2000—2014年喀喇昆仑山音苏盖提冰川表面高程变化

喀喇昆仑山区冰川由于存在正物质平衡或跃动、前进现象，被称之为“喀喇昆仑异常”，不过该地区冰川变化差异显著，尤其是大型表碛覆盖冰川，呈现与其他类型冰川明显的差异性响应，为理解喀喇昆仑冰川异常的机理，冰川尺度的详细变化研究十分必要。音苏盖提冰川位于喀喇昆仑山乔戈里峰北坡，是中国面积最大的冰川，是典型的大型表碛覆盖冰川。通过应用TanDEM-X/TerraSAR-X（2014年2月）与SRTM-X DEM（2000年2月）的差分干涉测量方法计算音苏盖提冰川表面高程变化，并结合冰川表面流速对冰川表面高程变化和跃动进行分析和讨论。结果表明：2000—2014年音苏盖提冰川表面高程平均下降了1.68±0.94 m，即冰川整体厚度在减薄，年变化率为-0.12±0.07 m·a^-1。冰川表面高程变化分布不均，其中南分支（S）冰流冰川整体减薄较为显著，冰川南分支冰流运动速度较快，前进/跃动的末端占据了冰川的主干，阻滞原主干冰川物质的向下运移（跃动），导致原主干冰舌表面高程上升；冰川厚度减薄随着海拔升高先下降后保持稳定，同时呈现一定的波动性；低海拔表碛区域消融大于裸冰区，可能存在较薄表碛，因热传导高、覆盖大量冰面湖塘和冰崖存在，加速了冰川消融；在坡度小于30 °的区域，冰川厚度减薄随着坡度的减小而加剧；坡向朝南冰川厚度略微增加（0.01 m），西南坡向冰川厚度略微减薄（-0.03 m），其他坡向冰川厚度减薄明显。近14 a来，表碛覆盖的音苏盖提冰川表面高程整体下降表明物质处于亏损状态，冰川跃动导致局部冰川表面高程的增加。     

无人机在冰川变化监测中的应用——以唐古拉山小冬克玛底冰川为例

近年来,无人机技术发展迅速。无人机的灵活、便携、超高分辨率等特性使其在冰川变化监测上具有很好的发展前景。论文以青藏高原腹地的唐古拉山小冬克玛底冰川为例,首次在海拔5400 m以上的地区开展了无人机航测,通过非冰川区的基岩对2019年7月20日、2019年9月27日和2020年7月16日3期航测产品进行相对校正,分析了小冬克玛底冰川在物质平衡年和消融期内的变化情况,并进一步讨论了无人机在冰川区观测时所遇到的问题及其优势,以期为后续研究提供参考。结果表明:利用无人机技术能够实现冰川在消融期内的末端、面积以及高程变化监测,并对冰川的细部特征进行分析,适合于小区域单条冰川的变化监测。     

1990-2019年贡嘎山地区典型冰川表碛覆盖变化及其空间差异

表碛覆盖型冰川是中国西部较为常见的冰川类型。表碛层存在于大气—冰川冰界面,强烈影响大气圈与冰冻圈之间的热交换。表碛厚度的空间异质性可极大地改变冰川的消融率和物质平衡过程,进而影响冰川径流过程和下游水资源。基于Landsat TM/TIRS数据,运用能量平衡方程反演了贡嘎山地区冰川表碛厚度,研究了贡嘎山地区冰川在1990—2019年间表碛覆盖范围及厚度变化情况,同时对比了东西坡差异。结果表明：① 贡嘎山地区冰川表碛扩张总面积达43.824 km²。其中,海螺沟冰川扩张2.606 km²、磨子沟冰川1.959 km²、燕子沟冰川1.243 km²、大贡巴冰川0.896 km²、小贡巴冰川0.509 km²、南门关沟冰川2.264 km²,年均扩张率分别为3.2%、11.1%、1.5%、0.9%、1.0%和6.5%;② 海螺沟冰川、磨子沟冰川、燕子沟冰川、大贡巴冰川、小贡巴冰川、南门关沟冰川表碛平均增厚分别为5.2 cm、3.1 cm、3.7 cm、6.8 cm、7.3 cm和13.1 cm;③ 西坡冰川表碛覆盖度高,表碛覆盖年均扩张率低,冰川末端退缩量小;东坡冰川表碛覆盖年均扩张率高,但表碛覆盖度总体低于西坡,冰川末端退缩量大。     

