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1.
Digital terrain modelling using Corona and ALOS PRISM data to investigate the distal part of Imja Glacier, Khumbu Himal, Nepal 总被引：2，自引：2，他引：0
This study used Corona KH-4A and Advanced Land Observing Satellite (ALOS) PRISM images to generate digital terrain models (DTMs) of the distal part of Imja Glacier,where a few supraglacial ponds (～0.07 km 2) expanded into the large Imja Glacier Lake (Imja Tsho,～0.91 km 2) between 1964 and 2006.DTMs and subsequently derived topographical maps with contour intervals of 1 m were created from the high-resolution images (Corona in 1964 and ALOS in 2006) in the Leica Photogrammetric Suite (LPS) platform.The DTMs and topographic maps provided excellent representation of the elevation and micro-topography of the glacier surface,such as its supra-glacial ponds/lake,surface depressions,and moraine ridges,with an error of about +/-4 m (maximum).The DTMs produced from the Corona and ALOS PRISM images are suitable for use in studies of the surface change of glaciers.The topographical maps produced from the Corona data (1964) showed that part of the dead ice in the down-glacier area was even higher than the top of the lateral moraine ridges,while the glacier surface in the up-glacier area was noticeably lower than the moraine crests.This suggests more extensive melting of glacier ice in the up-glacier area before 1964.The average lowering of the glacier surface from 1964 to 2006 was 16.9 m for the dead-ice area west of the lake and 47.4 m for the glacier surface east of the lake;between 1964 and 2002,the lake surface lowered by 82.3 m.These figures represent average lowering rates of 0.4,1.1,and 2.2 m/year for the respective areas. 相似文献
2.
帝企鹅是南极生态的指示器,其种群栖息地分布变化对研究南极气候具有重要意义,但传统的人工实地调查难以获取全面、准确的种群栖息地信息。本文依据帝企鹅种群排泄物在卫星影像上的蓝、红波段和近红外与短波红外波段的反射率差异,提出2种可以有效判别种群排泄物的光谱指数（NDII、EI）,据此精确识别帝企鹅种群排泄物并确定其种群栖息地位置。根据2009年195景时相合适、质量较好的Landsat 7 ETM+卫星影像,获取了南极共计38个帝企鹅种群栖息地,其中新发现7处（Bowman Island , Dibble Glacier , Auster, Point Geologie , Cape Crozier , Brownson Islands和Rupert Coast）,消失2处（Amundsen Bay 和Ledda Bay）,另外25处（除Thuston Glacier, Luitpold, Sanae, Gould, Ragnhild和Beaufort Island外）位置未发生明显变化,实现了全南极帝企鹅种群栖息地的识别与定位。种群栖息地提取的正确率为94%,提取结果受限于影像质量和种群规模,且随着种群规模的提高,该方法的提取效果也越好。帝企鹅种群栖息地的分布与气候要素息息相关,种群栖息地往往倾向于气温较低和海冰密集度较高的区域,气候变化对每个种群栖息地的影响不同,因此气候与种群栖息地变化的具体关系需要长时间、区域性的观测进行研究。随着气温持续上升和海冰密集度的变化,南纬70°以北的种群栖息地面临较大的威胁,帝企鹅种群呈现向极点逐渐收缩的趋势。 相似文献
3.
????2004??2008???ICESat???????????????GLA12???????????????????????????????????????仯????????????????????????????????????仯??????????????????????????????3 m??????????????????????仯????????????????????????????????? 相似文献
4.
Determination of ice thickness, subice topography and ice vol-ume at Glacier No. 1 in Tien Shan, China by ground penetrating radar 总被引：1，自引：0，他引：1
We describe a radio-echo sounding (RES) survey for the determination of ice thickness, subglacial topography and ice volume of Glacier No. 1 , in Tien Shan, China, using ground-penetrating radar (GPR). Radar data were collected with 100-MHz antennas that were spaced at 4 m with a step size of 8 m. The images produced from radar survey clearly show the continuity of bedrock echoes and the undulation features of the bedrock surface. Radar results show that the maximum ice thickness of Glacier No. 1 is 133 m, the thickness of the east branch of Glacier No. 1 averages at 58. 77 m while that of the west branch of Glacier No. 1 averages at 44. 84 m. Calculation on ice volume indicates that the ice volume of the east branch of Glacier No. 1 is 51. 87 × 106 m3 and that of the west branch of Glacier No. 1 is 20. 21 × 106 m3. The amplitude of the undulation of the bedrock surface topography revealed by radar profiles is larger than that of the glacier surface topography, indicating that the surface relief does 相似文献
5.
