Evolution of Derwael Ice Rise in Dronning Maud Land, Antarctica, over the last millennia
Evolution of Derwael Ice Rise in Dronning Maud Land, Antarctica, over the last millennia
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过去千年来南极洲德隆宁莫德地德瓦尔冰层的演变
DOI：
10.1002/2014jf003246
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
F. Pattyn
中科院分区：
文献类型：
--
作者：
R. Drews;K. Matsuoka;Chloe Martin;D. Callens;N. Bergeot;F. Pattyn
位于南极洲周围冰架带的冰升具有局部冰分带的空间受限流态。在裂缝下方，冰地层学经常发育拱形，其振幅记录了裂缝的水平停留时间和地表高程变化。为了研究南极洲Dronning Maud陆地Derwael冰隆的演变，我们将连续三次调查的雷达和GPS数据与二维、全Stokes、热机械耦合、瞬态冰流模型相结合。研究发现，地表物质平衡（SMB）在迎风坡较高，在下风坡较低。在峰顶附近，SMB异常低，在浅层地层中形成拱形，可通过雷达观测到。在较深的冰中，冰拱因此受到SMB和冰流变（雷蒙德效应）的影响。数据显示了拱幅值是如何随着沿山脊坡度的增加而减小的，强调雷达横截面的横向定位对于拱解释很重要。采用三种流变模型（各向同性n=3、各向异性n= 4.5和各向异性n=3），我们发现Derwael冰升接近稳定状态，但最好用冰各向异性和适度变薄来解释。虽然不是唯一的，但我们首选的情景表明，冰分水岭已经存在了至少5000年，在过去的3400年里，它以大约0.03 ma - 1的速度下降。独立于具体的变薄情景，我们的模型表明，至少自中全新世以来，德瓦孔冰上升已经表现出一种局部流动状态。
Ice rises situated in the ice‐shelf belt around Antarctica have a spatially confined flow regime with local ice divides. Beneath the divides, ice stratigraphy often develops arches with amplitudes that record the divide's horizontal residence time and surface elevation changes. To investigate the evolution of Derwael Ice Rise, Dronning Maud Land, Antarctica, we combine radar and GPS data from three consecutive surveys, with a two‐dimensional, full Stokes, thermomechanically coupled, transient ice‐flow model. We find that the surface mass balance (SMB) is higher on the upwind and lower on the downwind slopes. Near the crest, the SMB is anomalously low and causes arches to form in the shallow stratigraphy, observable by radar. In deeper ice, arches are consequently imprinted by both SMB and ice rheology (Raymond effect). The data show how arch amplitudes decrease as along‐ridge slope increases, emphasizing that the lateral positioning of radar cross sections is important for the arch interpretation. Using the model with three rheologies (isotropic with n=3,4.5 and anisotropic with n=3), we show that Derwael Ice Rise is close to steady state but is best explained using ice anisotropy and moderate thinning. Our preferred, albeit not unique, scenario suggests that the ice divide has existed for at least 5000 years and lowered at approximately 0.03 m a−1 over the last 3400 years. Independent of the specific thinning scenario, our modeling suggests that Derwael Ice Rise has exhibited a local flow regime at least since the Mid‐Holocene.
通过南极洲哈尔法里根冰穹的振动和爆炸地震调查来研究冰川反射
影响因子：
2.9
作者：
Hofstede;Jansen;Kristoffersen;Lambrecht
通讯作者：
Lambrecht
影响因子：
5.2
作者：
Bindschadler, R.;Choi, H.;Young, N.
通讯作者：
Young, N.