祁连山老虎沟12号冰川冰内结构特征分析

利用探地雷达(Ground Penetration Radar,GPR)调查冰川冰内结构和冰层厚度是一种监测冰川变化常用手段.应用麦克斯维(Maxwell)方程的二维时域有限差分(FDTD)方法,通过将模拟图像与老虎沟12号冰川的实测图像的对比,分析了雷达剖面中的几种反射特征,如冰裂隙、融洞、暖冰等.对比结果表明,GP...     

祁连山老虎沟12号冰川浅冰芯记录的气候环境信息

2006年6月在祁连山西段大雪山的老虎沟12号冰川钻取了一支20.12m的浅冰芯,对冰芯中化学组成成分的浓度变化特征和来源分析进行了研究.结果表明,冰芯中δ18 O和可溶性离子含量变化均显示了明显的周期性变化,δ18 O与祁连山西段温度有很好的正相关关系.通过相关分析和HYS-PLIT后向轨迹分析表明,老虎沟12号冰川...     

2000-2014年祁连山西段老虎沟12号冰川高程变化

祁连山冰川自1990s以来持续萎缩,冰川融水径流变化对邻近的干旱区水资源产生重要影响。以往遥感与实测研究显示祁连山西段老虎沟12号冰川面积减少、末端退缩、运动速度降低及平衡线高度升高。为了进一步验证老虎沟12号冰川变化规律,利用高分辨率TerraSAR-X/TanDEM-X微波影像数据,与SRTM-C DEM进行差分干涉,得出老虎沟12号冰川2000-2014年高程年平均变化值为（-0.29±0.09）m·a^-1。为了验证遥感观测结果,利用RTK-GPS对老虎沟12号冰川表面进行测高,并与SRTM-C DEM上相应点的高程值进行比较,计算测量点的高程年变化值,结果显示两种方法获得的年平均变化值之间具有很好的正相关性,表明利用TerraSAR-X/TanDEM-X微波影像数据及差分干涉技术监测祁连山冰川高程变化具有较好的可行性。     

青藏高原东南部贡嘎山海螺沟冰川冰下沉积物形成与变形

冰岩界面的冰川动力学是冰川系统的重要组成部分, 海螺沟冰川地处温暖湿润的海洋环境, 冰川运动速度较快, 冰川底部接近压融点, 是研究冰下过程的较理想地点. 在海螺沟冰川大型磨光面上浅显侵蚀坑内发现了碎屑物质. 对碎屑物质理化特征研究表明: 粒度特征、地球化学与石英砂SEM 分析表明沉积在冰岩界面上的物质来自于冰川底部的底碛层, 而不是冰上环境的产物. 偏光显微镜下观察到的冰下沉积物呈现出一系列塑性变形(微旋转、褶皱)和脆性变形(线性结构、支撑结构、断层)微观结构和构造. 两种变形结构的存在是碎屑物质在形成过程中其含水量波动情况的反映. 冰下碎屑物质是冰下融出、滞碛作用的共同产物. 在整个冰下碎屑物质形成与变形过程中, 由于冰下水系季节性变化带来的冰岩界面上冰川融水含量的波动起了决定性作用.     

天山乌鲁木齐河源一号冰川探地雷达测厚及其数据分析

探地雷达是一种利用电磁波的反射原理探测地下介质分布特征的地球物理勘探技术，在冰川研究中发挥了重要作用。在天山一号冰川上用探地雷达进行了探测，获得了能够清晰地分辨冰一岩界面的雷达剖面。根据这些雷达剖面读出冰厚值，再结合最新的冰川地形图，作出了天山一号冰川的冰厚等值线图和冰下地形图；并由天山一号冰川最新的表面积数据推算了冰储量。     

祁连山老虎沟12号冰川辐射各分量年变化特征

在资料比较稀少的山地冰川进行辐射收支研究对于揭示现代冰川发育的水热条件以及冰川与气候的相互关系具有重要意义.利用祁连山老虎沟12号冰川海拔5 040 m自动气象站资料,分析了2008年10月20日至2009年10月19日的辐射各分童年变化和平均日变化特征,结果表明:整年气温月平均值都高于冰川表面温度,大气是冰川的感热热...     

