西北太平洋异常变化

根据国家海洋局全部海洋站的水温和水位资料,以及“热带海洋和全球大气(TOGA)”的ADCP测流和CTD资料计算并分析了黑潮源流区输入西北太平洋的北向质量通量和西北太平洋及其邻近海域的水温、水位的异常变化,同时还应用美国宇航局Goddard地球观测系统(GEOS)/四维资料同化系统(DAS)计算并分析了西北太平洋的海面潜热通量的空间和时间变化.结果表明,北向质量通量具有明显的年际变化.这种年际变化与西北太平洋水温、水位和潜热通量的变化有着合理的因果关系.当前者减少时,后3者也明显减小.其物理解释是从热带西太平洋输入西北太平洋的海水质量和热量的减少将导致西北太平洋的减水和热量收入的减少,而热量收入的减少又将会引起水温和潜热通量的减小.     

Relationship between cadmium and phosphate in the northwest Pacific Ocean

The relationship between Cd and PO₄ in the Kuroshio and Oyashio regions and the Okhotsk Sea was examined. The resultant equations are as follows: Cd (ng l^–1)=37.0 PO₄ (M)+2.6; Cd(ng l^–1)=32.1 PO₄ (M)+1.2 and Cd (ng l^–1)=34.1 PO₄ (M)+7.9, respectively. These results are in good agreement with previously reported studies, and indicate that during removal from surface waters to deeper waters by biological assimilation and regeneration in deeper waters Cd and PO₄ maintain the same ratio in the open ocean. The relationship between Cd and PO₄ in coastal waters, however, differed from that in the open ocean.     

Diatoms in surface sediments of the Sea of Okhotsk and the northwest Pacific Ocean

The present investigation was targeted at diatom composition studies in the surface sediments (0–1 cm) sampled in the Sea of Okhotsk and the northwest Pacific in the depth range from 130 to 6110 m. The taxonomic analysis, as well as the quantitative (the diatom cell abundance per sediment dry weight unit) content and ecological group definition, was applied. Ten diatom taxa are the main body (80–100%) of the diatom assemblages: Bacterosira bathyomphala, Chaetoceros spp. (spores), Actinocyclus curvatulus, Thalassiosira latimarginata (group), T. antarctica (spores), Neodenticula seminae, Rhizosolenia hebetata f. hiemalis, Thalassiothrix longissima, Coscinodiscus marginatus, Coscinodiscus oculus iridis. The relative content of these species reflects the sedimentation conditions for different parts of the sea: the shelf, the continental slope, the open sea, and the ocean. The highest diatom content (45.6.3–60.0 10⁶ per g of dry weight) was found for the surface sediments in the central part of the Sea of Okhotsk and the continental slope of western Kamchatka.     

Crustal low-velocity zone south of Shatsky Rise,northwest Pacific Ocean

The detailed seismic refraction investigation of the oceanic crust south of Shatsky Rise in the Northwestern Pacific revealed a low velocity zone (LVZ) with an average compressional wave velocity of 6.3 km/s within layer 3. This conclusion is based on the shadow zone for refractions on the travel time curves in their first arrivals from the M discontinuity. The LVZ may be composed of oceanic plagiogranites because serpentinization of peridotites would probably lead to an increase in crustal block volume with a concomitent decrease in density and thereby thickening and upwelling at the place of now “overdeepened” ocean would be expected.     

南海及西北太平洋卫星高度计资料分析:海洋中尺度涡统计特征

采用AVISO提供的卫星高度计融合数据,对南海及西北太平洋(5°～35°N,105°～150°E)1993～2009年17a间的中尺度涡活动进行统计分析.结果表明南海中尺度涡活动具有明显的年际变化,每年观测到产生的中尺度涡个数平均为21～22个,标准差约为4个,占年平均值的20%;而西北太平洋中尺度涡个数的年际差异不大,平均每年观测到150～151个中尺度涡产生,标准差约为14个,仅占年平均值的9%.中尺度涡的逐月统计结果表明南海和西北太平洋的中尺度涡活动均有明显季节变化,1993～2009年间的各月南海和西北太平洋分别观测到30～31个和213～214个中尺度涡产生,标准差分别约为6个和41个,均占各自月平均值的19%.中尺度涡主要集中分布在南海东北部、越南东部和黑潮流轴附近海域.涡动能、海面高度距平均方根以及涡度均方根的空间分布大致与涡旋个数分布一致,但在西北太平洋的低纬海区和黑潮延伸体区域则不甚吻合.在相同的涡旋判别标准下,西北太平洋低纬海区(5°～15°N)观测到的中尺度涡个数比中高纬海区要少得多.     