表碛覆盖冰川信息提取方法——以波密县为例

针对表碛覆盖冰川提取困难的问题,本文结合TM影像、DEM和野外调查资料,基于地物光谱、地形和纹理特征,将研究区分为表碛覆盖冰川区、无表碛覆盖冰川区和阴影下冰川区,采用模糊逻辑方法建立定量化提取规则,综合利用了面向对象和波段比值两个方法的各自优点,建立面向对象-波段比值信息提取方法,进行了有无表碛物覆盖的冰川信息的分区提取,并以波密县为典型研究区,通过混淆矩阵进行精度分析。研究结果表明:1)提出的面向对象—波段比值法,能够较完整地提取研究区表碛覆盖冰川,精度可达93%,冰川信息提取总体精度为98%,kappa系数为0.97;2)研究区冰川总面积为7 655.27 km~2,占研究区总面积的46.18%,无表碛覆盖冰川、表碛覆盖冰川、阴影下冰川面积分别为5615.20 km~2、65.13 km~2、1 974.94 km~2,占总冰川73.35%、0.85%、25.80%。初步建立的表碛覆盖冰川自动信息提取方法可以为类似地区冰川遥感监测提供依据和参考。     

东帕米尔高原冰川运动特征分析

冰川运动控制着冰量输送变化,为冰川变化和冰川灾害研究提供重要信息。为了探讨东帕米尔高原冰川运动特征及其影响因素,基于ITS_LIVE和GoLIVE分析了不同规模、不同地形条件、表碛/非表碛区域的冰川运动速度状况。研究结果表明:(1)东帕米尔高原冰川平均运动速度为5.31 m·a^-1,冰川运动速度与冰川规模相关,表现为大冰川比小冰川运动快;(2)冰川运动速度与平均坡度相关,表现为随平均坡度增加先增后减,坡度过大不利于冰川积累,表现为厚度(规模)小,则速度慢。(3)西南(8.69 m·a^-1)、东南(11.67 m·a^-1)坡向的冰川运动速度大于其它坡向的冰川运动速度,与各个坡向的冰川规模相关。(4)表碛覆盖型冰川的运动速度小于非表碛覆盖型冰川,表碛对冰川运动速度起到抑制作用。(5)1989-2018年东帕米尔高原冰川运动速度表现稳定,与冰川年际变化稳定相对应。消融期冰川运动速度小于其它季节,与年内冰川厚度变化相关。     

1990—2015年喜马拉雅山冰川变化的遥感监测

基于Landsat系列遥感数据,运用比值阈值法（B3/B5）和目视解译,研究1990—2015年喜马拉雅山冰川面积的分布与变化特征。结果表明：25年间研究区冰川面积共减少2553.10 km²,年均退缩率为0.44%/a,研究时段冰川加速退缩。研究区冰川主要分布在西段地区,中段次之,东段最少,近25年来西段、东段和中段地区冰川均表现为退缩趋势,其中东段地区退缩最快,中段最慢。从地形分布和变化特征看,5°~25°范围内冰川的分布面积较多,近25年来各坡度等级冰川均在退缩,其中25°~30°之间冰川面积退缩较快,在极平缓/极陡峭地区退缩较慢。尽管8个坡向上冰川均表现为退缩趋势,但退缩幅度有所差异,北坡与西北坡冰川退缩较慢,其他坡向退缩较快。研究时段表碛物覆盖型与非表碛物覆盖型冰川均在退缩,但后者的退缩幅度较大,表明研究区表碛物在一定程度上抑制了冰川消融。     