Bijeesh KOZHIKKODAN VEETTIL Ulisses FRANZ BREMER Atilio EFRAIN BICA GRONDONA Sergio FLORENCIO DE SOUZA 《山地科学学报》2014,11(2):398-406
Recent changes occurred in terminus of the debris-covered Bilafond Glacier in the Karakoram Range in the Himalayas, Northern Pakistan was investigated in this research. Landsat MSS, TM and ETM＋ images were used for this study. Digital elevation models derived from ASTER GDEM and SRTM were also utilized. Visible, infrared and thermal infrared channels were utilized in order to get accurate glacier change maps. Three methods were tried to map this debris-covered glacier in this research. The glacier has been mapped successfully and the changes in the glacier terminus from 1978 to 2011 have been calculated. Manual, semi-automatic and thermal methods were found to give similar results. It was found that the glacier has undergone serious ablation during this period despite of the fact that many of the larger glaciers in the Hindu Kush and Karakoram mountain regions in the Upper Indus Basin were reported to be expanding. The terminus has been moved back about 600 meters during this period and there was an abrupt change in the glacier terminus during 1990-2002. We propose that debris thickness is not the only factor that influences the glacier ablation but the altitude of the debris-covered glacier as well. Many glaciers in the Karakoram region reported to be expanding were having higher altitudes compared to the study area. 相似文献
6.
7.
Ken MacClune 《山地科学学报》2010,7(1):1-14
A high-resolution 2000-year methane record has been constructed from an ice core recovered at 7200 m a.s.l. on the Dasuopu Glacier in the central Himalayas. This sub-tropical methane record reveals an increasing trend in the concentration of methane during the industrial era that is similar to observations from polar regions. However, we also observed the differences in the atmospheric methane mixing ratio between this monsoon record and those from polar regions during pre-industrial times. In the time interval 0-1850 A.D., the average methane concentration in the Dasuopu ice core was 782±40 ppbv and the maximum temporal variation exceeded 200 ppbv. The difference gradient of methane concentration in Dasuopu ice core with Greenland and Antarctica cores are 66±40 ppbv and 107±40 ppbv, respectively. This suggests that the tropical latitudes might have acted as a major global methane source in pre- industrial times. In addition, the temporal fluctuation of the pre-industrial methane records suggests that monsoon evolution incorporated with high methane emission from south Asia might be responsible for the relatively high methane concentration observed in the Dasuopu ice core around A.D. 800 and A.D. 1600. These results provide a rough understanding of the contribution of tropical methane source to the global methane budget and also the relationship between atmospheric methane and climate change. 相似文献
8.
The colorful satellite image maps with the scale of 1∶100 000 were made by processing the parameters-on-satellite under the condition of no data of field surveying. The purpose is to ensure the smooth performance of the choice of expedition route, navigation and research task before the Chinese National Antarctic Research Expedition (CHINARE) first made researches on the Grove Mountains. Moreover, on the basis of the visual interpretation of the satellite image, we preliminarily analyze and discuss the relief and landform, blue ice and meteorite distribution characteristics in the Grove Mountains.
Key words Grove Mountains, parameters-on-satellite, satellite image, digital mapping, blue ice, meteorites distribution. 相似文献
9.
The glaciers Austre Lovenbreen and Pedersenbreen are located at Ny-Alesund, Svalbard. The surface mass balance and ice flow velocity of both glaciers have been determined from the first year of observations (2005/2006), while the front edge of Austre Lovenbreen was also surveyed. The results are as follows : (1) The net mass balances of Austre Lovenbreen and Pedersenbreen are -0. 44 and -0. 20 m w. e. , the annual ablation is -0. 99 and -0. 94 m w. e. . and the corresponding equilibrium line altitudes are 478. 10 and 494. 87 m, respectively. (2) Austre Lovenbreen and Pedersenbreen are characterized as ice flow models of surge-type glaciers in Svalbard. The horizontal vectors of the ice flow velocities are parallel or converge to the central lines of both glaciers, with lower velocities in the lower ablation areas and higher velocities in the middle and upper reaches of the glaciers. The vertical vectors of ice flow velocities show that there is a mass loss in the ablation areas, which reduces with increasing altitude, while there is a mass gain near the equilibrium line of Austre Lovenbreen. (3) The front edge of Austre Lovenbreen receded at an average rate of 21. 83 m·a-1, with remarkable variability-a maximum rate of 77. 30 m·a-1 and a minimum rate of 2. 76 m·a-1. 相似文献
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11.