太平洋潮波特征比较

本文对TOPEX/Poseidon高度计资料直接分析得到4个主要分潮(M2、K1、S2和O1)的调和常数,将其与全球大洋潮波模式TPXO6.2的模拟结果以及太平洋中48个验潮站观测资料的分析结果进行了系统比较,得出高度计资料直接分析结果与潮波模式模拟结果总体比较一致.模拟出的无潮点的位置和高度计资料直接分析结果有差异,且K1和O1分潮差异较大.与站点结果比较表明TPXO6.2模式模拟结果与验潮站观测结果的振幅绝对偏差小于2cm的站点的百分比达到85%,迟角绝对偏差小于40°的站点的百分比达到70%以上,比高度计资料直接分析结果精确;矢量均方根误差比较表明,太平洋中部结果比整个太平洋结果准确,太平洋矢量均方根误差的值和其他研究者、其他模式的结果近似.     

Magnetic properties indicate the sources of hadal sediments in the Yap Trench,northwest Pacific Ocean

Magnetic minerals in marine sediments are often masked by the primary natural remanent magnetization and material source signals.In order to understand sedimentary environment and sources of sediments in the abyss,we studied 126 samples of five bottom surface cores collected by the Jiaolong Submersible at 4000-7000 m in depth during the third stage of the China's 38th Ocean Voyage.The magnetic properties of the sediments were analyzed using Thermosusceptibility(k-T)curves and Day plot.The results show that the magnetic minerals in the sediments of the Yap Trench are mainly maghemite,and the overall magnetic and soft magnetic properties were strong.The magnetic particles of sediments are dominated by pseudo single domains(PSD)grains.The main source of sediment is locally-derived basalt debris and volcanic debris,and the process of sedimentation is gravity-like flow deposition.     

西北太平洋海洋温度锋生与锋消机制的初步研究

海洋锋面区域对气候变化以及海气耦合作用的影响非常显著,通过分析其形成机制,可以帮助进一步了解海洋与大气的相互作用过程以及其物理过程。利用Argo数据、NCEP/NCAR再分析数据和遥感风场数据对西北太平洋的混合层温度与温度锋面的变化机制进行了研究。基于海洋混合层的热量收支模型,发现在北太平洋区域的海洋混合层温度主要受到净热通量控制,同时还存在一个季节变化明显的温度锋面。9~2月为温度锋面加强时期,3~4月温度锋面变化不明显,而5~8月温度锋面则迅速减弱。根据研究,该温度锋面的加强与减弱主要是由于净热通量的南北差异造成的,而在净热通量中则以短波辐射通量与潜热通量为主要影响因子。     

西北太平洋副热带环流区秋季水体叶绿素a分布及粒级结构

2002年10～11月在15°00′～27°40′N,121°30′～131°00′E的吕宋岛、台湾岛和琉球群岛以东的西北太平洋副热带环流区设测站121个,观测了该区表层和水柱中的叶绿素a质量浓度分布和光合浮游生物粒级结构。结果表明,观测海区秋季叶绿素a的质量浓度较低,变化幅度较小,变幅范围为0.039～0.271μg/dm3。台湾岛至琉球群岛以东的北部测区平均叶绿素a质量浓度高于吕宋岛以东的南部测区。叶绿素a含量的垂直分布在真光层内随深度的增加而增大,在真光层以下却随深度增加而降低。表层水的光合浮游植物细胞丰度较低,并以小粒径的硅藻占优势,细胞丰度约为103个/dm3。粒度分级结果表明,Pico级份的光合浮游生物占绝对优势(86%),Nano级份次之(11%),大细胞的Net级份所占比例最小(3%),呈现出微微型光合浮游生物在寡营养海区居重要地位的状况。     

