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1.
Dense water formation and circulation in the Barents Sea 总被引：1，自引：0，他引：1
M. Årthun R.B. Ingvaldsen L.H. Smedsrud C. Schrum 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(8):801-817
Dense water masses from Arctic shelf seas are an important part of the Arctic thermohaline system. We present previously unpublished observations from shallow banks in the Barents Sea, which reveal large interannual variability in dense water temperature and salinity. To examine the formation and circulation of dense water, and the processes governing interannual variability, a regional coupled ice-ocean model is applied to the Barents Sea for the period 1948-2007. Volume and characteristics of dense water are investigated with respect to the initial autumn surface salinity, atmospheric cooling, and sea-ice growth (salt flux). In the southern Barents Sea (Spitsbergen Bank and Central Bank) dense water formation is associated with advection of Atlantic Water into the Barents Sea and corresponding variations in initial salinities and heat loss at the air-sea interface. The characteristics of the dense water on the Spitsbergen Bank and Central Bank are thus determined by the regional climate of the Barents Sea. Preconditioning is also important to dense water variability on the northern banks, and can be related to local ice melt (Great Bank) and properties of the Novaya Zemlya Coastal Current (Novaya Zemlya Bank). The dense water mainly exits the Barents Sea between Frans Josef Land and Novaya Zemlya, where it constitutes 63% (1.2 Sv) of the net outflow and has an average density of 1028.07 kg m−3. An amount of 0.4 Sv enters the Arctic Ocean between Svalbard and Frans Josef Land. Covering 9% of the ocean area, the banks contribute with approximately 1/3 of the exported dense water. Formation on the banks is more important when the Barents Sea is in a cold state (less Atlantic Water inflow, more sea-ice). During warm periods with high throughflow more dense water is produced broadly over the shelf by general cooling of the northward flowing Atlantic Water. However, our results indicate that during extremely warm periods (1950s and late 2000s) the total export of dense water to the Arctic Ocean becomes strongly reduced. 相似文献
2.
Atlantic Water flow through the Barents and Kara Seas 总被引：2，自引：0，他引：2
Ursula Schauer Harald Loeng Bert Rudels Vladimir K. Ozhigin Wolfgang Dieck 《Deep Sea Research Part I: Oceanographic Research Papers》2002,49(12)
The pathway and transformation of water from the Norwegian Sea across the Barents Sea and through the St. Anna Trough are documented from hydrographic and current measurements of the 1990s. The transport through an array of moorings in the north-eastern Barents Sea was between 0.6 Sv in summer and 2.6 Sv in winter towards the Kara Sea and between zero and 0.3 Sv towards the Barents Sea with a record mean net flow of 1.5 Sv. The westward flow originates in the Fram Strait branch of Atlantic Water at the Eurasian continental slope, while the eastward flow constitutes the Barents Sea branch, continuing from the western Barents Sea opening.About 75% of the eastward flow was colder than 0°C. The flow was strongly sheared, with the highest velocities close to the bottom. A deep layer with almost constant temperature of about −0.5°C throughout the year formed about 50% of the flow to the Kara Sea. This water was a mixture between warm saline Atlantic Water and cold, brine-enriched water generated through freezing and convection in polynyas west of Novaya Zemlya, and possibly also at the Central Bank. Its salinity is lower than that of the Atlantic Water at its entrance to the Barents Sea, because the ice formation occurs in a low salinity surface layer. The released brine increases the salinity and density of the surface layer sufficiently for it to convect, but not necessarily above the salinity of the Atlantic Water. The freshwater west of Novaya Zemlya primarily stems from continental runoff and at the Central Bank probably from ice melt. The amount of fresh water compares to about 22% of the terrestrial freshwater supply to the western Barents Sea. The deep layer continues to the Kara Sea without further change and enters the Nansen Basin at or below the core depth of the warm, saline Fram Strait branch. Because it is colder than 0°C it will not be addressed as Atlantic Water in the Arctic Ocean.In earlier decades, the Atlantic Water advected from Fram Strait was colder by almost 2 K as compared to the 1990s, while the dense Barents Sea water was colder by up to 1 K only in a thin layer at the bottom and the salinity varied significantly. However, also with the resulting higher densities, deep Eurasian Basin water properties were met only in the 1970s. The very low salinities of the Great Salinity Anomaly in 1980 were not discovered in the outflow data. We conclude that the thermal variability of inflowing Atlantic water is damped in the Barents Sea, while the salinity variation is strongly modified through the freshwater conditions and ice growth in the convective area off Novaya Zemlya. 相似文献
3.
