北极快速增暖背景下冰冻圈变化及其影响研究综述

北极具有独特的地理位置和战略地位,是当前全球变化研究的热点区域之一.北极增暖是全球平均值的两倍以上,被称为"北极放大"现象.在北极快速增暖背景下,冰冻圈尤其是海冰显著萎缩,对北极乃至中纬度天气气候产生深远影响.对北极快速增暖背景下冰冻圈主要要素(包括海冰、冰盖、冰川、积雪和冻土)时空变化特征及未来预估进行了综述,同时总...     

北极海冰减退引起的北极放大机理与全球气候效应

自20世纪70年代以来,全球气温持续增高,对北极产生了深刻的影响。21世纪以来,北极的气温变化是全球平均水平的2倍,被称为"北极放大"现象。北极海冰覆盖范围呈不断减小的趋势,2012年北极海冰已经不足原来的40%,如此大幅度的减退是过去1 450年以来独有的现象。科学家预测,不久的将来,将会出现夏季无冰的北冰洋。全球变暖背景下北极内部发生的正反馈过程是北极放大现象的关键,不仅使极区的气候发生显著变化,而且对全球气候产生非常显著的影响,导致很多极端天气气候现象的发生。北极科学的重要使命之一是揭示这些正反馈过程背后的机理。北极放大有关的重大科学问题主要与气—冰—海相互作用有关,海冰是北极放大中最活跃的因素,要明确海冰结构的变化,充分考虑融池、侧向融化、积雪和海冰漂移等因素,将海冰热力学特性的改变定量表达出来。海洋是北极变化获取能量的关键因素,是太阳能的转换器和储存器,要认识海洋热通量背后的能量分配问题,即能量储存与释放的联系机理,认识淡水和跃层结构变化对海气耦合的影响。全面认识北极气候系统的变化是研究北极放大的最终目的,要揭示气—冰—海相互作用过程、北极海洋与大气之间反馈的机理、北极变化过程中的气旋和阻塞过程、北极云雾对北极变化的影响。在对北极海冰、海洋和气候深入研究的基础上,重点研究极地涡旋罗斯贝波的核心作用,以及罗斯贝波变异的物理过程,深入研究北极变化对我国气候影响的主要渠道、关键过程和机理。     

A model of Weichselian glacier variation in the North Atlantic region

The evidence for the extent and timing of Weichselian glaciation in Arctic regions shows that: (1) there were no major marine ice domes in the Arctic at 18,000 B.P. but that glaciers were relatively limited in extent; (2) there were no extensive ice shelves at 18,000 B.P. as envisaged by Hughes, Denton & Grosswald(1977); (3) the major periods of glacier expansion were between 125,000 and 80,000 B.P., just prior to 45,000 B.P., and between 11,000 and 8,000 B.P., and thus that glacier fluctuations at the southern margins of the Laurentide and Fennoscandian ice sheets were out of phase with those in the Arctic which advanced during southern interstadials. Phases of glacier advance in the Atlantic sector of the Arctic can be identified in deep sea cores by the peaks in concentration of iceberg-dropped detritus and an increase in sedimentation rates, which are highest when sub-polar water penetrates to the north. The key to the temporal pattern of Arctic glaciation and its association with oceanic changes is given by the intimate association of present-day Arctic glacierisation with the two major low pressure troughs which penetrate the Arctic in the Atlantic sector and in Baffin Bay. The chronology of glaciation in the Atlantic sector is associated with the activity of these troughs and the related oceanic circulation. Cooling of the Arctic due to reduction in solar radiation at the end of the last interglacial, when the pack ice lay north of 75d?N in the Atlantic, produced ideal conditions for Arctic glacier growth, with moisture transported by a strong cyclonic flux into a cooling Arctic from a strong North Atlantic Drift current. A positive feedback loop involving ocean and atmospheric circulation and pack ice, caused movement of the polar front to the south, thus slowly cutting off the supply of moisture to the Arctic. Further cooling at 75,000 B.P. caused a rapid extension of the polar front south of 45d?N, effectively cut off the northward movement of surface currents on the North Atlantic, and produced a strong zonal oceanic and atmospheric circulation which starved Arctic glaciers of nourishment and caused their retreat, and initiated rapid build up of the Fennoscandian and Laurentide ice sheets. Subsequent extensions of Arctic glaciers were associated with limited northward movement of sub-polar water and associated Atlantic depressions. The expansion of glaciers within the Arctic between 11,000 and 8,000 B.P. was associated with the first and diachronous penetration of moisture into a still cool Arctic during decay of the two great ice sheets.     