In this paper, by using ocean surface temperature data (COADS), the study is made of the characteristics of the monthly and annual changes of the SST in the tropical western Pacific and Indian Oceans, which have important influences on the climate change of the whole globe and the relation between ENSO(E1 Nino-Southern Oscillation) and the Antarctic ice area is also discussed. The result indicates that in the tropical western Pacific and the Indian Oceans the change of Sea Surface Temperture (SST) is conspicuous both monthly and armaully, and shows different change tendency between them. This result may be due to different relation in the vibration period of SST between the two Oceans. The better corresponding relationship is obvious in the annual change of SST in the tropical Indian Ocean with the occurrence El Nino and LaNlra. The change of the SST in the tropical western Pacific and the tropical Indian Oceans has a close relation to the Antarctic ice area, especially to the ice areas in the eastern-south Pole and Ross Sea, and its notable correlative relationship appears in 16 months when the SST of the tropical western Pacific and the Indian Oceans lag back the Antarctic ice area. 相似文献
12.
Ｓｔｕｄｉｅｓｓｈｏｗｔｈａｔｔｈｅｇｌｏｂａｌｓｕｒｆａｃｅｔｅｍｐｅｒａｔｕｒｅｗｉｌｒｉｓｅａｔａｒａｔｅｏｆ０．３℃ｐｅｒ１０ａｉｎｔｈｅｎｅｘｔｓｅｖｅｒａｌｄｅｃａｄｅｓ（Ｈｏｕｇｈｔｏｎｅｔａｌ．,１９９０,１９９２;Ｓｈｉ,１９９５;... 相似文献
13.
This study reports on the clean ice area and surface elevation changes of the Khersan and Merjikesh glaciers in the north of Iran between 1955 and 2010 based on several high to medium spatial resolution remote sensing data.The object-oriented classification technique has been applied to nine remote sensing images to estimate the debris-free areas.The satellite-based analysis revealed that the clean ice areas of Khersan and Merjikesh glaciers shrank since 2010 with an overall area decrease of about 45% and 60% respectively.It means that the dramatic proportions of 1955 glaciers surface area are covered with debris during the last five decades.Although the general trend is a clean ice area decrease,some advancement is observed over the period of 1997-2004.During 1987-1991 the maximum decrease in the clean ice area was observed.However,the clean ice area had steadily increased between 1997 and 2010.To quantify the elevation changes besides the debris-free change analysis,several Digital Elevation Models(DEMs) were extracted from aerial photo(1955),topographic map(1997),ASTER image(2002) and Worldview-2 image(2010) and after it a 3-D Coregistration and a linear relationship adjustments techniques were used to remove the systematic shifts and elevation dependent biases.Unlike the sinusoidal variation of our case studies which was inferred from planimetric analysis,the elevation change results revealed that the glacier surface lowering has occurred during 1955-2010 continuously without any thickening with the mean annual thinning of about 0.4 ± 0.04 m per year and 0.3 ± 0.026 m per year for Khersan and Merjikesh glaciers,respectively.The maximum thinning rate has been observed during 1997-2002(about 1.1 ± 0.09 per year and 0.96 ± 0.01 mper year,respectively),which was compatible partially with debris-free change analysis.The present result demonstrates that although in debris-covered glaciers clean ice area change analysis can illustrate the direction of changes(retreat or advance),due to the high uncertainty in glacier area delineation in such glaciers,it cannot reveal the actual glacier changes.Thus,both planimetric and volumetric change analyses are very critical to obtain accurate glacier variation results. 相似文献
14.
????????????????y?????GOCE???????????10??60??ε?????????????????GOCE??гλ????в?????????????????????????????????з????????30°??Χ????????仯??????????GOCE??????????????B????(-75°, 250°)???????仯??-9.15 cm/a????B??????????????????? 相似文献
15.
利用CSR提供的GRACE时变重力场数据反演2003~2016年南极地区冰盖质量变化。结果表明,南极地区冰盖整体呈现消融趋势,消融速率为（-101.27±7.02） Gt/a,且在不断加速。EA以质量积累为主,速率为（69.09±2.64） Gt/a,但近期速率大幅减小;WA冰盖消融速率为（-148.35±6.78） Gt/a,表现为加速消融趋势,为南极冰盖质量消融的主要地区;AP消融速率为（-22.01±1.44） Gt/a,变化相对平稳。 相似文献
16.
