On the Uncertainty of Archive Hydrographic Data Sets

As the international hydrographic community continues to address the question of irreducible uncertainty in modern surveys, a similar question must be asked of archived vertical beam echosounder (VBES) and leadline data sets. The Office of Naval Research funded STRATAFORM project surveyed an area of the New Jersey shelf around 39$^circ$12' N 72$^circ$50' W using an EM1000 multibeam echosounder (MBES). This area is also covered by National Oceanic and Atmospheric Administration surveys from 1936 to 1938 (from early visual indicating fathometers) and 1975–1976 (VBES). The analysis shows that the earlier data are biased in deeper water, most probably because of “hydrographic rounding” or instrument limitations, and may be unrecoverable, but that the VBES data appear approximately unbiased. Estimates of uncertainty for a surface model generated from the archive data are constructed, taking into account measurement, interpolation, and hydrographic uncertainty (addressing the problems of unobserved areas and surface reconstruction stability). Comparison of predicted depths against the MBES data shows that the VBES-derived surface is consistent given the quoted uncertainty and that the uncertainty corresponds with appropriate hydrographic survey standards. However, spatial aliasing of the VBES surface is observed, which may be the limiting factor in the applicability of this data.     

卫星测高在海洋测绘中的应用

研究了卫星测高数据在海山探测以及无图海域水深预测方面的应用。介绍了匹配滤波法检测海山的理论与方法，并研究了反演海底地形时的重力导纳理论以及滤波窗口和滤波函数的选择。实践表明，利用卫星测高数据反演海底地形的精度可优于水深的10％。     

海洋测绘资料综合数据仓库的设计

在介绍了海洋测绘资料综合数据仓库的存储对象、体系结构和建设目标的基础上,从实际需要出发,阐述了海洋测绘数字化生产对海洋测绘综合资料科学化和自动化保障的需求,以及系统的总体设计原则、安全需求、软件的设计思路、系统的功能模块和网络化安全的建设方案,并且重点介绍了系统建设中的各种关键技术。     

Routes of Agulhas rings in the southeastern Cape Basin

Using weekly sea surface height data, Agulhas rings from the period October 1992 to December 2006 are detected and tracked, from their formation dates and throughout the Cape Basin. While 102 of them formed at the Agulhas Current retroflection, their subsequent subdivisions and junctions led to 199 trajectories. The rings geographical probability of presence shows two maxima. One, related to numerous ring passages, lies in the submarine bight formed by the Erica seamount, the Schmitt-Ott seamount, and the northeastern tip of the Agulhas Ridge. The other one, to be ascribed to topographic blocking of the eddies, is southeast of the latter obstacle. On the basis of topographic effects three routes for Agulhas rings are distinguished, a Northern route for rings that enter the south-Atlantic northeast of the Erica seamount, a Central one for those passing westward between this seamount and the tip of the Agulhas Ridge, and a Southern one farther south. Despite its bathymetric obstacles, the central route is the dominant one, both in terms of percentage of eddy crossings at its definition segment, and in terms of conveyed volume transport. Specific behaviours of rings along each route are described, referring to observations in previous studies. Some rings from the Northern route interact with the flow regime of the South African continental slope. The southernmost trajectories of the Central route are thought to settle the location of the climatological Subtropical Front in that region. The rings of the Southern route experience important core property alteration as they transit through the subantarctic domain.     

Hydrographic structure in association with deep boundary current in the north of the Shikoku Basin

High quality CTD data were collected in the north of the Shikoku Basin where an abyssal boundary current has been observed through direct current measurements. Analyses of hydrographic data showed:

1. Colder and saltier water (heavier water) compared to surrounding waters is found above the continental shelf-toe and the eastern flank of the Kyushu-Palau Ridge where the existence of the abyssal boundary current has been expected. The heavier water has a horizontal extent of about 50 km.
2. The heavier water has the vertical scale of 2000 m from the sea bottom, and is associated with a thermal wind shear which enhances a component of the flow toward a direction looking the Nankai Trough (a trough located along the northern end of the Shikoku Basin) to the left in the abyss. The assumed “level of no motion” at about 2500 m depth gives the geostrophically estimated current in a good agreement with the directly measured current.