中国参与北极油气资源开发利用前景与方向

北极地区丰富的油气资源近年来引发全世界的广泛关注。评估结果显示,北极油气资源分布不均,主要集中在俄罗斯、美国阿拉斯加、挪威、加拿大和丹麦格陵兰。不同国家和地区北极油气资源勘探开发特点不同,在新形势下可能还会发生变化。中国是油气消费大国和进口大国,俄罗斯北极地区已日渐成为中国重要油气供应地之一。综合分析几个主要北极国家北极油气开发利用现状和未来发展前景,与中国目前参与北极油气开发利用的情况,对未来中国如何参与北极油气资源开发利用提出建议,将俄罗斯作为中国北极油气开发的长期合作伙伴,与其开展项目投资、技术入股、航道建设等多个方面的合作。      

北冰洋盐跃层研究进展

长年存在的盐跃层是北冰洋上层海洋独有的结构之一，对维持北冰洋表层的低温特征和海冰存在起着非常重要的作用。在过去的十几年中，北冰洋气候系统发生了前所未有的异常变化，北冰洋盐跃层也经历了从消退到近乎恢复的戏剧性变化。因此，北冰洋及其盐跃层的研究得到了广泛的重视。介绍了有关北冰洋盐跃层研究的进展情况，并对研究中存在的问题以及未来的发展进行了分析和阐述。有关北冰洋盐跃层的形成问题，先后有平流机制、对流机制等多种观点。认为由于现在欧亚海盆表层盐度普遍增高，其盐跃层的形成当以对流机制为主；而平流机制则更加适用于加拿大海盆的盐跃层。20世纪90年代，在北冰洋观测到一系列异常变化，包括盐跃层退缩、大西洋层增暖和北极海冰减少。实际上，这些变化是紧密联系在一起的，而后期盐跃层局部性的恢复似乎表明目前观测到的北冰洋气候系统的变化有可能是一种周期性的振荡。     

北极地区盆地分类与油气资源分布规律

北极地区油气资源潜力大,且油气勘探开发尚处于初期,是未来国内外油气工业发展的重要战略领域。文中综合运用全球领先信息服务公司埃信华迈（IHS）和美国地质调查局（USGS）的最新资料及已有研究成果,对北极地区的盆地类型和油气资源分布规律展开研究。结果表明:北极地区至少发育35个沉积盆地,具体划分为裂谷盆地（5个）、被动大陆边缘盆地（16个）、克拉通盆地（5个）、前陆盆地（5个）和大洋盆地（4个）。裂谷盆地是北极地区油气最富集的盆地类型,发现油气探明和控制可采储量（简称2P储量）441.12×108 t油当量,占北极地区油气总储量的74.6%,其次为前陆盆地、被动大陆边缘盆地和克拉通盆地。北极地区大部分油气储于白垩系、侏罗系和二叠系的碎屑岩储集层,仅有小部分油气储于石炭系和泥盆系碳酸盐岩储集层,且不同国家、不同含油气盆地的主力储集层存在明显差异。北极地区的油气主要源自侏罗系和白垩系的烃源岩,三叠系和泥盆系烃源岩次之。此外,复合圈闭是北极地区油气藏的主要圈闭类型,其次是构造圈闭。北极地区盆地类型和油气宏观分布规律的研究将为中国石油公司在北极地区的长远发展奠定基础。      

北极地区地面辐射量和云辐射强迫特征

In this paper the characteristics of surface radiative fluxes and cloud-radiative forcing are reviewed with a focus on the Arctic. Three aspects are addressed, including (i) changes in radiation flux over the global surface; (ii) characteristics of surface fluxes in the Arctic; and (iii) characteristics of cloud-radiative forcing in the Arctic. The clouds not only significantly reduce the peak summer radiative heating of the surface but also reduce the wintertime radiative cooling at the surface in　higher latitudes. The downward longwave fluxes dominates the incident radiative fluxes in the Arctic during most of the year. Incoming shortwave fluxes are negligible during late fall, winter and early spring, and even during the midsummer the incoming shortwave fluxes are only slightly greater than the downward longwave fluxes. The total net surface radiative flux is negative for most of the year and only positive during midsummer in the Arctic. The global net cloud-radiative forcing is negative, but the cloud-radiative forcing is positive in the Arctic, showing a warming effect, except for a short period in mid-summer. Positive cloud-radiative forcing in the Arctic is attributed　to the presence of snow and ice with high albedo and the absence of solar radiation during the polar night.     

