Pre-operational forecasting of sea level height for the Río de la Plata

This paper presents the implementation and calibration of a pre-operational numerical model for the Río de la Plata river. This model is capable of predicting sea level variations in the Río de la Plata, and therefore constitutes a numerical tool of great value for the fluvial–maritime navigation and regional environmental management. A two-dimensional model (MOHID) with nested domains was used to simulate the hydrodynamics. This model was forced with a meso-scale atmospheric model (WRF) and a global tidal model (FES2004). The results obtained include astronomic and meteorological sea level variations in the Río de la Plata. Comparisons of modeled water levels with data have shown very good qualitative and quantitative agreement. The pre-operational test presented in this paper, a 4-day hydrodynamic forecast, was conducted in approximately 18 h.     

Deep crustal structure of Baiyun Sag,northern South China Sea revealed from deep seismic reflection profile

This paper discusses deep crustal architecture of the Baiyun Sag of the Pearl River Mouth Basin, northern South China Sea based on velocity analysis, time-depth conversion and seismic interpretation of the deep seismic reflection profile DSRP-2002. The profile was acquired and processed to 14 S TWT by the China National Offshore Oil Corp. (CNOOC) in 2002. It extends across the Baiyun Sag of the Pearl River Mouth Basin, from the northern continental shelf of the SCS to the deepwater province. As the first deep seismic reflection profile in the Pearl River Mouth Basin, this profile reveals seismic phases from basement down to upper most mantle. The Moho surface appears in the profile as an undulating layer of varying thickness of 1-3 km. It is not a single reflector interface, but a velocity gradient or interconversion layer. The crust thins stepwisely from the shelf to the continental slope and the abyssal plain (from north to south), and also thins under depocenters. The crustal thickness is only 7 km in the depocenter of the main Baiyun Sag, which corresponds to a Moho upwelling mirroring the basement topography. In the lower slope and the ocean-continental transition zone of the southernmost portion of the profile, three sub-parallel, NW-dipping strong reflectors found at depths around 10--21 km are interpreted as indications of a subducted Mesozoic oceanic crust. Crustal faults exist in the northern and southern boundaries of the Baiyun Sag. The intense and persistent subsidence of the Baiyun Sag might be related to the long-term activity of the crustal faults.     

硫酸海胆内容物多糖化学结构的质谱法研究

将海胆内容物硫酸多糖XB-3进行脱硫得到多糖XB-3D,分别对XB-3和XB-3D进行甲基化,对脱硫前后的部分甲基化糖进行气相色谱-质谱测定,通过质谱分析法得出XB-3和XB-3D的结构信息,包括其主链和支链的构成、连接方式、硫酸基取代位置和结构模型。     

Opening and evolution of the South China Sea constrained by studies on volcanic rocks: Preliminary results and a research design

The South China Sea (SCS) is characterized by abundant seamounts, which provide important information about the evolution of the SCS and related deep processes. Cenozoic volcanism in the SCS and its surroundings comprises three stages relative to the spreading of the SCS:prespreading (>32 Ma), syn-spreading (32-16 Ma), and post-spreading (<16 Ma). The pre-spreading magmatism predominantly occurs on the northern margin of the SCS and in South China coastal areas and shows a bi-modal affinity. The syn-spreading magmatic activity was very limited on the periphery of the SCS, but may be concentrated in the SCS. However, seafloor samples of this stage are not available yet because of overlying thick sedimentary deposits. Post-spreading magmatism is widespread in the central and southwest sub-basins of the SCS, Hainan Island, Leizhou Peninsula, Thailand, and Vietnam. These are mainly alkali basalts with subordinate tholeiites, and display OIB-type geochemical characteristics. The Dupal isotope anomaly and presence of high-magnesian olivine phenocrysts suggests their possible derivation from the Hainan mantle plume. The temporal and spatial distribution of Cenozoic volcanism in the SCS and its surroundings may be accounted for either by plate stress re-organization before and after SCS spreading, or by ridge suction of plume flow during opening of the SCS. If the latter is the case, the volcanic rocks within the SCS basin may not be typical mid-ocean ridge basalts (MORB). It remains puz-zling, however, that the transition between the South China continental margin and the SCS basin does not have features typical of a volcanic rifted margin. Clearly, the relationship between mantle plume and SCS opening needs further evaluation. A better un-derstanding of the link between deep processes and opening of the SCS not only requires enhanced studies on igneous petrogene-sis, but also is heavily dependent on systematic sampling of seafloor rocks.     

