夏季加拿大海盆海冰边缘区声体积后向散射强度研究

声信号的体积后向散射强度是声传播过程中一个关键的参数。海冰边缘区的声体积后向散射强度研究对深入认识北极声场环境有着十分重要的意义。本文利用中国第六次北极科学考察获取的数据资料研究了海冰边缘区声体积后向散射强度特性。结果表明:加拿大海盆海冰边缘区是声体积后向散射强度的明显过渡区。无冰海面(海冰密集度小于15%)海洋深层水的声体积后向散射强度明显大于密集海冰区域的海水(海冰密集度大于50%)。讨论了声体积后向散射强度与海冰融化之间的关系,造成融冰区声体积后向散射强度增大的原因是水下悬浮泥沙、浮游生物等悬浮物质增加。根据海冰密集海域的海水后向散射强度弱的特点,对北极下放式声学多普勒测流仪(LADCP)观测的设置提出建议。     

中太平洋海盆锰结核之初步研究

国家海洋局于1986年在中太平洋海盆东北部(美国夏威夷群岛西南)进行了深海锰结核资源调查,整个测区面积约6×10²km²,获得一定数量锰结核.本文仅从不同形态类型锰结核中选出若干个样品作如下分析:油浸反光显微镜、X光射线衍射、红外光谱、电子探针、中子活化及常规化学分析等.重点了解深海锰结核的主要矿物相分布特点及与Fe、Mn、Cu、Co、Ni之关系,为圈定锰结核富集区和深入研究锰结核的生成机制打下基础.     

2008年加拿大海盆次表层暖水的精细结构的研究

自2004年以来,在加拿大海盆频繁发生的次表层暖水(near surface temperature maximum,NSTM)现象是北极快速变化响应的事实之一.采用2008年中国第3次北极科学考察的CTD数据和西北冰洋联合研究计划与美国波弗特环流观测系统计划2008年航次的CTD数据以及冰浮标ITP18数据,对加拿大...     

中太平洋海盆北部锰结核资源评价

中太平洋海盆北部锰结核资源评价ＰｒａｍｕａｎＫｏｈｐｉｎａ等洋底锰结核被看作是未来有经济价值金属的潜在资源，尽管对于商业性开采一些技术、经济和环境问题还有待解决。从１９７４年至１９８３年，日本地质调查所（ＧＳＪ）在进行锰结核矿床的地质和地球物理研究期...     

东太平洋海盆海山玄武岩特征

东太平洋海山玄武岩属于大洋岛屿拉斑玄武岩，主要由橄榄拉斑玄武岩、石英拉斑玄武岩和橄榄玄武岩组成，具有拉斑玄武岩系列和过渡玄武岩系列。岩石具有基质为拉斑玄武结构或间隐结构的斑状结构和气孔构造，斑晶主要由拉长石和普通辉石组成，基质除拉长石和玻璃质外，还有少量普通辉石和磁铁矿等，岩石化学成分中Ａｌ２Ｏ３、Ｎａ２Ｏ、Ｋ２Ｏ含量偏高。玄武岩中稀土元素分配型式基本相同，曲线较平坦，稀土分馏不明显，具Ｃｅ、Ｅｕ负异常，反映岩石具有共同的成因，属晚白垩世以来的产物     

边界条件对北太平洋海盆尺度环流模式的影响

采用Stevens开边界条件,将一个闭边界海盆尺度环流模式改造成开边界模式,对20°S以北太平洋大尺度环流进行了系统模拟。考察了开边界和不同等密面扩散系数对北太平洋环流和温盐结构的影响。模式较好地再现了太平洋大尺度环流特征,模拟出了表层赤道流系(包括北赤道流、黑潮和北太平流)以及对应的顺时针环流,同时还较好地反映了温盐场的基本分布特征。从年平均的纬向平均温度和盐度的断面分布可以看出,温跃层深度呈“W”型分布,在亚极地海区有一个梯度比较大的盐度锋区。南边界打开后使得模拟的北太平洋中层水温度和盐度更低,低盐水舌加深和向南延伸加强,更加接近观测值。增加沿等密面扩散系数后得到的中层水强度更大,尤其是34.6等盐线更接近观测资料。质量输运流函数分布表明,赤道两边各有一个翻转区,亚极地地区也存在一个浅的翻转区,打开南边界可以消除因为闭边界存在产生的假的下沉流,这些都为将来进行示踪物模拟打下基础。     