基于耳石微结构的西北太平洋秋刀鱼(Cololabis saira)年龄与生长研究

根据2014年6月和10-11月在西北太平洋公海采集的168尾秋刀鱼样本,基于耳石微结构并结合基础生物学数据,鉴定了秋刀鱼的日龄,推算了孵化日期,并建立了生长模型和生长率。研究发现:耳石微结构从核心到透明区边缘,轮纹宽度由宽至窄,亮度由暗至明,标记轮多分布在透明区。日龄范围为204~549 d,优势日龄组为231~290 d和381~470 d,日龄最小个体体长207 mm,体质量39 g,日龄最大个体体长291 mm,体质量131 g。孵化日期为2012年12月至2014年4月,孵化高峰期出现在1-3月和8-10月,初步推算秋刀鱼主要分为春生群和秋生群产卵群体。体长和体质量生长模型符合Logistic生长模型。体长平均绝对生长率和相对生长率别为0.224 mm/d和0.000 88,绝对生长率随着日龄增加而减小。体质量平均绝对生长率和相对生长率别为0.293 g/d和0.003 25,最大绝对生长率（0.504 mm/d）和最大相对生长率（0.004 86）出现在351~400 d。     

西北太平洋春、秋季悬浮颗粒物的粒径变化与物质组分

为了解日本以东的西北太平洋200m以浅上层水体悬浮颗粒物的粒径变化与物质组分,分别于2015年5月和9月在该海区应用LISST-100X型现场激光粒度仪进行了悬浮体粒径分布的测量,并采集悬浮体水样采用扫描电镜及能谱分析悬浮颗粒物的物质组分.结果表明,研究区的悬浮颗粒物主要由大粒径颗粒(大于133μm)组成,并在100m以浅的上表层集中分布,其余层位颗粒含量较少.秋季悬浮体浓度远高于春季,但大粒径颗粒所占的比重明显降低,中等大小的颗粒(36~133μm)所占比重相应增加,中等粒径颗粒和细小粒径颗粒(小于36μm)在200m水层以浅分布较均匀,并有随着粒径的增大悬浮体浓度逐渐增加的趋势.悬浮颗粒物组成成分主要为单矿物碎屑、生物碎屑、絮凝体,主要来源于海洋浮游生物和陆源输入.悬浮体浓度及粒径分布特征主要受生物生长、大陆风尘和洋流输送等因素的影响.     

太平洋中的主要起伏模态

对海洋中起伏运动(heaving)信号的时空分布研究能够帮助我们更好地了解气候系统中的年际和年代际变率。文章通过再分析资料和模式对太平洋区域的heaving主要模态进行了研究。研究结果表明: 太平洋区域主要存在两种heaving模态: 第一模态主要表现为赤道东西两侧的温跃层异常信号反位相; 第二模态表现为赤道区域和副热带区域的温跃层异常信号呈现反位相变化的规律。本文对这两个主要heaving模态所涉及的物理过程进行详细讨论, 结果表明: 东西反位相模态主要是受赤道波动调节的结果; 而经向结构模态则主要是由赤道地区的波动和副热带区域的风应力旋度异常作用共同导致。此外, 我们还讨论了heaving模态可以通过海洋波动以及Ekman输送等过程对海盆尺度的热输送(振幅约为5×10¹⁴W)以及海洋热含量(振幅约为1.5×10²⁰J)的再分配起到了关键的调制作用, 进一步表明heaving模态对全球气候变化有着重要的作用。     

Enhancement of particulate organic carbon export flux induced by atmospheric forcing in the subtropical oligotrophic northwest Pacific Ocean