Abstract. The consequences of the following episodic phenomena for the pelagic-benthic coupling in the Nordic Seas are illustrated: (1) Advection of water masses between fjords and shelf environments, (2) freshwater run-off and vertical stability, (3) dynamics of the marginal ice zone in the central and northern Barents Sea and the Polar Ocean, (4) drift patterns of sinking particles along the North Norwegian coast, (5) advection of zooplankton into subarctic fjords and the southern Barents Sea, zooplankton overwintering and composition, and (6) transport of organic particulate matter from the Barents Sea shelf. It is shown that physical processes in the north-eastern North Atlantic and Polar Ocean can be strongly variable on time scales of days to decades. They have a significant influence on the dynamics of pelagic-benthic coupling. The physical oceanography influences the vertical and horizontal particle flux not only directly (mixing, advection, up- and down-welling), but also indirectly through its impact on the biota (for example radiation, wind, ice cover, freshwater run-off and overwintering, advection and retention of zooplankton). Understanding pelagic-benthic coupling at high latitudes depends even more on a best possible understanding of the physical oceanography and the time scales involved than elsewhere. 相似文献
4.
E. V. Ivanova I. O. Murdmaa E. M. Emelyanov E. A. Seitkalieva E. P. Radionova G. N. Alekhina S. M. Sloistov 《Oceanology》2016,56(1):118-130
This paper presents reconstructions of ice sheet boundaries, lacustrine and marine paleobasins, as well as the connections of the Barents and Baltic seas with the North Atlantic from the Last Glacial Maximum to the Holocene. The reconstructions are based on original and published data obtained from the northern and western parts of the Barents Sea and Baltic depressions with account for the available regional schematic maps of deglaciation. The early deglaciation of the Scandinavian–Barents ice sheet culminated with the Bølling-Allerød interstadial (14.5–12.9 cal ka BP), which was characterized by a more vigorous Atlantic meridional overturning circulation (AMOC) and a corresponding increase in surface Atlantic water inflow into the Barents Sea through deep troughs. The Baltic Ice Lake (BIL) remained a dammed-up isolated basin during deglaciation from 16.0 to 11.7 cal ka BP. In the Younger Dryas (YD), the lake drained into the North Sea and was replaced by a brackish Yoldia Sea (YS) at the beginning of the Holocene (Preboreal, 11.7–10.7 cal ka BP), due to a limited connection between two basins through the Närke Strait. In the Barents Sea, the next increase in the Atlantic water influx into the deep basins corresponded to terminal YD and Preboreal events with a culmination in the Early Holocene. The Yoldia Sea became a lake again during the next stage, the Ancylus (~10.7–8.8 cal ka BP). Atlantic water inflow both into the Barents and Baltic seas varied during the Holocene, with a maximum contribution in the Early Holocene, when the Littorina Sea (LS, 8–4 cal ka BP) connection with the North Sea via the Danish Straits was formed to replace the Ancylus Lake. The recent, post-Littorina stage (PS, the last 4 cal ka) of the Baltic Sea evolution began in the Late Holocene. 相似文献
5.
Ecosystem dynamics of the Pacific-influenced Northern Bering and Chukchi Seas in the Amerasian Arctic 总被引：12，自引：0，他引：12
Jacqueline M. Grebmeier Lee W. Cooper Howard M. Feder Boris I. Sirenko 《Progress in Oceanography》2006,71(2-4):331
The shallow continental shelves and slope of the Amerasian Arctic are strongly influenced by nutrient-rich Pacific waters advected over the shelves from the northern Bering Sea into the Arctic Ocean. These high-latitude shelf systems are highly productive both as the ice melts and during the open-water period. The duration and extent of seasonal sea ice, seawater temperature and water mass structure are critical controls on water column production, organic carbon cycling and pelagic–benthic coupling. Short food chains and shallow depths are characteristic of high productivity areas in this region, so changes in lower trophic levels can impact higher trophic organisms rapidly, including pelagic- and benthic-feeding marine mammals and seabirds. Subsistence harvesting of many of these animals is locally important for human consumption. The vulnerability of the ecosystem to environmental change is thought to be high, particularly as sea ice extent declines and seawater warms. In this review, we focus on ecosystem dynamics in the northern Bering and Chukchi Seas, with a more limited discussion of the adjoining Pacific-influenced eastern section of the East Siberian Sea and the western section of the Beaufort Sea. Both primary and secondary production are enhanced in specific regions that we discuss here, with the northern Bering and Chukchi Seas sustaining some of the highest water column production and benthic faunal soft-bottom biomass in the world ocean. In addition, these organic carbon-rich Pacific waters are periodically advected into low productivity regions of the nearshore northern Bering, Chukchi and Beaufort Seas off Alaska and sometimes into the East Siberian Sea, all of which have lower productivity on an annual basis. Thus, these near shore areas are intimately tied to nutrients and advected particulate organic carbon from the Pacific influenced Bering Shelf-Anadyr water. Given the short food chains and dependence of many apex predators on sea ice, recent reductions in sea ice in the Pacific-influenced sector of the Arctic have the potential to cause an ecosystem reorganization that may alter this benthic-oriented system to one more dominated by pelagic processes. 相似文献
6.
