南极冰川学与全球变化研究新进展

南极冰川学与全球变化是最近举行的“南极与全球变化：相互作用和影响”国际学术研讨会的主题。南极冰盖净物质平衡的观测和估算，冰盖物质平衡与气候变化的预测模型；南极冰雪大气、气候和环境化学；南极深冰芯分析，及其与其它古环境记录的对比研究，是目前南极冰川学研究的几个热点、关键问题。     

南极地区冰雪消失对全球大气环流和气候影响的数值模拟

本文利用全球大气环流模式通过数值模拟研究了北半球夏季南极地区冰雪覆盖的消失对大气环流和全球气候影响的过程。结果表明南极冰雪消失不仅影响南半球大气环流异常,而且通过引起热带环流异常如增强东亚季风环流和减弱Walker环流等引起北半球大气环流和我国夏季气候的异常。南极冰雪覆盖的消失将给全球气候带来严重后果。文中也对南极冰雪气候效应的动力学机制进行了讨论。     

前言

前言＠李天杰前言“南极现代自然环境背景和自然过程研究”是国家八五重点攻关项目“南极地区晚更新世晚期以来气候与环境演变及现代环境背景研究”（８５－９０５－０２－０４）中的一个子课题。本课题依据攻关内容和南极与全球变化主题，共设置了５个专题：（１）南极中国站地...     

南极长城站气象观测与研究

1980年以来,中国对南极的气象观测和研究已取得了显著进展.1985年2月在乔治王岛建立了南极长城气象站,国际站号为89058,此后一直进行天气观测,并向世界天气监视网发出报告.近年来,根据观测资料并结合南极和南半球其他资料,开展了极区气旋、影晌南极半岛的天气系统、大气化学、高层大气、辐射特点、南极海冰状态与气候变化关系等项目研究.这些研究对了解南极当地气候的形成、发展和变化及其对全球气候的影响提供了重要资料.     

揭示气候变化的南极冰盖研究新进展

南极冰盖是气候的产物，对气候也有反馈作用，冰盖物质平衡变化与全球海平面升降息息相关，并引发地球系统内的一系列变化，南极冰盖是记录全球变化信息的良好载体，具有信息量大，时间序列长，保真性能强，分辨率高以及可进行现代过程定量研究等其他介质无法取代的独特优点，随着科学技术的发展和人类对全球问题的日益重视，南极冰盖与全球变化研究这一领域将会以高起点，多学科互相交叉，渗透为特色，成为未来南极研究的热点领域。     

南极乔治王岛的地理环境分析：兼论南极地缘政治问题

作者从地理环境,尤其是气候和资源对航空、航海、科学考察的影响,讨论了南极乔治王岛地区的战略意义。根据对地质基础、矿产、火山活动以及冰川侵蚀历史和地貌现象的讨论,指出该区是研究古气候、古环境、大陆漂移和冰川冰缘地貌的极好场所;并指出该区种类全、数量多且具有南极特征的动植物和奇特的食物链关系,是其成为重要生物资源区和受条约保护的特别科学兴趣场所的主要原因;最后讨论了本区归属问题,认为《南极条约》今后可能继续生效或会制定出类似条约使本区和南极继续成为全人类的共有财富。     

南极数值天气预报应用与研究进展

多个业务化的全球预报模式和有限区域预报模式应用于南极地区,已经成为南极天气预报和南极气候诊断研究的主要工具.现今南极地区的数值天气预报模式在模拟南极大气环流和天气系统方面性能不够理想,原因是多方面的:南极天气气候的特殊性(包括边界层的参数化、中尺度气旋等)、模式对南极复杂地形的描述不够充分、由于缺乏观测资料而使得模式的...     

