High-resolution subglacial topography around Dome Fuji, Antarctica, based on ground-based radar surveys over 30 years
High-resolution subglacial topography around Dome Fuji, Antarctica, based on ground-based radar surveys over 30 years
复制标题
DOI：
10.5194/tc-16-2967-2022
复制
发表时间：
2022-07
期刊：
影响因子：
--
通讯作者：
S. Tsutaki;S. Fujita;K. Kawamura;A. Abe‐Ouchi;K. Fukui;H. Motoyama;Yu Hoshina;F. Nakazawa;T. Obase;H. Ohno;Ikumi Oyabu;F. Saito;K. Sugiura;Toshitaka N. Suzuki
中科院分区：
文献类型：
--
作者：
S. Tsutaki;S. Fujita;K. Kawamura;A. Abe‐Ouchi;K. Fukui;H. Motoyama;Yu Hoshina;F. Nakazawa;T. Obase;H. Ohno;Ikumi Oyabu;F. Saito;K. Sugiura;Toshitaka N. Suzuki
抽象的。1MyR以上连续冰芯记录的反演是古气候学面临的一个重要挑战。为了确定适合钻探这类冰的地点，了解冰下地形和冰盖分层是至关重要的。为此，日本南极科考队在过去∼30年陆基雷达调查的基础上，于2017/18年和2018/19年南半球夏季对东南极高原的富士穹顶进行了广泛的陆基冰雷达调查。高增益八木天线被用来改善天线波束方向性，从而显著降低山区冰基界面回波中非聚焦沿轨道绕射双曲线的特征。我们将新的冰层厚度数据与自20世纪80年代以来记录的以前的陆基数据相结合，生成了准确的高空间分辨率(测线之间高达0.5公里)的冰层厚度图。这张地图显示了由冰下山谷和高地组成的网络组成的复杂景观。在新地图的基础上，我们考察了冰床界面的粗糙度、床面坡度、冰的驱动应力和冰层下的水文条件。这些新产品和分析对确定可能的新钻探地点设置了很大的限制。此外，我们还将我们的地图与早期独立工作基于机载雷达数据编制的几张床上地图进行了比较，以检查数据集之间的特征差异。我们的分析建议，在可能的情况下，应通过现场观测来验证广泛可用的床面地形产品。
Abstract. The retrieval of continuous ice core records of more than 1 Myr is an important challenge in palaeo-climatology. For identifying suitable sites for drilling such ice, knowledge of the subglacial topography and englacial layering is crucial. For this purpose, extensive ground-based ice radar surveys were carried out over Dome Fuji in the East Antarctic plateau during the 2017/18 and 2018/19 austral summers by the Japanese Antarctic Research Expedition, on the basis of ground-based radar surveys conducted over the previous ∼ 30 years. High-gain Yagi antennae were used to improve the antenna beam directivity, thereby significantly decreasing hyperbolic features of unfocused along-track diffraction hyperbolae in the echoes from mountainous ice–bedrock interfaces. We combined the new ice thickness data with the previous ground-based data, recorded since the 1980s, to generate an accurate high-spatial-resolution (up to 0.5 km between survey lines) ice thickness map. This map revealed a complex landscape composed of networks of subglacial valleys and highlands. Based on the new map, we examined the roughness of the ice–bed interface, the bed surface slope, the driving stress of ice and the subglacial hydrological condition. These new products and analyses set substantial constraints on identifying possible locations for new drilling. In addition, our map was compared with a few bed maps compiled by earlier independent efforts based on airborne radar data to examine the difference in features between datasets. Our analysis suggests that widely available bed topography products should be validated with in situ observations where possible.