基于无人机影像的冰面流速与高程变化提取方法

无人机遥感能够获取高精度、高分辨率的冰川表面三维形态,有助于揭示冰川的运动和消融变化,现已成为冰川变化监测的重要技术支撑。针对无人机高分辨率影像能够有效识别表碛覆盖型冰川表面细节特征点的优势,本文引入金字塔影像集和最小二乘匹配方法联合开展特征点的追踪,用以实现冰川表面特征点三维位移场提取和动态变化分析。以贡嘎山贡巴冰川冰舌区作为典型研究区域,利用高分辨率无人机影像生成消融期前后（2018年6月9日和10月17日）的正射影像数据和数字表面模型,基于2期正射影像提取冰川表面特征点并实施追踪以获得三维位移场,在此基础上初步探明贡巴冰川冰舌段表面位移速率最大为7.51 cm/d,垂向消融速率超过11 cm/d。本文相关研究数据和结果可为冰川及复杂地形山区地质灾害的监测提供参考。     

坡度和粗糙度对ICESat-GLAS回波特征及其光斑脚点高程误差的影响研究

为评价ICESat-GLAS数据在青藏高原地区冰川表面高程变化中的不确定性,采用GLA01产品和GLA14产品,基于SRTM DEM数据所派生的冰川区和非冰川区表面坡度、粗糙度数据,利用多元线性回归关系模型分析了表面粗糙度、坡度对GLAS光斑脚点高程的不确定误差。结果表明:当GLAS光斑脚点坡度小于10°时,GLAS光斑脚点高程偏差为0.1m,且高程偏差随着坡度的增加而增大。在受坡度和粗糙度影响复杂地形下,GLAS光斑的回波展宽较大,不确定性偏差为0.3m。此外,冰川区GLAS光斑脚点高程误差可通过高斯滤波进行展宽偏差校正,但当冰川表面坡度大于45°时,相应的GLAS光斑脚点高程在冰川表面高程变化估算中不可用。在后续的研究中,需考虑冰川运动、GLAS回波在冰雪表面渗透对冰川DEM高程精度以及GLAS光斑脚点水平位移的高程偏差影响。     

近40 a来天山台兰河流域冰川资源变化分析

台兰河流域作为阿克苏河的支流,是以冰川融水补给为主的河流,流域面积为1 324 km²。结合1：5万地形图、Landsat ETM+遥感影像及数字高程模型数据,通过综合计算机自动解译及目视解译的方法,将面向对象图像特征提取方法应用到该流域冰川信息提取中,并以影像叠加数字高程模型来提取表碛覆盖区的冰川末端边界,最后参照专家指导意见进行边界的再次修订,得到1972~2011年该流域的冰川变化数据,并分析了过去近40 a来冰川变化特征及其对气候变化的响应过程。结果表明：1972~2011年,台兰河流域冰川退缩明显,冰川总面积从435.44 km²退缩到385.38 km²,减少了50.06 km²,退缩率为11.50%,年均减少约1.25 km²,平均单条冰川面积减小0.31 km²;冰川总条数从113条减少到109条,消失冰川10条,有3条冰川分离成了9条,其余100条冰川都呈减小趋势。结合阿克苏和拜城气象站气象资料分析认为,台兰河流域冰川萎缩与该地区气温快速上升关系密切,气温上升导致的冰川消融在一定程度上抵消了降水增加对冰川的补给。     

中喀喇昆仑布拉尔杜冰川近期跃动分析

喀喇昆仑山分布有众多的跃动型冰川,跃动机理存在异质性。使用Landsat、Sentinel-1A、TSX/TDX等多源遥感数据,获取了中喀喇昆仑布拉尔杜冰川在跃动期间冰川表面高程和表面流速变化。结果表明：布拉尔杜冰川从2006年开始,流速逐渐增加;到2013年之后进入快速运动期,最高流速可达4.9 m·d^-1;2015年8月底,冰川表面速度急剧下降,随后保持较低的流速至2016年1月,而后流速再次增加,到同年2月初便进入平静期。2000—2014年冰川主干中上游有明显隆起,而冰川接收区明显减薄,最大减薄达89 m;2014—2018年冰川主干中上游以及各支流均有不同程度的减薄,冰川主干的接收区高程显著增加,最大增厚120 m。根据冰川表面高程变化以及流速变化的特征,认为布拉尔杜冰川的支流引发了此次跃动,且本次跃动受水文机制的影响较大;结合现有的数据和文献,推断布拉尔杜冰川的跃动间隔约为40 a;为喀喇昆仑冰川跃动研究提供更多的实例,也可为此区域冰川灾害预警研究提供参考。     

