近20 a中国天山东段典型冰川变化及其气候响应

冰川作为重要的淡水资源的存储体,也是气候变化的敏感"指示器"。在干旱半干旱区,冰川变化对人们的生产、生活和生态产生重要的影响。本文基于1990—2015年Landsat TM及ETM+遥感影像数据,利用雪盖指数法(NDSI)和阈值法,分析博格达峰及喀尔力克山的冰川面积变化,结合长时间序列的气温、降水数据分析天山东段典型冰川的气候响应。结果表明:(1)博格达峰与喀尔力克山的冰川均呈现退缩趋势,与气温和降水的变化趋势一致。(2)博格达峰和喀尔力克山冰川面积变化在东南坡向有波动增加趋势,其他坡向则未出现该现象。(3)从两个冰川不同坡向的面积和面积重心分布变化分析,博格达峰冰川面积在东坡方向退缩速率最大,而喀尔力克山的冰川在东北坡方向退缩速率最大。(4)根据栅格气象资料分析,近四五十年博格达地区冰川面积退缩速率大于喀尔力克山地区,并且博格达峰降水量的增加对冰川的退缩起到的作用不大,喀尔力克山的降水量对冰川面积的退缩起到了一定的抑制作用。(5)通过对博格达峰地区和喀尔力克山地区不同坡向的冰川面积与年均气温、年均降水量进行Person相关性分析,博格达峰地区、喀尔力克山地区各个坡向的冰川面积变化与降水相关系数均很小。但博格达峰地区北、东北、东南坡向的冰川面积与区域气温变化相关系数较高,喀尔力克山地区东南、东北坡向的冰川面积与区域气温的相关系数高且显著性明显。分析其原因,在年内尺度上,博格达峰地区、喀尔力克山地区是湿季气温升高所致,干湿两季降水量的增多,并没有使得冰川整体的退缩有所减缓。     

1960-2009年中国天山现代冰川末端变化特征

基于冰川定位观测、野外考察、航空摄影、遥感影像和地形图分析方法,研究了1960-2009年中国天山8条冰川末端变化特征。结果表明：1960-2009年,在天山地区气温与降水呈上升趋势的背景下,8条冰川均处于退缩状态,退缩速率由西向东逐渐减缓,其变化幅度因气候环境、地理位置、冰川规模和冰川形态等的不同而存在明显的区域性与阶段性差异。其中,乌鲁木齐河源1号冰川1962-1973年冰川末端退缩速率为5.96 m•a^-1,1973-1980年为3.28 m•a^-1,1980-1993年为3.93 m•a^-1,在1993年完全分离成东、西两支独立的冰川;博格达峰四工河4号冰川末端1962-1981年退缩速率为6 m•a^-1,1981-2006年为8.9 m•a^-1,2006-2009年为13.3 m•a^-1。表碛覆盖的青冰滩72号冰川和74号冰川末端1964-2009年退缩速率分别为41 m•a^-1和30 m•a^-1,远较无表碛覆盖的庙儿沟平顶冰川退缩迅速（1972-2007年冰川末端退缩速率为2.32 m•a^-1）。表面特征（表碛）亦是造成冰川变化差异的一个主要原因。     

Five decades of glacier changes in the Hulugou Basin of central Qilian Mountains,Northwest China

The Heihe River Basin is the second largest inland river basin in the arid regions of Northwest China. Glaciers provide a large proportion of water resources for human production and living. Studies of glacier changes and their impact on water resources in the arid lands are of vital importance. A joint expedition was carried out in 2010 for investigating glaciers in the Hulugou Basin, which is located in the upper reaches of Heihe River. Therefore, glacier changes in the Hulugou Basin of central Qilian Mountains during the past 50 years were analyzed in this study by comparing topographic maps, satellite images, digital elevation models and field observation data from different periods. Results showed that the total area of the 6 glaciers in the Hulugou Basin decreased by 0.590±0.005 km2 during the period 1956–2011, corresponding to a loss of 40.7% over the total area in 1956. The average area reduction rate of the 6 glaciers is 0.011 km2/a. During the past five decades, the glacier shrinkage was accelerated. The changes in glacier ice surface elevation ranged from –15 to 3 m with an average thinning of 10±8 m or an annual decrease of 0.23±0.18 m(0.20±0.15 m/a water equivalent) for the period 1956–2000. The area of Shiyi Glacier in the Hulugou Basin decreased from 0.64 km2 in 1956 to 0.53 km2 in 2011 with a reduction rate of 17.2%. The Shiyi Glacier had been divided into two separated glaciers because of severe melting. Comparative analysis showed that glacier shrinkage in the Hulugou Basin is more serious than that in the other regions of Qilian Mountains.     

