High Resolution Radar Profiling of Firn Stratigraphy in East Antarctia: The ITASE II Traverse from Victoria Land to South Pole Station

该合同支持获取高分辨率探地雷达剖面图，作为ITASE-2穿越的一部分，沿着东南极洲从维多利亚地到南极站的路线。 该项目将收集积雪地层剖面图，以帮助选择取芯地点，测量空间平均积雪率，并确定造成地层的冰动态。 探地雷达工作的雷达剖面图将与冰芯地层学和其他方面作为导线测量的一部分获得的全球定位系统数据相关联。 探地雷达还将用于裂缝探测和穿越路线安全，但根据先前工作的经验，这被认为是常规工作。 ITASE Ⅰ探地雷达在地层动力学方面的主要发现是：（1）大多数400 MHz层位是延伸超过500 km的独立和不同的子波：（2）层位似乎是由两层薄的白霜和冰的密度差异引起的; 3）不同的堆积过程以及不同的波长和冰速之间的相互作用可以导致褶皱，都被雷达速度下拉所缓和。方面的影响. 这一建议是基于这样的假设，即在南极洲西部相对较大和较温暖的堆积区产生和折叠反射层的相同过程也在南极洲东部相对较小和较冷的堆积区起作用，并且将被检测到，尽管以厘米为单位的任何密度的积雪的堆积率远远低于雷达的垂直分辨率。 本项目的主要目标是通过寻找薄层特征和差异累积动力学引起的褶皱证据来检验这一假设。 还将寻找构造褶皱的证据，最有可能是由跨南极山脉冰川的补给区内的收敛引起的，以及小规模的地平线连续性。对于两个实地年中的每一年，资金还将支持一名学生4个月，购买次要设备，旅行，编辑，出版物和用品。 学生将成为美国CRREL的临时雇员，在夏季为他或她提供支持。

This award supports the acquisition of high resolution ground-penetrating radar (GPR) profiles as part of the ITASE-2 traverse, along a route in East Antarctica from Victoria Land to South Pole Station. The project will collect profiles of the firn stratigraphy to aid in the selection of coring sites, measure spatially averaged snow accumulation rates and determine the ice dynamics that cause the stratigraphy. The radar profiles from the GPR work will be correlated with ice core stratigraphy and GPS data obtained by others as part of the traverse. GPR will also be used for crevasse detection and traverse route safety but this is considered routine, based on experience from prior work.. The major GPR findings in stratigraphic dynamics from ITASE I are: 1) most 400-MHz horizons are separate and distinct wavelets that extend over 500 km; 2) horizons appear to be caused by the density contrasts across clusters of thin, double-layers of hoar and ice; and 3) the folding can be caused by differential accumulation processes and the interaction between differential wavelength and ice speed, all tempered by radar velocity pulldown. effects. This proposal is based on the hypothesis that the same processes that generate and fold reflection horizons in the relatively greater and warmer accumulation zone of West Antarctica, are also at work in the relatively lesser and far colder accumulation zone of East Antarctica, and will be detected despite the fact that the accumulation rates, in cm of firn at any density, are far less than the vertical resolution of the radar. The major objectives of this project are to test this hypothesis by searching for thin layer signatures, and evidence of folding caused by differential accumulation dynamics. Evidence will also be sought of tectonic folding, most likely caused by convergence within feeder areas for the glaciers of the Transantarctic Mountains, and of the small scale continuity of horizons. For each of the two field years, the funding will also support a student for 4 months, minor equipment purchases, travel, editing, publications and supplies. The student will be a temporary employee of USA CRREL to support him or her during the summer months.