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1.
自1997年以来,乌鲁木齐河源1号冰川消融极为强烈,物质平衡呈大幅度亏损,连续12 a都处于强负平衡状态,平均物质平衡达-708 mm,且在2008年物质平衡达到历史最低值-999 mm,然而2009年出现了物质正平衡,物质平衡63 mm,年际变化量达1 062 mm。以2008-2009年物质平衡实测资料为基础,根据该地区的气温和降水资料分析,结果表明,造成这种现象的主要原因是夏季气温（5～8月）的降低,较2008年低1.8℃,致使冰川消融期的开始时间推迟至了7月份,结束时间提前到8月份,大大削弱了冰川的消融强度,其次是2005年以来逐渐增多的连续性降水,增加了冰川的积累量。  相似文献   

2.
Geografisk Tidsskrift, Danish Journal of Geography 108(1):121–136, 2008

SnowModel, a physically-based snow evolution modeling system that includes four submodels—MicroMet, EnBal, SnowPack, and SnowTran-3D—was used to simulate eight full-year (1998/99 through 2005/06) evolutions of snow accumulation, blowing snow sublimation, evaporation, snow and ice surface melt, runoff, and mass changes on the entire Mittivakkat Glacier (31 km2) in southeast Greenland. Meteorological observations from two meteorological stations inside the glacier catchment were used as model input, and glaciological mass balance observations were used for model calibration (1998/99 through 2001/02) and validation (2002/03 through 2005/06) of winter snow simulations. As confirmed by observations, the spatially modeled end-of-winter snow water equivalent (SWE) accumulation increased with elevation up to 700–800 m a.s.l. in response to elevation, topography, and dominating wind direction, and maximum snow deposition occurred on the lee side of the ridge east and south of the glacier. Simulated end-of-summer cumulative runoff decreased with elevation and minimum runoff occurred on the shadowed side of the ridge east and south of the glacier. The modeled test period averaged annual mass balance was 65 mm w. eq. y?1 or ～8% more than the observed. For the simulation period, the glacier net mass balance varies from -199 to -1,834 mm w.eq. y?1, averaging -900 (±470) mm w.eq.y?1. The glacier averaged annual modeled precipitation ranged from 1,299 to 1,613 mm w.eq. y?1, evaporation and sublimation from 206 to 289 mm w.eq., and runoff from 1,531 to 2,869 mm w.eq. y?1. The model simulated Mittivakkat Glacier net loss of900 mm w.eq. y?1 contributes approximately 42% to the average simulated runoff of 2,140 mm w.eq. y?1, indicating a mean specific runoff of 67.8 l s?1 km?2.  相似文献   

3.
As a solid reservoir, a glacier can regulate regional water resources. The annual net mass balance directly reflects the fluctuation of the glacier and climate variability. Based on 51 years of mass balance observation data, the mass balance of Tianshan Mountains Urumqi Glacier No. 1 experienced a nine times positive balance fluctuation and nine times negative balance fluctuation. There were 35 and 16 negative and positive balance years, respectively. From 1996/97 to 2008/09, 12 consecutive negative balance years were observed at Tianshan Mountains Urumqi Glacier No. 1. These results demonstrate that the Urumqi Glacier No. 1 is experiencing a strong negative balance, and the strongest negative balance, -931 mm w.e. (mm water equivalent), during the observation period occurred in 2008. In addition, the cumulative mass balance reached 13,709 mm w.e. in 2008. However, in 2009, the mass balance was positive at 63 mm w.e. The equilibrium-line altitude changes with the fluctuation in the mass balance, and the effective mass balance gradient is 7.4 mm/m. In this paper, the headwaters of the Urumqi River were analyzed using meteorological data from 1958 to 2009, including the average seasonal temperature and precipitation. The results showed that the main factor associated with the mass balance variation of Glacier No. 1 is the fluctuation in the summer air temperature, followed by changes in the precipitation.  相似文献   