Glacier variations and their response to climate change in an arid inland river basin of Northwest China

Glaciers are a critical freshwater resource of river recharge in arid areas around the world. In recent decades, glaciers have shown evidence of retreat due to climate change, and the accelerated ablation of glaciers and associated impacts on water resources have received widespread attention. Glacier variations result from climate change, so they can serve as an indicator of climate change. Considering the climatic differences in different elevation ranges, it is worthwhile to explore whether different responses exist between glacier area and air temperature in each elevation zone. In this study, we selected a typical arid inland river basin(Sugan Lake Basin) in the western Qilian Mountains of Northwest China to analyze the glacier variations and their response to climate change. The glacier area data from 1989 to 2016 were delineated using Landsat Thematic Mapper(TM), Enhanced TM+(ETM+) and Operational Land Imager(OLI) images. We compared the relationships between glacier area and air temperature at seven meteorological stations in the glacier-covered areas and in the Sugan Lake Basin, and further analyzed the relationship between glacier area and mean air temperature of the glacier surfaces in July–August in the elevation range of 4700–5500 m a.s.l. by the linear regression method and correlation analysis. In addition, based on the linear regression relationship established between glacier area and air temperature in each elevation zone, we predicted glacier areas under future climate scenarios during the periods of 2046–2065 and 2081–2100. The results indicate that the glaciers experienced a remarkable shrinkage from 1989 to 2016 with a shrinkage rate of –1.61 km2/a(–0.5%/a), and the rising temperature is the decisive factor dominating glacial retreat; there is a significant negative linear correlation between glacier area and mean air temperature of the glacier surfaces in July–August in each elevation zone from 1989 to 2016. The variations in glaciers are far less sensitive to changes in precipitation than to changes in air temperature. Due to the influence of climate and topographic conditions, the distribution of glacier area and the rate of glacier ablation first increased and then decreased in different elevation zones. The trend in glacier shrinkage will continue because air temperature will continue to increase in the future, and the result of glacier retreat in each elevation zone will be slightly slower than that in the entire study area. Quantitative glacier research can more accurately reflect the response of glacier variations to climate change, and the regression relationship can be used to predict the areas of glaciers under future climate scenarios. These conclusions can offer effective references for assessing glacier variations and their response to climate change in arid inland river basins in Northwest China as well as other similar regions in the world.     

近40a来南阿尔泰山区现代冰川变化及其对气候变化的响应

以1972,1989,2000,2011四个不同时段的遥感影像资料为基础,通过计算机自动提取结合人工解译获得研究区各时段冰川信息。参考世界冰川编目(WGI)分别对分布在中国、俄罗斯和哈萨克斯坦境内的冰川进行编目及属性更新,完成南阿尔泰山蒙古境内冰川编目。对不同时段冰川信息进行对比,并结合气温、降水等气候资料对其变化特征进行分析。结果表明:(1)1972-2011a,南阿尔泰山区冰川总面积从633.91km2减少至329.03km2,退缩面积304.88km2,占1972a冰川总面积的48.1%;(2)不同面积等级冰川数量与面积变化呈反相关关系,小冰川对气候的响应更为敏感;(3)研究区各坡向冰川均在退缩,其中南向、东北向、东向、北向退缩较快,西向、西南向、东南向、西北向相对缓慢;(4)1972-2008a研究区增温显著,降水以1987a为界先增后波动中稳定,二者的水热组合是区内冰川退缩的主要原因。     

北阿尔泰山近30年冰川变化研究

利用1980年的MSS影像,2000、2010年的Landsat TM影像为数据源,运用监督分类法、比值法,结合目视解译提取了北阿尔泰山30年来的冰川变化信息。结果表明:北阿尔泰山1980-2010年冰川面积减少了12.3%,年平均退缩速率为0.43%.a-1;冰储量减少了13.9%,年平均减少速率为0.46%.a-1,并且发现2000-2010年是冰川快速退缩期,在整个北阿尔泰山范围内又以卡通斯基山和北楚伊斯基山退缩较快。利用NECP/NCAR资料,分析了30年来温度、降水的变化与冰川退缩的关系,发现研究区的冰川的退缩主要受控于夏季温度变化,受降水影响较小。     