南极洲被巨厚冰雪覆盖,地质构造以南极横断山脉为界,总体分为东南极地盾和西南极活动带。数字高程模型（DEM）是研究南极冰盖变化的基础数据之一。通过多期次数字高程模型相比较获得高程的变化信息,是分析南极冰盖厚度变化和物质平衡的重要手段。然而不同类型DEM之间存的平面误差和垂直误差影响分析结果的精度。首先利用配准消除DEM间的水平误差,然后计算并按坡度提取CryoSat DEM与其他DEM的平均高程差和标准差,最后分析高程差的时空变化特征。通过分析发现,DEM之间存在不同的平面误差。其中TanDEM_X DEM与CryoSat DEM的高程平面偏差最小,而ICESat DEM与CryoSat DEM的高程平面偏差最大。在垂直方向上,0°~1°的坡度范围内,CryoSat DEM与TanDEM_X DEM的平均高程差在3.5~5.5 m之间,标准差小于18.0 m;CryoSat DEM和Bamber 1km DEM的平均高程差在-2.5~+1.0 m之间,标准差小于24.2 m;CryoSat DEM与ICESat DEM的平均高程差在-25.0~-1.0 m之间,标准差小于47.2 m;CryoSat DEM与RAMPv2 DEM的平均高程差在1.3~3.2 m之间,标准差小于45.6 m。通过研究发现南极冰盖内部高程增加,但西南极冰盖和东南极冰盖高程均在降低,且西南极降低明显,同时南极边缘地区高程降低明显。本研究为全球变化研究和南极物质平衡研究提供了重要参考。 相似文献
17.
1 Introduction Nowadaysglobalclimatechangehasbeenanimportantissueintheworld.Antarctic areaisjustthekeyandsensitiveregion,fromwhichscientistsaretryingtheirbesttofind theomenofglobalclimatechange.Andfortherevolvingglobalatmosphere,PolarRegions arecoldsource.TheoceanicandatmosphericconditionofPolarRegionsisimportantto globalatmosphericcirculationandclimatechange.Antarcticareaisoneofthecoldsources ofglobalearth atmospheresystem,whileequatorialareaisitsmainheatsource(seeZhou andLuetal.1996).… 相似文献
18.
国际南极大地参考框架的构建与进展 总被引：10，自引：2，他引：8
回顾了南极大地参考框架发展的历史,总结了由国际南极研究科学委员会(SCAR)组织的历次南极地区大地测量观测活动的成果,并结合2007~2008第四次国际极地年(IPY)对南极大地参考框架的前景进行了展望,其中重点介绍了我国对构建南极大地参考框架的贡献。 相似文献
19.
基于GRACE时变重力场反演南极冰盖质量变化 总被引：1，自引：0，他引：1
利用UTCSR发布的GRACE Level-2 RL04版本2003-01—2008-08月的重力场模型估计南极冰盖质量变化。由于GRACE提供的C20项不准确,利用SLR测得的C20项进行替换。对于经度方向上出现的条纹状信号,采用去相关滤波处理。选择去掉其中某一个月的位模型重新反演南极冰盖质量变化,发现相同区域的质量变化率并没有发生很大的变化。联合得到的位模型、滤波技术以及ICE-5G冰后回弹模型观测到的西南极Amundsen地区和南极半岛的冰盖质量消融现象,其等效水高变化分别为-5.28±0.95 cm/a、-1.82±0.77 cm/a;而Ronne冰架以及东部Enderby地区冰盖质量在增加,分别为1.42±0.69 cm/a、1.43±0.72 cm/a。与已有研究结果比较发现：西南极冰盖质量在加速融化,而Ronne冰架以及东部Enderby地区冰盖等效水高变化率没有发生大的变化。 相似文献
20.
1 IntroductionManymeteorologistsandoceanographerspaidmuchattentiontothestudyofthemechanismofENSOformanyyears,suchasBjerknes(1 966) ,Wyrtki(1 975) ,McCreary(1 983 ) ,Philander(1 984) ,ZhangandChao(1 993 )andMcCPhaden(1 998)havemadegreatdevelopmentinthestudyofENSO .Especiallyinthe 1 990’s,withtheincreasingofthedatainthedeepocean ,thesomeonearguedthattheENSOepisodehadcloserelation shipwiththeeasterntransportationoftheanomalousseasurfacetemperatureinthewestPacific(LiandMu 1 999;Huang 2… 相似文献