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在北极地区,有接通北美洲、欧洲北部和亚洲北部国家之间距离最短的直线路线,所以北极地区的战略位置日益重要。大气波导是重要的电波环境,利用大气波导可实现超短波、微波频段的超视距探测和通信应用。因此,研究北极大气波导有重要的意义。本文利用2007年1月—2016年12月十年的气象探空数据,统计分析了北极16个站点大气波导的时空分布,给出了大气波导出现概率与其波导层厚度、强度特征量的统计特征,并从天气和气候学角度初步探讨了其成因。统计结果显示:1.北极地区大气波导平均出现概率低于50%,且表面波导出现概率高于悬空波导; 2.表面波导层厚度、强度分别在30 m以下和10 M以下,悬空波导层厚度在40—80 m,强度小于10 M; 3.北欧海区和格陵兰岛为北极波导高发区,欧亚大陆的北部边缘为无波导区; 4.表面波导高发区在北欧海区和格陵兰岛,北大西洋暖流、格陵兰冷高压及极夜期的辐射逆温是表面波导形成的可能原因; 5.悬空波导高发区在北欧海区和白令海峡东北部区域,且在7—8月份的暖季极昼期间为其高发季,北欧海区暖季海雾、白令海峡东北部区域暖季受北极锋影响是悬空波导形成的可能原因。 相似文献
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North Atlantic Water (NAW) is an important source of heat and salt to the Nordic seas and the Arctic Ocean. To measure the transport and variability of one branch of NAW entering the Arctic, a transect across the entrance to the Barents Sea was occupied 13 times between July 1997 and November 1999, and hydrography and currents were measured. There is large variability between the cruises, but the mean currents and the hydrography show that the main inflow takes place in Bjørnøyrenna, with a transport of 1.6 Sv of NAW into the Barents Sea. Combining the flow field with measurements of temperature and salinity, this results in mean heat and salt transports by NAW into the Barents Sea of 3.9×1013 W and 5.7×107 kg s−1 , respectively. The NAW core increased in temperature and salinity by 0.7 °C yr−1 and 0.04 yr−1 , respectively, over the observation period. Variations in the transports of heat and salt are, however, dominated by the flow field, which did not exhibit a significant change. 相似文献
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Upper layer circulation of the Nordic seas as inferred from the spatial distribution of heat and freshwater content and potential energy 总被引：1，自引：0，他引：1
The spatial distribution of heat and freshwater content and potential energy of a several hundred metre thick surface layer are computed for the Nordic seas and adjacent parts of the northern North Atlantic and the Arctic Ocean using a total of almost 100 000 hydrographic stations. The fields clearly show the major features of the area's circulation, with warm salty water in the eastern part and fresher, colder water in the western part. Comparisons with published estimates show that the potential energy field, representing the baroclinic part of the flow, accounts for about 30 % of the total flow but roughly 100 % of the flow of Polar Water in the northern part of the East Greenland Current, about 50 % of the total flow in the Norwegian Atlantic Current, and just a small fraction of the flow in the eastern part of Fram Strait. This suggests that the barotropic circulation is quite important in many parts of the Nordic seas. The barotropic circulation is also clearly seen by its effects on the integrated fields with isolines following deep bathymetric contours. We speculate that the barotropic circulation in combination with topographic obstacles, like the Greenland–Scotland Ridge and the ridge system in the Jan Mayen area, may have large impact on the spreading of freshwater and heat in the Nordic seas. 相似文献
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Contribution of a pathway through the Arctic Ocean to the recent reduction in the ice cover 
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下载免费PDF全文 Motoyoshi Ikeda 《极地研究》2008,19(2):212-217