南极长城站和中山站的近期气候变化及其对南极涛动的响应

利用长城和中山站的多种气象观测资料,揭示了南极气候在近15—30年全球气候变化关键时期的最新动态及其对南极涛动变化的响应。结果显示,近15年来,位于南极半岛地区的长城站增暖趋势减缓且有变冷迹象,并伴随气压下降和降水增多的趋势,表明全球增暖停滞期南极半岛经历了与过去几十年长期趋势有所不同的新变化,而位于南极大陆沿海的中山站气象要素变化趋势相对平缓,表明南极半岛和南极大陆气候变化特征存在显著的区域性差异。两站多个气象要素与南极涛动指数显著相关,两站温度与南极涛动相关关系相反等研究事实说明了两站气候与南极涛动及其对应的大气环流区域特征有着密切的联系。     

南极大陆沿海湖泊生态结构研究

南极大陆沿海地带是南极海、陆、冰的交集带,它同时受到来自海洋、大陆冰以及人类活动的影响,因而成为南极生态环境最脆弱的环节。存在于该地带的许多湖泊,因其各自的地理环境和发育过程,以及所受诸多外部因子如气候、降水等的不同影响,不同湖泊中水体的理化因子差异很大,由此造成湖泊中生物种类分布和生态结构的显著不同。本文报道了对南极大陆沿海维斯特福尔德丘陵和拉斯曼丘陵等地湖泊中以浮游生物为主体,各类生物的组成分布和群落结构进行考察研究的结果,并分析讨论了不同类型湖泊的生物多样性、生物营养结构及其与环境的关系,为深入研究全球气候变化对南极区域环境的影响,和制订南极生态环境保护决策提供科学依据。     

极地和青藏高原地区的气候变化及其影响

南极、北极和青藏高原素有地球三极之称,是多个国际计划研究全球变化的关键地区.南北极和青藏高原是全球气候变化的敏感地区,要了解全球气候变化,必须对南北极和青藏高原地区有所研究.在当前全球变暖的大背景下,地球三极地区的气候变化在时间和空间上都是多样的,这些变化对全球大气环流和我国的天气气候也会发生影响.加强对南极、北极和青...     

南极冰盖的物质平衡研究:进展与展望

南极冰盖物质平衡最新的研究进展表明,西南极洲表现出两种变化模式,西部在增厚,而北面在更快地减薄。西南极冰盖总体可能正在减薄,其物质损失的速率可能足以使海平面每年上升近0.2mm。东南极冰盖物质不平衡可能很小,甚至其符号还不能被确定。南极半岛正在经历着快速变化。目前还不能可靠地估算南极冰盖的物质平衡状态。同时,大型冰川的停滞,一些冰川流速加快,冰盖大范围加速减薄,冰架大面积的快速崩解和支流冰川的加速,以及着地线强烈的底部融化等显示出南极冰盖存在快速变化。南极冰盖物质平衡未来的重点研究领域是开展冰盖表面高程变化的监测与模拟,确定表面物质平衡及其在各冰流盆地的分布,着地线的冰流通量,冰架底部的融化,了解冰后期冰盖退缩的动力过程,以及开发、对比和改进与冰盖物质平衡模拟和预测相关的各种模型。     

Late Quaternary Lakes in the McMurdo Sound Region of Antarctica

Lake levels within the enclosed drainage basins of the Dry Valleys adjacent to McMurdo Sound have fluctuated widely during the Late Quaternary due to (a) local climate change and the consequent variation in the evaporation–precipitation regime, and (b) glacial fluctuations, resulting in changes in the catchment and meltwater drainage areas of the glaciers and, in some cases, in the volumes of the available lake basins. Three types of lakes can be distinguished on the basis of their water source: (1) lakes receiving the bulk of their water from melting of local alpine glaciers; (2) proglacial lakes associated with outlet glaciers from the East Antarctic Ice Sheet; (3) proglacial lakes associated with the marine oxygen-isotope stage 2 Ross Sea ice sheet and its precursors. The Dry Valleys contain an exceptionally long lacustrine record, extending back at least 300,000 years. Lacustrinesedimentation is cyclical, occurring over periods of about 100,000 years. During the last such cycle, relatively small lakes, both adjacent to East Antarctic outlet glaciers and fed by meltwater from alpine glaciers, existed during stage 5. However, these local lakes gave way to large proglacial lakes adjacent to the Ross Sea ice sheet in stage 2. The same relationship apparently occurred during the previous 100,000-year cycle. Dating of lacustrine sediments suggests that lakes proglacial to the Ross Sea ice sheet have existed during episodes of sea-level lowering during global glaciations. Lakes proglacial to outlet glaciers from the East Antarctic Ice Sheet have formed coincident with episodes of high eustatic sea level during interglacial periods.     

