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祁连山老虎沟12号冰川雷达测厚和冰下地形特征研究 总被引：3，自引：3，他引：0
冰川地形是构建冰川流动模型的基础,对于认识冰川响应气候变化的动力机制具有重要意义.在2009年和2014年消融季,使用探地雷达对祁连山老虎沟12号冰川进行了厚度测量和冰下地形观测,获得了沿冰川中流线和多条横剖面的厚度资料,并对中流线上的厚度分布特征和槽谷形态进行了研究.研究结果表明,东、西支冰川的平均厚度分别为190m和150m,东支冰川冰下地形起伏大于西支,支冰川的表面坡度都较缓和.东、西支冰川进入汇合区时厚度分别为122m和157m,由于支冰川的横向挤压和汇流,汇合区中部冰川厚度增加到162m.冰川槽谷形态具有空间差异,东、西支冰川槽谷形态近似于对称的V型,但是在冰川汇合区,槽谷底部变宽,边坡变缓,发育有不对称槽谷. 相似文献
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冰厚分布和冰储量是冰川水资源、冰川变化和冰川动力学模拟研究的基础数据。本文基于七一冰川冰厚度雷达测量结果,结合GPS位置数据、遥感数据和冰川地形数据,运用协同克里金空间插值算法,绘制了冰厚分布图和冰床地形图,并运用厚度积分法估算了冰川冰储量。2015年七一冰川的面积为2.517km^(2),平均冰厚和冰储量分别为44.9m和0.1129km^(3),实测最大冰厚为115m。海拔4 480~4 600m和海拔4 640~4 800m是七一冰川两个冰厚值较大的区域,平均冰厚分别为88m和97m。 相似文献
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祁连山八一冰川雷达测厚与冰储量分析 总被引：12，自引：7，他引：5
基于2006年5月利用探地雷达对祁连山八一冰川厚度的系统测量资料,绘制了该冰川冰厚度分布等值线图,计算出了该冰川的平均厚度为54.2 m,冰储量为0.153 km2.这几乎是我国第一次冰川编目资料中给出的八一冰川平均厚度(30 m)和冰储量(0.0843 km3)数据的1倍.由此可见,准确评估我国冰川的冰储量是冰川水资源研究亟待解决的重要问题.将八一冰川冰面地形图与冰厚度分布图相结合,绘制了该冰川的冰床地形图,结果表明:其崎岖不平的冰床地形与其相对平缓的冰面地形形成了显明的对比,显示了冰帽冰川的形貌特征. 相似文献
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冰川厚度测量是冰储量估算的关键。基于2019年7月利用探地雷达在托来南山6号冰川主冰川的测厚结果,通过普通克里格法绘制了主冰川的冰厚分布图,计算出主冰川的平均厚度为（39.61±5.32） m,冰厚空间分布呈自边缘向中间逐渐增厚的特征,最大冰厚［（100.78±1.78） m］位于纵剖面海拔4 770 m附近的凹陷盆地,结合半物理公式估算出整条冰川的冰储量为（0.0504±0.0082） km3。冰床为典型槽谷地形,谷槽横剖面呈U形,且随海拔的升高谷槽宽度逐渐变小。现有的面积-体积公式并不适用于单条冰川的冰储量估算,但分类型拟合公式具有降低估算结果误差的潜力。 相似文献
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珠穆朗玛峰东绒布冰川厚度测量与地形特征分析 总被引：3，自引：3，他引：0
冰川地形特征的研究是构建冰川流动模型的基础. 根据探地雷达获取的冰川厚度数据(2009年)和1∶5万地形图(1974年), 得到沿珠穆朗玛峰东绒布冰川主流线的冰厚度分布以及5条冰川槽谷的形态特征. 结果表明: 沿东绒布冰川主流线的平均表面坡度约为0.08, 平均厚度约为190 m, 最大厚度约为320 m (海拔6 300 m); 在1974-2009年间沿冰川主流线冰厚度平均减薄约30 m; 东绒布冰川表碛覆盖区与白冰区尚未分离, 目前很可能是一条停滞冰川, 冰川末端位于海拔5 540 m附近(下游方向); 东绒布冰川槽谷形态接近于V型, 而不是U型(b指数变化范围约为0.7~1.3). 相似文献
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冰下地形与冰川体积的估算对冰川水资源研究具有重要意义.以萨吾尔山木斯岛冰川为研究对象,利用Landsat影像数据、探地雷达(ground penetrating radar,简称GPR)冰川厚度数据以及差分GPS数据,分析模拟了萨吾尔山木斯岛冰川横纵剖面的厚度分布特征,采用多种插值方法比较分析,得到木斯岛冰川冰舌区的厚度分布图,初步估算了该冰川的冰储量.结合数字高程模型数据及冰川厚度分布图,绘制了木斯岛冰川冰舌区冰床地形图.研究表明,两个横剖面的冰川槽谷形态存在较大的差异.横剖面B1-B2有典型的“U”型地形发育,冰川厚度可达116.4 m;C1-C2横剖面底部地形比较平缓,冰川厚度分布较均匀,平均在70~90 m.纵测线A1-A2冰下地形成阶梯状分布,纵剖面冰体平均厚度约为80.89 m,最大冰体厚度为122.67 m.木斯岛冰川的冰床地形图与该冰川的冰厚度等值线图形成明显对比.在海拔3 240 m和3 280 m处存在明显的冰斗地形地貌.初步估算木斯岛冰川冰舌区的平均厚度和冰储量分别为60.5 m和0.195 km3.与传统计算冰储量的方法相比,利用GPR测量得到的冰川厚度数据来插值计算冰储量的方法,具有更高的准确性. 相似文献
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东昆仑山煤矿冰川雷达测厚及冰储量估算 总被引：4，自引：3，他引：1
基于2015年5月东昆仑山煤矿冰川冰厚测量资料,结合2015年Landsat8 OLI影像,利用Ordinary Kriging插值方法对冰川非测厚区进行插值计算,绘制了该冰川厚度等值线并对该冰川冰储量进行了估算。2015年煤矿冰川最大厚度为87 m,位于海拔4 952 m主流线附近,平均厚度为25.77 m,冰储量为0.0242 km3。利用煤矿冰川冰面地形图与冰厚度分布图,获得该冰川冰床地形图。结果显示,冰川上宽下窄沿山谷分布,冰床地形复杂,在冰厚较大区域,地形呈近“V”字分布,显示了冰斗冰川的形貌特征。 相似文献
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探地雷达因其快速、准确、无损、高分辨率等优势而被广泛应用于冰川学领域。以天山托木尔峰青冰滩72号冰川为例,着重介绍了探地雷达在冰川厚度及冰下地形探测中的应用。通过对雷达图像的处理和解译,获取了高精度的冰川厚度数据,恢复了冰下地形,计算了冰储量,并分析了冰川厚度变化对气候变化的响应。结果表明:冰舌厚度为0～148 m;冰储量为0.055 860 km3,折合成水为0.050 274 km3。近50年来,该冰川呈现强烈消融,与冰川区气温快速上升有直接关系,雷达探测为研究此响应机制提供了定量化的科学依据。 相似文献
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基于V指数的他念他翁山中段冰川槽谷形态特征及影响因素分析 总被引：1，自引：1，他引：0
冰川槽谷作为冰川作用区分布最典型的冰川地貌之一,对其形态特征及影响因素的研究,有助于揭示冰川发育的动力学过程。基于V指数模型及MATLAB半自动提取方法,分析并探讨了他念他翁山中段冰川槽谷形态发育特征及造成槽谷形态差异的影响因素。结果表明：研究区共发育206条冰川槽谷,大多为“U”形或偏“U”形,长4.5~26 km之间,平均宽度1.8 km,深200~500 m,海拔高度介于5 730~3 274 m。槽谷形态横向分布规律：V指数多为0.2~0.3,北东向发育V指数大于0.3的谷地多于西南向,说明东坡槽谷侵蚀程度强于西坡。V指数沿槽谷纵向主要有两种变化趋势：V指数增大,冰川槽谷横剖面“U”形发育特点逐渐增强;V指数减小,冰川槽谷横剖面“U”形发育特点减弱。研究区冰川槽谷发育以侧蚀为主,形态的差异性是冰川自身特性、冰川作用区地形与基岩岩性等多种因素共同作用的结果。其中,冰川作用区的平均坡度、平均地形起伏度与古冰川作用区面积是造成这种分布差异的主要因素。 相似文献