玉龙雪山白水1号冰川近地层气象要素变化特征

利用2011年10月1日至2012年9月30日玉龙雪山白水1号冰川海拔4 500 m气象观测资料,对位于我国最南、亚欧大陆距赤道最近的海洋型冰川区近地层气象要素基本特征进行了分析,并与同海拔大陆型冰川——祁连山老虎沟12号冰川区近地层气象要素进行了对比。研究表明：海洋型与大陆型冰川区气温逐时变化呈单峰单谷型分布,均表现出升温快降温慢的特点,观测点5 m层气温高于2 m层气温,二者差值日变化呈单峰型,峰值出现在北京时间12：00;受季风气候影响,研究区干季相对湿度小,湿季相对湿度大,年均相对湿度为73.3%,与相对湿度相比,研究区水汽压变化更受控于气温;两冰川区冬半年气压低,夏半年气压高,均表现为典型的"高山型"气压;受冰川"冷效应"影响研究区干季风速大,湿季风速小,因冰川规模较小,研究区冰川风不发达,谷风发育强劲;受季风期云雨影响,白水1号冰川区总辐射在季风前期达到最大值,季风期达到极小值,年均总辐射量低于老虎沟12号冰川同海拔地区。     

点状不良地质体钻孔雷达响应特征 ——围岩及充填效应正演分析

钻孔地质雷达探测是一种有效获取高分辨率深部岩体信息的井中地球物理方法。针对钻孔地质雷达探测工作中常见的空洞、岩溶和地下埋藏物等点状不良地质体,利用时域有限差分数值模拟方法,对岩土体内点状不良地质体围岩介质和充填状况进行了雷达响应正演研究,分析了这些点状不良地质体围岩介质和充填状况对钻孔地质雷达反射信号的影响。研究结果表明,围岩与空洞内充填物的相对介电常数相对值,决定着雷达反射剖面信号的强弱对比,介电常数相对值较大时,更易确定目标地质体的前、后部界面位置,而低阻围岩的雷达波信号大部分被围岩介质吸收,通过单孔反射方法几乎不可能探测到空洞的存在。通过反射信号强度和正负相反射特性及其强弱变化,可以定性地判断空洞内填充物质的性质。     

基于Sr-Nd同位素研究祁连山老虎沟冰川区冰尘和粒雪粉尘来源

沉降在冰川表面的粉尘与微生物作用形成冰尘,冰尘能够降低冰川表面反照率,进而加速冰川消融。基于2012年和2014年夏季在祁连山老虎沟12号冰川采集的粒雪和冰尘样品,应用Sr-Nd同位素示踪手段研究了其Sr-Nd同位素组成的空间变化以及来源。研究获得了老虎沟12号冰川表面冰尘Sr-Nd同位素在冰川区不同海拔的空间分布特征,发现粒雪中的粉尘主要来源于柴达木沙漠、塔克拉玛干沙漠和巴丹吉林沙漠,而冰尘中同位素示踪发现其来源不同于粒雪,主要来源于该冰川区局地粉尘以及周边的青藏高原地表风化物。Sr-Nd同位素组成也反映了祁连山冰川区大气风尘传输的复杂环流信息。     

1958-2005年祁连山老虎沟12号冰川变化特征研究

老虎沟12号冰川是祁连山最大的冰川, 面积为21.9 km2, 为极大陆型冷性复式山谷冰川. 该冰川监测开始于1958年, 1962年监测被迫终止;其后于20世纪70-80年代有过短期考察, 2005年恢复全面观测. 基于野外GPS观测, 两期1∶50 000地形图和两期1∶10 000地形图及Landsat ETM 遥感影像, 分析了过去近50 a来多时间段冰川的变化特征及其对气候变化的响应过程. 结果表明: 1957-1976年间冰川退缩约100 m, 平均退缩速率5 m·5a-1, 此后冰川归于平稳态; 1985-2005年间冰川退缩140.12 m, 退缩速率较之前(1957-1976年)提高了40.2%. 结合玉门镇气象资料分析认为, 升温幅度的增大是影响20世纪90年代中期以来老虎沟12号冰川退缩加剧的根本原因, 冰川在持续高温情景下的气候响应要敏感于低温情景.     

Imaging the debris internal structure and estimating the effect of debris layer on ablation of Glacier ice

This study is a comparative investigation of the debris layer and underlying ice of the Koxkar Glacier using multi-frequency GPR with antennae having different frequencies. Together with analysis of the fluctuation of the radar signal amplitude and polarity, the debris layer and underlying ice were analyzed on the basis of high-resolution GPR images. It was found that the optimal average velocity in the shallow layer (0–4 m) is 0.06 m/ns. Images obtained with different frequency antennas have different characteristics; and the performance of the 200 MHz antenna for a debriscovered glacier is the best. The interpretation of typical GPR image is validated by using FDTD numerical model. Combining the debris layer thickness and the underlying ice structure, the effect of debris layer on ablation of glacier ice and forecast of the glacier change in the aspect of thickness-thinning and glacier retreat can be estimated. This study can provide as a reference to the formation mechanisms and estimation of the ice volume of glaciers covered by debris.     