A volume transport associated with the colder and higher salinity water is estimated to be about 2 Sv off Cape Shiono-misaki which may include a recirculation above the Nankai Trough. This is about twice of the transport estimated in the interior of the Shikoku Basin through a vorticity balance between the stretching term and latitudinal variation of the planetary vorticity.     

Mass, Heat and Salt Balances in the Eastern Barents Sea Obtained by Inversion of Hydrographic Section Data

Standard hydrological section data, collected in the eastern Barents Sea in September 1997, have been analyzed using a variational data assimilation technique. This method allows us to obtain temperature, salinity and velocity fields that are consistent with observations and dynamically balanced within the framework of a steady-state model describing large-scale nearly geostrophic circulation. Error bars of the optimized fields are computed by explicit inversion of the Hessian matrix. The optimized velocity field is in agreement with independent velocity observations derived from surface drifter trajectories in the southwestern part of the Barents Sea. Optimized fields provide the following estimates of integral characteristics of the circulation in the region: i) the North Cape current transport is 2.12 ± 0.25 Sv; ii) the Karskie Vorota Strait throughflow is 0.7 ± 0.06 Sv; iii) heat flux with Atlantic water is 4.7 ± 0.16⋅10¹¹ W; iv) salt import from the Atlantic Ocean is 7.41 ± 0.46⋅10³ kg/s. The imbalance of the heat budget in the eastern part of the Barents Sea indicates the presence of statistically insignificant surface heat fluxes which are less than 1 W/m². This revised version was published online in July 2006 with corrections to the Cover Date.     

海洋测绘成果在港口与航道维护保障中的应用

详细介绍了海洋测绘成果在港口与航道疏浚工程水下挖槽量、回淤量和航道边坡土方量及超宽量计算中的应用,探讨了维护疏浚工程效益分析方法,提出了扩大海洋测绘成果在港口与航道通航保障应用范围的建议.     

Low 210Pb in the upper thermocline in the Canadian Basin: scavenge process over the Chukchi Sea

210Pb was measured during the 3rd Chinese National Arctic Research Expedition cruise to investigate its spatial pattern in the western Arctic Ocean, as well as its relation with the thermocline in the Canadian Basin. The specific activities varied from 0.04 to 2.72, 0.013 to 4.37, and 0.1 to 4.85 Bq/m3 for dissolved, particulate, and bulk 210Pb, respectively, corresponding to respective averages of 0.65, 0.43, and 1.08 Bq/m3. In the Canadian Basin, the minimum 210Pb activities occurred in the thermocline, which was characterized by low temperature of-1.52°C and salinity of 33.1. Combining the spatial distribution of 210Pb and hydrographical characteristics in the western Arctic Ocean, this scenario was ascribed to the effective scavenging of 210Pb when the Pacific water flowed across the Chukchi Shelf. Quantitatively, this interpretation was supported by both the shorter residence times and higher scavenging efficiencies(SE) of dissolved 210Pb over the Chukchi Shelf. The highest SE values were observed in the Herald Shoal and bottom waters over the slope.     

通过焦磷酸测序揭示北极海水的微生物群落结构

This study aimed to determine the microbial community structure of seawater in(ICE-1) and out(FUBIAO) of the pack ice zone in the Arctic region.Approximate 10 L seawater was filtrated by 0.2 μm Whatman nuclepore filters and the environmental genomic DNA was extracted.We conducted a detailed census of microbial communities by pyrosequencing.Analysis of the microbial community structures indicated that these two samples had high bacterial,archaeal and eukaryotic diversity.Proteobacteria and Bacteroidetes were the two dominant members of the bacterioplankton community in both samples,and their relative abundance were 51.29% and 35.39%,72.95%and 23.21%,respectively.Euryarchaeota was the most abundant archaeal phylum,and the relative abundance was nearly up to 100% in FUBIAO and 60% in ICE-1.As for the eukaryotes,no_rank_Eukaryota,Arthropoda and no_rank_Metazoa were the most abundant groups in Sample FUBIAO,accounting for 85.29% of the total reads.The relative abundance of the most abundant phylum in Sample ICE-1,no_rank_Eukaryota and no_rank_Metazoa,was up to 90.69% of the total reads.Alphaproteobacteria,Flavobacteria and Gammaproteobacteria were the top three abundant classes in the two samples at the bacterial class level.There were also differences in the top ten abundant bacterial,archaeal and eukaryotic OTUs at the level of 97% similarity between the two samples.     