巴伦支海-喀拉海是北冰洋最大的边缘海,能够对环境变化做出快速的响应和反馈,是全球气候变化最为敏感的区域之一,其古海洋环境演变及海冰变化研究是全球气候变化研究的重要组成部分。末次盛冰期以来,该区域的古海洋环境受到太阳辐射、海流强度、海平面变化、温盐环流和河流输入等因素影响发生了一系列不同尺度的波动。巴伦支海受到北大西洋暖水和极地冷水两大水团相互作用的影响,在水团交界处 （极锋) 由于不同水团性质的差异,导致其海水温度、盐度及海冰发生剧烈变化。而喀拉海则受到叶尼塞河和鄂毕河大量淡水输入影响,海流系统较巴伦支海相对复杂,沉积物主要来源于河流输入的陆源物质,并可以通过磁化率的分析明确区分两条河流的陆源物质。由于受到冷水和暖水的相互作用,巴伦支海-喀拉海海冰变化迅速,并且在全新世中晚期存在 0.4 ka 和 0.95 ka 的变化周期,但海冰变化的影响因素并不是单一的,而是气候系统内部各因子相互作用的结果。目前古海冰重建研究工作主要为定性研究,定量研究相对较少,所选用的重建指标也相对单一,另外存在年代框架差、分辨率低等不足。本文以巴伦支海和喀拉海为中心,总结了其快速气候突变事件、古温度盐度、海平面及海冰的变化,对影响因素进行了探讨,并通过分析末次盛冰期以来古海洋环境研究的不足,提出了相应的展望。 相似文献
7.
The paleoceanography in the Nordic seas was characterized by apparently repeated switching on and off of Atlantic water advection. In contrast, a continous influx of Atlantic waters probably occurred along the northern Barents Sea margin during the last 150?ka. Temporary ice-free conditions enhanced by subsurface Atlantic water advection and coastal polynyas accelerated the final ice sheet build-up during glacial times. The virtually complete dissolution of biogenic calcite during interglacial intervals was controlled mainly by CO2-rich bottom waters and oxidation of higher levels of marine organic carbon and indicates intensive Atlantic water inflow and a stable ice margin. 相似文献
8.
Benthic foraminiferal and sediment biogeochemical data (total organic carbon, calcium carbonate and biogenic opal contents)
in two cores (1265 and 1312 m water depths) from the southeastern Sakhalin slope and one core (839 m water depth) from the
southwestern Kamchatka slope were investigated to reconstruct variations of the oxygen minimum zone during the last 50 ka
in the Okhotsk Sea. The oxygen minimum zone was less pronounced during cooling in the MIS 2 that is suggested to be caused
by a maximal expansion of sea ice cover, decrease of marine productivity and increase of production of the oxygenated Okhotsk
Sea Intermediate Water (OSIW). A two-step-like strengthening of oxygen minimum zone during the warmings in the Termination
1a and 1b was linked to (1) enhanced oxygen consumption due to degradation of large amount of organic matter in the water
column and bottom sediments, originated from increased marine productivity and supply of terrigenous material from the submerged
northern shelves; (2) sea ice cover retreat and reduction of OSIW production; (3) freely inflow of the oxygen-depleted intermediate
water mass from the North Pacific. 相似文献
9.