Spatial Sciences on Ice: 50 years of Australian activities on the Amery Ice Shelf,East Antarctica

The Antarctic climate system involves many complex interactions between the atmosphere, oceans and ice and is sensitive to variations in these components. Ice shelves represent the ice–ocean–atmosphere interface of the Antarctic continent and are therefore very important indicators of climate change in the region. The Amery Ice Shelf is the largest ice shelf in East Antarctica and has been the focus of many scientific research projects over the past 50 years. This paper presents a history of the use of spatial science techniques from basic survey equipment to satellite systems in Australian research projects based on the Amery Ice Shelf (and surrounding glaciers) since 1955. The application of these spatial data to projects based primarily in the fields of geodesy, glaciology, climatology, and oceanography has allowed the measurement and monitoring of the physical, dynamic and environmental characteristics of this large and remote region. This new information provides scientists with a better understanding of the ice shelf/ocean/atmosphere system allowing future monitoring to observe the effects of global climate change.     

Reconstruction of the Ross Ice Drainage System, Antarctica, at the Last Glacial Maximum

We present here a revised reconstruction of the Ross ice drainage system of Antarctica at the last glacial maximum (LGM) based on a recent convergence of terrestrial and marine data. The Ross drainage system includes all ice flowlines that enter the marine Ross Embayment. Today, it encompasses one-fourth of the ice-sheet surface, extending far inland into both East and West Antarctica. Grounding lines now situated in the inner Ross Embayment advanced seaward at the LGM (radiocarbon chronology in Denton and Marchant 2000 and in Hall and Denton 2000a, b), resulting in a thick grounded ice sheet across the Ross continental shelf. In response to this grounding in the Ross (and Weddell) Embayment, ice-surface elevations of the marine-based West Antarctic Ice Sheet were somewhat higher at the LGM than at present (Steig and White 1997; Borns et al. 1998; Ackert et al. 1999). At the same time, surface elevations of the East Antarctic Ice Sheet inland of the Transantarctic Mountains were slightly lower than now, except near outlet glaciers that were dammed by grounded ice in the Ross Embayment. The probable reason for this contrasting behavior is that lowered global sea level at the LGM, from growth of Northern Hemisphere ice sheets, caused widespread grounding of the marine portion of the Antarctic Ice Sheet, whereas decreased LGM accumulation led to slight surface lowering of the interior terrestrial ice sheet in East Antarctica. Rising sea level after the LGM tripped grounding-line recession in the Ross Embayment, which has probably continued to the present day (Conway et al. 1999). Hence, gravitational collapse of the grounded ice sheet from the Ross Embayment, accompanied by lowering of the interior West Antarctic ice surface and of outlet glaciers in the Transantarctic Mountains, occurred largely during the Holocene. At the same time, increased Holocene accumulation caused a slight rise of the inland East Antarctic ice surface.     