STRUCTURAL GLACIOLOGY OF A TEMPERATE MARITIME GLACIER: LOWER FOX GLACIER,NEW ZEALAND

This paper describes the structural glaciology of the lower Fox Glacier, a 12.7 km‐long valley glacier draining the western side of the Southern Alps, New Zealand. Field data are combined with analysis of aerial photographs to present a structural interpretation of a 5 km‐long segment covering the lower trunk of the glacier, from the upper icefall down‐glacier to the terminus. The glacier typifies the structural patterns observed in many other alpine glaciers, including: primary stratification visible within crevasse walls in the lower icefall; foliation visible in crevasses below the lower icefall; a complex set of intersecting crevasse traces; splaying and chevron crevasses at the glacier margins; transverse crevasses forming due to longitudinal extension; longitudinal crevasses due to lateral extension near the snout; and, arcuate up‐glacier dipping structures between the foot of the lower icefall and the terminus. The latter are interpreted as crevasse traces that have been reactivated as thrust faults, accommodating longitudinal compression at the glacier snout. Weak band‐ogives are visible below the upper icefall, and these could be formed by multiple shearing zones uplifting basal ice to the glacier surface to produce the darker bands, rather than by discrete fault planes. Many structures such as crevasses traces do not show a clear relationship with measured surface strain‐rates, in which case they may be ‘close to crevassing’, or are undergoing passive transport down‐glacier.     

Debris-covered Glaciers and Rock Glaciers in the Nanga Parbat Himalaya, Pakistan

The origin and mobilization of the extensive debris cover associated with the glaciers of the Nanga Parbat Himalaya is complex. In this paper we propose a mechanism by which glaciers can form rock glaciers through inefficiency of sediment transfer from glacier ice to meltwater. Inefficient transfer is caused by various processes that promote plentiful sediment supply and decrease sediment transfer potential. Most debris‐covered glaciers on Nanga Parbat with higher velocities of movement and/ or efficient debris transfer mechanisms do not form rock glaciers, perhaps because debris is mobilized quickly and removed from such glacier systems. Those whose ice movement activity is lower and those where inefficient sediment transfer mechanisms allow plentiful debris to accumulate, can form classic rock glaciers. We document here with maps, satellite images, and field observations the probable evolution of part of a slow and inefficient ice glacier into a rock glacier at the margins of Sachen Glacier in c. 50 years, as well as several other examples that formed in a longer period of time. Sachen Glacier receives all of its nourishment from ice and snow avalanches from surrounding areas of high relief, but has low ice velocities and no efficient system of debris removal. Consequently it has a pronounced digitate terminus with four lobes that have moved outward from the lateral moraines as rock glaciers with prounced transverse ridges and furrows and steep fronts at the angle of repose. Raikot Glacier has a velocity five times higher than Sachen Glacier and a thick cover of rock debris at its terminus that is efficienctly removed. During the advance stage of the glacier since 1994, ice cliffs were exposed at the terminus, and an outbreak flood swept away much debris from its margins and terminus. Like the Sachen Glacier that it resembles, Shaigiri Glacier receives all its nourishment from ice and snow avalanches and has an extensive debris cover with steep margins close to the angle of repose. It has a high velocity similar to Raikot Glacier and catastrophic breakout floods have removed debris from its terminus twice in the recent past. In addition, the Shaigiri terminus blocked the Rupal River during the Little Ice Age and is presently being undercut and steepened by the river. With higher velocities and more efficient sediment transfer systems, neither the Raikot nor the Shaigiri form classic rock‐glacier morphologies.     

