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1.
At present, the mechanism research on glacial lake outburst mainly focuses on the ice quake and ice landslide, etc. To some glacial lakes, the seepage deformation is the dominant factor in outburst process. Taking the Yindapu Glacial Lake in Tibet as an example, using SEEP/W module of FEM software (GEO-STUDIO), the authors analyzed seepage stability of terminal moraine ridge dam. The leading role of seepage deformation in some glacial lake outburst mechanism is proposed and proved. 相似文献
2.
冰湖溃决灾害是指冰湖坝体突然破坏引发溃决洪水或溃决泥石流的现象,对下游人类活动和自然环境造成严重影响。近年来,藏东南地区冰川快速退缩,冰湖数量和规模显著增加,冰湖溃决事件广泛发生。基于1995-2021年多时相Landsat系列遥感影像、Sentinel-2A遥感影像,结合RAMMS水文动力学模型方法,对藏东南地区多依弄巴流域内冰湖、冰川进行动态变化分析,模拟冰崩危险体触发冰湖溃决和冰湖溃决泥石流的演进过程,根据泥石流模拟中的流速和流深对冰湖溃决可能影响的区域进行危险性分区。结果表明:流域内冰川面积由1995年的14.05 km2退缩为2021年的9.43 km2,年均退缩率约为0.15 km2/a。流域内共发育3处冰崩危险体,均可能触发冰湖溃决。潜在危险冰湖在全溃情况下,溃决泥石流会冲出沟口堵塞然乌湖湖口和帕隆藏布主河道,对下游居民和道路造成影响,影响范围约4.05 km2,其中高危险性区域约2.55 km2。危险性评价结果可为多依弄巴流域未来土地利用规划和防灾减灾提供依据,也能为藏东南地区冰湖溃决型泥石流危险评估提供参考。 相似文献
3.
以1972、1989、1996、2006、2017年5个不同时段的Landsat MSS/TM/ETM+/OLI遥感影像数据、数字高程模型（DEM）数据和气象数据为数据源,通过计算机自动提取与人工目视解译相结合的方法获取南阿尔泰山中部地区各时段的冰湖信息,利用GIS空间分析方法对该地区的冰湖面积进行统计,并分析研究区冰湖在不同规模、不同坡度、不同海拔状态下的时空变化特征。结果表明:①近45年来南阿尔泰山中部地区的冰湖面积呈"先减后增"趋势。1972-1996年研究区的冰湖面积从411.14 km2减少至400.83 km2,共减少了10.31 km2,减少速率为0.43 km2/a。从1996-2017年冰湖面积增加了15.42 km2;增长率为0.514 km2/a。②研究区冰湖分布主要集中在海拔低于2 200 m、坡度小于25°的区域,不同海拔区间和不同坡度区间的冰湖面积均呈"先减后增"趋势。③结合气温、降水、冰川面积以及冰储量变化数据分析发现,南阿尔泰山中部地区冰湖对气候变化具有明显的响应。温度、降水量及冰川融水是影响冰湖面积变化的主要因素;且这三者之间存在一种平衡关系,即温度升高冰川消融速度加快,从而对冰湖的收支平衡产生直接影响。当冰湖的补给量（即冰川融水和降水量之和）大于由温度升高引起的蒸发量时,冰湖面积会呈增长趋势;反之亦然。1970-1980年整个阿勒泰地区年代际降水量减少了19.28 mm,温度上升了0.25℃,因此1972-1989年研究区冰湖的蒸发水量大于补给水量,导致该时段冰湖面积呈退缩态势。1989-1996年该区降水量增加了19.67%,温度升高了0.62℃,但是增加的降水量却无法弥补由温度升高引起的冰湖蒸发量,因此1989-1996年研究区冰湖面积仍处于退缩状态。1996-2017年由于温度和降水量大幅增加导致冰湖面积呈不断增长趋势。 相似文献
4.