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冰川厚度和冰下地形是冰川学研究中相当宝贵的数据。2018年5月,利用探地雷达（GPR）对西藏阿里地区喀喇昆仑山脉南部的嘎尼冰川进行了冰川厚度测量。基于ArcGIS中的地统计分析模块,运用Kriging插值方法对冰川非测厚区进行插值计算,结合差分GPS数据、遥感影像数据和地形数据,分析了嘎尼冰川横、纵剖面厚度特征,绘制了冰川冰下地形图和冰川厚度分布图,并估算了该冰川冰储量。结果表明：嘎尼冰川冰下地形存在空间差异,东支冰下地形起伏较大,西支相对平缓,冰川作用以下蚀作用为主,冰川面积为4.31 km2,平均厚度51.2 m,最大厚度出现在东支海拔5 970 m处,约为136.6 m,冰储量为0.218 km3。 相似文献
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PUYU WANG ZHONGQIN LI SHUANG JIN PING ZHOU HONGBING YAO WENBIN WANG 《Journal of Earth System Science》2014,123(3):581-591
The results of radar survey for three times are presented, aiming to determine ice thickness, volume and subglacial topography of Urumqi Glacier No. 1, Tianshan Mountains, central Asia. Results show that the distribution of ice is more in the center and lesser at both ends of the glacier. The bedrock is quite regular with altitudes decreasing towards the ice front, showing the U-shaped subglacial valley. By comparison, typical ice thinning along the centerline of the East Branch of the glacier was 10–18 m for the period 1981–2006, reaching a maximum of ～30 m at the terminus. The corresponding ice volume was 10296.2 × 10 4 m 3, 8797.9 × 10 4 m 3 and 8115.0 × 10 4 m 3 in 1981, 2001 and 2006, respectively. It has decreased by 21.2% during the past 25 years, which is the direct result of glacier thinning. In the same period, the ice thickness, area and terminus decreased by 12.2%, 10.3%, and 3.6%, respectively. These changes are responses to the regional climatic warming, which show a dramatic increase of 0.6°C (10 a) ?1 during the period 1981–2006. 相似文献
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A two‐part basal till at Knud Strand, Denmark reveals a uniform fabric pattern and strength, petrographical composition and clay mineralogy. The nature of the contact with the underlying sediments, ductile deformation structures, partly intact soft sediment clasts, small meltwater channels and thin horizontal outwash stringers dispersed in the till indicate both bed deformation and basal decoupling by pressurised subglacial water. A time‐transgressive model is suggested to explain the lack of vertical gradation in till properties in which debris released from the active ice sole is sheared in a thin zone moving upward as till accretion proceeds. It is suggested that, although strain indicators occur throughout the entire till thickness, the deformation at any point of time encompassed the uppermost part of the till only, allowing preservation of fragile clasts below. The substantial thickness of the till (up to 6 m) coupled with a much smaller (by more than one order of magnitude) inferred thickness of the deforming bed suggests that the bulk of till material was transported englacially prior to deposition. The lack of petrographical gradation in the till is attributed to effective mixing and homogenisation of material along the ice flow path. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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High‐resolution swath bathymetry and TOPAS sub‐bottom profiler acoustic data from the inner and middle continental shelf of north‐east Greenland record the presence of streamlined mega‐scale glacial lineations and other subglacial landforms that are formed in the surface of a continuous soft sediment layer. The best‐developed lineations are found in Westwind Trough, a bathymetric trough connecting Nioghalvfjerdsfjorden Gletscher and Zachariae Isstrøm to the continental shelf edge. The geomorphological and stratigraphical data indicate that the Greenland Ice Sheet covered the