Ivar Murdmaa Elena Ivanova Jean-Claude Duplessy Michael Levitan Tatyana Khusid Maria Bourtman Galina Alekhina Tatyana Alekseeva Michael Belousov Valentina Serova 《Marine Geology》2006,230(3-4):275-303
Twenty-two sediment cores raised from the central and eastern parts of the Barents Sea have been studied to reconstruct the evolution of the facies system since the Late Weichselian glaciation. Multiproxy records reveal four lithostratigraphic units, which reflect major development stages of paleoenvironments. Age control is provided by 23 AMS 14C dates for Holocene sections of four cores. Continental moraine deposits of the last glaciation are overlain by proximal glaciomarine facies of the initial deglaciation phase. During this phase, the Barents Sea ice sheet detached from the ground resulting in seawater penetration into troughs, iceberg calving, deposition of IRD and fine-grained glacier meltwater load in newly formed marine basins. The main deglaciation phase is characterized by pulsed sedimentation from various gravity flows resulting in accumulation of distal glaciomarine facies comprising laminated clay and sand sequences with minor IRD. Redistribution of fine-grained suspended matter by bottom currents and brine-induced nepheloid flows combined with biogenic processes and minor ice rafting caused facies diversity of the Holocene marine sediments. The Holocene facies of shelf depressions reflect rather high, but variable productivity responding to climate changes and variations of Atlantic water inflow into the Barents Sea. 相似文献
10.
北冰洋西部表层沉积物中生源组分及其古海洋学意义 总被引：4，自引：0，他引：4
通过对中国首次和第二次北极科学考察在北冰洋西部所采取的66个表层沉积物中生源组分的分析,探讨了该海区表层生产力变化与水团的相互关系。楚科奇海西南部呈现出高的有机碳和生源蛋白石含量,而中部和东部哈罗德浅滩至阿拉斯加沿岸,以及楚科奇海台、北风脊和加拿大海盆表现出低的有机碳和生源蛋白石含量。楚科奇海陆架区表层沉积物以底栖有孔虫为主,丰度低;而楚科奇海台、北风脊和加拿大海盆则以浮游有孔虫占绝对优势,丰度较高。生源组分的分布特征显然与通过白令海峡进入楚科奇海的三股太平洋水和大西洋次表层水相关。楚科奇海西侧沿富营养的阿纳德尔流方向的区域呈现出高的表层生产力。而东侧受寡营养的阿拉斯加沿岸流及阿拉斯加西北沿岸陆源物质输入的影响,呈现出低的表层生产力。北纬75°以北及加拿大海盆受海冰覆盖影响,也表现出最低的表层生产力。而受北大西洋次表层水的影响,楚科奇海陆架外侧高纬海域表现出较高的钙质生物生产力。表层沉积物中Corg/N比值及其分布反映楚科奇海表层沉积物中的有机碳以海洋自身来源为主,且主要受生物泵过程控制。有机碳和生源蛋白石含量呈现高的正相关关系,说明硅藻等浮游植物的初级生产力可能控制着生物泵对碳的吸收和释放。 相似文献
11.
The paleoceanography in the Nordic seas was characterized by apparently repeated switching on and off of Atlantic water advection.
In contrast, a continous influx of Atlantic waters probably occurred along the northern Barents Sea margin during the last
150 ka. Temporary ice-free conditions enhanced by subsurface Atlantic water advection and coastal polynyas accelerated the
final ice sheet build-up during glacial times. The virtually complete dissolution of biogenic calcite during interglacial
intervals was controlled mainly by CO2-rich bottom waters and oxidation of higher levels of marine organic carbon and indicates intensive Atlantic water inflow
and a stable ice margin.
Received: 25 February 1997 / Revision received: 4 March 1998 相似文献
12.
13.
《Marine Geology》2001,172(3-4):309-330
The link between smectite composition in sediments from the northern North Atlantic and Labrador Sea, and deep circulation is being further investigated through detailed studies of the X-ray pattern of smectites and cation saturations. This allows clear distinction of dominant terrigenous sources associated to the main components of the modern Western Boundary Undercurrent. Time variations of smectite characteristics in two piston cores from the inlet and outlet of the Western Boundary Undercurrent gyre in the Labrador Sea indicate: (1) a more southern circulation of North East Atlantic Deep Water during the Late Glacial; (2) a step by step transition to the modern pattern of deep circulation during the Late Glacial/Holocene transition, with intensification of North East Atlantic Deep Water and Davis Strait Overflow; (3) an expansion of Davis Strait Overflow and Labrador Sea Water circulation in relation to ice surges and deposition of detrital layers; (4) an intensified circulation of North East Atlantic Deep Water during the Younger Dryas; and (5) a very recent increased influence of Denmark Strait Overflow Water beginning between 4.4 and <1 kyr. 相似文献
14.