Direct measurement of the deep circulation within the Brazil Basin

In support of the Deep Basin Experiment, part of the World Ocean Circulation Experiment, a large number of neutrally buoyant floats were released within the Brazil Basin during the 1990s in an attempt to measure directly the circulation in the deep ocean interior. Three levels corresponding to the three major subthermocline water masses were selected, and results from the deeper two (North Atlantic Deep Water, NADW, and Antarctic Bottom Water, AABW) are described. At this writing processing of acquired tracking data is incomplete. Hence, this paper reports on the progress of the observational program and gives our initial conclusions.It appears that the flow in the deep Brazil Basin is unlike previous conjectures in which the circulation patterns can be characterized as being primarily meridional, both along the western boundary and in the interior. The existence of a deep western boundary current (DWBC) is quite clear in the float data at the NADW level, but less prominent in the AABW, and the interior flow is dominantly zonal with unexpectedly small meridional space scales. Integral time scales are long, of order 20–30 days, and eddy kinetic energy levels are low, of order 1 cm²/s². In spite of the low energy levels a surprising number of our floats became caught up in vortices.A line of seamounts extending offshore near 20°S, known as the Vitória–Trindade Seamounts, interrupts the DWBCs and is the location for eddy formation and apparent flow away from the boundary into the interior. Although it has been speculated that this could feed a narrow zonal current of NADW (the “Namib Col Current”) our float trajectories suggest a return to the western boundary, rather than a continuation to the east.     

Ridge development as revealed by sub-bottom profiles on the central New Jersey shelf

Closely-spaced 3.5 kHz seismic profiles were collected over the north-easterly trending ridge and swale system 50 km east-southeast of Atlantic City, New Jersey. They yield information on the Late Quaternary depositional history of the area, and on the origin of the ridge system. Four of the sub-bottom reflectors identified were sufficiently persistent to warrant investigation and interpretation. These reflectors, which have been cored, lithologically identified, and radiocarbon dated, are stratigraphically higher than the reflectors dealt with by the majority of previous studies. The upper three reflectors are definitely mid- and post-Wisconsin in age and present a record of the most recent glacial cycle. The upper three units associated with the observed reflectors appear to exert a pronounced influence on the bathymetry. The gently corrugated ridge system of Holocene sand is formed over the regionally flat-lying upper unit, an Early Holocene lagoonal silty clay. The characteristically flat, broad depressions of the area are floored by this lagoonal material. Locally, however, marine scour has cut through the silty clay into an underlying unit of unconsolidated fine Pleistocene sand. Several stages of trough development appear to be represented. After penetrating the lagoonal clay, troughs are initially narrow, but when incised through the sand into a lower, Pleistocene, silty-clay unit, the troughs become notably wider. As downcutting is inhibited by the lower clay, the upper clay is undercut as the trough widens in a fashion similar to a desert blowout.

The sub-bottom reflectors indicate that ridge development on the central shelf has involved aggradation as well as erosion. Some ridges seem to have grown by vertical and lateral accretion from small cores. The internal structure of other ridges suggests that they formed by the coalescence of several small ridges. Others appear to have undergone appreciable lateral migration.

The ridges appear to be in a state of continuing adjustment to the hydraulic regime of the deepening post-Pleistocene water column.     

