西北太平洋热带气旋风压关系的变异分析

利用1949 ～2008年共60年的热带气旋(TC)历史资料,分析TC中心最低气压和平均最大风速的相互关系,发现存在阶段性特征变异,继而对其进行了定量分析,得出过去60年中国整编的历史热带气旋资料中,风压关系序列前后明显不一致,存在变异现象,其变异点有两个,即1971/1972年、1974/1975年,其中以前者最为明...     

热带东太平洋晚第四纪的古海洋及古气候记录

热带东太平洋8001柱状样晚第四纪以来放射虫标志种Buccinospharea invaginata和Collosphaera tuberosa的研究发现, 它们的初现面(FAD) 出现于柱深22cm和45cm处, 年龄分别为0.21Ma和0.42Ma.它们的初现面年龄与SPECMAP氧同位素记录结合为该柱建立了地层框架.该柱放射虫丰度、生源蛋白石和有机碳含量、粒度的分析显示, 大约在氧同位素11、9~8.4、5~3和1期, 高的放射虫总丰度、第四纪常见种丰度和始新世-渐新世种丰度大致对应于高的中值粒径和平均粒径, 以及大约氧同位素5期以来增加的有机碳含量, 表明此期间贸易风增强, 搬运的陆源颗粒增大, 北赤道洋流加强, 导致上升流增强, 表层水生产力提高, 同时, 南极底层流的活动也加强.大约在氧同位素10、8.3~6和2期, 低的放射虫总丰度、第四纪常见种丰度和始新世-渐新世种丰度大致对应于减小的中值粒径和平均粒径, 反映此期间贸易风减弱, 搬运的陆源颗粒减小, 北赤道洋流减弱, 导致上升流消失, 表层水生产力降低, 同时, 南极底层流的活动也减弱.      

Wind-driven circulation in the subarctic north Pacific using altimeter data

Time-dependent wind-driven circulation in the subarctic north Pacific is investigated by using Topex/Poseidon (T/P) altimeter data and European Centre for Medium-Range Weather Forecasts (ECMWF) wind data for about 6 years. The first empirical orthogonal function (EOF) of the T/Pderived sea level anomaly (SLA) without the variation related to the steric height change (SLA1) and the first EOF of the ECMWF-based wind stress curl fields represent basin-sized south-north oscillations and their time series agree well with a correlation of 0.49. They appear to express the spin-up and spin-down of the subarctic gyre. The third EOF of SLA (SLA3) and the second EOF of the wind stress curl are also related to the variation of the subarctic gyre. Though the correlation of their time series is 0.27, drastic changes in early winter coincide well. The two EOF pairs can be considered to mean that the SLA variation followed by the latitudinal migration of the Aleutian low is separated into two standing oscillation patterns, that is, the sea level variation combined with SLA1 and SLA3 expresses seasonal variations of the wind-driven circulation of the subarctic gyre. The interannual SLAs constructed by subtracting the SLA1 and SLA3 components clearly show trans-pacific westward propagation even in the high-latitudes. The time series of SLA1 is in agreement with that ofin situ SLAs measured with the tide gauge at Petropavlovsk (53-01N, 158-38E), which implies the possibility to monitor the subarctic circulation using tide gauge data.     

基于高斯混合模型的太平洋深海盆地多金属结核成因分类

多金属结核类型成因分类是海底矿产资源关注的重要地质问题,诸多学者一直探索利用多金属结核地球化学特征进行多金属结核成因判别。近年来,随着大数据分析方法的应用,为探索利用机器学习技术进行多金属结核地球化学特征进行成因分类提供了很好的思路和方法。本文基于多年调查研究获取的太平洋多金属结核地球化学数据,利用高斯混合模型聚类分析技术,实现了太平洋深海盆地多金属结核成因分类,并对水成型结核进行了进一步判别分析,共划分出成岩型、混合型、水成Ⅰ型和水成Ⅱ型四类成因多金属结核,为太平洋深海找矿突破和资源评价提供重要依据。同时,不同成因类型结核空间预测结果显示,西北太平洋海域是水成Ⅰ型富钴多金属结核的主要分布区域之一,主要分布在马尔库斯—威克海山群、麦哲伦海山群北部、马绍尔海山群和中太平洋海山群西南部的山间盆地,以及附近的皮嘉费他海盆和中太平洋海盆西北部,是未来西太平洋富钴多金属结核资源找矿突破需要关注的关键海域。     

