Distribution of <Superscript>226</Superscript>Ra in the Arctic Ocean and the Bering Sea and its hydrologic implications

Radium-226 (²²⁶Ra) activities were measured in the surface water samples collected from the Arctic Ocean and the Bering Sea during the First Chinese National Arctic Research Expedition. The results showed that ²²⁶Ra concentrations in the surface water ranged from 0.28 to 1.56 Bq/m³ with an average of 0.76 Bq/m³ in the Arctic Ocean, and from 0.25 to 1.26 Bq/m³ with an average of 0.71 Bq/m³ in the Bering Sea. The values were obviously lower than those from open oceans in middle and low latitudes, indicating that the study area may be partly influenced by sea ice meltwater. In the Bering Sea, ²²⁶Ra in the surface water decreased northward, probably as a result of the exchange between the ²²⁶Ra-deficient sea ice meltwater and the ²²⁶Ra-rich Pacific water. In the Arctic Ocean, ²²⁶Ra in the surface water increased northward and eastward. This spatial distribution of ²²⁶Ra reflected the variation of the ²²⁶Ra-enriched river component in the water mass of the Arctic Ocean. The vertical profiles of ²²⁶Ra in the Canadian Basin showed a concentration maximum at 200 m, which could be attributed to the inputs of the Pacific water or/and the bottom shelf water with high ²²⁶Ra concentration. This conclusion was consistent with the results from ²H, ¹⁸O tracers.     

Sea ice thickness measurement and its underside morphology analysis using radar penetration in the Arctic Ocean

Sea ice, as an important component of the Arctic climate system, has drawn significant sci-entific interest. Sea ice thickness and its morphology have dramatic impacts on ocean-atmos- phere-ice interactions[1—4], which directly affect the exchange proces…     

Observational estimation of heat budgets on drifting ice and open water over the Arctic Ocean

It is of major scientific interests to determine the parameters of momentum, heat and vapor exchange in the planetary boundary layer in order to study the effects of ocean-ice-atmosphere interactions and their feedback mechanisms on global climate[1]. Lin…     

Assessment of potential transport of pollutants into the Barents Sea via sea ice--an observational approach

The present estimates of ice drift in the Arctic include utilization of satellite imagery data (special sensor microwave/imager) and a reconstruction of air pressure for the period 1899-1998. A significant part of the sea ice in the Arctic Ocean has its origin in the Kara Sea and melts in the Greenland and the Barents Sea (BS). Consequently there may be a particular risk of pollutants in the Kara Sea entering the food webs of the Greenland and BS. The ice export from the Kara Sea between 1988 and 1994 was about 208,000 km2 (154 km3) per year. The import of ice into the BS was during the same period 161,000 km2 (183 km3) per year while the ice drift through the Fram Strait into the Greenland Sea was 583,000 km2 (1859 km3) per year. Ice which formed adjacent to the Ob and Yenisey rivers in early January, drifted into the BS within two years (with a probability of about 50%.     

楚科奇海的水螅水母类及其分布

本文报道 1 999年 7月至 8月我国首次北极科学考察期间“雪龙”号破冰船在楚科奇海采集的浮游水螅水母类及其分布。分析鉴定了 8种水螅水母 ,其中 4种属于花水母目 ,2种属于软水母目 ,1种属于硬水母目 ,1种属于筐水母目。短新塔水母在楚科奇海是首次记录。简要记述了这些种类的形态特征并附图。楚科奇海这 8种水螅水母都是冷水种 ,其中 6种为近岸性的 ,2种是大洋性的。根据其地理分布可分为北极种、北极 -北方种和北方寒温带种等 3个类型 ,从动物地理观点看 ,楚科奇海的水螅水母类应属于北极区系。楚科奇海水螅水母类的丰度一般较低 ,其平均丰度为 1 0 8个 /1 0 0 m3,水平分布状况主要由优势种所左右 ,八斑腕唇水母和指腺华丽水母为优势种。垂直分层采样结果表明 ,指腺华丽水母分布于 0～ 30 0 m,其中以 50～ 1 0 0 m居多     

Incipient weathering rind development on introduced machine‐polished granite discs in an Arctic alpine environment,northern Scandinavia

