共查询到19条相似文献，搜索用时 156 毫秒
1.
东南极Lambert冰川流域表面雪层中稳定同位素分布及近几十年来的气候变化(英) 总被引：8，自引：1，他引：7
The Lambert Glacier basin is one of particular regions in East Antarctica, because of its distinctive topography. During the repeat inland traverses carried out in recent several years, surface 2 m snow samples and shallow (10～27 m deep) cores were collected at several ten stations and at near ten stations, respectively. The stable isotopic ratios of these samples and cores were measured in order to investigate the relation of isotopes with temperature and to study the climatic change in recent decades over this area. The correlation between isotopic ratios and mean annual temperature gives that δ-temperature gradient is relatively close to that along a traverse route between Vostok and Mirnyy stations. The inconsistency of δ18O profiles of these cores makes it difficult to distinguish an overall trend of climatic change in past decades. After incorporating the result of snow accumulation variability and temperature record over 30 years at the coast station, it is believed that climate was in a little cooling and drying from 1950s to 1980s and has been in a warming period since then. 相似文献
2.
Ship-based sea ice observation data (concentrations,ice thickness,topography and overlying snow cover) were collected from Middle Weddell Sea to Prydz Bay,Antarctic during the period of 4 to 17 Jan 2003.Antarctic ice chart of first week of Jan 2003 was derived from National Ice Center (NIC).The compared analysis of sea ice concentrations and thickness distributions were conducted though in situ data and NIC chart.Results from sea ice concentration-analysis indicated the presence of large-scale open water between 2000 and 4100 km along transit route resulted from sea ice drifting.We describe the existence of mostly smooth first-year sea ice in study region ranged between 30 and 120 era.We also display the derived overlying snow coverage.Our results reveal the strong correspondence between ship-based observations and remotely sensed ice charts whatever in ice concentrations and ice thickness distributions. 相似文献
3.
WANG Zi-Pan 《冰川冻土》1998,(4)
Ecological investigation has been done in some saline lakes in the Vestfold Hills (60°38'S, 78°06' E), East Antarctica. The results show that changes of natural environment and physicalchemical factors, as well as the structure of biotic species and succession do occur in some lakes, due to seasonal and local climate changes and geographic variances in regions. These should be strong ecological proofs to explain that the processes of globle climate change and ice sheet retreating, and isostatic uplift raising, could be continueing in present time, and should be significant to the study on Antarctic and global changes. 相似文献
4.
We present relative sea level （RSL） curves in Antarctica derived from glacial isostatic adjustment （GIA）predictions based on the melting scenarios of the Antarctic ice sheet since the Last Glacial Maximum （LGM）given in previous works.Simultaneously,Holocene-age RSL observations obtained at the raised beaches along the coast of Antarctica are shown to be in agreement with the GIA predictions.The differences from previously published ice-loading models regarding the spatial distribution and total mass change of the melted ice are significant.These models were also derived from GIA modelling; the variations can be attributed to the lack of geological and geographical evidence regarding the history of crustal movement due to ice sheet evolution.Next,we summarise the previously published ice load models and demonstrate the RSL curves based on combinations of different ice and earth models.The RSL curves calculated by GIA models indicate that the model dependence of both the ice and earth models is significantly large at several sites where RSL observations were obtained.In particular,GIA predictions based on the thin lithospheric thickness show the spatial distributions that are dependent on the melted ice thickness at each sites.These characteristics result from the short-wavelength deformation of the Earth.However,our predictions strongly suggest that it is possible to find the average ice model despite the use of the different models of lithospheric thickness.By sea level and crustal movement observations,we can deduce the geometry of the post-LGM ice sheets in detail and remove the GIA contribution from the crustal deformation and gravity change observed by space geodetic techniques,such as GPS and GRACE,for the estimation of the Antarctic ice mass change associated with recent global warming. 相似文献
5.
正1 Introduction Cold environments on the planet occur in the Antarctic,the Arctic and high mountains which cover with ice and snow permanently.Microorganism adapted to cold habitats has been detected,but most of them were prokaryotes.(Morgan-Kiss et al,2006;jungbut et al,2012).Research on cold-adapted microorganism has 相似文献
6.
Zhouqing XIE Siqi XU Liguang SUN Yuying HUANG Wei HE 《中国地球化学学报》2006,25(B08):196-196
In this study, we applied synchrotron radiation X-ray fluorescence technique （SR-XRF） to investigate the heavy metals including Hg and Pb in a few single strands of pinnule of the outermost wing feather of snow petrel （Pagodroma Nivea） collected in the Antarctic. The microscopic distributions of Hg and Pb along with the strand of pinnule show significant variation and the types of distribution are different for pinules, suggesting that external contamination may have an important impact on the levels of Hg and Pb, rather than reflecting levels in the blood during feather formation. This should be taken into account in future monitoring studies. The sources of Hg and Pb detected in the feather were also discussed. Using feathers of snow petrel to investigate the springtime mercury depletion events （MDEs） in the Antarctic were proposed. 相似文献
7.