On some future tsunamis in the Pacific Ocean

Possible tsunamis in the Pacific Ocean, especially in its northeastern part, are discussed in relation to a predicted major earthquake in the Shumagin Seismic Gap (located in the eastern part of the Aleutian Island Chain) and to a major eruption of the St. Augustine volcano in Cook Inlet, Alaska. The deep-water propagation of the tsunami generated in the Shumagin Gap is simulated through the use of a spherical polar coordinate grid of the approximate size of 14km. The tsunami generated by the St. Augustine volcano is studied through the fine mesh grid confined to the Cook Inlet only. The numerical models were calibrated against historical tsunami data. The properties of the tsunami signal are described by the maximum amplitude which occurs in the tsunami record. This allows us to single out the direction along which a maximum tsunami is to be expected.Presented at the International Conference on Natural and Man-Made Hazards in Coastal Zones, held in Ensenada, Mexico, August 1988.     

中太平洋多金属结壳的地球化学特征

采用XRF和ICP AES法对中太平洋CA等6座海山的4 0多个站位的多金属结壳中化学元素进行测试与分析, 并结合其他资料对调查区结壳主要成矿元素的含量组成、特征变化、元素间的相关关系以及结壳与水深、地形等重要环境因子进行探讨.研究表明太平洋海山结壳中元素丰度特征具有多种变化类型, 中太平洋结壳主成分和成矿元素丰度明显高于马绍尔群岛, 而与西北太平洋、麦哲伦海山相近; 中太平洋结壳化学元素相关关系分析表明: Ca与P、Al与K呈显著正相关性; Mn与Al呈显著负相关性.研究还发现中太平洋结壳富Co(0.6 3%)而贫Cu(0.1 1 %)及高Fe(1 6.9%)低Mn(2 1.3%)的分布特征, 与深海多金属结核在含量分布特征上存在较大差异.与多金属结核相比: 结壳中Mn组元素含量显著降低, Fe组元素含量和稀土总量明显增大, 尤其是Co和REEs的变化最为突出。      

末次冰消期太平洋地区大洋通风研究及展望

作为对气候变化敏感的温室气体,CO₂的变化和气候变化密切相关。末次冰消期(18.0~11.7 ka)以来CO₂含量的大幅波动和大洋环流格局变化密切相关,尽管北大西洋和南大洋环流格局变化显著,但对于太平洋地区环流格局变化及其如何响应CO₂含量变化的波动尚无明确定论,合理阐述太平洋地区通风演变历史及其机制将有助于理解不同气候系统之间的相互作用机制。本文综述了末次冰消期以来太平洋地区大洋通风的研究现状,认为在冰消期冷期北太平洋主要被活跃的北太平洋中层水占据,而南太平洋则被携带有亏损碳库特征的南极中层水所占据,在冰消期暖期则恢复到现在的气候状态,这样的变化和大洋环流格局及CO₂浓度的变化密切相关。冰消期南北源水团的相互竞争可能主导着太平洋对全球气候的响应。另外,大洋表层储库年龄及深层水研究的缺乏极大地限制着当前太平洋地区大洋通风的研究。而不同深度的水团尤其是中层水的综合演化亟须建立。

     

New data on the morphology and geological structure of the Gramberg Guyot (Magellan Seamounts, Pacific Ocean)

The geological-geophysical studies carried out in the western part of the Pacific Ocean by the State Research Center “Yuzhmorgeologiya“ during cruises of the R/V “Gelendzhik” in 2002–2004 yielded new data on the relief of the Gramberg Guyot and its constituting rocks, which appeared to be Early Cretaceous to Pleistocene in age. The analysis of macro- and microfaunal remains in sedimentary rocks made it possible to define the transgressive phases in the development of seamounts (the Cenomanian-Turonian, Late Campanian-Maastrichtian, and Late Cenozoic). The geological development of the Gramberg Guyot is compared with that of other similar structures of the Magellan Seamounts.     

New geological and paleontological data on Alba Guyot (Magellan Seamounts, Pacific Ocean)

New materials obtained in the Pacific during cruises of the R/V Gelendzhik carried out by the State Scientific Center Yuzhmorgeologiya in 2000–2001 make it possible to specify the geologic and geomorphologic structure of Alba Guyot and clarify lithological and paleontological characteristics of lithotectonic rock complexes ranging from the Early Cretaceous to Pleistocene in age. Based on macro-and microfossils from sedimentary rocks several “transgressive” phases are distinguished in the guyot development: Cenomanian-Turonian, late Campanian-Maastrichtian, late Paleocene-middle Eocene, and Late Cenozoic. Finds of Paleogene molluscan and coral remains, together with planktonic foraminifers, imply relatively shallow sedimentation settings on Alba Guyot during the early Paleocene.     