藏东南嘎隆拉冰川表碛冻融过程与零点幕效应

冰川表碛区冻融过程的观测分析有助于厘清各层之间能量和水分传输的关系,从而为构建相应的能量平衡模型以及冰川径流模型提供理论支持。基于2015年10月至2016年11月嘎隆拉冰川表碛区自动气象站气象资料,对表碛区冻融过程进行分析,结果表明：表碛中出现冻土中常见的秋季和春季零点幕效应,秋季零点幕持续时间32天,春季零点幕持续58天;春季零点幕期间,气温和地表温度均呈现清晨低,午后高的日变化特征,而表碛层内温度没有明显的日变化特征,其体积含水率呈“脉冲式”变化;春季零点幕效应结束,底层冻结层破坏后,冰川冰消融才开始;嘎隆拉冰川表碛对冰川冰消融的影响不仅是因为表碛较厚,在消融量上抑制了冰川冰的消融,而且更重要的是表碛产生零点幕效应,延迟了表碛下冰川冰开始消融的日期,在时间上抑制了冰川冰消融。     

萨吾尔山木斯岛冰川厚度特征及冰储量估算

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.      

西天山托木尔峰南麓大型山谷冰川冰舌区消融特征分析

基于对托木尔峰南麓托木尔型山谷冰川的野外考察和典型冰川的定位观测,对冰面被表碛广泛覆盖的所谓“托木尔型”冰川冰舌区表碛与冰面消融的关系进行了研究. 结果表明：表碛对冰面消融、冰川水文过程、冰川变化等均具有重要影响,当表碛厚度超过3 cm时,表碛对冰面消融就产生明显抑制作用,且随着厚度增加,冰面消融显明减弱. 科其喀尔冰川表面的观测表明,由末端向上,表碛厚度逐渐减薄. 受表碛影响,科其喀尔冰川区最大的消融量出现在海拔3 800~3 900 m之间、表碛物厚度小于10 cm的区域内;冰川消融强度由此向上随着海拔的升高而下降,向下随表碛厚度的增大而减弱. 冰面湖的发育是表碛覆盖冰川的又一主要特征,湖水对冰面的融蚀和快速排泄成为冰面产汇流的主要过程. 科其喀尔冰川研究表明,两三个冰面湖排泄形成的融蚀冰量就相当于冰川末端退缩造成的冰量损失. 因此,冰面湖等热喀斯特地形的形成、扩张融蚀、融穿排泄、形成湖区低地,这一周而复始的过程不仅是其主要消融方式之一,而且也强烈的影响着冰川水文及冰川变化. 托木尔峰南麓地区大型冰川变化主要以厚度减薄为主,而不是像大多数冰川显著的变化主要表现在末端和面积减少方面.     

Glacier volume estimation from ice-thickness data,applied to the Muz Taw glacier,Sawir Mountains,China

In this work, ground penetrating radar (GPR) data, global position system (GPS) data, Landsat remote sensing images and digital elevation model (DEM) SRTM were used to study the Muz Taw glacier in the Sawir Mountains. By a variety of interpolation methods, spatial pattern of thickness of the Muz Taw glacier was obtained. The results show that there are obvious differences between the available GPR transverse profiles. The lower transverse profile has typical “U”-type topographic feature, the maximum glacier thickness is up to 116.4 m; glacier thickness distribution in the higher profile is relatively flat, with an average about 70–90 m. The longitudinal profile forms a ladder-like distribution, which in the middle of the ice bedrock topography has obvious depression. The average longitudinal ice thickness is about 80.89 m; the maximum ice thickness is up to 122.61 m. In addition, the preliminary estimation of the average thickness and total terminus ice volume were approximately 60.5 m and 0.195 km³, respectively.     

Changes of the Hailuogou Glacier, Mt. Gongga,China, against the Background of Global Warming in the Last Several Decades