The effects of extreme atmospheric forcing on the export flux of particulate organic carbon (POC) in the warm oligotrophic nitrogen-limited northwest Pacific Ocean were examined in 2007 during the spring Asian dust storm period. Several strong northeast monsoon events (maximum sustained wind speeds approaching 16.7 m s^? 1, and gusts up to 19.0 m s^? 1) accompanied by dust storms occurred during a 1-month period. The cold stormy events decreased surface water temperature and induced strong wind-driven vertical mixing of the water column, resulting in nutrient entrainment into the mixed layer from subsurface waters. As a result, the export flux of POC ranged from 49 to 98 (average value = 71 ± 16) mg m^? 2 day^? 1, approximately 2–3 times greater than average values in other seasons. As dry and wet deposition of nitrogen attributable to Asian dust storm events does not account for the associated increases in POC stocks in this N-limited oligotrophic oceanic region, the enhancement of POC flux must have been caused by nutrient entrainment from subsurface waters because of the high winds accompanying the dust storm events.     

Ambient noise measurements in the northwest Indian Ocean

Ambient noise measurements were made at seven different locations during the first four months of 1977. The measurement systems included: two types of towed arrays, a bottomed array, and systems with sensors distributed throughout the water column. The noise in the frequency regime dominated by shipping was found to be extremely high with a spectrum level of 92 dB//1 /spl mu/Pa at 50 Hz. These high levels were attributed to the high-density shipping. Horizontal directionality of the noise varied from site to site, ranging from highly directional to nearly nondirectional. The character of the directionality was highly dependent on the site position relative to shipping lanes. The noise showed very little dependence on depth.     

西北太平洋山间盆地沉积物有机碳质量累积速率及影响因素

海洋碳汇作用是大洋生态系统的重要生态系统服务功能,不仅影响着海洋生态系统的能量流动,也是元素循环的重要驱动力。本文以中国大洋48航次采集自西北太平洋典型海山区海盆的沉积物样品和资料为基础,对西北太平洋山间盆地沉积物有机碳质量累积速率(F_orgc)特征及影响因素展开初步研究。结果表明,西北太平洋山间盆地有机碳质量累积速率变化范围为1.41～1.73 g/(m²·ka),均值为1.60 g/(m²·ka),以中部偏西海区的有机碳质量累积速率最高;全区平均净初级生产力转移效率约为0.003 1%。西北太平洋山间盆地有机碳质量累积速率和净初级生产力转移效率均低于东太平洋海区和赤道太平洋海区。本区有机碳质量累积速率受水层和沉积层的生物地球化学循环驱动因素,如海洋净初级生产力、沉积物质量累积速率、有机碳含量、氧化还原电位等的综合影响,同时也受距海山距离、水深等地形因子的影响。     

Spreading cycles in the Pacific Ocean

Changes in the spreading rates in the Pharallon-Pacific-Izanagi (Kula) triple junction during the Cretaceous and Cenozoic are revised using new data of the dynamics of the Pacific plate. The cyclic character of the spreading is recognized, and the stages of its acceleration and deceleration are distinguished. Approximately 130, 87, and 42 My B.P., at the culminations of the cycles, when maximal spreading rates were reached, the principal rearrangements in the tectonic evolution of the ocean occurred. The spreading rates were minimal about 140, 120, 65, and 15 My B.P. The latter periods are marked by pulses of basalt magmatism in the west, east, and northeast of the Pacific Ocean. The study recognized no signs of the intrusion of the Middle Cretaceous superplume, which was suggested by Larson. Both the cycling revealed and the pulsations of the intraplate volcanism are most probably related to the regularities of the deformations of the oceanic lithosphere and reflect the periodic alternations of regimes of compression and extension of the Pacific plate during the last 180 My.     