Geochemistry of dissolved rare earth elements in the Equatorial Pacific Ocean

Seawater samples were collected from four locations in the Equatorial Pacific Ocean during the MR02-K06 cruise of the R/V Mirai and analyzed for dissolved rare earth elements (REEs) using inductively coupled plasma mass spectrometry. According to variations of REE concentrations and Yb/La ratios, the results show that the river input of the Papua New Guinea islands may affect the compositions of REEs in the Equatorial Pacific surface water. The Yb/La values and the REE concentrations in the waters deeper than 3,000 m in the western South Pacific and the Equatorial Pacific Oceans, which represent the characteristics of Antarctic Bottom Water (AABW), demonstrate similar variation trend with depth. This result also indicates that the REEs which originated from the South Pacific Ocean have entered the North Pacific Ocean across the equator with AABW intrusion.     

热带太平洋海洋环流与暖池的结构特征、变异机理和气候效应

热带西太平洋暖池是引发强烈的大气对流、驱动Walker环流和Hadley环流系统的主要热源之一,对全球、尤其是东亚气候有重要影响。针对我国在提升气候预测水平方面的重大和迫切需求,国家重点基础研究发展计划项目"热带太平洋海洋环流与暖池的结构特征、变异机理和气候效应"于2011年7月正式立项。项目拟解决的关键科学问题包括:①调控暖池形成和变异的海洋环流多尺度相互作用过程;②海洋动力过程在暖池热盐结构变异中的作用及其机理;③暖池变异对不同类型El Nio影响机理的异同和对东亚季风变异的调制机理。围绕上述关键科学问题,项目将以暖池变异为中心,关注影响和控制暖池结构与变异的关键海洋过程,以及暖池海气相互作用影响ENSO循环、东亚季风年际变异的过程和机理,重点组织开展以下3个方面有针对性的调查研究:①热带太平洋环流和暖池的结构和变异特征;②热带太平洋环流与暖池相互作用的关键过程和机理;③暖池变异的海洋—大气耦合过程及其气候效应。在此基础上,项目将力争阐明暖池影响东亚季风和我国气候变异的过程、机理与敏感区,改进模式的混合参数化方案,提出有效提高ENSO预报技巧的同化方案,为我国短期气候预测能力的提高提供科学支撑。     

Crustal velocity structure beneath the western Andes of Colombian using receiver-function inversion

Analysis of teleseismic records obtained in two broadband seismic stations of three components located on the Andean region of Colombia is presented in this work. The two stations are located at the Western Cordillera (WC), station BOL, and at the Central Cordillera (CC), station PBLA. The analysis of seismograms was performed by inversion of the receiver functions (RF) in order to obtain the crustal velocity structure beneath the receivers. The receiver function is a spectral ratio obtained from teleseismic earthquakes recorded by broadband seismic stations, which allows the calculation of the velocity structure beneath the receiver by removing source effects in the horizontal components of the seismic traces. Data stacking was performed in order to improve signal to noise ratio and then the data was inverted by using two optimization algorithms: a genetic algorithm (GA), and a simulated annealing algorithm (SA). The present work calculates the receiver functions using teleseismic earthquakes at epicentral distances (Δ) ranging between 30° and 90° and recorded at the two stations within the years 2007 and 2009.Delay times between P and PS waves converted at the Moho boundary were used to constrain the velocity structure. The receiver functions at the stations were generated from seismic events within a broad range of back azimuth. Data from gravity and magnetism were also used during the geophysical survey. The depth of the Moho boundary was found to be at 40 km in the WC beneath station BOL and at 43 km in the CC beneath station PBLA. The upper crust, with a thickness of 5 km, is characterized by a shear wave velocity of about 3.0 km s⁻¹; the shallower layers, at approximately 1.0 km, have shear wave velocities between 2.2 and 2.6 km s⁻¹, which corresponds to sediments overlying the upper crust. These observations support the hypothesis of a thickness of the crust at the root of the mountain range to be between 32 and 50 km. The calculated receiver functions were compared with artificial ones generated from the inversion of 48000 models of horizontal layers for each station using a GA and an SA that allowed a satisfactory coverage of all the sample space in order to avoid non-unique solutions. Beneath station BOL a moderate low-velocity zone (LVZ) was found, which was caused by accretionary processes of the ophiolite complex in the WC.     