全球海面简单高效实现技术研究

在数字地球上模拟海面,是数字地球可视化以及海洋仿真的重要需求之一。利用屏幕细分自适应算法对海面网格进行计算,并在GPU中处理其网格点相应的坐标转换和计算,大大减少了对CPU的占用率。在可视范围内,对海面网格进行实时的优化处理,提高了效率,满足数字地球相关仿真系统对海面仿真的需求。在解决海洋和陆地分离显示上,提出了一种简单的设置透明度的实现方法,既满足了现实需要,也大大提高了使用效率。     

钦州湾茅尾海周年环境因子及浮游植物群落特征

2010年1月、3月、6月及9月,共设14个调查站位对钦州湾茅尾海海域的环境因子及浮游植物的种类组成、优势种类、数量分布和群落多样性进行调查分析。结果茅尾海海区营养盐中POi—P值为0．01～0．07mg／dm^3,DIN值为0．16～O．78mg／dm^3,POi—P值和DIN值均有超4类海水水质标准现象。浮游植物共鉴定出82属,262种,优势种类16种,年平均丰度为6．29×10^4cells／L,生物多样性指数的年平均值为3．87。2010年茅尾海浮游植物种类和数量都比较丰富,种类的季节变化呈现由冬至秋减少的趋势,数量的季节变化比较明显,春季最低,平均密度仅为3．28×10^4cells／L,夏季最高,平均密度为9．25×10^4cells／L。     

Effects of fish farm loading on sea grass Posidonia oceanica at Vrgada Island (Central Adriatic): a nitrogen stable isotope study

Analyses of nitrogen stable isotopes in the marine sea grass Posidonia oceanica were used to investigate the influence of fish farming on the coastal ecosystem of Vrgada Island in the Murter Sea, Central Adriatic. The results show a statistically significant ¹⁵N enrichment (up to 4.7‰ at p?<?0.005) in P. oceanica leaf and shoot tissues from fish cage sites with respect to the unaffected offshore reference site of Lumbarda Reef Flat (Kornati Islands). Heavy nitrogen enrichment was also detected in other benthic organisms analysed during this study and is attributed to the absorption and assimilation of ¹⁵N-enriched fish farm derived nitrogen waste.     

Distribution pattern of artificial radionuclides in the Baltic Sea in the special event of the Chernobyl fallout

Extensive investigations on radioactive contamination and on its spatial and temporal changes in the Baltic Sea have been carried out by the National Board for Atomic Safety and Radiation Protection since 1986. The results were compared with data obtained in the years prior to the Chernobyl accident. Due to the composition of the accidental releases and the physical half-life of the released radionuclides, special emphasis was laid on Cs-134 and Cs-137. Other radionuclides, such as H-3, Sr-90, Ru-103 and Ru-106 turned out to be insignificant compared with the caesium isotopes. The radionuclides Cs-134 and Cs-137 accounting for the highest percentage of the released long-lived radionuclides were deposited on the sea surface with an initial ratio of 0.5. Their distribution pattern on the sea surface was affected by the meteorological conditions prevailing during the release period. The horizontal dislocation of higher contaminated water masses and the vertical penetration of radioactive caesium resulted in a prolonged uniformity of the contamination level of the Baltic Sea.     

On radar accuracy using beam wave in random media

The accuracy of radar detection is measured in this paper through comparing the laser radar cross-section (LRCS) to RCS data for plane-wave incidence in free space. This is to study the performance of backscattering enhancement from conducting targets with finite size. LRCS is calculated using beam wave incidence propagating in a random medium. Targets are of large size with relatively complex cross-sections. E-wave polarization is assumed for incident waves in continuous random media with different spatial coherency.     

Flame Emission Spectrometry Using Atomic Absorption Apparatus (I) Determination of Sr In Sea Water

Flame emission determination of Sr in sea water is studied using an ordinary atomic absorption apparatus. The analytical line 4607 A is used with background correction at 4616 A. The ionization is found to be negligible in air acetylene flame with sea water, and the interference of H₂SO₄ is elimentated using the higher part of the flame.