The sea ice cover in the Arctic Ocean has been reducing and hit the low record in the summer of 2007.The anomaly was extremely large in the Pacific sector. The sea level height in the Bering Sea vs.the Greenland Sea has been analyzed and compared with the current meter data through the Bering Strait.A recent peak existed as a consequence of atmospheric circulation and is considered to contribute to inflow of the Pacific Water into the Arctic Basin.The timing of the Pacific Water inflow matched with the sea ice reduction in the Pacific sector and suggests a significant increase in heat flux.This component should be included in the model prediction for answering the question when the Arctic sea ice becomes a seasonal ice cover. 相似文献
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从北极海运货源角度出发,根据北极贸易、油气开发以及远东-西北欧、远东-北美东部当前海运货量状况,分析得出未来北极航道主要货物类型和规模的最大理论值为：（1）从俄罗斯、北欧北极地区到远东的液化天然气单向贸易流型式,到2030年,为1 000万t;（2）从远东到欧美的集装箱货物双向贸易流型式,北极东北航道、中央航道分担远东到西北欧航线的货运量,北极西北航道分担远东到北美东部的货运量,如果技术上能够低成本保障全季航行,按分担传统运河航线50%计算,到2030年,北极航道集装箱货运规模最大值约为1 743万TEU,是2011年传统运河航线的85%。由此得出结论：近中期东北航道天然气运输占据主要地位,但对北极航道更大运输需求是集装箱运输。此外,本文还比较了北极航道与运河航线的成本。 相似文献
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Dorthe Klitgaard-Kristensen Hans Fetter Sejrup Haflidi Haflidason 《Polar research》2002,21(2):275-282
This paper compiles new and previously published data on recent calcareous benthic foraminifera (dead and living assemblages) in surface sediment samples from the northern North Sea area, focussing on the dead benthic foraminifera and their relation to the environment. Five dead benthic foraminiferal assemblages have been identified. In Scottish coastal areas Cibicides lobatulus and Rosalina sp. dominate in areas with strong current activity and coarse-grained sediments, whereas C. lobatulus and Trifarina angulosa dominate at similar conditions in the Norwegian coastal areas. Cassidulina laevigata assemblages occur in areas influenced by inflow of Atlantic water into the northern North Sea. In the central part of the Norwegian Channel Uvigerina mediterranea prevails in fine-grained sediments with high organic content and possibly low oxygen content. This species' restricted distribution to the Norwegian Channel could possibly be related to the availability of food. Bulimina marginata and Hyalinea balthica dominate on the Fladen Ground where seasonal stratification is pronounced. This presumably leads to a decrease in the oxygen content in the bottom-waters during part of the year. 相似文献
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Features of the physical oceanographic conditions of the Barents Sea 总被引：17，自引：2，他引：15
Harald Loeng 《Polar research》1991,10(1):5-18
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Modeling Arctic Ocean heat transport and warming episodes in the 20th century caused by the intruding Atlantic Water 下载免费PDF全文
下载免费PDF全文 Jun Takahashi Tatsuo Suzuki Igor V Polyakov Kohei Mizobata Moto Ikeda Fancois J.Saucier Markus Meier 《极地研究》2008,19(2):159-167
This study investigates the Arctic Ocean warming episodes in the 20th century using both a high-resolution coupled global climate model and historical observations .The model,with no flux adjustment,reproduces well the Atlantic Water core temperature(AWCT) in the Arctic Ocean and shows that four largest decadal-scale warming episodes occurred in the 1930s,70s,80s,and 90s,in agreement with the hydrographic observational data.The difference is that there was no pre-warming prior to the 1930s episode,while there were two pre-warming episodes in the 1970s and 80s prior to the 1990s,leading the 1990s into the largest and prolonged warming in the 20th century.Over the last century,the simulated heat transport via Fram Strait and the Barents Sea was estimated to be,on average,31.32 TW and 14.82 TW,respectively,while the Bering Strait also provides 15.94 TW heat into the western Arctic