Great change, associated with global warming, has occurred at the Hailuogou (海螺沟)has retreated 1 822 m in the past 106 years, with an annual mean retreat of 17.2 m, and the front elevation has risen by 300 m since 1823. Comparison of glacier variations and temperature fluctuations in China and the Northern Hemisphere, over the last 100 years, indicates that glacier retreat stages occurred during the warm phase, and vice versa. Mass balance records during 1959/60--2003/04 have shown that the glacier has suffered a constant mass loss of snow and ice. The accumulated mass balance, -10.83 m water equivalent, indicates an annual mean value of -0.24 m water equivalent. The correlation between the mass balance and temperature is significant, which also indicates that climate warming is the crucial cause of glacier loss.Local hydrological and climatic data demonstrate that runoff from the glacier has been increasing both seasonally and annually.The correlation analysis and trend analysis indicate that ice and snow melted water is the main cause of an increase in the runoff. As the climate has become warmer, changes in the glacier surface morphology have obviously occurred. These include a decrease in glacier thickness, enlargement of glacial caves, and reduction of the size of clefts on the glacier surface. The ablation period has lengthened and the ablation area has expanded. A variety of factors thus provide evidence that the Hailuogou glacier has suffered a rapid loss of snow and ice as a result of climatic warming.     

Internal structure and significance of ice‐marginal moraine in the Kebnekaise Mountains,northern Sweden

Despite a long history of glaciological research, the palaeo‐environmental significance of moraine systems in the Kebnekaise Mountains, Sweden, has remained uncertain. These landforms offer the potential to elucidate glacier response prior to the period of direct monitoring and provide an insight into the ice‐marginal processes operating at polythermal valley glaciers. This study set out to test existing interpretations of Scandinavian ice‐marginal moraines, which invoke ice stagnation, pushing, stacking/dumping and push‐deformation as important moraine forming processes. Moraines at Isfallsglaciären were investigated using ground‐penetrating radar to document the internal structural characteristics of the landform assemblage. Radar surveys revealed a range of substrate composition and reflectors, indicating a debris‐ice interface and bounding surfaces within the moraine. The moraine is demonstrated to contain both ice‐rich and debris‐rich zones, reflecting a complex depositional history and a polygenetic origin. As a consequence of glacier overriding, the morphology of these landforms provides a misleading indicator of glacial history. Traditional geochronological methods are unlikely to be effective on this type of landform as the fresh surface may post‐date the formation of the landform following reoccupation of the moraine rampart by the glacier. This research highlights that the interpretation of geochronological data sets from similar moraine systems should be undertaken with caution.     

Rock glaciers and block fields,review and new data

Tongue-shaped and lobate rock glaciers are recognized in most alpine regions today. For the tongue-shaped, two situations emerge: those with buried glacier ice (debris-covered glaciers) called ice-cored rock glaciers, and those with interstitial ice known as ice-cemented rock glaciers. Those with ice cores are revealed by depressions between rock glacier and headwall cliff (where a former glacier melted), longitudinal marginal and central meandering furrows, and collapse pits. Ice-cemented rock glaciers ordinarily do not possess these features. As applied to 18 rock glaciers in the Colorado Front Range, 11 of 12 east of the Continental Divide are ice-cored, 6 west of the Divide are ice-cemented. The majority of lobate rock glaciers in the Colorado Front Range are on the south sides of valleys, and, except for talus, are the most voluminous form of mass wasting. All those active and above treeline have characteristics common to all rock glaciers. In addition, they originate from talus, contain interstitial ice, move outward from valley walls at 1–6 cm/yr, and transport more debris as a process of erosion than heretofore realized. Block fields and block slopes, in polar and alpine regions, are thin accumulations of angular to subrounded blocks, on bedrock, weathered rock, or transported debris. They extend along slopes parallel to the contour. Block streams are similar but extend downslope normal to the contour and into valleys. They are made of interlocked blocks without interstitial detritus, but many have finer material deeper inside. The fabric of surface blocks indicates that motion most likely occurred during a periglacial time when interstitial debris, now washed or piped out, permitted movement of the whole deposit.     

天山南坡科其喀尔冰川消融区运动特征分析

基于2009年5月至2011年10月科其喀尔冰川的花杆观测资料,对其消融区的表面运动特征进行分析. 结果表明：冰川消融区的年水平运动速度最大值为86.69 m·a^-1,年垂直运动速度最大值为15.34 m·a^-1,均出现在冰川海拔4 000~4 200 m的消融区上部;在靠近冰川末端的冰舌下部,受冰量补给减弱、厚层表碛覆盖等影响,冰川运动缓慢,年水平运动速度小于5 m·a^-1,而垂直运动速度值小于2 m·a^-1. 大多数横剖面的水平运动速度具有从中部向边缘逐渐减小的特征,而有的剖面却出现局部速度增大的区域. 整体而言,冰川水平及垂直运动速度随海拔降低而减小,符合冰川运动的一般规律,但主要受地形作用的影响,垂直运动速度随海拔的变化会出现波动. 消融期月水平运动速度与同期气温和降水的变化具有一定的相关性,可能反映出气候快速变化对冰川运动的影响.