西太平洋782A钻孔新生代的有孔虫

大洋钻探工程” 1 2 5航次的 782 A钻孔位于西太平洋菲律宾海东北部 ,井深 4 76.8m。基底为安山岩 ,上覆盖层为中始新统—更新统的沉积层 ,其中保存有低丰度的有孔虫。自下而上可划分出 8个浮游有孔虫带。由于出现 Catapsydrax dissimilis,C.stainforthi为 N5 、N6 带的带化石 ,表明本钻孔存在早中新世的地层。同时由于缺失浮游有孔虫带 P1 5 — P1 6 下部 ,N3上部—N4,N7—N1 1 带的带化石 ,说明在中始新世与晚始新世之间、晚渐新世与早中新世之间、早中新世与中中新世之间存在 3个沉积间断。钻孔中的有孔虫标志本区当时处于温暖亚热带环境。根据不同时期温度的变化 ,可划分出 5个阶段 ,包括 3个偏暖时期和 2个温凉时期。     

中太平洋地区两个铁锰结壳的生长幕研究

通过对3块中太平洋铁锰结壳样品进行的生物地层学及其结构构造、元素地球化学剖面的综合研究发现,铁锰结壳的生长主要集中于两个形成环境存在差异分别由不同因素控制的形成阶段,一个是约25Ma以来其形成环境氧化程度由南极底层流(AABW)控制的对应于结壳新壳层的生长幕,另一个是渐新世之前其形成环境氧化程度由环赤道表中层洋流和高密度温盐表层水下沉控制的对应于结壳老壳层的生长幕,而在早、中渐新世处于两种环境的转换期,也正好是海退期、大洋低生产力期、低CCD和生物碳酸盐低产率期,形成结壳生长的主要生长间断。该研究成果对于进一步了解太平洋的古海洋、古环境演变有一定意义。     

中太平洋多金属结核和沉积物的地质特征及样品采集

简要介绍了中太平洋样区的地质概貌;多金属结核及沉积物的地质特性、化学成分、粒度特征和物理性质;同时讨论了采样方法技术以及采样的代表性等问题。     

太平洋富稀土深海沉积物中稀土元素赋存载体研究

太平洋深海沉积物中富含稀土(含Y,简称REY),尤其是(含)沸石粘土,其主要由粘土组分、沸石、鱼牙骨、微结核及生物残渣等组成,目前对于该类稀土矿床中REY的赋存载体存在争议。本文在中、西太平洋选取两个富REY的沸石粘土样品利用地球化学和矿物学对稀土赋存状态进行定量研究。矿物微区成分表明,鱼牙骨主要成分为磷灰石,含有最高的REY含量,为2497×10~(- 6)~18623×10~(- 6),微结核和沸石颗粒含有较低的REY含量,分别为246×10~(- 6)~333×10~(- 6)和29.36×10~(- 6)~256×10~(- 6)。通过三种矿物相在沉积物63~250μm粒级组分中各自所占质量比例,计算得出磷灰石对REY的贡献率可达90%以上,说明此粒级中磷灰石为主要REY赋存载体,然而相对全岩总的REY含量,该粒级中磷灰石的贡献仍较小。通过对全岩和粉砂级组分(小于63μm)主微量地球化学分析和XRD矿物相分析表明,2个样品中REY主要存在于粉砂级组分中,其中的磷灰石对全岩REY的贡献最高均可达70%左右。另外通过对粘土组分(2μm)研究发现2个样品粘土组分的REY含量相似,分别为530×10~(- 6)和631×10~(- 6),粘土组分对全岩沉积物的REY贡献意义不大,对整个沉积物REY而言其贡献率仅为2%~5%左右。因此认为磷灰石为整个沸石粘土中REY主要赋存载体。     

控制北太平洋深水中 Pb、Nd 同位素演化的不同因素

近年研究表明，大洋中溶解的 Pb和 Nd 以陆源来源占主导。但对 Pb和Nd 进入大洋的途径存在很大争议。笔者研究了3块中北太平洋铁锰结壳（CJ01，CLD01，CB12）的元素含量和 Pb、Nd 同位素组成。根据 Co 含量经验公式法定年，结合几块结壳的剖面 Pb 同位素演化曲线与 Os 同位素演化曲线，确定所研究的中北太平洋铁锰结壳的底部年龄约为 75Ma。3块结壳不论磷酸盐化与否，其 Pi、Nd 同位素随时间的演变曲线均十分相似，且 Pb 同位素演化趋势与北太平洋岩心（LL44－GPC3）中的风沙的 Pb 同位素演化趋势相似。这些结壳的 Nd 同位素演化趋势也相似，但与岩心 LL44－GPC3 中风沙的 Nd 同位素的演化曲线完全不同。由此得到以下结论:(1)通过研究2块结壳，首次提出太平洋铁锰结壳的年龄超过70Ma，得到了白垩纪末及整个新生代中北太平洋深水 Pb、Nd 同位素的演化。并且揭示磷酸盐化不会明显改变结壳中的 Pb、Nd 同位素组成。（2）风沙是中太平洋深水溶解 Pb 的主要来源。太平洋中的 Pb 由来自大陆风沙富放射成因 Pb 和来自火山弧非放射性成因 Pb 之混合，二者的量随时间变化。60Ma 之前，北美大陆粉尘是太平洋 Pb 的主要来源，而从40 Ma 开始，亚洲大陆粉尘对 Pb 总量的贡献日益重要。在约55 Ma 期间是大陆粉尘对海水 Pb 贡献最小的时期，与温暖气候相吻合。（3）风成粉尘对中北太平洋深水中的 Nd 的贡献可以忽略。新生代太平洋边缘火山岩风化侵蚀作用加强，是中北太平洋ENd值升高的主要原因。     