4.
Annual balance measurements on the Lemon Creek Glacier, Alaska conducted by the Juneau Icefield Research Program (JIRP) from 1953 through 1998 provide a continuous 46 year record. This is one of the nine American glaciers selected in a global monitoring network during the International Geophysical year, 1957/58. These data have been acquired primarily by employing consistent ground methods, conducted on similar annual dates and calculated using comparable methodology. The results have been until now fairly precise, but of uncertain accuracy. An adjunct comparison of topographic surface maps of the glacier made in 1957 and 32 years later in 1989 provides a rough determination of glacier surface elevation changes which are clearly of less precision than the compilation of annual ground data. Airborne surface profiling in 1995, and global positioning system leveling transects in 1996–1998 update the record of surface elevation changes over the past decade. The mean glacier ice thickness reductions suggested by these methods from 1957–1989, from 1957–1995 and from 1957–1998 are ?13.2 m, ?16.4 m, and ?21.7 m, respectively. It is of interest that the geodetic interpretations agree fairly well with the trend of sequential balances from ground-level stratigraphic measurements. To date, however, the infrequent mapping methods in this study have yielded specific balances averaging between 5 and 11% less than those resulting from our annual on-site glaciological monitoring. For future studies this can be an important factor. The ground data are, therefore, the ones in which we have most confidence. These show cumulative ice losses of ?13.9 m (12.7 m water equivalent w.e.) from 1957–1989, of ?19.0 m (?17.1 m w.e.) from 1957–1995, of ?24.4 m (22 m w.e.) from 1957–1998, and ?24.7 m (22.2 m w.e.) for the total cumulative loss over the full 46 years between 1953 and 1998. Although the balance trend has been increasingly negative it averages ?0.48 m/a in w.e. or 0.52 m of ice loss per year. To refine the reliability of density determinations in this data set the effects of internal accumulation from refrozen meltwater producing diagenetic ice structures in the annual firnpack have been taken into account. An unusual dearth of such structures within the 1997/98 firnpack provided a unique opportunity to facilitate application of the probing technique over broad areas of the nv. This added to our ground truth and verified accuracy of the test-pit measurements used in these long-term mass balance computations. The glacier's continuing negative mass balance has fueled a terminal retreat of 800 m during the 1953–1998 period. The annual balance trend indicates that despite a higher mean elevation and a higher elevation terminus from thinning and retreat, mean annual balance has been strongly negative since 1977 (?0.78 m/a w.e.). Dramatically increased negative mass balances have occurred in the 1990s, with 1996 and 1997 being the only years on record with no retained accumulation since field observations were initiated in the glacier source areas in 1948.  相似文献   

5.
天山乌一号冰川物质平衡特征的统计分析   总被引：5，自引：1，他引：4  
利用天山乌鲁木齐河源一号冰川物质平衡的多年观测资料,通过数学统计方法提取主成分,获得影响该冰川物质平衡的主要因素,通过成分矩阵的旋转获得表示冰川物质平衡特征的两个主因子,其中第一主因子为影响冰川物质平衡的常年因子,代表该冰川的多年持续变化方向与趋势,第二主因子为影响冰川物质平衡的年际因子,代表该冰川在平衡年内的物质平衡变化特征。常年因子的持续下降反映了冰川持续后退的现实,年际因子在上世纪80年代中期以后突然强劲上升,实际上是冰川物质平衡水平提高,平衡年内积累量和消融量都增加的表现,清晰地指示了西北地区气候由暖干向暖湿的转型。常年因子是冰川物质平衡变化的主导因子,控制了冰川变化的方向。常年因子具有较好的周期性,以6年周期最为明显,但其形成原因尚不明。年际因子周期性不明显,但可以看出其周期与太阳黑子变化具有相关性,同时受到常年因子的影响。  相似文献   

