Radio-echo sounding and waveform modeling reveal abundant marine ice in former rifts and basal crevasses within Crary Ice Rise, Antarctica
Radio-echo sounding and waveform modeling reveal abundant marine ice in former rifts and basal crevasses within Crary Ice Rise, Antarctica
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无线电回波探测和波形模型揭示了南极洲克拉里冰隆内以前的裂谷和基底裂缝中存在丰富的海冰
作者：
Trevor R. Hillebrand;H. Conway;M. Koutnik;C. Martín;J. Paden;J. Winberry
摘要克拉里冰隆形成于距今约100万年前罗斯冰架重新搁浅之后。我们提供了来自中心频率为7 MHz和750 MHz的两个系统的新冰穿透雷达数据，证实冰上升是由随后积累所掩埋的前冰架组成的。冰内绕射双曲线的堆叠几乎遍布中央冰隆的各处，并延伸至海床上方约350 m处。在许多情况下，衍射双曲线下方的床反射在高达1公里的距离内是模糊的。波形模拟表明，绕射双曲线可能是由以前的底裂缝和裂谷中的海冰沉积物引起的。裂缝和底裂缝的填充可能加强了冰隆与周围冰架之间的联系，这可能影响了当地和区域的冰动力学。三个内部反射地平线标志着在冰隆的不同部分的扰动冰和衍射双曲线的上限，表明至少有三个阶段的流动稳定的冰隆。中分辨率成像分光仪图像中可见的表面线理在空间上对应于这些层的加深和强烈变形，与南极洲其他地方观察到的前接地线的特征一致。
Abstract Crary Ice Rise formed after the Ross Ice Shelf re-grounded ~1 kyr BP. We present new ice-penetrating radar data from two systems operating at center frequencies of 7 and 750 MHz that confirm the ice rise is composed of a former ice shelf buried by subsequent accumulation. Stacks of englacial diffraction hyperbolas are present almost everywhere across the central ice rise and extend up to ~350 m above the bed. In many cases, bed reflections beneath the diffraction hyperbolas are obscured for distances up to 1 km. Waveform modeling indicates that the diffraction hyperbolas are likely caused by marine ice deposits in former basal crevasses and rifts. The in-filling of rifts and basal crevasses may have strengthened the connection between the ice rise and the surrounding ice shelf, which could have influenced local and regional ice dynamics. Three internal reflection horizons mark the upper limit of disturbed ice and diffraction hyperbolas in different sections of the ice rise, indicating at least three stages of flow stabilization across the ice rise. A surface lineation visible in MODIS imagery corresponds spatially to deepening and strong deformation of these layers, consistent with the characteristics of former grounding lines observed elsewhere in Antarctica.
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DOI：
10.1029/2019jf005241
发表时间：
2020-03
期刊：
Journal of Geophysical Research: Earth Surface
影响因子：
--
作者：
I. Das;L. Padman;R. Bell;H. Fricker;K. Tinto;C. Hulbe;C. Siddoway;T. Dhakal;N. Frearson;C. Mosbeux;S. Cordero;M. Siegfried
通讯作者：
I. Das;L. Padman;R. Bell;H. Fricker;K. Tinto;C. Hulbe;C. Siddoway;T. Dhakal;N. Frearson;C. Mosbeux;S. Cordero;M. Siegfried
使用射电望远镜 LOFAR 确定雷云中的电场
DOI：
10.1029/2019jd031433
发表时间：
2020
期刊：
Journal of Geophysical Research: Atmospheres
影响因子：
--
作者：
Trinh, T. N.;Scholten, O.;Buitink, S.;Ebert, U.;Hare, B. M.;Krehbiel, P. R.;Leijnse, H.;Bonardi, A.;Corstanje, A.;Falcke, H.
通讯作者：
Falcke, H.
影响因子：
12.1
作者：
K. Matsuoka;R. Hindmarsh;G. Moholdt;M. J. Bentley;H. Pritchard;Joel Brown;H. Conway;R. Drews;G. Durand;D. Goldberg;T. Hattermann;J. Kingslake;J. Lenaerts;C. Martín;R. Mulvaney;K. Nicholls;F. Pattyn;N. Ross;T. Scambos;P. Whitehouse
通讯作者：
K. Matsuoka;R. Hindmarsh;G. Moholdt;M. J. Bentley;H. Pritchard;Joel Brown;H. Conway;R. Drews;G. Durand;D. Goldberg;T. Hattermann;J. Kingslake;J. Lenaerts;C. Martín;R. Mulvaney;K. Nicholls;F. Pattyn;N. Ross;T. Scambos;P. Whitehouse
影响因子：
5.2
作者：
Howat, Ian M.;Porter, Claire;Morin, Paul
通讯作者：
Morin, Paul
影响因子：
3.9
作者：
Jansen, Daniela;Luckman, Adrian;King, Edward C.
通讯作者：
King, Edward C.