LATE QUATERNARY ENVIRONMENTAL CHANGES IN THE ANTARCTIC AND THEIR CORRELATION WITH GLOBAL CHANGE

TheAnturCticisoneofthemostimpohantcoldsourcesonEarth,asabout24.5xlo'km'oficewhichtakes9opeamtoftotalicevolumeontheglobecoveronit.RotreaoradvanceOftheAntarcticIceSheetwillaffatfluCtuationofsealevel.ItiscalculatalthatiftheAntercticIceSheetlscomplotelymeltaw…     

南极冰盖与冰川的快速变化

近10年的观测研究表明,南极冰盖和冰川存在快速的变化阿蒙森海扇区的主要冰流系统正在迅速变薄,减薄趋势可上溯至内陆150km处;罗斯冰流出现了停滞或明显减速,有的流动方向发生了改变,引发冰流袭夺;南极半岛冰架大面积崩塌,补给冰川加速,冰川出现了跃动;变暖的海水进一步侵蚀了冰架,着地线附近底部冰层融化强烈。上述发现改变了南极冰盖缓慢变化的传统观点,并对今后的冰川动力学研究,冰流模型模拟,冰盖物质平衡研究及预测具有重要意义。     

海平面变化与南极大陆沿海西福尔丘陵湖泊环境演变

对东南极大陆沿海西福尔丘陵 ( Vestfold Hills,68°38′S,78°0 6′E)若干主要湖泊及其周边环境进行了现代生态学和古生态学研究。分析了不同类型湖泊的地理地貌环境和理化要素的动态特征、生态群落结构类型。利用湖岸古化石的生态组成与放射性同位素测定资料 ,推断了晚更新世以来随着全球海平面变化 ,该地区所经历的海侵、海退及其地理地貌改变过程 ,尤其重现了本区 1 80 0 0年以来因两次海侵而发生的湖泊生态演替过程。本文首次推出了该区海成湖泊 4种环境演化模式 ,认为这些湖泊环境演化模式不仅是区域环境生态历史演变的缩影 ,而且也是现今南极局部环境变化和全球气候变化的具体反映     

Sea level change and environmental evolution of coastal lakes in Vestfold Hills, Antarctica

Ecological and palaeoecological studies were carried out in a series of lakes in the Vestfold Hills (68°38′S, 78°06′E) on eastern Antarctic continent. Dynamics types of the lakes in environmental geomorphology and physic chemistry, as well as features of biological community structures in different lakes were analyzed. Marine macro and micro fossils collected from the terraces and beaches surrounding these lakes and determined in 14 C radiocarbon ages to be the Late Pleistocene, were used as evidences to show the evolutionary processes of the lakes after sea level changes and transgressions since 18000 a B.P.. Basic modals of evolution for the lakes given in the paper could be regarded as not only explaining the history of environmental and ecological changes in VH lakes, and also reflecting of local environmental evolution in Antarctic region and global climate changes from past to present time.     

东南极内陆格罗夫山地区新生代冰川活动和古气候演化记录

地处东南极内陆的格罗夫山地区是研究南极冰川进退和气候演化的理想场所。我国第22次南极考察(2005/2006)进行了该地区冰盖进退和古气候演化专题研究。笔者在野外考察过程中,对格罗夫山地区新生代冰川活动记录(包括冰川侵蚀地貌及冰川堆积物)进行了详细的观测,获得了很多有关该地区冰盖进退及古气候演化方面的第一手材料,同时系统回收了对反映该地区古冰川活动具有重要意义的新生代沉积岩漂砾。本文简要报道本次野外考察在冰盖进退和古气候演化方面所取得的主要成果。     

Dome A冰川学研究进展及深冰芯计划展望

目前,位于东南极冰盖分冰岭中心的冰穹-Dome A已成为深入理解南极冰盖演化、稳定性和找寻地球气候久远记录的研究热点。通过整理总结在Dome A获得的冰川学研究进展,结合国际冰芯科学研究计划(International Partnerships in Ice Core Sciences,简称IPICS)有关寻找最古老冰芯的相关资料,对Dome A的气象要素、地貌、冰厚、冰下地形、冰体流速、冰盖内部结构等环境特征进行归纳分析,讨论Dome A冰川学的最新发展及其对深冰芯钻探计划的影响,并分析概述Dome A深冰芯钻探需考虑的问题和未来发展动向。