With the global warming,the disasters of Glacier Lake Outburst Flood(GLOF) have taken place frequently in Tibet in recent years and attracted more and more attention.A systematic survey was conducted on the 19 GLOFs in Tibet to study their two main mechanisms.Investigations indicated that all the events occurred in end-moraine lakes,and the outburst occurred partially and instantly.And the breach had the shape of an arc or a trapezoid in overflow outburst and its top width was 3-5 times more than the height.The two main mechanisms of GLOFs in Tibetan end-moraine Lake were overflow and piping,and the overflow mechanism caused by iceberg collapse was dominated in most cases.A formula was proposed to calculate the critical thickness of iceberg tongue that determines the collapse.Granular analysis of the moraine materials revealed that seepage deformation is crucial in the outburst process.Finally,we conducted a case study of the Guangxiecuo Lake to show its possible process of outburst and estimated the peak discharge of the resulted flood. 相似文献
5.
Finu Shrestha Xiao Gao Narendra Raj Khanal Sudan Bikash Maharjan Rajendra Bahadur Shrestha Li-zong Wu Pradeep Kumar Mool Samjwal Ratna Bajracharya 《山地科学学报》2017,14(10):1969-1984
Changes in glacial lakes and the consequences of these changes, particularly on the development of water resources and management of glacial lake outburst flood(GLOF) risk, has become one of the challenges in the sustainable development of high mountain areas in the context of global warming. This paper presents the findings of a study on the distribution of, and area changes in, glacial lakes in the Koshi basin in the central Himalayas.Data on the number of glacial lakes and their area was generated for the years 1977, 1990, 2000, and 2010 using Landsat satellite images. According to the glacial lake inventory in 2010, there were a total of 2168 glacial lakes with a total area of 127.61 km~2 and average size of 0.06 km~2 in the Koshi basin. Of these,47% were moraine dammed lakes, 34.8% bedrock dammed lakes and 17.7% ice dammed lakes. The number of glacial lakes increased consistently over the study period from 1160 in 1977 to 2168 in 2010, an overall growth rate of 86.9%. The area of glacial lakes also increased from 94.44 km~2 in 1977 to 127.61 km~2 in 2010, a growth rate of 35.1%. A large number of glacial lakes in the inventory are small in size(≤ 0.1km~2). End moraine dammed lakes with area greater than 0.1 km~2 were selected to analyze the change characteristics of glacial lakes in the basin. The results show that, in 2010, there were 129 lakes greater than 0.1 km~2 in area; these lakes had a total area of 42.92km~2 in 1997, increasing to 63.28 km~2 in 2010. The distribution of lakes on the north side of the Himalayas(in China) was three times higher than on the south side of the Himalayas(in Nepal).Comparing the mean growth rate in area for the 33 year study period(1977-2010), the growth rate on the north side was found to be a little slower than that on the south side. A total of 42 glacial lakes with an area greater than 0.2 km~2 are rapidly growing between 1977 and 2010 in the Koshi basin, which need to be paid more attention to monitoring in the future and to identify how critical they are in terms of GLOF. 相似文献
6.
1OVERFLOWBURSTOFMORAINELAKEFloodwater and debris flow caused by glacial lake burst is an important land process and a serious moun-tain disaster in glacial area. Glacial lakes with burst can divided into the glacier-obstructed lake (ice dam lake) and the terminal moraine lake (XU and FENG, 1988). Typical burst of ice dam lake happens in the modern glacier area of the upper reaches of the Kele-qing River in Uygur Autonomous Region of Xinjiang (WANG, 1990). But most of burst gla… 相似文献
7.
《山地科学学报》2020,17(10):2497-2511
The Diexi ancient dammed lake is in the upper reaches of the Minjiang River. Six terraces with lacustrine sediments occur at the base. These terraces are the products of the graded outburst of the Diexi ancient dammed lake. The outburst of the ancient dammed lake would certainly have had an impact on the Chengdu Plain in the lower reaches of the Minjiang River. In this paper, on-site sampling and laboratory analysis were used to analyze the sediments of the Diexi ancient dammed lake and the Jinsha site in Chengdu Plain, and the environmental indicators of each sediment layer were tested. Through a comparative analysis of the environmental indicators in the sediments at the two locations, the following results were obtained: the palaeoclimatic and palaeoenvironmental characteristics at the two locations generally show consistent changes. The most important finding is that the types and content of the major pollen taxa at the two locations are similar. The Pinus content strongly proves that the soil layers at the Jinsha site was sourced from the upper reaches of the Minjiang River. Considering that the demise of the ancient culture at the Jinsha site occurred close in time to the outburst of the ancient dammed lake, this similarity suggests that the cultural change at the Jinsha site may have been related to the outburst of the Diexi ancient dammed lake. 相似文献
8.