inner‐middle shelf in north‐east Greenland during the most recent ice advance of the Late Weichselian glaciation. Earlier sedimentological and chronological studies indicated that the last major delivery of glacigenic sediment to the shelf and Fram Strait was prior to the Holocene during Marine Isotope Stage 2, supporting our assertion that the subglacial landforms and ice sheet expansion in north‐east Greenland occurred during the Late Weichselian. Glacimarine sediment gravity flow deposits found on the north‐east Greenland continental slope imply that the ice sheet extended beyond the middle continental shelf, and supplied subglacial sediment direct to the shelf edge with subsequent remobilisation downslope. These marine geophysical data indicate that the flow of the Late Weichselian Greenland Ice Sheet through Westwind Trough was in the form of a fast‐flowing palaeo‐ice stream, and that it provides the first direct geomorphological evidence for the former presence of ice streams on the Greenland continental shelf. The presence of streamlined subglacially derived landforms and till layers on the shallow AWI Bank and Northwind Shoal indicates that ice sheet flow was not only channelled through the cross‐shelf bathymetric troughs but also occurred across the shallow intra‐trough regions of north‐east Greenland. Collectively these data record for the first time that ice streams were an important glacio‐dynamic feature that drained interior basins of the Late Weichselian Greenland Ice Sheet across the adjacent continental margin, and that the ice sheet was far more extensive in north‐east Greenland during the Last Glacial Maximum than the previous terrestrial–glacial reconstructions showed. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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Geophysical data from Gerlache Strait, Croker Passage, Bismarck Strait and the adjacent continental shelf reveal streamlined subglacial bedforms that were produced at the bed of the Antarctic Peninsula Ice Sheet (APIS) during the last glaciation. The spatial arrangement and orientation of these bedforms record the former drainage pattern and flow dynamics of an APIS outlet up‐flow, and feeding into, a palaeo‐ice stream in the Western Bransfield Basin. Evidence suggests that together, they represent a single ice‐flow system that drained the APIS during the last glaciation. The ice‐sheet outlet flowed north/northeastwards through Gerlache Strait and Croker Passage and converged with a second, more easterly ice‐flow tributary on the middle shelf to form the main palaeo‐ice stream. The dominance of drumlins with low elongation ratios suggests that ice‐sheet outlet draining through Gerlache Strait was comparatively slower than the main palaeo‐ice stream in the Western Bransfield Basin, although the low elongation ratios may also partly reflect the lack of sediment. Progressive elongation of drumlins further down‐flow indicates that the ice sheet accelerated through Croker Passage and the western tributary trough, and fed into the main zone of streaming flow in the Western Bransfield Basin. Topography would have exerted a strong control on the development of the palaeo‐ice stream system but subglacial geology may also have been significant given the transition from crystalline bedrock to sedimentary strata on the inner–mid‐shelf. In the broader context, the APIS was drained by a number of major fast‐flowing outlets through cross‐shelf troughs to the outer continental shelf during the last glaciation. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献