6.
为认识全球变暖背景下中国西部大陆性冰川与海洋性冰川物质平衡变化及其对气候响应,本研究以天山乌鲁木齐河源1号冰川和藏东南帕隆94号冰川为例,结合大西沟与察隅站气象资料,对1980 — 2015年两条冰川的物质平衡变化特征及差异进行了分析。结果表明：36 a来乌源1号冰川与帕隆94号冰川物质平衡总体上均呈下降趋势,累积物质平衡达-17102与-8159 mm w.e.,相当于冰川厚度减薄19与9.01 m,且分别于1996、2004年左右发生突变。同期两条冰川所处区域年均温呈显著上升趋势,而降水量却表现出不同的变化态势;二者年内气温分配相仿,但降水分配差异较大。初步分析认为气温上升是导致乌源1号冰川与帕隆94号冰川物质亏损的主要原因,冰川区气温和降水变化幅度的差异和地性因子（坡度、冰川面积）的不同使得乌源1号冰川对气候变化响应的敏感性高于帕隆94号冰川,由于目前海洋性冰川物质平衡监测时段相对较短,为深入研究中国西部冰川物质平衡变化及过程仍需加强对冰川的持续观测。  相似文献   

7.
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.  相似文献   

8.
The evolution of Maladeta Glacier (Maladeta massif, central Spanish Pyrenees) since the Little Ice Age maximum is analyzed in this work. The extent of the glacier was mapped into 10 stages using morainic deposits and graphic documents. Climatic data (temperature and precipitation) were reconstructed by using dendroclimatic techniques complemented by recent instrumental records. The results thus obtained confirm the control of the above mentioned climatic factors, particularly annual temperature and winter precipitation, in the evolution of Maladeta Glacier, which has receded from an extent of 152.3 ha in 1820–1830 to 54.5 ha in 2000, a 35.7% reduction in size. The rate of ice wastage has varied during that period, defining several phases of glacial stabilization (1820–1830 to 1857; 1914–1920 to 1934–1935; 1957 to 1981), moderated glacial depletion (1901–1904 to 1914–1920; 1934–1935 to 1957) and marked glacial depletion (1857 to 1901–1904; 1981 to 2000). The evolution of Maladeta Glacier is also in keeping with trends observed from other alpine Mediterranean glaciers, which have experienced a consistent rise in their equilibrium line altitudes during the 19th and 20th centuries as well as associated and prolonged periods of negative mass balance.  相似文献   

9.
过去44年乌鲁木齐河源一号冰川物质平衡结果及其过程研究   总被引：12，自引：2，他引：10  
通过1997—2003年度天山乌鲁木齐河源一号冰川物质平衡的观测结果,分析比较了过去44年间一号冰川物质平衡、累积物质平衡的变化过程,以及反映气候一地形要素和冰川发育条件要素的平衡线高度和冰川积累区比率,认为一号冰川负平衡波动期随时间推移而递增,目前处于其观测历史上物质平衡亏损最为强烈的时期。  相似文献   

10.
The most labour-intensive and time-consuming part of many mass balance programmes is the acquisition of snow depth data. The standard technique, which involves probing the snow cover at intervals along a series of profiles, generally by an individual on skis, may involve more than 300 discrete measurements along a total of more than 20 km of profiling at a single glacier. Kinematic surveying with a global positioning system (GPS) in differential mode provides much more information about changes of glacier surface level and snow thickness between surveys. The positions of a large number of points can be fixed in a relatively short time by GPS surveying, and the technique is usable in adverse weather conditions. With real-time kinematic GPS surveying, it is possible to return to the same positions (longitude, latitude) during successive field programmes, and a previously followed route can be retraced precisely. GPS surveying facilitates the production of accurate glacier maps for mass balance programmes. Data obtained by snow depth probing and GPS surveying in 1995 at Austre Okstindbreen, the largest glacier of the Okstindan area, Norway (66°N), indicate that repeated GPS surveys are likely to provide a large amount of information on withinyear and between-year changes of surface topography and are not subject to the errors in mass balance calculations which arise from probing snow depths along selected profiles. Kinematic GPS surveying of several glaciers within an area would overcome the difficulties arising when mass balance studies are confined to a single glacier within a particular area.  相似文献   