广布于松辽平原科尔沁沙地的巨型弧形沙垄的成因一直未能得到很好解释,该项研究采用罗根冰碛变形机理对该区的巨型弧形沙垄、密布的湖泡等特征地貌进行分析,发现其与斯堪的纳维亚冰盖、劳伦泰德冰盖的冰下软基变形地貌特征具有同一性,从而确认巨型弧形沙垄为冰盖冰流形成的巨型流线、罗根冰碛与锅穴构造的遗留,从而佐证了“松辽冰盖”的存在。研究发现松辽平原的巨型弧形流线显示出具有从盆地周围向沉降中心延伸、汇聚的特征,这表明流线的走向受制于地势的控制,而非所谓的风力所为。此外根据巨型冰川流线的展布形态与松辽分水岭之间存在的反常关系,发现在冰盖消融后松辽分水岭发生了北移现象,这一现象的产生可能与冰盖消融后导致的松辽盆地的失压反弹隆升有关。根据松辽分水岭的迁移时间、风沙层序年龄、荷载构造扰动地层年龄的综合约束,初步判断松辽冰盖的最近一次的发生时间在晚更新世早期(MIS4阶段)的东山冰期。 相似文献
9.
我国东部中低山区第四纪冰川的存在与否一直存在争议,但冰川必然对山体进行冰蚀作用形成冰蚀地貌。为了分析我国东部中低山区的山体地貌是否具有冰蚀特征,该文选取了现代冰川集中发育区-喜马拉雅山脉作为冰蚀地貌的研究对象,通过宏观分析,除了由缩口、三角脊、残弧组成的冰斗系统外,还发现冰蚀作用过程存在避谷、吞脊、切壁、穿梁等特殊习性。分析认为冰蚀过程主要受制于雪线高程、积雪高程与坡向坡角三方面因素的控制。以此为基础,对我国东部的江西庐山、山东蒙山、大兴安岭主峰黄岗梁三个地区的山体地貌进行对比分析,发现这些山区的山体地貌与喜马拉雅山脉的冰蚀地貌具有一致性。文章从冰蚀过程的角度确认了我国东部中低山区存在第四纪冰川的事实。 相似文献
10.
我国东部中低山区第四纪冰川的存在与否一直存在争议,但冰川必然对山体进行冰蚀作用形成冰蚀地貌。为了分析我国东部中低山区的山体地貌是否具有冰蚀特征,该文选取了现代冰川集中发育区—喜马拉雅山脉作为冰蚀地貌的研究对象,通过宏观分析,除了由缩口、三角脊、残弧组成的冰斗系统外,还发现冰蚀作用过程存在避谷、吞脊、切壁、穿梁等特殊习性。分析认为冰蚀过程主要受制于雪线高程、积雪高程与坡向坡角三方面因素的控制。以此为基础,对我国东部的江西庐山、山东蒙山、大兴安岭主峰黄岗梁三个地区的山体地貌进行对比分析,发现这些山区的山体地貌与喜马拉雅山脉的冰蚀地貌具有一致性。文章从冰蚀过程的角度确认了我国东部中低山区存在第四纪冰川的事实。 相似文献
11.
