Benn, D. I.
通讯作者：
Benn, D. I.
影响因子：
5.2
作者：
Bindschadler, R.;Choi, H.;Young, N.
通讯作者：
Young, N.
影响因子：
3.9
作者：
Jansen, Daniela;Luckman, Adrian;King, Edward C.
通讯作者：
King, Edward C.