Ocean.Heat transport into the Arctic Ocean by the Atlantic Water via Fram Strait and the Barents Sea correlates significantly with AWCT(C=0.75 ) at 0- lag.The modeled North Atlantic Oscillation(NAO) index has a significant correlation with the heat transport(C=0.37).The observed AWCT has a significant correlation with both the modeled AWCT(C=0.49) and the heat transport(C=0.41). However,the modeled NAO index does not significantly correlate with either the observed AWCT(C=0.03) or modeled AWCT(C=0.16) at a zero-lag,indicating that the Arctic climate system is far more complex than expected. 相似文献
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北极地区具有超过4 000亿桶油当量的待发现技术可采储量, 是未来全球油气勘探与开发的重要增长点。本文按照地理和地质构造因素将北极地区分为北冰洋海盆区和环北极含油气区（含潜在含油气盆地）,按照板块演化及盆地发育历史将后者划分为北太平洋极地盆地群、俄罗斯极地盆地群和欧洲极地盆地群。根据大量文献和IHS数据, 结合生油层、储层、盖层及圈闭特征方面的研究, 系统对比、分析北极地区石油、天然气分布特征:北太平洋极地盆地群重要烃源岩形成于侏罗纪和白垩纪, 盆地群中重要储层大部分都分布于新生界布鲁克斯层, 油气系统以构造圈闭为主。俄罗斯极地盆地群中多数盆地具有古生代基底, 受斯堪的纳维亚早古生代造山期变形、西伯利亚板块古生代西部造山变形影响, 60%以上的烃源岩产自中生界, 储层以中生界前陆、克拉通盆地沉积物为主,盖层分布较广, 以中生界居多。欧洲极地盆地群受控于北大西洋洋脊的扩张和迁移, 各盆地烃源岩分布于中生界, 大部分储层分布于上白垩统—古新系, 自生自储、古生新储为该区域盆地的主要成藏模式。其中, 俄罗斯极地盆地油气储量最多, 占北极地区总储量45%以上且勘探潜力最大。 相似文献
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Interannual variability of dense shelf water salinities in the north-western Barents Sea 总被引：1，自引：0，他引：1
Sönke Maus 《Polar research》2003,22(1):59-66
The maximum dense shelf water salinity formed during winter in the Svalbard Bank area of the north-western Barents Sea is reconstructed for the period 1952–2000 by analysing the transformation of summer remnants. The variability of 34.7 - 35.4, waters being at the freezing point, is mainly generated by interannual variations in the near surface salinity. On interannual time scales the latter is strongly linked to the sea ice import. In contrast, no correlation of the salinity of the Atlantic Water (AW) throughflow to the Arctic Ocean with the ice import is found. Salinities of both the dense shelf water site in the north-west Barents Sea and the north-eastward AW throughflow show a long term decrease, which can partly be explained by a less saline inflow of AW from the Norwegian Sea. The unusually low dense water salinities in the north-west Barents Sea during the 1990s appear to have a different origin, consistent with a response to oceanic heat advection and decreasing sea ice extent. 相似文献
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欧亚秋季雪盖与北半球冬季大气环流的联系 总被引：1，自引：0，他引：1
利用NOAA 提供的1973-2004 年32 年欧亚雪盖面积资料和NCEP/NCAR 再分析资料, 采用相关和合成方法对比分析了欧亚秋、冬季雪盖与北半球冬季大气环流的关系,得到了一个观测事实: 欧亚秋季雪盖与后期冬季北半球中高纬大气环流存在显著的相关关系, 尤其是与北半球冬季大气环流的最主要模态北极涛动(AO) 或北大西洋涛动(NAO) 呈显著的负相关关系, 而且欧亚秋季雪盖面积与后期冬季北半球大气环流的关系比欧亚冬季雪盖与同期大气环流的关系更好。最后提出了一个联系欧亚秋季雪盖与冬季大气环流的可能原因: 欧亚秋季雪盖异常可能是导致后期冬季北半球大气环流变化的一个主要强迫因子。 相似文献
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We analyzed Holocene sedimentary records from two lakes in the Lofoten Islands, northern Norway to evaluate environmental changes during the Holocene related to northern North Atlantic climate dynamics. The lakes are located in different geomorphological settings, and thus provide a contrast in their response to regional climate change. Environmental changes at both lakes were interpreted based on magnetic susceptibility, organic-matter flux, C/N, ??13Corg, Ti concentrations, and mass accumulation rates. Chronologies were established using 16 AMS radiocarbon dates, and average deposition rates in both environments are higher than 0.2?mm/year throughout the Holocene. At Vikjordvatnet, sedimentary geochemical properties define three distinct phases of sedimentation related to changes in aquatic productivity and gradual landscape