The Antarctic continent and surrounding oceans,which are cold and isolated from human activities,constitute a key region for multidisciplinary investigations.Since the early interest during the International Geophysical Year （IGY） during 1957-1958,numerous scientific studies have so far been carried out in Antarctica by different countries,which have provided important insights into Earth and environmental processes such as regional climate warming and its effect to biodiversity,changes in ice sheet and ocean circulation,ozone depletion,and origin and evolution of continents.The challenge of the next phase of Antarctic research will be to integrate all fields of science into a holistic understanding of Earth and life processes of the Antarctic region.In this thematic issue of Geoscience Frontiers,we assemble a set of scientific papers related to geomorphology,biology,molecular spectroscopy,and geology reflecting the recent research activity in the Antarctic region. 相似文献
8.
Extent and chronology of Quaternary glaciation 总被引：1，自引：0，他引：1
Jurgen Ehlers Philip Gibbard 《《幕》》2008,31(2):211-218
In a recent INQUA project the extent of Pleistocene glaciations has been digitally mapped and the chronology of events reviewed. The onset of the present Ice Age in both hemispheres dates back to the Palaeogene. In Greenland, Iceland, North America and southernmost South America sizeable ice sheets formed well before 2.6 ka BP. In Alaska and on Tierra del Fuego the ice advanced further than in any later glaciations. Evidence for Early Pleistocene glaciation （2.6-0. 78 Ma） has been reported from many parts of the world, but in most cases dating remains problematic, and the size of the glaciers and ice sheets is unknown. 相似文献
9.
Methanesulphonate was investigated as a potential contributor to the sulphur budget based on the analysis on Antarctic snow/ice from Coffins Ice Cap, King George Island (62°10' S, 58°50,W). The anion was found to be present at a mean concentration of 0. 17 μeq. L-1 with a maximum of 0.73 μeq. L-1. A distinct seasonal variation exists in the top 10 m of the core, equivalent to more than two years of deposition. Dating resulted from δ18O profile suggests that the principal peaks of methanesulphonate are associated with snow deposited in autumn and secondary peaks in spring. The seasonal patterns of methanesulphonate in the subantarctic snow displays a phase difference from that observed in marine air from low and middle latitudes. 相似文献
10.
Eric W Wolff 《《幕》》2008,31(2):219-221
The later parts of the Quaternary are of particular importance for assessing our ability to understand the future operation of the Earth because the main boundary conditions are similar to those of today, and because we have a density of data that allows hypotheses to be tested rigorously. An important source of such data is Antarctic ice cores, now extending back 800 ka, and containing signals both of climate, and of climate forcing factors. The Antarctic ice core deuterium record, representing Antarctic temperature, is one of the iconic Quaternary records. 相似文献
11.
中国南极冰川学研究10年回顾与展望 总被引：2，自引：0，他引：2
扼要回顾中国南极冰川学研究历程,当前国际南极冰川学研究背景和发展趋势,并从南极冰盖雪冰物理特征研究,冰盖气候环境记录的现代过程研究以及冰芯研究等方面总结我国南极冰川学研究取得的成果,认为８０年代后期以来,中国南极冰川研究成果显著,尤其是对南冰盖气候环境记录的现代过程研究取得了很大进展,居于国际研究的前沿地位。 相似文献
12.
Concentrations of lead have been measured by ultraclean Isotope Dilution Mass Spectrometry in snow cores covering the last two centuries collected at an inland site in East Antarctica using an ultra clean all plastic hand operated auger and in a prehistoric blue ice block collected at an Antarctic coastal site. Lead contamination of 16 to 200 pg Pb/g existed on the outside of the snow cores, but the measured concentrations decreased more or less abruptly along a radius from the outside to the centers of the snow cores, establishing interior values in the 1 to 5 pg Pb/g range. Some of these interior values are however possibly still slightly affected by lead contamination which could have intruded to the center of the cores because of slight melting of some of the snow cores before laboratory analysis. The interior of the blue ice block appears not to have been significantly contaminated, and contains about 1.7 pg Pb/g.These new data show that most previously published data on lead in Antarctic snow and ice were in high positive error because of contamination during field sampling, laboratory analysis or both. They show that lead concentrations could not have increased in Antarctic snows or ice from prehistoric times to present more than 2 to 3 fold, confirming that the remote polar areas of the Southern Hemisphere are still little affected by industrial lead pollution. Prehistoric Antarctic ice is shown to contain about 1 pg Pb/g natural excess lead above silicate dust lead; this excess cannot be entirely accounted for by volcanoes or sea spray, which suggests the possible existence of some other unknown natural source of prehistoric excess lead. Present day mean eolian fallout flux of lead in Antarctica is estimated to be about 0.07 ng Pb cm?2 yr?1, which stands in about the same proportion to that in the South Pacific Westerlies (about 1:30) as the flux in Greenland is observed to stand to those in the North Pacific and North Atlantic Westerlies. 相似文献
13.