西北太平洋柔鱼冬春生群体栖息地的变化研究

柔鱼（Ommastrephes bartramii）是短生命周期鱼种,其适宜栖息地范围受海洋水温条件的显著影响。本文根据2006-2015年7-11月中国鱿钓技术组提供的西北太平洋柔鱼冬生群体的捕捞数据以及海表温度（SST）数据,利用捕捞努力量与SST的频率分布关系,估算柔鱼各月适宜温度范围（PFSST）,对1985-2015年柔鱼PFSST进行估算,同时分析柔鱼PFSST的年代际变化规律,并评估不同强度厄尔尼诺和拉尼娜事件对柔鱼栖息地的影响。研究表明,2006-2015年柔鱼各月适宜的SST具有明显变化,7-11月对应适宜的SST范围分别为16~19℃、17~21℃、15~19℃、14~16℃和12~13℃。单位捕捞努力量渔获量大小随PFSST变动而发生相应变化,两者具有显著正相关关系,这说明了柔鱼渔场范围内适宜温度面积增加,对应柔鱼资源丰度上升。1985-2015年柔鱼PFSST呈现显著的月间和年际变化,7-11月PFSST具有先增加后递减的变化规律,且7-9月PFSST年际波动相似,10和11月PFSST年际变化相似。同时,柔鱼PFSST与渔场内SST具有显著正相关关系。柔鱼渔场内PFSST受厄尔尼诺和拉尼娜事件调控,其面积随气候事件的强度发生变化,具体表现为:弱拉尼娜事件和正常气候条件下,柔鱼渔场范围内水温最高,适宜栖息面积显著增长;中等强度和高强度拉尼娜条件下,柔鱼渔场内平均水温较高,但适宜栖息面积较前两者显著减小;弱强度、中等强度和超高强度厄尔尼诺条件下,柔鱼渔场内水温均较低,但弱强度和超高强度厄尔尼诺条件下柔鱼适宜栖息面积均大于中等强度厄尔尼诺条件。     

The diagnosis for the tropical Pacific Ocean conditions in 1990

In this paper, on the basis of the observational hydrographic data obtained from the eighth cruise of PRC-USA bilateral air-sea interaction program, and combined with the sea surface temperature (SST) charts provided by NOAA, the data obtained from moored thermistor chains supplied by L. J. Mangum and sea level data provided by K. Wyrtki, the ocean conditions since October, 1989 in the western tropical Pacific are exposed, which indicate that 1990 is a year with weak El Nino event similar to the 1980 El Nino event, and the North Equatorial Countercurrent (NECC) has made a good contribution to the propagation of warm water from the Western to the Central and Eastern Pacific, a characteristic similar to that of the 1976 El Nino event. The 1990 weak El Nino event will soon fall into decay.     

The seasonal cycle of diabatic heat storage in the Pacific Ocean

This study quantifies uncertainties in closing the seasonal cycle of diabatic heat storage (DHS) over the Pacific Ocean from 20°S to 60°N through the synthesis of World Ocean Circulation Experiment (WOCE) reanalysis products from 1993 to 1999. These products are DHS from Scripps Institution of Oceanography (SIO); near-surface geostrophic and Ekman currents from Earth and Space Research (ESR); and air-sea heat fluxes from Comprehensive Ocean-Atmosphere Data Set (COADS), National Centers for Environmental Prediction (NCEP), and European Center for Mid-Range Weather Forecasts (ECMWF). With these products, we compute residual heat budget components by differencing long-term monthly means from the long-term annual mean. This allows the seasonal cycle of the DHS tendency to be modeled. Everywhere latent heat flux residuals dominate sensible heat flux residuals, shortwave heat flux residuals dominate longwave heat flux residuals, and residual Ekman heat advection dominates residual geostrophic heat advection, with residual dissipation significant only in the Kuroshio-Oyashio current extension. The root-mean-square (RMS) of the differences between observed and model residual DHS tendencies (averaged over 10° latitude-by-20° longitude boxes) is <20 W m⁻² in the interior ocean and <100 W m⁻² in the Kuroshio-Oyashio current extension. This reveals that the residual DHS tendency is driven everywhere by some mix of residual latent heat flux, shortwave heat flux, and Ekman heat advection. Suppressing bias errors in residual air-sea turbulent heat fluxes and Ekman heat advection through minimization of the RMS differences reduces the latter to <10 W m⁻² over the interior ocean and <25 W m⁻² in the Kuroshio-Oyashio current extension. This reveals air-sea temperature and specific humidity differences from in situ surface marine weather observations to be a principal source of bias error, overestimated over most of ocean but underestimated near the Intertropical Convergence Zone.