Study on the change of Keqikaer Glacier during the last 30 years,Mt. Tuomuer,Western China

Using radio echo sounder, ice thickness of Keqikaer Glacier tongue was measured in 1981 and 2004. Data obtained by comparing topographical maps, aerial and satellite photographs at different times, illustrates changes of the thickness and advance/retreat of Keqikaer Glacier. Keqikaer Glacier has been in intensive retreat since the 1990s and become thinner since the 1980s. Measured thickness of the ice tongue indicates reducing with a speed of 0.5–1.5 m a⁻¹ since 1981. The shrinkage of the glacier terminus is less than 2% of the total length during the last 30 years; however, the retreat of terminus position and the thinning of the ice thickness provides significant information that these glaciers on the south slope of Mt. Tuomuer are in an intensively decreasing phase in recent time.     

天山乌鲁木齐河源1号冰川消融期反照率特征

消融期冰川反照率特征研究对于深入理解冰川消融过程及其对气候变化的响应机理具有重要意义。利用Landsat卫星影像反演反照率数据,MODIS逐日反照率产品数据以及野外观测反照率数据,分析了天山乌鲁木齐河源1号冰川2016年消融期（5—8月）反照率时空变化特征。研究表明：消融早期,冰川反照率空间变化不明显;消融中后期,总体上呈现随海拔的升高而增大的趋势,在平衡线附近增速最快。消融期冰川反照率整体呈下降趋势,而且在6—7月份变化最为剧烈。平衡线附近反照率时间变化尤其显著,积累区次之,消融区最弱。冰川反照率的时空变化主要由冰面特征决定。气温和固态降水是其驱动因素。冰川反照率随气温的升高而降低,但固态降水会打破其随气温的变化趋势,引起反照率的增加。污化物显著降低冰面反照率,尤其在可见光波段（380~760 nm）。此外,即使冰面特征相对均一,反照率还呈现随太阳入射角的增大而增大的趋势,主要由冰川局部地形（坡度与坡向）差异所致。     

Radiocarbon wiggle-match dating of proglacial lake sediments – Implications for the 8.2 ka event

The problem of insufficient age-control limits the utilisation of the 8.2 ka BP event for modelling freshwater forcing in climate change studies. High-resolution radiocarbon dates, magnetic susceptibility and lithostratigraphic evidence from a lake sediment core from Nedre Hervavatnet located at Sygnefjell in western Norway provide a record of the early Holocene. We use the method of radiocarbon wiggle-match dating of the lake sediments using the non-linear relationship between the ¹⁴C calibration curve and the consecutive accumulation order of the sample series in order to build a high-resolution age-model. The timing and duration of Holocene environmental changes is estimated using 38 AMS radiocarbon dates on terrestrial macrofossils, insects and chironomids covering the time period from 9750 to 1180 cal BP. Chironomids, Salix and Betula leaves produce the most consistent results. Sedimentological and physical properties of the core suggest that three meltwater events with high sedimentation rates are superimposed on a long-term trend with glacier retreat between 9750 and 8000 cal BP. The lake sediment sequence of Nedre Hervavatnet demonstrates the following: only a reliable high-resolution geochronology based on carefully selected terrestrial macrofossils allows the reconstruction of a more refined and complex environmental change history before and during the 8.2 ka event.     

冰川及其径流对气候变化响应过程的模拟模型——以乌鲁木齐河源1号冰川为例

用冰川动力模型对乌鲁木齐河源１号冰川东支进行模拟计算结果表明：１号冰川东支在维持目前的气候变化水平下还将继续退缩到约１６００ｍ长度；若气温升高１℃，１号冰川将退缩为约只有３００ｍ长的悬冰川。随着冰川退缩，冰川冷却作用减弱，冰川区的升温将高于非冰川区。１号冰川目前的冰川径流是处在一个高值期（相对于它的稳定状态），若气候继续变暖，冰川径流还将继续增大，达到一峰值后将迅速减小。     

Geomorphology and sedimentology of the Caol Lairig valley,Scottish Highlands: evidence for local glacier margin advance and retreat during the Loch Lomond Stadial