A surge of Skobreen, Svalbard

Surging glaciers are common in Svalbard yet relatively few glaciers have been observed during a surge. This paper presents observations of the currently surging glacier Skobreen, in southern Spitsbergen. The study is based on examinations of new and archival photographs and maps. Skobreen, an 18 km² valley glacier terminating into the lower part of the glacier Paulabreen, has not been registered previously as a surging glacier. Skobreen experienced a build-up in its upper part, while there has been a lowering of the surface in the terminal region. Photographs from 1990 show incipient crevassing in the upper part. Photographs from 2003 show a slight advance of the terminus and marginal crevassing, indicating an initiation period of about 15 years for a surge of this glacier. In June 2005 transverse crevassing appeared in the upper part of the glacier, while the middle section moved as a block with strong shear margins and a pronounced drawdown of the ice surface. No traces of a surge front could be seen in the crevasse pattern. However, the crevasse pattern indicates an initiation area in the transition zone between the transverse crevassing in the upper part and the block of ice in the middle region.     

RESPONSE OF A TEMPERATE ALPINE VALLEY GLACIER TO CLIMATE CHANGE AT THE DECADAL SCALE

Glacier advance and recession are considered key indicators of climate change. Understanding the relationship between climatic variations and glacial responses is crucial. Here, we apply archival digital photogrammetry to reconstruct the decadal scale glacial history of an unmonitored Alpine valley glacier, the Haut Glacier d'Arolla, Switzerland, and we use the data generated to explore the linkages between glacier recession and climate forcing. High precision digital elevation models were derived. They show continual recession of the glacier since 1967, associated with long‐term climatic amelioration but only a weak reaction to shorter‐term climatic deterioration. Glacier surface velocity estimates obtained using surface particle tracking showed that, unlike for most Swiss glaciers during the late 1970s and early 1980s, ice mass flux from the accumulation zone was too low to compensate for the effects of glacier thinning and subsequent snout recession, especially during the rapid warming that occurred through the 1980s. The results emphasise the dangers of inferring glacier response to climate forcing from measurements of the terminus position only and the importance of using remote sensing methods as an alternative, especially where historical imagery is available.     

风景名胜区旅游垃圾实证研究——以梅里雪山雨崩村为例

旅游垃圾是人类旅游活动的伴生物、旅游业的副产品,也是旅游业不可忽视的环境问题。梅里雪山风景区生态脆弱,远离城市,位置偏僻,其环境的脆弱性使旅游垃圾影响更加显著,梅里雪山的垃圾已经成为当地一个非常严重的社会环境问题,影响到当地藏族村民的正常生活,从微观层面研究在生态脆弱地区、在特殊自然地理环境和社区背景下的旅游垃圾问题,寻找有效的解决途径。     

Estimate of Ablation Rate of Glacier Ice under a Supraglacial Debris Layer

The ablation rate under a debris layer is very difficult to measure directly at debris-covered glaciers, because the surface is highly heterogeneous, and the ablation rate varies tremendously from place to place. Heat budget considerations with a debris layer on top of glacier ice suggested that 'thermal resistance' of the debris layer could be estimated from surface temperature and the heat fluxes at the debris surface, and the ablation rate of the underlying glacier ice from the thermal resistance and meteorological data. The method was tested at the Lirung Glacier in Langtang Valley, Nepal Himalayas, using the thermal band of LANDSAT satellite for estimating surface temperature distribution of the debris top surface. The amount of melt water thus estimated was compatible with the observed discharge data from the glacier basin for periods of the monsoon season in 1985 and the pre-monsoon to the monsoon season in 1996. The investigation also revealed that the amount of discharge was much larger than the amount of precipitation over the basin, and it was suggested that the melt water from the debris-covered glacier contributes significantly to the river flow as a result of the shrinkage of the glacier.     