N. O. Chistyakova E. V. Ivanova B. Risebrobakken E. A. Ovsepyan Ya. S. Ovsepyan 《Oceanology》2010,50(4):573-581
Environmental changes in the surface and bottom water layers of the Ingøydjupet Basin and the history of the Atlantic Water inflow to the southwestern Barents Sea during the last 16 ka are reconstructed based on planktic and benthic foraminiferal assemblages. The multiproxy study of sediment cores PSh-5159R and PSh-5159N, including AMS 14C dating, provides a time resolution of about 200 years for the deglaciation, 100 years for the Holocene, and 25–50 years for the last 400 years. Stable polar conditions with the sea ice at the surface were typical for the Early Deglaciation period. Unstable bottom settings and the onset of ice rafting marked the Oldest Dryas. The cold Atlantic Water inflow increased notably during the Bölling-Alleröd interstadial nearby the site location and then decreased during the Younger Dryas. The initial Holocene was characterized by abrupt warming in bottom and surface water layers, especially ～9.7–7.6 ka BP. Stable conditions prevailed during the Middle Holocene. Remarkable changes in the sea-surface temperature and bottom environments occurred during the last 2.5 cal. ka BP. 相似文献
15.
北冰洋西伯利亚陆架海是北极气候快速变化最为显著的海域之一,而沉积硅藻作为极地海洋生态系统的重要组成部分,对环境变化具有敏感的响应。对楚科奇海、东西伯利亚海和拉普捷夫海表层沉积物开展了硅藻组成鉴定,利用典型对应分析方法分析了硅藻属种与1986～2015年环境变量之间的关系。结果表明,夏季和秋季海冰密集度、表层海水盐度是影响研究区表层硅藻分布特征最主要的因素。此外,根据表层站位与环境变量的典型对应分析,可将西伯利亚极地海域划分为4个区域,分别为海冰硅藻组合带、暖水硅藻组合带、沿岸硅藻组合带和混合硅藻组合带。这些表层站位的分区与相应区域的海流模式有明显的相关性,海冰硅藻组合带仅分布于研究区北部的高纬度地区;暖水硅藻组合带位于受白令水和太平洋海水的分支——阿拉斯加沿岸水影响为主的区域;拉普捷夫海南部的沿岸硅藻组合带则受到河流径流和西伯利亚沿岸流的强烈影响;混合硅藻组合带受极地冷水、海冰覆盖、太平洋暖水和陆地径流的共同影响。 相似文献
16.
Under the influence of global warming, the sea ice in the Arctic Ocean (AO) is expected to reduce with a transition toward a seasonal ice cover by the end of this century. A comparison of climate-model predictions with measurements shows that the actual rate of ice cover decay in the AO is higher than the predicted one. This paper argues that the rapid shrinking of the Arctic summer ice cover is due to its increased seasonality, while seasonal oscillations of the Atlantic origin water temperature create favorable conditions for the formation of negative anomalies in the ice-cover area in winter. The basis for this hypothesis is the fundamental possibility of the activation of positive feedback provided by a specific feature of the seasonal cycle of the inflowing Atlantic origin water and the peaking of temperature in the Nansen Basin in midwinter. The recently accelerated reduction in the summer ice cover in the AO leads to an increased accumulation of heat in the upper ocean layer during the summer season. The extra heat content of the upper ocean layer favors prerequisite conditions for winter thermohaline convection and the transfer of heat from the Atlantic water (AW) layer to the ice cover. This, in turn, contributes to further ice thinning and a decrease in ice concentration, accelerated melting in summer, and a greater accumulation of heat in the ocean by the end of the following summer. An important role is played by the seasonal variability of the temperature of AW, which forms on the border between the North European and Arctic basins. The phase of seasonal oscillation changes while the AW is moving through the Nansen Basin. As a result, the timing of temperature peak shifts from summer to winter, additionally contributing to enhanced ice melting in winter. The formulated theoretical concept is substantiated by a simplified mathematical model and comparison with observations. 相似文献
17.