东南极冰盖中山站－DOme A断面路线考察的初步结果 总被引：7，自引：11，他引：7
1996年以来，中国国家南极考察队连续3次进行了南极冰盖内陆考察，最远点距海岸1100km,海拔3900米，沿考察路线对冰盖表面地形，表面雪层特征，雪积累速率，冰体厚度和运动速度等进行现场观测，采集0．6－3．3米深度雪坑样品，在4个地点钻取50－100m，深度冰芯5支，部分资料和样品的初步分析表明，由于研究区域毗邻Lambert冰川和格罗夫山，冰面地形较多起伏，中段很大区域坡面朝向Lambert冰川，自中山站向内陆460km积累速率为46－210kg.m^-2.a^-1(相当于12－60厘米厚度雪层），表面1米深度雪的密度为350－450kg/m^-3，雪变成冰的深度（密度达830kg.m^-3)在几个冰芯钻取地点大约为60米，说明研究区域内雪的变质过程基本相同，300km处50米冰芯初步分析显示，过去几十年积累速率和温度均呈上升趋势，这虽然与南极地区其他针点的结果相一致，但却和毗邻的Lambert冰川西侧研究结果相反。 相似文献
14.
The mass balance of the Antarctic Ice Sheet has been calculated based on instrumental estimates of the grounded ice discharge
and snow accumulation data. The boundaries and sectional areas of the main ice catchment basins in West and East Antarctica
have been determined, and the data on the grounded ice discharge and snow accumulation in these basins have been systematized.
The intensity of accumulation and ablation processes in Antarctica has noticeably increased over the last 50 years. The mass
balance of the ice sheet in East Antarctica has been and remains positive, while in West Antarctica it was positive in the
middle of the last century and has become negative by now. The mass balance of the entire Antarctic Ice Sheet has been and
remains positive, while the mass growth has noticeably decreased over the last 50 years. 相似文献
15.
随着国际横穿南极科学考察计划的实施, 近年来开展了沿中山站-Dome A考察路线的冰芯研究, 获得了伊丽莎白公主地250 a来气候环境变化的高分辨率记录. 通过与Lambert冰川流域西侧有关研究结果的对比, 揭示了该冰川谷地为东南极洲重要气候分界线的特征. 综合南极地区其它地点冰芯记录和冰盖变化研究结果, 发现以小冰期为代表的寒冷期在东南极洲较为明显, 在西南极洲则不明显, 甚或恰好相反, 表现为温暖阶段. 就东南极洲来说, 也存在明显的区域差异: 以Lambert冰川谷地为界, 东部地区, 如Wilkes Land (Law Dome), Victoria Land北部(Hercules Neve)等地, 小冰期冷期比较突出;西部地区, 如Dronning Maud Land和Mizuho高原, 情况不是很明确. Lambert冰川流域是非常特殊的地方, 虽然小冰期冷期也存在, 但1850年前后的显著高温和近100多年来的降温与南极洲其它地方都不一样, 而与南极半岛北侧一冰芯所给出的400 a温度变化记录极为相似, 我们尚不能解释为何如此遥远的两个地点具有很好的一致性而与其它地方则不一致. 相似文献
16.
南极地区自然界现存的冰雪体,是南极冰川学研究的对象。南极冰雪体及其变化对全球水体的分布和循环以及气候、环境演变具有十分重要的影响,因而使南极冰川学研究不仅在南极科学中处于主要地位,而且在全球变化研究中举足轻重。 南极冰盖巨厚的冰雪内保留有数十万年乃至上百万年地球环境和气候变化的详细记录,冰芯综合研究受到高度重视。目前,南极冰川学正在向大尺度宏观方向和冰体内部微观方向两个方面迅速发展,涉及的学科更加广泛。其热点为:1、冰盖的物质和动态平衡——海平面和气候变化;2、冰芯综合研究。 中国南极研究起步较晚,南极热的兴起仅是最近十年的事情,总体水平与国际先进水平相比存在较大差距。为此,笔者提下列几点建议:1、南极冰川学是一门国际性很强的学科,其研究工作只能从横向与各国同行相比,要求研究内容具有国际水平;2、为接近和达到国际水平,需要培养一批年富力强、德才兼备的南极冰川学科研骨干队伍;3、抓紧建设南极冰川学实验室的建设;4、切实加强国内各部门、各学科之间的联系和合作。 相似文献
17.