Improvement of glacial lakes detection under shadow environment using ASTER data in Himalayas, Nepal
The detection of glacial lake change in the Himalayas, Nepal is extremely significant since the glacial lake change is one of the crucial indicators of global climate change in this area, where is the most sensitive area of the global climate changes. In the Himalayas, some of glacial lakes are covered by the dark mountains′ shadow because of their location. Therefore, these lakes can not be detected by conventional method such as Normalized Difference Water Index (NDWI), because the reflectance feature of shadowed glacial lake is different comparing to the ones which are located in the open flat area. The shadow causes two major problems: 1) glacial lakes which are covered by shadow completely result in underestimation of the number of glacial lakes; 2) glacial lakes which are partly identified are considered to undervalue the area of glacial lakes. The aim of this study is to develop a new model, named Detection of Shadowed Glacial Lakes (DSGL) model, to identify glacial lakes under the shadow environment by using Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) data in the Himalayas, Nepal. The DSGL model is based on integration of two different modifications of NDWI, namely NDWIs model and NDWI she model. NDWIs is defined as integration of the NDWI and slope analysis and used for detecting non-shadowed lake in the mountain area. The NDWIshe is proposed as a new methodology to overcome the weakness of NDWIs on identifying shadowed lakes in highly elevated mountainous area such as the Himalayas. The first step of the NDWIshe is to enhance the data from ASTER 1B using the histogram equalization (HE) method, and its outcome product is named ASTER he . We used the ASTER he for calculating the NDWI he and the NDWIshe . Integrated with terrain analysis using Digital Elevation Model (DEM) data, the NDWI she can be used to identify the shadowed glacial lakes in the Himalayas. NDWIs value of 0.41 is used to identify the glacier lake (NDWIs≥0.41), and 0.3 of NDWIshe is used to identify the shadowed glacier lake (NDWIshe≤0.3). The DSGL model was proved to be able to classify the glacial lakes more accurately, while the NDWI model had tendency to underestimate the presence of actual glacial lakes. Correct classification rate regarding the products from NDWI model and DSGL model were 57% and 99%, respectively. The results of this paper demonstrated that the DSGL model is promising to detect glacial lakes in the shadowed environment at high mountains. 相似文献
12.
系统回顾多手段地形变监测应用于地震中长期预测和中短期预报的若干实例,以及震后总结给出的突出形变异常和巨幅形变异常未能对应地震的实例,展示了形变手段用于强震预测的有效性和局限性,并针对实践中发现的若干问题进行讨论,提出看法和建议. 相似文献
13.
非固结储水系统形变的体积互换机理及意义 总被引：2，自引：1，他引：1
从不同假定条件下质量守恒方程的物理意义分析入手，提出了反映非固结储水系统形变量与地下水补排水量关系的体积互换机理的理论，为抽注地下流体导致的地形变量的计算及允许开采量的确定提供了理论依据，阐明了储水层形变的水动力学原因在于渗流的非稳定过程。从环境地质及水文地质角度探讨了由于体积互换机理导致的非固结储水层的形变模型与水流模型耦合的必然性以及重新定义非固结储水层随时间变化的导储水参数的必要性。研究成果加深了对地层形变尤其是人类抽注地下流体导致的地层形变灾害(如地裂缝、地面沉降、井管折损等地质灾害)产生机理的理解，为进一步完善地层形变与渗流理论指出了新的研究方向。 相似文献
14.
QI Miao-miao LIU Shi-yin YAO Xiao-jun Richard Grünwald GAO Yong-peng DUAN Hong-yu LIU Juan 《山地科学学报》2020,(4):851-870
There are a large number of glaciers and lakes developed in the Nyang Qu Basin of China. Recent climate change has significant impacted on the high-mountain glacial environment. Rapid melting of glaciers contributes to the formation and expansion of moraine-dammed lakes which increase the probability of glacial lake outburst floods(GLOFs). We calculated a multi-temporal lake inventory based on(1) topographic maps in the 1970 s,(2) satellite imageries from 1990 to 2016,(3) First Chinese Glacier Inventory(FCGI),(4) Glacier Inventory of Southeastern Tibet(GIST) and(5) meteorological data. A total of 880 lakes(>0.01 km^2) have been mapped in 2016, with 318 being glacial lakes(GLs) and 462 non-glacier lakes(NGLs). Most of the lakes were mainly located at 4500 m a.s.l. and the lakes dominated by small lakes(<0.1 km^2) where the change of their actual sizes are more significant compared to the larger ones. Meanwhile, we found that there were 178 newly formed GLs and 51 of them had disappeared between 1970 and 2016. During the same period, there can be identified 157 newly formed GLs and 226 had disappeared. We additionally performed a hazard and risk assessment for GL in 2016 and exposed 14 potentially dangerous morainedammed lakes(PDMDLs), covering a total area of 5.88 km2 in the Nyang Qu Basin. There can be found 4 GLs with very high risk, 3 GLs with high risk, 4 GLs with medium risk and 4 GLs with low risk of GLOFs susceptibility. The findings of this study can be used for the future policy of risk management and also be adapted for promoting water resources management. 相似文献
15.
Extreme Rainfall Events and Associated Natural Hazards in Alaknanda Valley, Indian Himalayan Region 总被引：2，自引：0，他引：2
JOSHI Varun KUMAR Kireet 《山地科学学报》2006,3(3):228-236
Introduction The Himalaya is considered to be the youngest mountains on the earth, and is tectonically very active, and hence inherently (geologically) vulnerable to hazards. Extreme rainfall events, landslides, debris flows, torrents and flash floods due… 相似文献
16.