Pliocene export production and terrigenous provenance of the Southern Cape Basin, southwest African margin

We have analyzed 33 Pliocene bulk sediment samples from Ocean Drilling Program Site 1085 in the Cape Basin, located offshore of western Africa in the Angola–Benguela Current system, for 17 major and trace elements, and interpreted their associations and temporal variations in the context of an allied data set of CaCO₃, opal, and C_org. We base our interpretations on elemental ratios, accumulation rates, inter-element correlations, and several multi-element statistical techniques. On the basis of qualitative assessment of downhole changes in the distributions of P and Ba, utilized as proxies of export production, we conclude that highs in bulk and biogenic accumulation that occur at 3.2 Ma, 3.0 Ma, 2.4 Ma, and 2.25 Ma were caused by increases in export production as well as terrigenous flux, and record a greater sequestering of organic matter during these time periods. Studies of refractory elements and other indicator proxies (SiO₂, Al₂O₃, TiO₂, Fe₂O₃, MgO, V, Cr, Sr, and Zr) strongly suggest that the terrigenous component of the bulk sediment is composed of two compositional end-members, one being ‘basaltic’ in composition and the other similar to an ‘average shale’. The basaltic end-member comprises approximately 10–15% of the total bulk sediment and its presence is consistent with the local geology of source material in the drainage basin of the nearby Orange River. The increase in bulk accumulation at 2.4 Ma appears to reflect a greater relative increase in basaltic input than the relative increase in shale-type input. Although studies such as this cannot precisely identify the transport mechanisms of the different terrigenous components, these results are most consistent with variations in sea level (and associated changes in shelf geometry and fluvial input) being responsible for the changing depositional conditions along the Angolan Margin during this time period.     

潮汐作用下渤海温跃层波动与起伏的数值研究

研究了潮汐(四大分潮 M₂,S₂,K₁,O₁同时输入)作用下渤海温跃层起伏与波动的三维数值模型(将海洋分为3层,即上混和层、跃层和下混和层),揭示了整个海区温跃层上界面处跃层起伏(在文中指每个时刻跃层波高的周期平均值)的地理分布及叠加在起伏之上的潮周期波动的时空变化,模拟出跃层波动与实测基本一致.结果发现大振幅的跃层波动均发生在海峡及近海地形突变之处.一般界面波动的波高大于甚至远远大于同一位置的表层潮波.从位相以及周期来看,潮波和跃层上下界面波动相互之间,有些海域一致,有些地方则相差甚远.跃层上界深度及厚度的梯度,对跃层起伏分布有一定的影响.跃层起伏还可能与海岸海底摩擦有关.     

Recent changes in the Labrador Sea Water within the Deep Western Boundary Current southeast of Cape Cod

Water properties measured by the central mooring in the Line W mooring array southeast of Cape Cod document a large character shift during the period of November 2001 to April 2008. The observed temperature, salinity and planetary potential vorticity (PPV) anomalies manifest changes in the formation region of the water masses present at Station W, specifically upper Labrador Sea Water (uLSW), deep Labrador Sea Water (dLSW) and Overflow Water (OW). During the observation period, the minimum in the PPV anomaly field relative to the record mean PPV profile migrated from 1500 m, where it was originally found, to 700 m. Temporal changes in the vertical distribution of temperature and salinity were correlated with the PPV changes. This suggests a dLSW-dominated first half of the record versus an uLSW-dominated second half. The structure of these anomalies is consistent with observations within the Labrador Sea, and their transit time to Line W agrees well with tracer-derived times for signals spreading along the western boundary. In that context, the observed water properties at Line W in the early 2000s reflected the intense deep convection in the Labrador Sea in the mid-1990s, with less intense convection subsequently affecting lighter isopycnals. The observed velocity field is dominated by high-frequency (periods of days to months) fluctuations, however, a fraction of the velocity variability is correlated with changes in water mass properties, and indicate a gradual acceleration of the southwestward flow, with a corresponding increase in Deep Western Boundary Current transport.     