格陵兰海海冰外缘线变化特征分析

格陵兰海作为北冰洋的边缘海之一,容纳了北极输出的海冰,其海冰外缘线的变化既受北极海冰输出量的影响,也受局地海冰融化和冻结过程的影响。利用2003年1月到2011年6月AMSR-E卫星亮温数据反演的海冰密集度产品,对格陵兰海海冰外缘线的变化特征进行了分析。结果表明,格陵兰海海冰外缘线不仅存在一年的变化周期,还存在比较显著的半年变化周期,与海冰在春秋两季向岸收缩有关。格陵兰海冬季的海冰外缘线极大值呈逐年下降的趋势,体现了北极增暖导致的冬季海冰范围减小;而夏季海冰外缘线离岸距离的极小值呈上升趋势,表明夏季来自北冰洋的海冰输出量增大。2003—2004年是格陵兰海夏季海冰融化最严重的2年。2007年北冰洋夏季海冰覆盖范围达到历史最小;而格陵兰海夏季的最小海冰范围最大,表明2007年北冰洋海冰的输出量大于其他年份。此外,夏季格陵兰岛冰雪融化形成的地表径流对海冰外缘线有一定的影响。对海冰外缘线影响最大的不是格陵兰海的局地风场,而是弗拉姆海峡(Fram Strait)区域的经向风,它直接驱动了北冰洋海冰向格陵兰海的输运,进而对格陵兰海海冰外缘线的分布产生滞后的影响。     

Clay-mineral distribution in surface sediments of the Eurasian Arctic Ocean and continental margin as indicator for source areas and transport pathways — a synthesis

Clay-mineral distributions in the Arctic Ocean and the adjacent Eurasian shelf areas are discussed to identify source areas and transport pathways of terrigenous material in the Arctic Ocean. The main clay minerals in Eurasian Arctic Ocean sediments are illite and chlorite. Smectite and kaolinite occur in minor amounts in these sediments, but show strong variations in the shelf areas. These two minerals are therefore reliable in reconstructions of source areas of sediments from the Eurasian Arctic. The Kara Sea and the western part of the Laptev Sea are enriched in smectite, with highest values of up to 70% in the deltas of the Ob and Yenisey rivers. Illite is the dominant clay mineral in all the investigated sediments except for parts of the Kara Sea. The highest concentrations with more than 70% illite occur in the East Siberian Sea and around Svalbard. Chlorite represents the clay mineral with lowest concentration changes in the Eastern Arctic, ranging between 10 and 25%. The main source areas for kaolinite in the Eurasian Arctic are Mesozoic sedimentary rocks on Franz-Josef Land islands. Based on clay-mineral data, transport of the clay fraction via sea ice is of minor importance for the modern sedimentary budget in the Arctic basins.     

A geodynamic model of the evolution of the Arctic basin and adjacent territories in the Mesozoic and Cenozoic and the outer limit of the Russian Continental Shelf

The tectonic evolution of the Arctic Region in the Mesozoic and Cenozoic is considered with allowance for the Paleozoic stage of evolution of the ancient Arctida continent. A new geodynamic model of the evolution of the Arctic is based on the idea of the development of upper mantle convection beneath the continent caused by subduction of the Pacific lithosphere under the Eurasian and North American lithospheric plates. The structure of the Amerasia and Eurasia basins of the Arctic is shown to have formed progressively due to destruction of the ancient Arctida continent, a retained fragment of which comprises the structural units of the central segment of the Arctic Ocean, including the Lomonosov Ridge, the Alpha-Mendeleev Rise, and the Podvodnikov and Makarov basins. The proposed model is considered to be a scientific substantiation of the updated Russian territorial claim to the UN Commission on the determination of the Limits of the Continental Shelf in the Arctic Region.     

Geology and hydrocarbon resources of the continental shelf in Russian Arctic seas and the prospects of their development

The overall jump in global demand for gas, and especially oil, gives rise to particular concern regarding mankind’s energy future. In the middle and late 21st century, the crucial role in securing oil and gas supply of mankind will be played by sedimentary basins in the Arctic Ocean deep-water area, including those of the continental shelf in Russia’s Arctic seas. There is a 0.90 probability that the initial in-place resources of hydrocarbons in the Arctic Ocean will be greater than 90 Btoe. The estimates predict the rise of oil and gas industries on the Arctic shelves in the near future.     