对以褶皱构造为主要构造型式的突出矿片来说，用褶皱变形系数这一定量指标，通过控制煤和瓦斯突出褶皱构造的研究，在一定程度上能提高突出预测的准确率。本文针对平顶山东矿区煤层褶皱变形的特点，分别用剖面变形系数法和平面变形系数法进行了突出危险性预测研究，取得了较可靠的预测结果。 相似文献
17.
《山地科学学报》2015,(5)
Global climate change during the twentieth century had a significant impact on the glaciers that resulted in creation of new lakes and expansion of existing ones, and ultimately an increase in the number of glacial lake outburst floods(GLOFs) in the Himalayan region. This study reports variation of the end-moraine dammed lakes in the high altitude Hindukush-Karakoram-Himalaya(HKH) region of Pakistan to evaluate future floods hazard under changing climate in this region. An integrated temporal remote sensing and Geographic information system(GIS) based approach using satellite images of Landsat-7 and 8 was adopted to detect 482 endmoraine dammed lakes out of which 339 lakes(0.02 km2) were selected for temporal change analysis during the 2001-2013 period. The findings of the study revealed a net expansion in the end-moraine dammed lakes area in the Karakoram(about 7.7%) and in the Himalayas(4.6%), while there was a net shrinkage of about 1.5% in the lakes area in the Hindukush range during this period. The percentage increase in the lakes' area was highest above 4500 m asl in the Hindukush, within 3500-4000 m asl in the Himalayas and below 3500 m asl in the Karakoram range. The overall positive change in the lakes' area appears to prevail in various altitudinal ranges of the region. The heterogeneous areal changes in the endmoraine dammed lakes might be attributed to different climate regimes and glacial hydrodynamics in the three HKH ranges. A periodic monitoring of the glacial lakes and their associated glaciers is essential for developing effective hazard assessment and risk reduction strategies for this high altitude Himalayan region. 相似文献
18.
湖水与地下水交互作用对于水资源合理开发与利用有着重要意义。基于温度示踪的原理，采用解析法、数值法2种方法，分析了湖床底部埋深0~0.4 m湖水与浅层地下水交互关系，并与水动力学方法进行了对比。结果表明，2018年5月20日至28日，湖水与地下水之间的垂向渗流速度为2×10-7~1×10-6 m/s，且在埋深0.4 m时大于埋深0.2 m处。降水会对解析法的结果造成一定影响，0.4 m处受到降雨影响表现为一定的滞后性。无降雨干扰情况下，数值法与水动力学方法估算结果较为吻合，且3种方法的计算结果处于同一数量级。同时，湖床沉积物体积热容和孔隙度2种参数对计算结果影响较大。在半干旱地区湖水与地下水交互研究中，数据较完备时，数值模拟法是更好的选择。 相似文献
19.
杨学祥 《大地测量与地球动力学》1994,(4)
本文根据冰川和海平面变化资料，探讨地壳形变对冰川消长和海平面升降的响应，并由此得出可以解释相应的地球物理现象的有益结果。这些结果对地壳形变的测量和地震预报有重要意义。 相似文献
20.
该文在查明区域水文地质条件、湖区地下水的类型、分布、埋藏条件、含水层及隔水层特征、岩性结构以及地下水的补给、径流、排泄条件的基础上,通过现场试验,确定了天然状态下湖区各含水层之间的水力联系、黄河侧渗补给量及湖区向小清河的排泄量,结合数值模拟,预测了湖区维持设计蓄水位21.5m时黄河的侧渗补给量、湖区向小清河的排泄量及湖区对周边地下水位的影响。结果表明,天然状态下,黄河侧渗补给量为748.23m~3/d,湖区向小清河排泄量大约为52.03m~3/d,黄河侧渗补给量远大于湖区向小清河的排泄量。数值模拟结果表明,湖区维持设计蓄水位21.5m时,不同水文年湖区接受的侧渗补给量均大于湖区的渗漏量,且对周围地下水位的影响不超过1.5m,因此,湖区维持设计蓄水位21.5m时可不考虑防渗措施。 相似文献