Seasonal variability in velocity and ablation of Te Moeka o Tuawe/Fox Glacier, south Westland, New Zealand

Abstract:  Seasonal variations in ablation and surface velocity were investigated on the lower Fox Glacier. Variations occur between summer and winter ablation, with surface velocity also showing marked seasonality. Recent advance has resulted in the glacier gaining around 200 m length since late 2004. Longer term, Fox Glacier appears linked to the Southern Oscillation Index, with positive glacier mass balances associated with negative Southern Oscillation Index (El Niño). An estimated glacier response time of approximately 9–14 years suggests the current terminus advance was linked to mass gains in the mid-1990s. Recent collapses at the terminal face continue to prove a hazard at this busy tourist destination.     

THE RESPONSE OF PARTIALLY DEBRIS‐COVERED VALLEY GLACIERS TO CLIMATE CHANGE: THE EXAMPLE OF THE PASTERZE GLACIER (AUSTRIA) IN THE PERIOD 1964 TO 2006

Long‐term observations of partly debris‐covered glaciers have allowed us to assess the impact of supra‐glacial debris on volumetric changes. In this paper, the behaviour of the partially debris‐covered, 3.6 km² tongue of Pasterze Glacier (47°05′N, 12°44′E) was studied in the context of ongoing climate changes. The right part of the glacier tongue is covered by a continuous supra‐glacial debris mantle with variable thicknesses (a few centimetres to about 1 m). For the period 1964–2000 three digital elevation models (1964, 1981, 2000) and related debris‐cover distributions were analysed. These datasets were compared with long‐term series of glaciological field data (displacement, elevation change, glacier terminus behaviour) from the 1960s to 2006. Differences between the debriscovered and the clean ice parts were emphasised. Results show that volumetric losses increased by 2.3 times between the periods 1964–1981 and 1981–2000 with significant regional variations at the glacier tongue. Such variations are controlled by the glacier emergence velocity pattern, existence and thickness of supra‐glacial debris, direct solar radiation, counter‐radiation from the valley sides and their changes over time. The downward‐increasing debris thickness is counteracting to a compensational stage against the common decrease of ablation with elevation. A continuous debris cover not less than 15 cm in thickness reduces ablation rates by 30–35%. No relationship exists between glacier retreat rates and summer air temperatures. Substantial and varying differences of the two different terminus parts occurred. Our findings clearly underline the importance of supra‐glacial debris on mass balance and glacier tongue morphology.     

近50 年来天山地区典型冰川厚度及储量变化

冰川储量变化与冰川水资源量变化以及冰川对河川径流的贡献量密切相关。在GPR-3S技术支持下, 本研究基于雷达测厚数据、不同时期的高分辨率遥感影像、地形图及实测资料, 分析了天山三个典型地区四条代表性冰川近期厚度及储量变化特征, 并通过对比探讨了造成变化差异的可能原因。结果表明, 1962-2006 年乌鲁木齐河源1 号冰川厚度平均减薄0.15m a^-1, 冰储量亏损26.2×10⁶ m³, 冰川末端平均退缩3.8 m a^-1;博格达峰南坡的黑沟8 号冰川在1986-2009 年间, 冰舌平均减薄0.57 m a^-1, 冰储量损失了25.5×10⁶ m³, 末端平均退缩11.0 m a^-1;位于博格达峰北坡的四工河4 号冰川在1962-2009 年间冰舌平均减薄0.32 m a^-1, 冰储量亏损14.0×10⁶ m³, 末端平均后退8.0 m a^-1;1964-2008 年间, 托木尔峰青冰滩72 号冰川冰舌平均减薄0.22 m a^-1, 由此至少造成冰储量亏损14.1×10⁶ m³, 末端退缩达40.0 m a^-1。对比分析显示, 青冰滩72 号冰川消融退缩最为强烈, 黑沟8 号冰川次之, 与乌鲁木齐河源1 号冰川、科其喀尔冰川相差不大, 稍大于四工河4 号冰川和哈密庙尔沟冰川。这种差异可能与区域气候变化和冰川物理特征有直接关系。