Cryosphere as a temporal sink and source of microplastics in the Arctic region

Microplastics (MPs) pollution has become a serious environmental issue of growing global concern due to the increasing plastic production and usage. Under climate warming, the cryosphere, defined as the part of Earth’s layer characterized by the low temperatures and the presence of frozen water, has been experiencing significant changes. The Arctic cryosphere (e.g., sea ice, snow cover, Greenland ice sheet, permafrost) can store and release pollutants into environments, making Arctic an important temporal sink and source of MPs. Here, we summarized the distributions of MPs in Arctic snow, sea ice, seawater, rivers, and sediments, to illustrate their potential sources, transport pathways, storage and release, and possible effects in this sentinel region. Items concentrations of MPs in snow and ice varied about 1–6 orders of magnitude in different regions, which were mostly attributed to the different sampling and measurement methods, and potential sources of MPs. MPs concentrations from Arctic seawater, river/lake water, and sediments also fluctuated largely, ranging from several items of per unit to >40,000 items m^?3, 100 items m^?3, and 10,000 items kg^?1 dw, respectively. Arctic land snow cover can be a temporal storage of MPs, with MPs deposition flux of about (4.9–14.26) × 10⁸ items km^?2 yr^?1. MPs transported by rivers to Arctic ocean was estimated to be approximately 8–48 ton/yr, with discharge flux of MPs at about (1.65–9.35) × 10⁸ items/s. Average storage of MPs in sea ice was estimated to be about 6.1×10¹⁸ items, with annual release of about 5.1×10¹⁸ items. Atmospheric transport of MPs from long-distance terrestrial sources contributed significantly to MPs deposition in Arctic land snow cover, sea ice and oceanic surface waters. Arctic Great Rivers can flow MPs into the Arctic Ocean. Sea ice can temporally store, transport and then release MPs in the surrounded environment. Ocean currents from the Atlantic brought high concentrations of MPs into the Arctic. However, there existed large uncertainties of estimation on the storage and release of MPs in Arctic cryosphere owing to the hypothesis of average MPs concentrations. Meanwhile, representatives of MPs data across the large Arctic region should be mutually verified with in situ observations and modeling. Therefore, we suggested that systematic monitoring MPs in the Arctic cryosphere, potential threats on Arctic ecosystems, and the carbon cycle under increasing Arctic warming, are urgently needed to be studied in future.     

Review on Researches of Legacy POPs and Emerging POPs in the Arctic Regions

The specific geographic location and natural conditions of the Arctic region play a significant role in the global climate change. As a result of perennial low temperature, simple ecological structure, and fragile ecosystem and weak stability in the Arctic, Persistent Organic Pollutants (POPs) accumulating from the region of middle and low latitudes may cause tremendous pressure in the arctic ecological environment. Therefore, the research of POPs in the Arctic region is not only conducive to more in-depth understanding of POPs distribution and transformation process in the global range, but to reasonably assess the harm of human activities on the arctic ecological environment. Thus, in the past 40 years, especially after nine new kinds of emerging organic contaminants being added to the list of Stockholm Convention in 2009, more and more scientific community and general public have pay attention to the research of POPs in the Arctic region. At present, the understanding of legacy POPs in the Arctic is limited, and the research of emerging POPs is in the initial stage. This paper aimed to summarize some conclusions and implications of the research, and focused on the occurrence level, historical evolution, bioaccumulation and source of POPs in atmosphere, waters, sediments and organisms in the Arctic region. Finally, the future changes and key scientific problems of POPs in the Arctic region were proposed.     

全球变化中的北极碳汇：现状与未来

由于海冰覆盖，北极碳汇（Arctic Carbon Sink）在全球碳通量预算中经常被忽略或简单处理。但随着全球变化加剧，北极发生快速变化，北极碳循环及其对全球变化的响应与反馈日趋重要。综合对北极碳汇的研究结果，分析了北极碳汇的来源、变化以及主要调控因子，评估了北极碳汇现状。探讨了在全球变化中，影响北极碳汇变化的因素及其对未来北极碳汇变化趋势的影响。      

