楚科奇海阿拉斯加沿岸冰间湖的变化及其影响因素分析          下载免费PDF全文

梁敏仪  史久新 《极地研究》2015,27(4):379-391

利用2003—2011年AMSR-E(Advanced Microwave Scanning Radiometer-Earth Observing System)日平均海冰密集度数据,对楚科奇海阿拉斯加沿岸冰间湖进行了分析。针对冰间湖的特点,在阈值法的基础上,通过统计冰间湖出现的频率,限定冰间湖的最大范围,区分各个冰间湖。通过计算阿拉斯加沿岸冰间湖的面积,结合NCEP-DOE(National Centers for Environmental Prediction-Department of Energy)再分析风场数据和白令海峡潜标观测的温盐和海流数据,初步探讨冰间湖发生和发展的规律。为了排除海冰外缘区对判断冰间湖的影响,研究仅限于白令海峡完全冰封的1—4月,可得到以下结论:阿拉斯加西北沿岸海域每年冬季都会出现5个冰间湖,多数时间为紧靠大陆边缘的沿岸冰间湖,巴罗角附近海岸在3月和4月会出现位于沿岸固定冰之外的裂缝冰间湖。冰间湖面积每天都发生变化,表现出天气尺度的变化特征,经历长达数日的发展和消失的过程,与风场的转换有密切关系。离岸风有利于沿岸冰间湖的扩展,但是该海域1—4月的盛行风为东北风和北风,对于多数冰间湖而言为沿岸风,不利于冰间湖的形成,因而冰间湖有时消失长达数十日。在偏北风的影响下,太平洋入流对北部冰间湖几无作用,而对南部冰间湖的空间分布有着重要影响。  相似文献   

Characteristics of <Emphasis Type="Italic">p</Emphasis>CO<Subscript>2</Subscript> in surface water of the Bering Abyssal Plain and their effects on carbon cycle in the     

Liqi?ChenEmail author  Zhongyong?Gao  Weiqiang?Wang  Xulin?Yang 《中国科学D辑(英文版)》2004,47(11):1035-1044

Characteristics of the pCO₂ distribution in surface water of the Bering Abyssal Plain and their relationships with the ambient hydrological conditions were discussed using variations of the partial pressure of CO₂ in surface water of the Bering Abyssal Plain and the Chukchi Sea. Data in this study are from a field investigation during the First Chinese National Arctic Research Expedition in 1999. Compared to the high productivity in the Bering Continental Shelf, much lower levels of chlorophyll a were observed in the Bering Abyssal Plain. The effect of hydrological factors on the pCO₂ distribution in surface seawater of the Plain in summer has become a major driving force and dominated over biological factors. The Plain also presents a High Nutrient Low Chlorophyll (HNLC). In addition, the pCO₂ distribution in the Bering Abyssal Plain has also been found to be influenced from the Bering Slope Current which would transform to the Anadyr Current when it inflows northwestward over the Plain. The Anadyr Current would bring a high nutrient water to the western Arctic Ocean where local nutrients are almost depleted in the surface water during the summer time. Resupplying nutrients would stimulate the growth of phytoplankton and enhance capacity of absorbing atmospheric CO₂ in the surface water. Otherwise, in the Bering Sea the dissolved inorganic carbon brought from freshwater are not deposited down to the deep sea water but most of them would be transported into the western Arctic Ocean by the Alaska Coastal Current to form a carbon sink there. Therefore, the two carbon sinks in the western Arctic Ocean, one carried by the Anadyr Current and another by the Alaska Costal Current, will implicate the western Arctic Ocean in global change.  相似文献   

A year in the physical oceanography of the Chukchi Sea: Moored measurements from autumn 1990–1991     

Rebecca A. Woodgate  Knut Aagaard  Thomas J. Weingartner 《Deep Sea Research Part II: Topical Studies in Oceanography》2005,52(24-26):3116