Climatic Characteristics of Binary Tropical Cyclones in the Northwest Pacific Ocean

Based on typhoon best track data of China Meteorological Administration and NCEP global reanalysis data, this study analyzed the characteristics of binary tropical cyclones (TC) in the Northwest Pacific Ocean during 1951 to 2014 by using the objective determine standard. When the distance between the two TCs d≤ 1 800 km, they are defined as binary tropical cyclones or binary typhoons. And binary typhoons are divided into two different types which are typical binary typhoons and atypical binary typhoons. The climatic characteristics of binary tropical cyclones are as follows: There were 699 pairs of binary typhoons in Northwest Pacific Ocean during 1951 to 2014. In these cases, there were 446 pairs of typical binary typhoons and 253 pairs of atypical cases, occupying 63.8% and 36.2%, respectively. The proportion of typical cases increased with the shortest distance decreasing, while the proportion of atypical cases decreased with the shortest distance decreasing. When the speed of typical binary typhoons moving towards each other reached the peak, binary typhoons mainly showed the east to west direction. At this time, typhoons were controlled by easterly stream of the southern edge of the subtropical high. In this situation, the east typhoon moved toward the west typhoon quickly. When the anticlockwise angular velocity of typical binary typhoons reached the peak, binary cases distributed northeast to southwest or east-northeast to west-southwest, appearing in west and southwest edge of the subtropical high and mainly being controlled by southeasterly stream, thus benefiting the anticlockwise rotation between the typical binary typhoons.     

南太平洋东劳扩张中心表层沉积物氨基酸组成所揭示的生物地球化学意义

通过对南太平洋劳盆地东劳扩张中心(ELSC)表层沉积物进行水解氨基酸(THAA)分析、氨基酸对映异构体比值(D/L)分析及总有机碳(TOC)分析,对沉积物中氨基酸含量和来源、有机质降解程度和采样区域生物活动性及温度特征等问题进行了探讨。结果表明,ELSC区域样品中有机质含量较低,TOC含量为0.70～2.15 mg/g(干重),THAA含量为30～511μg/g(干重),热液活动区域原位化能合成作用对沉积物中氨基酸的相对富集有较大的贡献。沉积物中THAA含量和生物群落活动状况与分布范围有关,样品矿物组分对氨基酸的保存亦有一定的影响。由于各采样点热液活动、沉积物类型、生物群落的类型及分布均有所不同,样品中个体氨基酸的组成分布特征有较大差异。以TOC中氨基酸态碳所占百分比TAAC%作为指标对样品有机质活性进行了判别,热液喷口区域样品有机质新鲜程度要普遍高于非热液喷口区域样品,高温热液环境对氨基酸降解途径有一定的影响。样品中个体氨基酸D/L比值变化范围较大,天冬氨酸(Asp)为0.08～0.46,谷氨酸(Glu)为0.06～0.19,丝氨酸(Ser)为0.01～0.81,丙氨酸(Ala)为0.10～0.30。根据样品中THAA含量、TAAC%及个体氨基酸的D/L比值可以粗略判断生物活动性的大小及细菌对THAA的相对贡献,但并不能准确地区分热液活动活跃区域和非活跃区域在温度和生物活动性方面的差异。     

西太平洋富钴结壳元素组合特征及其地质意义

海山富钴结壳是一种重要的海底固体矿产。对西太平洋海山的56个结壳样品进行了23种化学组分分析,并利用R型聚类分析和R型因子分析,分别提取四组元素组合和四个主因子。综合特征表明．富钴结壳在形成过程中,经历了一次强度较大的锰矿物相成矿作用,Co、Ni等元素的富集与此有关;铁矿物相的成矿作用强度较小,但表现出多期次的特点;锰、铁矿物是不同成矿作用的产物;结壳形成过程中,可能遭受了二次磷酸盐化作用,结壳中磷酸盐矿物的形成对铁矿物相的形成可能有抑制作用。