11.
Small mountain glaciers have short mass balance response times to climate change and are consequently very important for short‐term contributions to sea level. However, a distinct research and knowledge gap exists between (1) wider regional studies that produce overview patterns and trends in glacier changes, and (2) in situ local scale studies that emphasise spatial heterogeneity and complexity in glacier responses to climate. This study of a small glacier in central Austria presents a spatiotemporally detailed analysis of changes in glacier geometry and changes in glaciological behaviour. It integrates geomorphological surveys, historical maps, aerial photographs, airborne LiDAR data, ground‐based differential global positioning surveys and Ground Penetrating Radar surveys to produce three‐dimensional glacier geometry at 13 time increments spanning from 1850 to 2013. Glacier length, area and volume parameters all generally showed reductions with time. The glacier equilibrium line altitude increased by 90 m between 1850 and 2008. Calculations of the mean bed shear stress rapidly approaching less than 100 kPA, of the volume–area ratio fast approaching 1.458, and comparison of the geometric reconstructions with a 1D theoretical model could together be interpreted to suggest evolution of the glacier geometry towards steady state. If the present linear trend in declining ice volume continues, then the Ödenwinkelkees will disappear by the year 2040, but we conceptualise that non‐linear effects of bed overdeepenings on ice dynamics, of supraglacial debris cover on the surface energy balance, and of local topographically driven controls, namely wind‐redistributed snow deposition, avalanching and solar shading, will become proportionally more important factors in the glacier net balance.  相似文献   

12.
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。  相似文献   

13.
The movement of a glacier can redistribute glacier mass balance and change water and thermal conditions of the glacier.Thus,the glacier can maintain its dynamic balance.Surface velocity of a glacier is a basic feature of glacier movement.With successive monthly observations from 2006 to 2008,we obtained spatial and temporal variations for surface velocity of Glacier No.1 at the headwater of Urumqi River,Tianshan Mountain.Dynamic simulation was used to verify the findings.Results show that altitudinal distribution of glacier velocity was influenced by synthetic effects such as glacier thickness,slope,and bedrock morphology.However,seasonal variation was influenced by changing glacier thickness.  相似文献   

14.
Feature tracking of orthorectified pairs of Advanced Spaceborne Thermal Emission and Reflection Radiometer satellite images is used to calculate velocities for the Tasman Glacier, New Zealand (2002–2014) and the Khumbu Glacier, Nepal (2001–2008). Velocities in the middle and upper ablation zones of both glaciers show a long‐term decrease of ～10–20%, while the terminus of Khumbu Glacier has remained near stagnation throughout the study period. In contrast, there has been a recent acceleration of the lower terminus of Tasman Glacier, from ～5 m a–1 in 2002 to 40 m a–1 in 2014. Both of these glaciers have an extensive supraglacial debris cover across their lower ablation regions, with the Khumbu Glacier terminating on land and the Tasman Glacier terminating in a proglacial lake. The rapid recent increase in velocity of the terminus of Tasman Glacier is closely correlated with the increase in size of its proglacial lake. These results indicate the complex dynamic changes that mountain valley glaciers may undergo in response to long‐term negative mass balance.  相似文献   

15.
A glacier mass balance model that requires only low-altitude precipitation and temperature observations and the glacier's areaaltitude distribution is presented as an alternative to direct field measurements. Input to the model for South Cascade Glacier are daily weather observations at stations 30–60 km from the glacier and at altitudes 1300 to 1500 m lower than the glacier. The model relies on the internal consistency of mass balance variables that are generated by simulation using the low-altitude weather data. The daily values of such balance variables as snowline altitude, zero balance altitude, glacier balance, balance flux and the accumulation area ratio are correlated throughout the ablation season using two-degree polynomial regressions to obtain the lowest fitting error. When the minimum average error (or maximum R 2) is attained, the generated balances and other variables are considered to be real. A simplex optimization technique is used to determine the optimal coefficient values that are used in algorithms to convert meteorological observations to snow accumulation and snow and ice ablation. The independently produced simulation results for the 1959–1996 period are compared with balances measured at the glacier. The agreement between annual balances for individual years is fair and between long-term volume changes measured by the geodetic method is excellent.  相似文献   