development. Following deglaciation, during the early Holocene (11.6?C7.2?ka), aquatic productivity increased and the landscape stabilized as regional temperatures increased in response to higher summer insolation and increasing inflow of warm Atlantic water into the Norwegian Sea. Centennial-scale intervals of decreased organic-matter flux, from 10.9 to 10.2?ka and 9.2 to 8.0?ka, record episodes of instability during the early Holocene. These may represent regional cooling events related to freshwater forcing and a slowdown of the northward transport of warm water into the North Atlantic. During the mid-Holocene (7.2?C4.8?ka) organic-matter properties show less variability and the timing of this phase corresponds with the regional Holocene thermal maximum. The late Holocene sediments (4.8?ka?Cpresent) record a transition to colder climate conditions. The record from Fiskeb?lvatnet captures periodic changes in clastic input related to runoff and exhibits high-frequency variations over the last 9.5?ka. The most significant change in sedimentation was during the late Holocene (4.3?ka?Cpresent) when the frequency and magnitude of runoff events show an abrupt transition to wetter conditions. The timing of this shift corresponds to other regional reconstructions that indicate wetter and colder conditions during the late Holocene. 相似文献
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北极地区人口数量、组成与分布 总被引：3，自引：2，他引：1
以环北极国家的北极行政区域为统计范围,利用环北极国家2001年和2006年的官方人口统计数据,对北极地区的人口状况及其演变趋势作了统计和初步分析,结果表明：（1）2006年,北极地区总人口约为1044万．人口密度为0．63人／平方公里．是地球上除南极大陆以外人口最稀少的地区：（2）在全球人口数量不断增加的情况下．北极地区近年来人口非但没有增加．而且略有减少。2006年与2001年相比．总人口减少了5．3万左右．主要原因是受俄罗斯北极区域人口减少的影响（减少了约12万）,其他国家的北极地区则呈现变化不大或略有增加的趋势：（3）北极地区地广人稀,人口分布极不均匀．主要集中在少数几个城市或城镇：北极地区首府的人口250万左右,约占总人口的24％;（4）分布在俄罗斯、北美、北欧北极地区的原住民人口约为200万．俄罗斯原住民以楚科奇-堪察加语族、阿尔泰语族、乌拉阿尔语族等北方少数民族为主,北美加拿大、美国主要以困纽特人和印第安人为主．北欧原住民则以萨米人为主。 相似文献
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Genrich V. Alekseev Ola M. Johannessen Alexander A. Korablev Vladimir V. Ivanov Dmitry V. Kovalevsky 《Polar research》2001,20(2):201-208
Oceanographic data covering the period 1950–1998 are used to determine interannual variations in the convection intensity and water mass structure in the Greenland Sea and adjacent areas. Extremely cold winters throughout 1965–1970 assisted intensification of the water vertical exchange in the Greenland and Norwegian seas. As a result, cold and fresh Greenland Sea Deep Water (GSDW) production was extremely high in the central Greenland Sea while in the southern Norwegian Sea warm and salty water spread downwards. The recent rapid warming in the Greenland Sea Gyre interior from 1980 originates, we argue, from an increase in the Atlantic Water (AW) temperature due to the advection of warm waters into the region with the Return Atlantic Current. The negative water temperature and salinity trends in the upper 300 m layer of the Atlantic Water in the Norwegian Sea prevailed during 1950–1990, whereas during 1980–1990 the water temperature trends are indicative of warming of that layer. Observation series obtained onboard the Ocean Weather Ship Mike confirmed the existence of layers with advectiondriven high oxygen concentrations in intermediate and deep layers. The depth of oxygen maxima and the values of oceanographic parameters at this horizon can be regarded as indicators of the convection intensity in the Arctic domain. A simultaneous rise in NAO index and GSDW temperature points to a link between atmospheric and thermohaline circulation. Weakening in water exchange with the North Atlantic could be the reason for the Polar Water recirculation increase within the Nordic seas. 相似文献