Year-long time-series of temperature, salinity and velocity from 12 locations throughout the Chukchi Sea from September 1990 to October 1991 document physical transformations and significant seasonal changes in the throughflow from the Pacific to the Arctic Ocean for one year. In most of the Chukchi, the flow field responds rapidly to the local wind, with high spatial coherence over the basin scale—effectively the ocean takes on the lengthscales of the wind forcing. Although weekly transport variability is very large (ca. -2 to ), the mean flow is northwards, opposed by the mean wind (which is southward), but presumably forced by a sea-level slope between the Pacific and the Arctic, which these data suggest may have significant variability on long (order a year) timescales. The high flow variability yields a significant range of residence times for waters in the Chukchi (i.e. one to six months for half the transit) with the larger values applicable in winter.Temperature and salinity (TS) records show a strong annual cycle of freezing, salinization, freshening and warming, with sizable interannual variability. The largest seasonal variability is seen in the east, where warm, fresh waters escape from the buoyant, coastally trapped Alaskan Coastal Current into the interior Chukchi. In the west, the seasonally present Siberian Coastal Current provides a source of cold, fresh waters and a flow field less linked to the local wind. Cold, dense polynya waters are observed near Cape Lisburne and occasional upwelling events bring lower Arctic Ocean halocline waters to the head of Barrow Canyon. For about half the year, at least at depth, the entire Chukchi is condensed into a small region of TS-space at the freezing temperature, suggesting ventilation occurs to near-bottom, driven by cooling and brine rejection in autumn/winter and by storm-mixing all year.In 1990–1991, the ca. 0.8 Sv annual mean inflow through Bering Strait exits the Chukchi in four outflows—via Long Strait, Herald Valley, the Central Channel, and Barrow Canyon—each outflow being comparable (order 0.1–0.3 Sv) and showing significant changes in volume and water properties (and hence equilibrium depth in the Arctic Ocean) throughout the year. The clearest seasonal cycle in properties and flow is in Herald Valley, where the outflow is only weakly related to the local wind. In this one year, the outflows ventilate above and below (but not in) the Arctic halocline mode of 33.1 psu. A volumetric comparison with Bering Strait indicates significant cooling during transit through the Chukchi, but remarkably little change in salinity, at least in the denser waters. This suggests that, with the exception of (in this year small) polynya events, the salinity cycle in the Chukchi can be considered as being set by the input through Bering Strait and thus, since density is dominated by salinity at these temperatures, Bering Strait salinities are a reasonable predictor of ventilation of the Arctic Ocean.  相似文献   

Application of long-chain alkenones and U_(37)~k values for paleotemperature estimation in the Arctic Chukchi Sea-Bering Sea area     

Lu Bing  Chen Ronghua  Wang Zipan  Chen Jianfang  Liu Zhensheng . Key Laboratory of Submarine Geosciences  Second Institute of Oceanography  State Oceanic Administration  Hangzhou  China 《海洋学报(英文版)》2001,(3)

lwnoowrlowIt is a hot spot in the world to carry out palcoocean and paleo-climate studies by using sur-face sediments. One of the direct effects of the global clirnate changes or short Periedic abnor-mal clirnate events is the variety of sea surface temPerature (wr). Increase or deCrease of theSST wil1 have certainly imPact, the unsaturate ratio (U)v) of long-chain alkenones (LCA)compe Of planktonic algae. The ratio Ulv records the information of SST changes, whichwill be entirely and or…  相似文献   

Uptake of atmospheric carbon dioxide in Arctic shelf seas: evaluation of the relative importance of processes that influence pCO₂ in water transported over the Bering–Chukchi Sea shelf     

Staffan Kaltin  Leif G. Anderson   《Marine Chemistry》2005,94(1-4):67

The uptake of atmospheric carbon dioxide in the water transported over the Bering–Chukchi shelves has been assessed from the change in carbon-related chemical constituents. The calculated uptake of atmospheric CO₂ from the time that the water enters the Bering Sea shelf until it reaches the northern Chukchi Sea shelf slope (1 year) was estimated to be 86±22 g C m⁻² in the upper 100 m. Combining the average uptake per m³ with a volume flow of 0.83×10⁶ m³ s⁻¹ through the Bering Strait yields a flux of 22×10¹² g C year⁻¹. We have also estimated the relative contribution from cooling, biology, freshening, CaCO₃ dissolution, and denitrification for the modification of the seawater pCO₂ over the shelf. The latter three had negligible impact on pCO₂ compared to biology and cooling. Biology was found to be almost twice as important as cooling for lowering the pCO₂ in the water on the Bering–Chukchi shelves. Those results were compared with earlier surveys made in the Barents Sea, where the uptake of atmospheric CO₂ was about half that estimated in the Bering–Chukchi Seas. Cooling and biology were of nearly equal significance in the Barents Sea in driving the flux of CO₂ into the ocean. The differences between the two regions are discussed. The loss of inorganic carbon due to primary production was estimated from the change in phosphate concentration in the water column. A larger loss of nitrate relative to phosphate compared to the classical ΔN/ΔP ratio of 16 was found. This excess loss was about 30% of the initial nitrate concentration and could possibly be explained by denitrification in the sediment of the Bering and Chukchi Seas.  相似文献   

北极楚科奇海及其附近海域海底底栖贝类遗壳分布   总被引：2，自引：0，他引：2  

高爱国  徐凤山  李朗  刘峰  陈爱萍  孙海青 《海洋学报》2005,27(6):65-74

对采自北极的23个站的底栖贝类遗壳进行鉴定,结果表明这些贝类遗壳计有17个种,其中双壳纲13种,腹足纲4种.根据鉴定到种的13个种可将所鉴定的软体动物分为两个区系:北极和环北极寒温带种,它们是Astarte montagui,Liocyma fluctusa,Macoma calcarea,M.moesta alas-kana,Mya pseudoarenaria,Nuculana pernula,N.radiata,Nucula bellotii,Serripes groenlan-dicus和Turritella polaris,共计10种,它们是北极水域软体动物区系组成中的主要成分;北极北太平洋寒温带种,它们是Argobuccinum oregonense,Cyclocardia crebricostata和Trichotropis cor-onata有3种.根据食性又可将它们分成滤食性、肉食性和碎食性三种,其中摄食沉积物中有机碎屑的碎食性种类占优势,包括双壳类中的Macoma calcarea,M.moesta alaskana,Macoma sp.,Nuculana pernula,N.radiata,Nucula bellotii,和腹足类的Trichotropis coronata,共计7种,它们不仅种类多,丰度高,而且在调查区的分布同细颗粒的沉积物有密切关系.  相似文献   