16.
Worldwide examination of glacier change is based on detailed observations from only a small number of glaciers. The ground-based detailed individual glacier monitoring is of strong need and extremely important in both regional and global scales. A long-term integrated multi-level monitoring has been carried out on Urumqi Glacier No. 1 (UG1) at the headwaters of the Urumqi River in the eastern Tianshan Mountains of Central Asia since 1959 by the Tianshan Glaciological Station, Chinese Acamedey of Sciences (CAS), and the glaciological datasets promise to be the best in China. The boundaries of all glacier zones moved up, resulting in a shrunk accumulation area. The stratigraphy features of the snowpack on the glacier were found to be significantly altered by climate warming. Mass balances of UG1 show accelerated mass loss since 1960, which were attributed to three mechanisms. The glacier has been contracting at an accelerated rate since 1962, resulting in a total reduction of 0.37 km2 or 19.3% from 1962 to 2018. Glacier runoff measured at the UG1 hydrometeorological station demonstrates a significant increase from 1959 to 2018 with a large interannual fluctuation, which is inversely correlated with the glacier's mass balance. This study analyzes on the changes in glacier zones, mass balance, area and length, and streamflow in the nival glacial catchment over the past 60 years. It provides critical insight into the processes and mechanisms of glacier recession in response to climate change. The results are not only representative of those glaciers in the Tianshan mountains, but also for the continental-type throughout the world. The direct observation data form an essential basis for evaluating mountain glacier changes and the impact of glacier shrinkage on water resources in the interior drainage rivers within the vast arid and semi-arid land in northwestern China as well as Central Asia.  相似文献   

17.
Correlograms from multiple time series of point mass balance, measured on White Glacier (Axel Heiberg Island, Canada) and Abramov Glacier (Alai Range, Kirgizia), show that the correlation decreases with the difference in elevation between the points. The correlogram is used to calculate an integral spatial scale or effective sample area which, when divided into the area of the glacier, yields an estimate of the number of degrees of freedom in a stake-based estimate of the whole-glacier balance. This number – the 'effective sample size'– is a small fraction of the number of point measurements; indeed, it is independent of the number of measurements. Estimates of average balance for elevation bands are at one remove from raw stake measurements, but they are amenable to a principal component analysis which confirms that the effective sample size is very small. The small effective sample size means that uncertainty in a typical measurement of whole-glacier mass balance cannot be much less than the large value implied by the conservative assumption that stakes are perfectly correlated. One way around this difficulty would be to increase the role of prior physical understanding by seeking to model the spatial variability of mass balance. A successful model would need only a few parameters, and would allow for the joint estimation of both magnitude and uncertainty; the uncertainty in mass balance could be derived objectively from the uncertainty in the parameters. This, however, would require good estimates of the variability of mass balance at the elevation-band scale, which might in turn require that many measurement networks be redesigned.  相似文献   

18.
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.  相似文献   

19.
Glacier mass balance is more sensitive to warming than cooling, but feedbacks related to the exposure of previously buried firn and ice in very warm years is not generally considered in sensitivity studies. A ground‐penetrating radar survey in the accumulation area of Rolleston Glacier, New Zealand shows that five years of previous net accumulation was removed by melt from parts of the glacier above the long‐term equilibrium line altitude during a single negative mass balance year. Rolleston Glacier receives a large amount of accumulation from snow avalanches, which may temporarily buffer it from climate warming by providing additional mass that has accumulated at higher elevations, effectively increasing the elevation range of the glacier. However, glaciers reliant on avalanche input may have high sensitivity to climatic variations because the extra mass is concentrated on a small part of the glacier, and small variations in avalanche input could have a large impact on overall glacier accumulation. Further research is needed to better estimate the amount and spatial distribution of accumulation by avalanche in order to quantify the climate sensitivity of small avalanche‐fed glaciers.  相似文献   

20.
极地记录冰川和达尔克冰川流速的遥感监测研究   总被引：1，自引：0，他引：1       下载免费PDF全文
测定南极冰川的流速 ,对于研究南极冰雪物质平衡、南极环境变化及其对全球环境的影响有重大意义。本文论述了利用多时相卫星遥感影像监测冰川变化的原理和方法 ,通过对英格里特 .克里斯泰森海岸不同时期的遥感影像进行几何纠正和配准及叠加处理 ,测量和计算出极地记录冰川和达尔克冰川的平均流速 ,并对它们的变化特点进行了初步的分析和评价。  相似文献   

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