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Based on temperature reconstruction and proxy data from 14 sites in the Northern Hemisphere, this paper focused on comparing the cycles of temperature variations between the Arctic and other areas, including Atlantic, Europe, China, Asia, Pacific, Indian Ocean, and America during the transition from the last Interstade to the Last Glacial Maximum, from the Last Glacial Maximum to megathermal period in Holocene and the transition of the Little Ice Age （LIA） by the methods of Singular Spectrum Analysis （SSA） and Maximum Entropy Spectrum （MES）. The results showed that environmental changes in the Arctic are most similar to that in the North American and better similar to Asia, Atlantic and Pacific, the least similar to Indian Ocean and Europe. The 1500-year oscillation of temperature existed both in Arctic and Europe. 相似文献
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Based on temperature reconstruction and proxy data from 14 sites in the Northern Hemisphere, this paper focused on comparing the cycles of temperature variations between the Arctic and other areas, including Atlantic, Europe, China, Asia, Pacific, Indian Ocean, and America during the transition from the last Interstade to the Last Glacial Maximum, from the Last Glacial Maximum to megathermal period in Holocene and the transition of the Little Ice Age (LIA) by the methods of Singular Spectrum Analysis (SSA) and Maximum Entropy Spec-trum (MES). The results showed that environmental changes in the Arctic are most similar to that in the North American and better similar to Asia, Atlantic and Pacific, the least similar to Indian Ocean and Europe. The 1500-year oscillation of temperature existed both in Arctic and Europe. 相似文献
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本文用了 1 999年夏季中国首次北极科学考察队对海冰、大气和海洋进行的同步和准同步的综合立体观测所获取的资料 ,研究海冰在海 气相互作用中扮演的角色。发现海冰的种类、分布、冰厚等变化对海气热交换都有重要影响。在浮冰区海洋以潜热的形式向大气输送热量 ,潜热通量与浮冰密集度的大小密切有关 ,浮冰越少潜热通量越大 ,潜热通量约为2 1～ 2 3 .6W /m2 ,潜热通量大于感热通量 ;在冰盖和大浮冰块上 ,大气以感热的形式向冰雪面上输送热量。新生的浮冰区或冰间湖是海气热交换最激烈的地方 ,是气候最敏感的区域 ,是北冰洋蒸汽雾生成的重要条件。用层结大气整体动力学输送法 ,计算了一次大范围的蒸汽雾过程的海气热交换 ,海洋向大气输送的热量总功率约为 1 4 8亿千瓦 ,相当于中国发电能力的 69倍 ,相当于大西洋向北冰洋输送热量平均功率的 1 / 2 0。北冰洋的夏季能够形成各种类型的海雾 :辐射雾、蒸汽雾和平流雾 ,其重要原因就是因为海冰的存在 ,使下垫面的性质复杂化 ,海气交换复杂化。 相似文献
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Early Holocene cooling events in Malangenfjord and the adjoining shelf, north-east Norwegian Sea 总被引：1，自引：0，他引：1
A high resolution study of early Holocene climate and palaeoceanography has been performed on two combined sediment cores from Malangenfjord, northern Norway. The fjord provides a regional oceanographic climatic signal reflecting changes in the North Atlantic heat flux at this latitude because of its deep sill and the relatively narrow adjoining continental shelf. Fauna and stable oxygen and carbon isotopes indicate cool, meltwater-depleted water masses in the fjord from 12000 to 11400 cal. yr BP followed by a warming between 11400-10300 cal. yr BP. The climatic variability can be explained partly by freshwater forcing hampering the North Atlantic heat conveyor, and partly by changing solar irradiance. A major cooling event at 11500-11400 cal. yr BP, followed by a rapid warming, is correlated to the Preboreal Oscillation, a widespread signal in the North Atlantic region which is probably linked to the increased meltwater flux to the northern North Atlantic at this time. Brief and small-scale cooling events between 10 300 and 10100 cal. yr BP, correlated to the onset of increased 10 Be flux in the Greenland ice cores, suggest a response to solar forcing. 相似文献