Dinoflagellate cysts were studied in 42 samples from the surface sediments of the White Sea. The total concentration of dinocysts varies from single cysts to 25 000 cyst/g of dry sediments, which reflects the biological productivity in the White Sea waters and the regional particular features of the sedimentation processes. The highest concentrations are observed in silts; they are related to the regions of propagation of the highly productive Barents Sea waters in the White Sea. Generally, the spatial distribution of dinocysts species in the surface sediments corresponds to the distribution of the major types of water masses in the White Sea. The cysts of the relatively warm-water species (Operculodinium centrocarpum, Spiniferites sp.) of North Atlantic origin that dominate in the sediments indicate an intensive intrusion of the Barents Sea water masses to the White Sea along with hydrological dwelling conditions in the White Sea favorable for the development of these species during their vegetation period. The cold-water dinocyst assemblage (Islandinium minutum, Polykrikos sp.) is rather strictly confined to the inner parts of shallow-water bays, firstly, those adjacent to the Onega and Severnaya Dvina river mouths. 相似文献
18.
The circulation and hydrography of the north-eastern North Atlantic has been studied with an emphasis on the upper layers and the deep water types which take part in the thermohaline overturning of the Oceanic Conveyor Belt. Over 900 hydrographic stations were used for this study, mainly from the 1987–1991 period. The hydrographic properties of Subpolar Mode Water in the upper layer, which is transported towards the Norwegian Sea, showed large regional variation. The deep water mass was dominated by the cold inflow of deep water from the Norwegian Sea and by a cyclonic recirculation of Lower Deep Water with a high Antarctic Bottom Water content. At intermediate levels the dominating water type was Labrador Sea Water with only minor influence of Mediterranean Sea Water. In the permanent pycnocline traces of Antarctic Intermediate Water were found.Geostrophic transports have been estimated, and these agreed in order of magnitude with the local heat budget, with current measurements, with data from surface drifters, and with the observed water mass modification. A total of 23 Sv of surface water entered the region, of which 20 Sv originated from the North Atlantic Current, while 3 Sv entered via an eastern boundary current. Of this total, 13 Sv of surface water left the area across the Reykjanes Ridge, and 7 Sv entered the Norwegian Sea, while 3 Sv was entrained by the cold overflow across the Iceland-Scotland Ridge. Approximately 1.4 Sv of Norwegian Sea Deep Water was involved in the overflow into the Iceland Basin, which, with about 1.1 Sv of entrained water and 1.1 Sv recirculating Lower Deep Water, formed a deep northern boundary current in the Iceland Basin. At intermediate depths, where Labrador Sea Water formed the dominant water type, about 2 Sv of entrained surface water contributed to a saline water mass which was transported westwards along the south Icelandic slope. 相似文献
19.
On the basis of the CTD data obtained within the Bering Sea shelf by the Second to Sixth Chinese National Arctic Research Expedition in the summers of 2003, 2008, 2010, 2012 and 2014, the classification and interannual variation of water masses on the central Bering Sea shelf and the northern Bering Sea shelf are analyzed. The results indicate that there are both connection and difference between two regions in hydrological features. On the central Bering Sea shelf, there are mainly four types of water masses distribute orderly from the slope to the coast of Alaska: Bering Slope Current Water(BSCW), MW(Mixed Water), Bering Shelf Water(BSW) and Alaska Coastal Water(ACW). In summer, BSW can be divided into Bering Shelf Surface Water(BSW_S) and Bering Shelf Cold Water(BSW_C). On the northern Bering Sea shelf near the Bering Strait,it contains Anadyr Water(AW), BSW and ACW from west to east. But the spatial-temporal features are also remarkable in each region. On the central shelf, the BSCW is saltiest and occupies the west of 177°W, which has the highest salinity in 2014. The BSW_C is the coldest water mass and warmest in 2014; the ACW is freshest and mainly occupies the east of 170°W, which has the highest temperature and salinity in 2012. On the northern Bering Sea shelf near the Bering Strait, the AW is saltiest with temperature decreasing sharply compared with BSCW on the central shelf. In the process of moving northward to the Bering Strait, the AW demonstrates a trend of eastward expansion. The ACW is freshest but saltier than the ACW on the central shelf,which is usually located above the BSW and is saltiest in 2014. The BSW distributes between the AW and the ACW and coldest in 2012, but the cold water of the BSW_C on the central shelf, whose temperature less than 0°C, does not exist on the northern shelf. Although there are so many changes, the respond to a climate change is synchronized in the both regions, which can be divided into the warm years(2003 and 2014) and cold years(2008, 2010 and 2012). The year of 2014 may be a new beginning of warm period. 相似文献
20.
1 IntroductionTheBeringStrait, with them aximum depth lessthan 60 m , isthe uniquepassagebetween the ArcticOcean and the North Pacific Ocean, and links twoshelfseas:theBeringSeainthesouthandtheChukchiSea in the north. The background flow field oftheBering… 相似文献