Gas hydrate within the Winona Basin, offshore western Canada

In western Canada gas hydrates have been thought to exist primarily in the Cascadia accretionary prism off southern Vancouver Island, British Columbia (BC). We present evidence for the existence of gas hydrate in folds and ridges of the Winona Basin up to 40 km seaward from the foot of the continental slope off northern Vancouver Island. The occurrence of a bottom-simulating reflector (BSR) observed in a number of vintage seismic reflection profiles is strongly correlated to faulted, and folded sedimentary ridges and buried folds. The observed tectonic structures of the Winona Basin are within the rapidly evolving Juan de Fuca - Cascadia - Queen Charlotte triple junction off BC. Re-processing of multi-channel data imaged mildly to strongly deformed sediments; the BSR is confined to sediments with stronger deformation. Changes in the amplitude character of sediment-reflections above and below the depth of the base of gas hydrate stability zone were also used as an indicator for the presence of gas hydrate. Additionally, regional amplitude and frequency reduction below some strong BSR occurrences may indicate free gas accumulations. Gas hydrate formation in the Winona Basin appears strongly constrained to folds and ridges and thus correlated to deeper-routed fluid-advection regimes. Methane production from in situ microbial activities as a source of gas to form gas hydrates, as proposed to be a major contributor for gas hydrates within the accretionary prism to the south, appears to be insufficient to produce the widespread gas hydrate occurrences in the Winona Basin. Potential reasons for the lack of sufficient in situ gas production may be that sedimentation rates are 5-100 times higher than those in the accretionary prism so that available organic carbon moves too quickly through the gas hydrate stability field. The confinement of BSRs to ridges and folds within the Winona Basin results in an areal extent of gas hydrate occurrences that is a factor of five less than what is expected from regional gas hydrate stability field mapping using water-depth (pressure) as the only controlling factor only.     

Phytoplankton dynamics associated with the monsoon in the Sulu Sea as revealed by pigment signature

Phytoplankton dynamics during the northeast monsoon was investigated in the Sulu Sea from algal pigment analysis. We visited the Sulu Sea in February 2000, a mid period of the northeast monsoon, and in November and December 2002, the beginning of the northeast monsoon. SeaWiFS images showed generally low concentrations of surface chlorophyll a (Chl a) during the southwest monsoon and higher concentrations with several peaks during the northeast monsoon. In the beginning of the northeast monsoon, subsurface chlorophyll maxima (SCM) occurred, where vertical variation in class-specific composition as estimated from pigment signatures was prominent. Prochlorococcus, cyanobacteria, prymnesiophytes and crysophytes were important groups above the SCM, and the contribution of cyanobacteria to Chl a became much lower at and below the SCM. Contributions of chlorophytes and prasinophytes to Chl a generally showed maxima near the SCM. This distribution was accompanied by vertical changes in the concentration of photoprotective pigments relative to photosynthetic accessory pigments. During the mid northeast monsoon, the upward supply of nutrients was probably enhanced at some stations due to vertical mixing, and as a consequence diatoms dominated in the upper 100 m water column of these stations, and other eukaryotic flagellates including prymnesiophytes, chrysophytes and cryptophytes were secondary major components of the community. The elevation of Chl a concentration and changes in phytoplankton community during the northeast monsoon likely influence the variation in biological production at higher trophic levels in the Sulu Sea.     

Germplasm of breeding Pseudosciaena crocea as revealed by microsatellite markers

The germplasm of breeding large yellow croaker （Pseudosciaena crocea Richardson） was revealed using 12 microsatellite markers. The results showed that the genetic diversities were on a mediated level in the bred Daiqu and Min - Yue stocks and two hybrid groups, as represented by 4.83 of the mean number of alleles and 0.561 of the average observed heterozygosity. The value of pair- wise differentiation coefficient（ FST ） was only 13. 1% between Daiqu and Min -Yue stocks, demonstrating the low level of differentiation and a close relationship. However, STRUCTURE simulations and phylogenetic tree based on the UPGMA method supported that they are geographically different populations of the same species with distinct genetic structures. Examinations of individual admixture showed that Min - Yue stock had been contaminated by alien individuals. Moreover, the genetic structures of the two hybrid groups resembled those of their parents, especially affected more by their female parents. Finally, the values of average observed heterozygosity between parents and their ascendants were compared and tested, as a result of no detectable differences （P 〉 0. 05）.     

多源数据融合分析揭示闽江流域环境演化主控因素

<正>0引言闽江全长2 872 km,是中国东南地区的重要水源涵养地,流经福州市、南平市和三明市,为福建省40%经济总量的用水需求和1/3人口的饮水提供保障。闽江流域具有“八山一水一分田”的地貌特征,人口沿河谷聚集,受自然地理和经济发展的复合影响,流域内生态环境演化具有独特性。通过近30年多种数据融合分析,揭示了流域内人类活动强度的变化和相关环境要素之间的隐藏关系,以期为中国流域进一步的生态环境治理提供新思路。