南极海冰与西北太平洋台风

本文利用最大熵谱分别计算了南极４个区海冰和西北太平洋台风发生频数的变化周期，并对前３年的南极海冰强弱和当年的台风发生频率数进行了逐月时间序列相关分析。     

东北太平洋海盆铁锰结核分布规律

地我国东北太平洋海盆铁锰结核开辟区（ＤＹ８５－１、ＤＹ８５－３航次调查区）的系统取样和对铁锰结核富集的沉积环境条件的分析研究结果表明，研究区的呼种沉积环境中的铁锰结核分布是不均匀的，具有较高经济价值的铁锰结核分布在水深５０００－５２００ｍ、硅质粘土分布的海底丘陵地区。     

Characterization of the summer pack ice biotic community of Canada Basin

1Introduction Theoccurrenceofseaiceisoneofthemostim- portantcharacteristicsoftheArcticOcean.Mostofsea iceispackice.Thepermanentpackiceareaisaswide as7.8×106km2,morethanhalfofthemaximumice coveringarea.Studieshaveshownthatthepackicebi- oticcommunityplaysasignificantroleinthearctic marineecosystem.Previousstudieshaveshownthat highprimaryproductionoccursinthearcticseasand theprimaryproductioninseaicecontributesabout onefourthofthetotal(Legendreetal.,1992;Chenet al.,2002).Studiesinrecentyearsh…     

2008年夏季加拿大海盆永久冰区的淡水累积现象

A combination of δ~(18)O and salinity data was employed to explore the freshwater balance in the Canada Basin in summer 2008.The Arctic river water and Pacific river water were quantitatively distinguished by using different saline end-members.The fractions of total river water,including the Arctic and Pacific river water,were high in the upper 50 m and decreased with depth as well as increasing latitude.In contrast,the fraction of Pacific river water increased gradually with depth but decreased toward north.The inventory of total river water in the Canada Basin was higher than other arctic seas,indicating that Canada Basin was a main storage region for river water in the Arctic Ocean.The fraction of Arctic river water was higher than Pacific river water in the upper 50 m while the opposite was true below 50 m.As a result,the inventories of Pacific river water were higher than those of Arctic river water,demonstrating that the Pacific inflow through the Bering Strait is the main source of freshwater in the Canada Basin.Both the river water and sea-ice melted water in the permanent ice zone were more abundant than those in the region with sea-ice just melted.The fractions of total river water,Arctic river water,Pacific river water increased northward to the north of 82°N,indicating an additional source of river water in the permanent ice zone of the northern Canada Basin.A possible reason for the extra river water in the permanent ice zone is the lateral advection of shelf waters by the Trans-Polar Drift.The penetration depth of sea-ice melted waters was less than 30 m in the southern Canada Basin,while it extended to 125 m in the northern Canada Basin.The inventory of seaice melted water suggested that sea-ice melted waters were also accumulated in the permanent ice zone,attributing to the trap of earlier melted waters in the permanent ice zone via the Beaufort Gyre.     

Characterization of sea ice and its snow cover in the Arctic Pacific sector during the summer of 2016

A comprehensive analysis of sea ice and its snow cover during the summer in the Arctic Pacific sector was conducted using the observations recorded during the 7th Chinese National Arctic Research Expedition(CHIANRE-2016) and the satellite-derived parameters of the melt pond fraction(MPF) and snow grain size(SGS)from MODIS data. The results show that there were many low-concentration ice areas in the south of 78°N, while the ice concentration and thickness increased significantly with the latitud...     