A total of 24 tephra-bearing volcanic layers have been recognized between 550 and 987 m depth in the Siple Dome A (SDM-A) ice core, in addition to a number already recognized tephra in the upper 550 m (Dunbar et al., 2003, Kurbatov et al., 2006). The uniform composition and distinctive morphological of the particles composing these tephra layers suggest deposition as a result of explosive volcanic eruptions and that the layers therefore represent time-stratigraphic markers in the ice core. Despite the very fine grain size of these tephra (mostly less than 20 microns), robust geochemical compositions were determined by electron microprobe analysis. The source volcanoes for these tephra layers are largely found within the Antarctic plate. Statistical geochemical correlations tie nine of the tephra layers to known eruptions from Mt. Berlin, a West Antarctic volcano that has been very active for the past 100,000 years. Previous correlations were made to an eruption of Mt. Takahe, another West Antarctic volcano, and one to Mt. Hudson, located in South America (Kurbatov et al., 2006). The lowest tephra layer in the ice core, located at 986.21 m depth, is correlated to a source eruption with an age of 118.1 ± 1.3 ka, suggesting a chronological pinning point for the lower ice. An episode of anomalously high volcanic activity in the ice in the SDM-A core between 18 and 35 ka (Gow and Meese, 2007) appears to be related to eruptive activity of Mt. Berlin volcano. At least some of the tephra layers found in the SDM-A core appear to be the result of very explosive eruptions that spread ash across large parts of West Antarctica, off the West Antarctic coast, as well as also being recognized in East Antarctica (Basile et al., 2001, Narcisi et al., 2005, Narcisi et al., 2006). Some of these layers would be expected to should be found in other deep Antarctic ice cores, particularly ones drilled in West Antarctica, providing correlative markers between different cores. The analysis of the tephra layers in the Siple Dome core, along with other Antarctic cores, provides a timing framework for the relatively proximal Antarctic and South American volcanic eruptive events, allowing these to be distinguished from the tropical eruptions that may play a greater role in climate forcing. 相似文献
18.
国际南极冰盖与海平面变化研究述评 总被引：2，自引：1，他引：1
海平面上升是全球变暖的主要后果之一。尽管有少数冰川学家认为,气候变暖并不能确保雪积累量的显著增加,同时可能出现冰流的突然变化,因此南极冰盖在未来海平面变化中的作用存在很大的不确定性。但近几十年来南极半岛气温的急剧上升,已使大量的冰架崩解。冰架崩解并不对海平面产生真正的影响,但反映出南极洲气候与冰川存在急剧变化的可能。 相似文献
19.
Amaelle Landais Mathieu Casado Frédéric Prié Olivier Magand Laurent Arnaud Alexey Ekaykin Jean-Robert Petit Ghislain Picard Michel Fily Bénédicte Minster Alexandra Touzeau Sentia Goursaud Valérie Masson-Delmotte Jean Jouzel Anaïs Orsi 《Comptes Rendus Geoscience》2017,349(4):139-150
Polar ice cores are unique climate archives. Indeed, most of them have a continuous stratigraphy and present high temporal resolution of many climate variables in a single archive. While water isotopic records (δD or δ18O) in ice cores are often taken as references for past atmospheric temperature variations, their relationship to temperature is associated with a large uncertainty. Several reasons are invoked to explain the limitation of such an approach; in particular, post-deposition effects are important in East Antarctica because of the low accumulation rates. The strong influence of post-deposition processes highlights the need for surface polar research programs in addition to deep drilling programs. We present here new results on water isotopes from several recent surface programs, mostly over East Antarctica. Together with previously published data, the new data presented in this study have several implications for the climatic reconstructions based on ice core isotopic data: (1) The spatial relationship between surface mean temperature and mean snow isotopic composition over the first meters in depth can be explained quite straightforwardly using simple isotopic models tuned to d-excess vs. δ18O evolution in transects on the East Antarctic sector. The observed spatial slopes are significantly higher (～ 0.7–0.8‰·°C?1 for δ18O vs. temperature) than seasonal slopes inferred from precipitation data at Vostok and Dome C (0.35 to 0.46‰·°C?1). We explain these differences by changes in condensation versus surface temperature between summer and winter in the central East Antarctic plateau, where the inversion layer vanishes in summer. (2) Post-deposition effects linked to exchanges between the snow surface and the atmospheric water vapor lead to an evolution of δ18O in the surface snow, even in the absence of any precipitation event. This evolution preserves the positive correlation between the δ18O of snow and surface temperature, but is associated with a much slower δ18O-vs-temperature slope than the slope observed in the seasonal precipitation. (3) Post-deposition effects clearly limit the archiving of high-resolution (seasonal) climatic variability in the polar snow, but we suggest that sites with an accumulation rate of the order of 40 kg.m?2.yr?1 may record a seasonal cycle at shallow depths. 相似文献