加拿大海盆与楚科奇海表层沉积物中硫酸盐还原菌丰度分布状况   总被引：2，自引：0，他引：2  

陈皓文  高爱国  林学政 《海洋科学进展》2007,25(3):295-301

对中国第2次北极科学考察海洋表层沉积物(0～1 cm)中硫酸盐还原菌进行4℃、25℃的培养实验,结合首次北极科学考察海洋沉积物硫酸盐还原菌研究成果,研究了研究区硫酸盐还原菌丰度的分布。结果表明,4℃培养得出硫酸盐还原菌丰度为0～2.4×104个/g(湿样),平均3 433个/g(湿样),并呈现有规律的分布趋势:低纬区的高于高纬区的,浅水区的高于深水区的。本区硫酸盐还原菌丰度高于中国东海、南海和黄海部分海区沉积物中的,低于胶州湾以及西北冰洋某些海区中的。25℃培养时硫酸盐还原菌丰度为0～2.4×104个/g(湿样),平均4 062个/g(湿样),在1 880 m以浅水域其丰度与4℃培养时的一致,而在1 880 m以深水域其丰度高于4℃培养时丰度。  相似文献   

Foraminifera in surface sediments of the Bering and Chukchi Seas and their sedimentary environment     

Meng Yi  Chen Ronghu  Zheng Yulong 《海洋学报(英文版)》2002,21(1):67-76

Based on a quantitative analysis of foraminifera in 39 surface samples of the Bering andChukchi Seas, the nearly absence of planktonic foraminifera in the surface sediments can be related to the low surface primary productivity and strong carbonate dissolution in the study area. It has been revealed that the surface primary productivity, and carbonate dissolution and properties of water masses related to the water depth mainly control the distribution of benthic foraminifera. The shelf of the Chukchi Sea is dominated by the Elphidium spp. assemblage and Nonionella robusta assemblage with low foraminiferal abundance and diversity, which is controlled by the coastal water mass of the Arctic Ocean. The slope of the Bering Sea is dominated by the Uvigerina peregrina - Globobulimina affinis assemblage with abundant N. robusta, and relatively high foraminiferal abundance and diversity, which is controlled by the intermediate and deep water masses of the Pacific Ocean. However, the Bering Sea has relatively sha  相似文献   

Application of long-chain alkenones and U₃₇^k values for paleotemperature estimation in the Arctic Chukchi Sea-Bering Sea area     

Lu Bing  Chen Ronghu  Wang Zipan  Chen Jianfang  Liu Zhensheng 《海洋学报(英文版)》2001,20(3):371-381

-Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is pre dominate in the long-chain alkenones from the Chukchi and Bering Sea sediments. The abundance of C37to C39 unsaturated alkenones changes in an order of C37 ＞C38 ＞C39. Based on ∑37/∑38 ratio, the de tected organism precursors of the long-chain alkenones are mainly coccolithophrid (Emiliania huxleyi).By the calibration relationship between U3k7 and U37k indices, the sea surface paleotemperature in these seas is estimated. The estimated values of U37k vary from 4.147℃ to 5. 706℃, with a mean value of 5.092℃.  相似文献   

北极楚科奇海海底表层沉积物有机碳的生物地球化学特征   总被引：5，自引：0，他引：5  

郝玉  龙江平 《海洋科学进展》2007,25(1):63-72

1999年7月和2003年7月在北极科学考察中获取的楚科奇海海底表层沉积物有机碳质量分数的分析结果表明,楚科奇海海底表层沉积物有机碳平均质量分数约为1.41%,远高于我国东海和世界部分大陆架沉积物;有机碳/氮比值为8.69,反映了有机物以海洋自生为主的混合性来源;有机碳与有机氮之间显著相关(R=0.93);有机碳质量分数与粒度明显相关(R=0.71),细粒粘土质沉积物中的有机碳质量分数高于砂质沉积物的;在水深200m以内,有机碳质量分数随水深加大有一定的增加;有机碳质量分数与生源硅质量分数明显相关;有机碳质量分数随纬度变化较小。结合2次北极考察的实测结果,对楚科奇海海底表层沉积物中的有机碳来源进行了初步讨论,认为沉积有机碳埋葬可能主要取决于生物泵。  相似文献