Spatial variation of radar-derived basal conditions on Kamb Ice Stream, West Antarctica
Spatial variation of radar-derived basal conditions on Kamb Ice Stream, West Antarctica
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南极洲西部卡姆冰流雷达基础条件的空间变化
DOI：
10.3189/172756409789097504
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发表时间：
2009
影响因子：
2.9
通讯作者：
J. MacGregor
中科院分区：
文献类型：
--
作者：
R. Jacobel;B. Welch;D. Osterhouse;R. Pettersson;J. MacGregor
摘要冰床回波强度雷达剖面图可以测量冰床界面的状况，检验冰床是否有水。然而，从河床回波强度中提取有关基础条件的信息需要估计通过冰的衰减损失。我们使用床回波强度从恒定偏移距雷达数据和冰厚度之间的关系，估计深度平均衰减率在几个位置上和附近的坎布冰流（KIS），西南极洲。我们发现的值从29 dBkm-1在Siple圆顶到15 dBkm-1在KIS的主干区域，在协议与以前的测量和模型。使用这些衰减率值，我们计算了整个KIS调查的相对床反射率，发现树干中的大部分床具有高的基底反射率，与在床处发现水的钻孔位置中获得的反射率相似。低反射率区域仅限于粘点，钻孔发现此处为干床，以及沿着KIS边缘。这些结果支持了先前的假设，即KIS上的粘点等位置的基础条件控制其停滞和可能的重新激活。
Abstract Radar profiles of bed echo intensity can survey conditions at the ice–bed interface and test for the presence or absence of water. However, extracting information about basal conditions from bed echo intensities requires an estimate of the attenuation loss through the ice. We used the relationship between bed echo intensities from constant-offset radar data and ice thickness to estimate depth-averaged attenuation rates at several locations on and near Kamb Ice Stream (KIS), West Antarctica. We found values varying from 29 dBkm–1 at Siple Dome to 15 dBkm–1 in the main trunk region of KIS, in agreement with a previous measurement and models. Using these attenuation-rate values, we calculated the relative bed reflectivity throughout our KIS surveys and found that most of the bed in the trunk has high basal reflectivities, similar to those obtained in the location of boreholes that found water at the bed. Areas of lower bed reflectivity are limited to the sticky spot, where a borehole found a dry bed, and along the margins of KIS. These results support previous hypotheses that the basal conditions at locations like the sticky spot on KIS control its stagnation and possible reactivation.
影响因子：
18.3
作者：
Rignot, Eric;Bamber, Jonathan L.;Van Meijgaard, Erik
通讯作者：
Van Meijgaard, Erik