托木尔峰地区神奇峰冰川3950m处物质平衡与气象要素关系分析

2008年夏季,中国科学院天山冰川观测试验站科研人员对天山托木尔峰地区神奇峰冰川(也称青冰滩72号冰川)进行了大规模综合性的野外科考活动,获得了2008年7月30日至8月31日期间的冰川海拔3950m处的实测气象资料,包括气温、降水等。文中将这些气象资料与物质平衡数据相结合,对它们的关系进行了分析。2008年夏季青冰滩72号冰川野外观测资料分析结果表明:研究时段内,冰川日平均气温在0℃以上的天数达到了96%,冰川基本上处于消融状态;降水前后伴随的气温变化幅度大;基于观测数据,对气温和物质平衡进行了回归分析,回归系数为0.631;并利用灰熵关联度分析了降水和物质平衡之间的关系,它们之间的关联度系数为0.497。     

新疆天山天池风景名胜区的后续开发

新疆天山天池风景名胜区旅游开发目前主要集中在以天池为中心的湖滨区，景区已出现旅游吸引力不足、旅游活动内容单调、旅游环境容量有限等一系列问题，着手进行后续旅游开发势在必行。实际上，就资源、客源、交通等条件而言，天池景区的后续开发均有保障，并预期有良好的社会、经济、环境效益。通过实际调查，建议选择开发吉岩坚沟百花园景区，在三个岔沟的冰川和冰湖区建立冰川公园。同时必须关注天池湖面缩小、旅游与牧业、相邻行政区协调、自然保护区区域划分等相关问题，尤其是做好防止天池退缩的环境保护工程。     

Region-wide glacier area and mass budgets for the Shaksgam River Basin,Karakoram Mountains,during 2000–2016

The Karakoram Mountains are well known for their widespread surge-type glaciers and slight glacier mass gains.On the one hand,glaciers are one of the sensitive indicators of climate change,their area and thickness will adjust with climate change.On the other hand,glaciers provide freshwater resources for agricultural irrigation and hydroelectric generation in the downstream areas of the Shaksgam River Basin(SRB)in western China.The shrinkage of glaciers caused by climate change can significantly affect the security and sustainable development of regional water resources.In this study,we analyzed the changes in glacier area from 2000 to 2016 in the SRB using Landsat TM(Thematic Mapper)/ETM+(Enhanced Mapper Plus)/OLI(Operational Land Imager)images.It is shown that the SRB contained 472 glaciers,with an area of 1840.3 km2,in 2016.The glacier area decreased by 0.14%/a since 2000,and the shrinkage of glacier in the southeast,east and south directions were the most,while the northeast,north directions were the least.Debris-covered area accounted for 8.0%of the total glacier area.We estimated elevation and mass changes using the 1 arc-second SRTM(Shuttle Radar Topography Mission)DEM(Digital Elevation Model)(2000)and the resolution of 8 m HMA(High Mountain Asia)DEM(2016).An average thickness of 0.08(±0.03)m/a,or a slight mass increase of 0.06(±0.02)m w.e./a has been obtained since 2000.We found thinning was significantly lesser on the clean ice than the debris-covered ice.In addition,the elevation of glacier surface is spatially heterogeneous,showing that the accumulation of mass is dominant in high altitude regions,and the main mass loss is in low altitude regions,excluding the surge-type glacier.For surge-type glaciers,the mass may transfer from the reservoir to the receiving area rapidly when surges,then resulting in an advance of glacier terminus.The main surge mechanism is still unclear,it is worth noting that the surge did not increase the glacier mass in this study.     

近50年来新疆天山南北坡典型流域冰川与冰川水资源的变化

冰川是大自然修筑的"固体水库",在水资源的构成中占有重要地位。新疆地处内陆干旱区,是我国现代冰川面积分布最广的地区之一。冰川和冰川融水为新疆灌溉农业发展提供了可靠的水资源保障。本文根据中国冰川编目及近年来其它冰川研究成果和监测资料,对1960年以来新疆,主要是天山山区的冰川与冰川径流的变化进行了分析。分析表明,受全球气候变暖的影响,上世纪60年代以来至本世纪初,天山冰川的变化整体上以退缩为主,1963-2000年冰川面积平均减少12.5%。但受地理位置和地势条件的影响,不同流域的冰川变化存在着较大的区域性差异。随着冰川的强烈退缩和冰川融水的增加,使得近十余年来新疆天山地区大部分冰川补给河流径流量呈增加的趋势。     

1976-2010年祁连山中段岗格尔肖合力雪山冰川退缩和气候变化的关系研究

运用最大似然监督分类法和比值阈值法（TM3/TM5）结合目视解译方法,从1976、1990、2001和2010的MSS、TM、ETM影像中提取了岗格尔肖合力雪山四个时段的冰川边界,并结合距其较近的托勒、野牛沟、祁连、德令哈和刚察5个气象站点1960-2010年年总降水量数据和年平均气温数据进行了分析,得到如下结论：1）...     