Weathering rinds, zones of alteration on the exterior surfaces of rock outcrops and coarse unconsolidated surficial debris are widely used by geomorphologists and Quaternary geologists as indicators of the relative age of landforms and landscapes. Additionally they provide unique insights into the earliest stages of rock and mineral weathering, yet the origin of these alteration zones is relatively poorly understood. This lack of understanding applies especially to the initial stages of rind formation. The study reported in this paper has two principal objectives. The first is to use lightly polished granite discs inserted in soil profiles under several different plant communities in an Arctic alpine environment for a period of four or five years to investigate the nature of incipient weathering rind development. The second is to investigate the factors responsible for spatial variability in the nature and rates of rind formation. Incipient weathering rind development on the outer edges of the granite discs is observable and measurable over a period of time as short as four years in the mild Arctic alpine environment of Swedish Lapland. The earliest stages of rind development involve the development of a porous structure consisting of a combination of pits and fractures which have been solutionally enlarged and modified. Solution appears to be preferentially concentrated on the surfaces of feldspars and, to a lesser extent, quartz. In addition, iron oxides are present along grain boundaries and in grain interiors and are interpreted to have been derived from the oxidation of ferromagnesian minerals. Spatial variability in weathering rind development appears to be particularly driven by differences in moisture but is not related to soil pH. Copyright © 2005 John Wiley & Sons, Ltd.     

极地大气科学与全球变化研究进展

南极和北极是地球上的气候敏感地区, 也是多个国际科学计划研究全球气候变化的关键地区。极地大气科学考察与研究是极地科学研究的重要组成部分。中国气象科学研究院的极地大气科学考察与研究始于20世纪80年代, 25年来有较大进展。中国气象科学研究院参加了我国组织的23次南极考察、2次北冰洋考察和3次北极考察; 承担了南极长城站和中山站、北极黄河站气象业务建设和维持, 以及中-澳合作南极冰盖3个无人自动气象站工作; 进行了常规地面气象、Brewer大气臭氧、近地面物理、冰雪和大气化学等观测, 获得了较为系统的极地大气环境资料。开展了有关极地大气科学与全球变化的研究, 在极地天气气候特征及气候变化时空多样性、极地海冰变化和南极海冰涛动、极地近地面物理特征和海-冰-气相互作用、中山站臭氧变化特征及南极臭氧洞和大气化学、气候代用资料获取和古气候环境以及极地大气环境变化对东亚环流和中国天气气候影响等方面的研究取得了新进展。中国极地大气科学正积极通过多学科交叉、走国际合作道路, 努力提高对极地在全球变化中作用的认识水平, 并积极探索极地变化对我国气候、环境的影响。     

利用三维GPR探测北极夏季海冰厚度及下表面形态特征分析

海冰在全球气候系统中扮演着重要角色。在中国第二次北极科学考察中，使用3D雷达探测结合冰钻进行海冰测量。雷达剖面上可清楚识别冰-水界面，与冰钻测量结果较好地吻合。雷达3D图像清晰显示了冰底界面在3D方向的起伏变化以及冰内构造的空间展布情况。对三维探测区域内海冰厚度统计显示，所测冰盘的平均厚度为4．15m，较厚的区域位于左下角，最大厚度约为6．4m，较薄的区域是在中央和左上角区域，最小的厚度小于3．0m。经过进一步计算可提供如海冰上下表面面积、海冰体积等参数，为遥感和数值模拟提供地面校核数据，也为海冰形成机制和动力作用过程研究提供佐证和依据。     

400年来北极巴罗角的温度变化特征

近４００年湖泊岩芯温度记录揭示,巴罗地区总的变化趋势是升温,平均升温速率为每百年０．４℃,但近２００年呈降温趋势。熵谱分析表明,近代巴罗地区温度波动存在３３年、４０年、２９年周期和９０年左右的世纪周期;１９２１～１９９４年巴罗气象台逐月温度资料统计分析和熵谱分析表明,现代巴罗温度变化有４个月、半年、１４个月、１６个月、３年、４年、７年和１０年周期。     

Chemical ozone loss in the Arctic vortex in the winter 1995–96: HALOE measurements in conjunction with other observations

Severe chemical ozone loss has been detected in the Arctic in the winter and spring of 1995–96 by a variety of methods. Extreme reductions in column ozone due to halogen catalysed chemistry were derived from measurements of the Halogen Occultation Experiment (HALOE) on board the Upper Atmosphere Research Satellite in the Arctic vortex. Here, we discuss further aspects of the HALOE observations in the Arctic over this period. Potential problems, both in the data themselves and in the methodology of the data analysis are considered and the reason for the differences between the Arctic ozone losses deduced from HALOE data version 17 and 18 is analysed. Moreover, it is shown that HALOE measurements in the Arctic in winter and spring 1995–96 compare well with observations by other ground-based and satellite instruments.