西太平洋副热带高压对黄海夏季海雾年际变化的影响

基于2004—2018年的地面观测数据和大气再分析数据,探究了西太平洋副热带高压(简称西太副高)对黄海夏季海雾年际变化的影响.结果表明:1)黄海夏季海雾雾日数存在明显的年际变化;多雾年偏南水汽通量输入可以达到少雾年的2.54倍,水汽通量净收支约是少雾年的2.76倍.2)在对流层中低层,多雾年的水汽输送存在2个通道,分别...     

北极夏季海冰单轴抗压强度研究

The results on the uniaxial compressive strength of Arctic summer sea ice are presented based on the samples collected during the fifth Chinese National Arctic Research Expedition in 2012(CHINARE-2012). Experimental studies were carried out at different testing temperatures(-3,-6 and-9°C), and vertical samples were loaded at stress rates ranging from 0.001 to 1 MPa/s. The temperature, density, and salinity of the ice were measured to calculate the total porosity of the ice. In order to study the effects of the total porosity and the density on the uniaxial compressive strength, the measured strengths for a narrow range of stress rates from 0.01 to 0.03 MPa/s were analyzed. The results show that the uniaxial compressive strength decreases linearly with increasing total porosity, and when the density was lower than 0.86 g/cm3, the uniaxial compressive strength increases in a power-law manner with density. The uniaxial compressive behavior of the Arctic summer sea ice is sensitive to the loading rate, and the peak uniaxial compressive strength is reached in the brittle-ductile transition range. The dependence of the strength on the temperature shows that the calculated average strength in the brittle-ductile transition range, which was considered as the peak uniaxial compressive strength, increases steadily in the temperature range from-3 to-9°C.     

Arctic sea ice distribution in summer based on aerial photos

1Introduction TheArcticOceanisoneoftheimportantcold sourcesontheearth,whichaffectsglobalclimateand oceancirculationseriously.Itsinteractionwithglobal climatesystemisrepresentedbyseaice,whichisthe mainfeatureonthesurfaceoftheArcticOcean(Aa- gaard,etal.,1989).Firstly,seaiceplaysapivotalrole intheheatandmassbalanceonthesurfaceoftheArc- ticOcean.Seaicenotonlyobstructstheheatexchange betweenatmosphereandocean,butalsoreflectsthe mostofthelocalsolarradiationbacktotheatmo- spherebecauseofitshighalb…     

加拿大海盆冰下表层海水湍扩散系数估计

海洋的湍粘性系数和湍扩散系数是研究海洋动量传输、热扩散和物质扩散的物理基础,是海洋模式的重要参数。北冰洋是海冰覆盖的海洋,其湍粘性系数和湍扩散系数与其他大洋有显著不同。本文以Pacanowski＆Philander的参数化方案为基础,采用二次北极科考的连续观测冰站和单次观测冰站的资料,定量计算了加拿大海盆74°N-78°N,144°W-164°W区域冰下60 m以浅的垂向湍粘性系数v和湍扩散系数kT,并分3个区域比较。结果表明：v和kT的垂向分布具有较好的一致性,表层和60 m处量值较大,中间较小;区域的不同主要体现在24 m以浅。     

Variation of freshwater components in the Canada Basin during 1967–2010

As a conservative tracer, oxygen isotopes in seawater are widely used for water mass analysis, along with temperature and salinity. In this study, seawater oxygen-18 datasets in the Canada Basin during 1967–2010 were obtained from the four cruises of the Chinese National Arctic Research Expedition(1999, 2003, 2008, and 2010) and the NASA database. Fractions of sea ice meltwater and river runoff were determined from the salinity-18O system. Our results showed that the river runoff decreased from the south to the north in the Canada Basin. The enhanced amount of river runoff observed in the southern Canada Basin may originate from the Mackenzie River, transported by the Beaufort Gyre. The river runoff component showed maximum fractions during 1967–1969, 1978–1979, 1984–1985, 1993–1994, and 2008–2010, indicating the refresh time of the river runoff was 5.0–16.0 a in the Canada Basin. The temporal variation of the river runoff was related to the change of the Arctic Oscillation(AO) index, suggesting the freshwater stored in the Canada Basin was affected by surface sea ice drift and water mass movement driven by atmospheric circulation.