Glacier mass balance in High Mountain Asia inferred from a GRACE release-6 gravity solution for the period 2002–2016

We provide estimates of glacier mass changes in the High Mountain Asia (HMA) area from April2002 to August 2016 by employing a new version of gravity solutions of the Gravity Recovery and ClimateExperiment (GRACE) twin-satellite mission. We find a total mass loss trend of the HMA glaciers at a rateof –22.17 (±1.96) Gt/a. The largest mass loss rates of –7.02 (±0.94) and –6.73 (±0.78) Gt/a are found forthe glaciers in Nyainqentanglha Mountains and Eastern Himalayas, respectively. Although most glaciers inthe HMA area show a mass loss, we find a small glacier mass gain of 1.19 (±0.55) and 0.77 (±0.37) Gt/a inKarakoram Mountains and Western Kunlun Mountains, respectively. There is also a nearly zero massbalance in Pamirs. Our estimates of glacier mass change trends confirm previous results from the analysisof altimetry data of the ICESat (ICE, Cloud and Land Elevation Satellite) and ASTER (AdvancedSpaceborne Thermal Emission and Reflection Radiometer) DEM (Digital Elevation Model) satellites inmost of the selected glacier areas. However, they largely differ to previous GRACE-based studies which weattribute to our different post-processing techniques of the newer GRACE data. In addition, we explicitlyshow regional mass change features for both the interannual glacier mass changes and the 14-a averagedseasonal glacier mass changes. These changes can be explained in parts by total net precipitation (netsnowfall and net rainfall) and net snowfall, but mostly by total net radiation energy when compared to datafrom the ERA5-Land meteorological reanalysis. Moreover, nearly all the non-trend interannual masschanges and most seasonal mass changes can be explained by the total net radiation energy data. The massloss trends could be partly related to a heat effect due to increased net rainfall in Tianshan Mountains, QilianMountains, Nyainqentanglha Mountains and Eastern Himalayas. Our new results for the glacier mass changein this study could help improve the understanding of glacier variation in the HMA area and contribute tothe study of global change. They could also serve the utilization of water resources there and in neighboringareas.     

基于面向对象分类的马兰冰帽变化与气候响应

以Landsat遥感影像和数字高程数据为基础数据,利用面向对象分类方法提取了马兰冰帽1990、2000、2015年3期冰川边界,并分析了冰帽变化情况。结果表明:马兰冰帽在近25 a来一直处于退缩状态。由1990年的195.87 km~2减少到2015年的188.60 km~2,退缩了7.27 km~2,占1990年冰帽面积的3.71%,退缩速率为0.15%·a~(-1);不同时段内冰帽变化速率具有差异性,1990—2000、2000—2015年2个时段内冰帽退缩速率分别为0.16%·a~(-1)、0.14%·a~(-1),冰帽退缩速率处于减慢状态;不同朝向的冰川发育特点和变化差异显著,南坡冰川退缩速率较北坡慢。25 a来,研究区域内夏季平均气温升高了2.21℃,升温显著,增温率为0.67℃·(10a)~(-1),年降水量增加了53.52 mm,线性增加率为16.22 mm·(10a)~(-1),增加速度缓慢。由此推断,夏季气温显著升高是引起马兰冰帽持续退缩的主要原因。同时,研究发现地形条件对冰川规模变化也产生重要影响。     

Climate change and its impacts on mountain glaciers during 1960-2017 in western China