The Younger Dryas and the Sea of Ancient Ice

We propose that prior to the Younger Dryas period, the Arctic Ocean supported extremely thick multi-year fast ice overlain by superimposed ice and firn. We re-introduce the historical term paleocrystic ice to describe this. The ice was independent of continental (glacier) ice and formed a massive floating body trapped within the almost closed Arctic Basin, when sea-level was lower during the last glacial maximum. As sea-level rose and the Barents Sea Shelf became deglaciated, the volume of warm Atlantic water entering the Arctic Ocean increased, as did the corresponding egress, driving the paleocrystic ice towards Fram Strait. New evidence shows that Bering Strait was resubmerged around the same time, providing further dynamical forcing of the ice as the Transpolar Drift became established. Additional freshwater entered the Arctic Basin from Siberia and North America, from proglacial lakes and meltwater derived from the Laurentide Ice Sheet. Collectively, these forces drove large volumes of thick paleocrystic ice and relatively fresh water from the Arctic Ocean into the Greenland Sea, shutting down deepwater formation and creating conditions conducive for extensive sea-ice to form and persist as far south as 60°N. We propose that the forcing responsible for the Younger Dryas cold episode was thus the result of extremely thick sea-ice being driven from the Arctic Ocean, dampening or shutting off the thermohaline circulation, as sea-level rose and Atlantic and Pacific waters entered the Arctic Basin. This hypothesis focuses attention on the potential role of Arctic sea-ice in causing the Younger Dryas episode, but does not preclude other factors that may also have played a role.     

Clay Minerals in Sediments of the Arctic Seas

The distribution of clay minerals in recent sediments on the Arctic shelf off the Eurasian and North American continents is considered. Prominence is given to the East Siberian and Laptev seas. The illite belt established on the basis of the composition of clay minerals in seven Arctic seas stretches from the Beaufort Sea to the White Sea and reveals a mineralogical zonality. The belt can be devided into smectite and chlorite provinces. Factors governing the formation of the Arctic illite belt and features of the distribution of individual clay minerals are discussed. The identification of the illite belt in sediments on the Arctic shelf complements the system of planetary latitudinal zones of clay minerals formulated by previous researchers.     

多尺度评估的贡献及经验教训

简要介绍了千年生态系统评估（MA）项目亚全球评估工作组的报告《生态系统与人类福祉：多尺度评估》的核心内容，重点在于多尺度评估的贡献以及从中获取的经验教训。多尺度评估的贡献主要表现在：① 全面、系统地阐述了生态系统服务与人类福祉在多种尺度上的重要联系；② 从多种尺度上揭示了生态系统服务的状况与变化趋势；③ 制定提高人类福祉和保护生态系统服务的有效对策，需要考虑不同尺度上的驱动力和利益相关方的参与；④ 当地社区对生态系统服务的变化具有积极的适应与管理能力。此外，在对全球评估的概念框架的修改、对开展多尺度评估的利弊分析、多尺度评估需要克服的限制因素以及今后需要权衡与考虑的问题等方面，MA的多尺度评估也提供了宝贵的经验教训。      

ESI高影响论文揭示的北极自然科学研究特点

在全球气候持续变暖背景下,北极地区冻土退化、冰川退缩、海冰减少等导致了一系列的生态环境问题,同时也使得资源勘探开发与国际新航道开通成为可能,北极地区的重要性日益凸显.依据2009—2019年6月期间有关北极研究的408篇ESI高影响论文,对发文量、主要作者、研究机构、国家、研究方向等字段进行分析,从自然科学角度,宏观而...     

The climate-forming role of Early Paleogene marine currents in high latitudes of Eurasia

Paleobotanical evidence for the climate-forming significance of marine currents in the Early Paleogene of the Arctic is reported. It is based on the analysis of mega- and microfossil plant assemblages derived from the outcrops located along the Arctic coastline of Eurasia and on the islands within the Arctic shelf. The occurrence of warm marine water masses is inferred from findings of Lower Paleogene microplankton and megafossils and palynomorphs of higher plants including Lauraceae, Magnoliaceae, Araliaceae, Loranthaceae, Palmaceae, and members of other thermophilic groups along the Arctic coast. The Early Paleogene climate in this realm was milder and was influenced by currents washing the continent and by marine heat transfer via the Trans-Siberian strait together with the atmospheric heat transfer.     

与全球变化有关的几个北极海洋地质问题

极地区域是全球变化研究的重点区域 ,在北极地区与全球变化有关的地质问题主要是北极地区的海陆变化对全球变化的影响 ,以及全球变化在地层中的记录。这涉及到北极形态变化及与其它大洋沟通的水道开闭情况 ,地形起伏对大气、大洋环流的影响 ,地壳升降与海平面变化对河流流量和海岸稳定性的影响 ,气体水合物及有机碳等变化对全球碳循环的影响 ,以及这些影响与气候变化信息在极地沉积物中的记录。文章在对上述影响及海洋地质研究状况进行探讨后 ,又简要介绍了中国的首次北极考察海洋地质研究状况