A sedimentological investigation of new sections of Loch Lomond Stadial (LLS) age deposits is presented from Caol Lairig valley, located adjacent to Glen Roy, Lochaber, Scottish Highlands. The ice lobes in Caol Lairig and Glen Roy blocked local fluvial drainage systems forming lakes that cut shorelines, the ‘Parallel Roads of Glen Roy’ (Agassiz, 1840; Jamieson, 1863, 1892). Within Caol Lairig sediment sequences of proximal, distal and deltaic glaciolacustrine sediments and a subglacial till are reported. The till was deposited during ice advance into the valley and the different glaciolacustrine facies formed in the gap between the head of Caol Lairig and the receding ice margin. When the sediments are related to the shoreline and glacial geomorphological evidence, phases of ice advance and ice retreat and the concomitant changes in lake levels are identified. Initially ice retreat in Glen Roy and Caol Lairig was synchronous but after the fall to 325 m the ice in Glen Roy retreated more quickly than in Caol Lairig. Differences in the ice thickness and the lake water depth in Glen Roy and Caol Lairig may have lead to preferential calving of the Glen Roy ice margin hastening ice retreat.     

珠穆朗玛峰东绒布冰川厚度测量与地形特征分析

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).     

2010-2020年祁连山东段冷龙岭宁缠河1号冰川变化综合观测研究

冰川物质平衡研究对流域内水资源的分配和利用具有重要的指导意义.发源于祁连山的冰川融水是河西走廊和柴达木盆地重要的淡水来源.近年来,祁连山地区的冰川经历了不同程度的退缩,东段退缩尤其明显.基于祁连山东段冷龙岭地区宁缠河1号(NC01)冰川2010-2020年冰川物质平衡观测数据,结合Google Earth高分辨率历史影...     

帕米尔中部North Kyzkurgan冰川跃动变化遥感监测

跃动冰川作为一种特殊类型的冰川,蕴含着巨大的灾害风险,对其开展监测研究具有重要意义。本研究基于1973年以来的Landsat影像、ASTER立体像对和ITS_LIVE数据产品,监测分析了帕米尔中部North Kyzkurgan冰川在跃动前、跃动中、跃动后的面积、高程、流速变化,揭示了该冰川完整的跃动发生过程。结果表明：North Kyzkurgan冰川是一条典型的跃动冰川,在1973—2011年处于恢复阶;2011—2016年处于跃动阶;2016年之后重新进入恢复阶。North Kyzkurgan冰川所在地区气候寒冷,降雪量丰富,同时该冰川积累区面积比率超过0.8,冰川作用正差近1 000 m,因此冰川补给物质充足。在积蓄区物质积累、不断增厚的情况下,冰川底部达到压力熔点,融水不断增多,在融水的润滑和顶托作用下,最终导致冰川发生跃动。因此,North Kyzkurgan冰川跃动的发生主要与热力学因素有关。     

冰雪对珠峰北坡绒布河谷局地环流影响的数值试验

利用RAMS中尺度模式对珠峰北坡绒布河谷地区的局地环流进行了数值模拟,包括控制试验和敏感试验.观测结果表明,珠峰北坡绒布河谷地区午后盛行来自珠峰方向的偏南风,这与其他山区的山谷风日变化存在显著差异.与观测结果比较;模拟结果(控制试验)能够较好地再现绒布河谷中的偏南主导气流.模拟结果(敏感试验)还显示,在去除高大山体的冰雪下垫面后,绒布河谷地区下午仍可存在偏南气流,但偏南风出现时间明显滞后,此时该气流来自珠峰南坡的强劲偏南谷风气流.因此,我们认为珠峰北坡的冰雪表面对绒布河谷地区盛行的偏南气流存在很大影响,但热力驱动的山谷风环流也是维持该地区强烈下泄流的主要原因.     

科其喀尔冰川表碛区冰崖形态调查

采用随机抽样的方法对科其喀尔冰川表碛区冰崖的规模及形态进行了调查.在冰崖比较集中的表碛区东侧任意选取了20个冰崖,利用测绳、皮尺并结合GPS测量的方法对冰崖的长度和高度进行了调查,同时用地质罗盘对冰崖的坡向和坡度进行了测量,从而了解冰崖的长度、高度、坡面面积、坡向和坡度等形态特征及其关系.对冰崖形态的分析表明,消融区内冰崖的规模相差很大,且随着海拔高度的增加,冰崖规模有减小的趋势;这可能主要与地形起伏随海拔高度的差异性变化有关,消融区下部冰崖表面消融过程较为活跃也是一个重要的因素.通过对冰崖的坡向和规模之间的分析可以看到,坡向为NW和NNE方向的冰崖最多,其规模也较大,而太阳直接辐射是影响冰崖发育坡向和发育规模的重要因素.