Mountain glaciers are highly sensitive to climate change. In this paper, we systematically analyzed and discussed the responses of glaciers to climate change during 1960-2017 in western China by the methods of least squares and correlation analysis. Results show that the maximum temperature, minimum temperature, average temperature, and precipitation significantly increased in western China at the rates of 0.32°C/10a, 0.48°C/10a, 0.39°C/10a, and 11.20 mm/10a, respectively. However, the wind speed, hours of sunshine, snowfall, and snowy days displayed decreasing trends at the rates of -0.53 m/(s?10a), 3.72 h/10a, -2.90 mm/10a, and -0.10 d/10a, respectively. The annual percentage of glacier area decreased by approximately 0.42%, and the average glacier area decreased by 2.76 km²/a. Meanwhile, glacial shrinkages were greater in the Altay Mountains, Tanggula Mountains, and Qilian Mountains than in the other mountainous regions. Glacier accumulation decreased while melt volume increased at a rate of 2.7×10⁴ m³/a. The area of melt volume was 1.3 times that of the glacier accumulation area. The glacier mass balance (GMB) decreased substantially at a rate of -14.0 mm/a, whereas the equilibrium line altitude (ELA) showed an increasing trend at a rate of 0.5 mm/a. After 1997, the mass was smaller than -500.0 mm, indicating a huge loss in glaciers. Furthermore, relationships between ELA and GMB and various climatic factors were established. Temperature and precipitation demonstrated a significantly negative correlation, whereas wind speed and snowy days had significantly positive correlations with GMB. Snowy days also exhibited a remarkably negative correlation with ELA. The strong warming trend and less snowy days were thought to be the main factors leading to glacial melting, whereas the increase in precipitation, and reductions of sunshine hours and wind speed might slow glacial melting.     

近年来祁连山中段冰川变化

基于遥感和实测的方法,对近50 a来祁连山中段,包括黑河流域和北大河流域的冰川变化特征进行了分析。研究表明：1956-2003年,祁连山中段所研究的910条冰川面积共缩小了21.7%。其中,黑河流域冰川面积缩小了29.6%,北大河流域冰川面积缩小了18.7%。小冰川面积变化较大冰川要大,其对气候变化的敏感性较强。由于祁连山中段东西跨度较大,气候和地形等因素的不同,直接造成了冰川变化的区域差异。近期野外考察发现,位于黑河上游的葫芦沟流域,1956-2010年冰川面积缩小了30.1%,近7 a冰川面积缩小的比率达到前期的近5倍,且其中的十一冰川由于消融严重,已经完全分离成2条独立的冰川。雪冰融水径流是该流域中重要的水源,在稳定河川径流、调节其年际变化和年内分配方面发挥着重要作用。     

祁连山北大河流域冰川变化遥感监测

基于1956年地形图和2003年ASTER影像数据,在RS和GIS技术支持下,确定了1956年和2003年的冰川边界,对祁连山北大河流域冰川近47 a来的变化进行了研究。结果表明：该流域372条冰川面积在47 a间共减小了33.56 km²,平均每条减小0.09 km²,变化率-15.42%,冰川末端累计退缩51 015 m。分析显示,小冰川比大冰川消融的更快。对研究区附近气象站近年来的年平均气温、夏季平均气温和年降水量进行分析,认为气温升高是北大河流域冰川快速萎缩的主要原因。与中国西部其他冰川进行对比研究发现,北大河流域冰川消融速率比新疆要快,但较黑河流域及其他子流域要慢,初步推测是由冰川所在区域的气候及冰川自身因素共同作用的结果。     

30 a来长江源区冰川变化遥感监测

根据地形图、航空相片和Landsat ETM+数字影像,采用比值阈值法对青藏高原东北部长江源区1969/1971-1999/2002年间的冰川变化进行了研究;同时,选取覆盖同一区域（格拉丹东峰北坡）的Landsat MSS (1973年)、Landsat TM (1992年)以及2景2005/2006年获取的1B级ASTER数字遥感影像,进一步分析源区冰川的连续变化规律。结果表明：① 研究区的冰川平均退缩了108.3 m,冰川面积减少了5.3%,其中,色的日峰地区的面积变化率最大,冰川面积减少12.9%;唐古拉山北坡冰川相对处于稳定状态,面积仅减少了4.3%。② 格拉丹东峰北坡冰川面积变化速率不均匀,1969-1973年冰川面积变化最快,平均变化量为-1.16 km²·a^-1,1973年后冰川变化有所减缓,1973-1992年和1992-2002年平均变化量均为-0.59 km²·a^-1,而2002年后冰川面积变化又有所加快,平均变化量为-0.95 km²·a^-1。③ 沱沱河、五道梁和治多3个气象站的气温和降水变化显示,暖季气温升高是导致研究区冰川退缩的主要因素,此外,气温升高的快慢可能是引起上述3个区域冰川变化差异的重要原因之一。     

Ice thickness distribution and volume estimation of Burqin Glacier No. 18 in the Chinese Altay Mountains

