贼鸥用于南极环境大型指示生物种的初步研究

对南极长城站附近棕贼鸥(C.s.lonnberg)、灰贼鸥(C.maccormicki)和两者的混合配对(hybrid)的食性与考察站环境质量的相关性进行研究,结果表明,贼鸥的食物结构受站区人类废弃物的直接影响。贼鸥食性构成同时与人类活动和动物生态习性相关而起到双重信息载体作用,可作为南极环境生态评价的重要指标之一,对推动实现南极环境生态评价的量化有重要意义。     

对岩体缺陷调查与工程处理方法的研究

在各类岩体内 ,存在着许多影响工程地质与水文地质性质的岩体缺陷 ,对这些缺陷必须进行工程处理方能达到某种要求。目前几乎普遍存在着对处理方向和处理工艺不考虑或很少考虑岩体的工程地质与水文地质条件 ,因而获效不甚理想 ,本文提出了解决这些问题的研究成果     

Antarctic environmental variability since the late Miocene: ODP Site 745, the East Kerguelen sediment drift

Characterization of sediment from Ocean Drilling Program Site 745, representing the East Kerguelen Ridge sediment drift, addresses important issues surrounding the timing of Miocene to present East Antarctic ice sheet stability and oceanic environmental change. Our results show three periods of greatly enhanced accumulation of Antarctic-derived sediment, at 6.4-5.9 Ma, 4.9-4.4 Ma and 1.1-0.8 Ma, potentially indicative of warmer, less stable ice sheets at these times. Conversely, the accumulation of Antarctic-derived material is comparatively less during the middle of the Pliocene warm epoch (4.8-3.2 Ma). The deep flow forming the Kerguelen drift was stronger during the latest Miocene and earliest Pliocene and has decreased in intensity continuously since then.     

南极和北极地区在全球变化中的作用研究

近半个世纪的调查基本揭示了极地在地球系统中的作用。两极保持了世界 99%的冰川 ,相当于全球淡水的 78% ,全部融化将使地球海平面上升 70m。极区又是世界气候系统中最活泼的组成 ,通过其冰盖、大气和周围海域的强烈耦合过程而影响全球。同时 ,南极上空臭氧空洞的出现 ,北极地区冻土带的北移等都表明全球变化也在明显地影响着两极。中国 2 0年来对南极的考察过程中 ,建立两个南极科学考察站 ,拥有极地考察破冰船 ,1999年开展了中国首次北极科学考察 ,对南北极的区域特征及其在全球变化中的作用提出了新的认识。     

Study of background aerosols in the Antarctic troposphere

Systematic year-round observations of submicron aerosols were carried out at Syowa Station (69°00'S, 39°35'E) in 1978. On the basis of the results of these observations, it is concluded that two types of aerosols originating from different sources are present in the Antarctic croposphere. With the intrusion of maritime air, mostly in the polar night months, sea salt particles and ammonium sulfate particles contained originally in the clean maritime air are dominant. The size distribution of such aerosols is monomodal, having a single mode at around 0.03 m in radii. On the other hand, in the sunlit months, sulfuric acid droplets are predominant and the size distribution is bimodal, having an additional mode at around 0.005 m in radii. Those sulfuric acid particles seem to be formed photochemically within a specific layer in the mid to lower troposphere over Antarctica. Most Antarctic submicron particles are of tropospheric origin, not of stratospheric nor anthropogenic origin.     

Heavy metal enrichment in Antarctic precipitation and near surface snow

Ion exchange and flameless atomic absorption spectrophotometry methods were used to measure the concentrations of sodium, manganese, iron and silver in snow accumulating at several sites on the Antarctic continent. The results show that the ratio of Mn/Fe is consistently close to the crustal value at all sites. The silver concentrations observed suggest a different origin, probably oceanic. When referenced to sodium, the degrees of enrichment of silver, manganese and iron increase by factors of 8, 2 and 2 respectively over a distance of 500 km from the ocean, after changes in sodium are accounted for.Investigation of the heavy metal content of fresh falling precipitation occorring on the Ross Ice Shelf, has shown that more enhanced enrichments of silver, manganese and iron occur in this fresh precipitation by factors up to 100, than in samples of snow and firn collected from shallow (up to 2 meters depth) pits at the same locations. Because the occurrences of these precipitation types vary temporally and geographically, it seems apparent that the shear stress conditions in the near surface boundary layer need to be considered in studies of snow and ice chemistry, particularly in polar regions where the chemical composition of permanent snow and ice fields are often investigated for evidence of climatic change, of glaciological behavior and of origins of chemical constituents.     

Rock-weathering by lichens in Antarctic: patterns and mechanisms

Saxicolous species of lichens are able to induce and accelerate weathering of their rock substrate, and effects of lichens on substrate can be attributed to both physical and chemical causes. This paper is focused on biotic weathering actions of epilithic and endolithic species on the different rock types (sandstones and volcanogenic rocks) in Antarctica. The patterns, mechanisms, processes and neoformations of rock-weathering resulting from lichen colonization are expounded in detail. Furthermore, it is pointed out that, for a better understanding of the impacts of lichens on environments, the studies on the rate of biotic weathering and the comprehensive involvement of the lichen effects on weathering of natural rocks remain to be carried out in Antarctica.     

Sea level in the late Quaternary: patterns of variation and implications

Studies of oxygen isotopes in foraminifers from deepsea sediments yield information about rates of change of sea level, for hundreds of thousands of years with a resolution of roughly 1,000 years. The statistics regarding fluctuations for the late Quaternary (the last 900,000 years) suggest that a rise of 10 m per 1,000 years (1 m per century) is not unusual, even when the system resides within a warm stage, as now. Values near 2 m per century, while rare, are well within the range of a warm system, beyond the 5-percentile of the overall range. Once sea level is near +10 m, further rise becomes highly unlikely within the conditions of the late Quaternary, suggesting the presence of some kind of natural barrier; that is, lack of vulnerable ice. The present volume of ice generally considered vulnerable (Greenland and West-Antarctic ice sheet) adds up (roughly) to the observed limit.     

冰穹C的大气条件:天文含意

在南极洲高原的冰穹C有望发现非凡的天文观测条件,受此鼓舞,许多国际小组协同努力对该地的大气条件作全面的测量．评述对冰穹C的选址现况,讨论过去、现在和计划中的选址仪器,迄今已得到的结果,以及这些结果的天文含意．     

利用ICESat数据解算南极冰盖冰雪质量变化

南极冰盖冰雪质量变化反映了全球气候变化,并且直接影响着全球海平面变化.ICESat测高卫星的主要任务之一就是要确定南北两极冰盖的质量变化情况并评估其对全球海平面变化的影响.本文利用2003年10月至2008年12月的ICESat测高数据,针对南极DEM分辨率有限的特殊性,通过求解坡度改正值,解决重复轨道地面脚点不重合的问题,计算了南极大陆(86°S以北区域,后文所述南极冰盖均不包括86°S以南区域)在这5年里的冰雪质量变化情况,得到东南极冰盖的质量变化为-18±20Gt/a,西南极-26±6Gt/a,南极冰盖的冰雪质量变化为-44±21Gt/a,对全球海平面上升的影响约为0.12mm·a~(-1).解算结果表明,南极冰盖质量亏损主要集中在西南极阿蒙森海岸附近冰川以及东南极波因塞特角区域.