Information on the thickness distribution and volume of glacier ice is highly important for glaciological applications; however, detailed measurements of the ice thickness of many glaciers in the Chinese Altay Mountains remain lacking. Burqin Glacier No. 18 is a northeast-orientated cirque glacier located on the southern side of the Altay Mountains. This study used PulseEKKO^® PRO 100A enhancement ground-penetrating radar (GPR) to survey the ice thickness and volume of Burqin Glacier No. 18 in summer 2018. Together with GPR surveying, spatial distributed profiles of the GPR measurements were concurrently surveyed using the real-time kinematic (RTK) global navigation satellite system (GNSS, Unistrong E650). Besides, we used QuickBird, WorldView-2, and Landsat TM to delineate accurate boundary of the glacier for undertaking estimation of glacier ice volume. GPR measurements revealed that the basal topography of profile B1-B2 was flat, the basal topography of profile C1-C2 presented a V-type form, and the basal topography of profile D1-D2 had a typical U-type topographic feature because the bedrock near the central elevation of the glacier was relatively flat. The longitudinal profile A1-A2 showed a ladder-like distribution. Glacier ice was thin at the terminus and its thickness increased gradually from the elevation of approximately 2620 m a.s.l. along the main axis of the glacier tongue with an average value of 80 (±1) m. The average ice thickness of the glacier was determined as 27 (±2) m and its total ice volume was estimated at 0.031 (±0.002) km³. Interpretation of remote sensing images indicated that during 1989-2016, the glacier area reduced from 1.30 to 1.17 km² (reduction of 0.37%/a) and the glacier terminus retreated at the rate of 8.48 m/a. The mean ice thickness of Burqin Glacier No. 18 was less than that of the majority of other observed glaciers in China, especially those in the Qilian Mountains and Central Chinese Tianshan Mountains; this is probably attributable to differences in glacier type and climatic setting.     

Effect of topography on the changes of Urumqi Glacier No. 1 in the Chinese Tianshan Mountains

Topography plays an important role in determining the glacier changes. However, topography has often been oversimplified in the studies of the glacier changes. No systematic studies have been conducted to evaluate the relationship between the glacier changes and topographic features. The present study provided a detailed insight into the changes in the two branches (east branch and west branch) of Urumqi Glacier No. 1 in the Chinese Tianshan Mountains since 1993 and systematically discussed the effect of topography on the glacier parameters. This study analyzed comprehensive recently observed data (from 1992/1993 to 2018/2019), including mass balance, ice thickness, surface elevation, ice velocity, terminus, and area, and then determined the differences in the changes of the two branches and explored the effect of topography on the glacier changes. We also applied a topographic solar radiation model to analyze the influence of topography on the incoming shortwave radiation (SW_in) across the entire glacier, focusing on the difference in the SW_in between the two branches. The glacier mass balance of the east branch was more negative than that of the west branch from 1992/1993 to 2018/2019, and this was mainly attributed to the lower average altitude of the east branch. Compared with the west branch, the decrease rate of the ice velocity was lower in the east branch owing to its relatively increased slope. The narrow shape of the west branch and its southeast aspect in the earlier period resulted in a larger glacier terminus retreat of the west branch. The spatial variability of the SW_in across the glacier surface became much larger as altitude increased. The SW_in received by the east branch was slightly larger than that received by the west branch, and the northern aspect could receive more SW_in, leading to glacier melting. In the future, the difference of the glacier changes between the two branches will continue to exist due to their topographic differences. This work is fundamental to understanding how topographic features affect the glacier changes, and provides information for building different types of relationship between the glacier area and ice volume to promote further studies on the basin-scale glacier classification.     

近23年来北天山冰川面积变化对气候的响应

利用1989、1998、2011年的Landsat TM、ETM+遥感影像为数据源,运用比值阈值法(b3/b5)结合目视解译方法,提取了北天山3个时段的冰川边界,并在地理信息系统技术支持下分析了该区域冰川的变化情况。研究表明:北天山整体变化幅度较大,冰川表现为萎缩的趋势,近23年来冰川面积减小了14.93%。分析认为,较大的变化率是由于研究区面积<1km2的冰川数量占总数的比重较大(近80%)造成的。同时分析了北天山冰川空间结构特征,<0.5km2面积的冰川对气候变化最为敏感,消融率最高,1～5km2面积的冰川对消融总量贡献比例最大。依据分形理论对未来冰川变化进行初步预测,分析认为研究区冰川的消融率仍保持比较高的状态。