Turbulence and Fossil Turbulence in Oceans and Lakes

Turbulence is defined as an eddy-like state of fluid motion where the inertial-vortex forces of the eddies are larger than any of the other forces that tend to damp the eddies out. Energy cascades of irrotational flows from large scales to small are non-turbulent, even if they supply energy to turbulence. Turbulent flows are rotational and cascade from small scales to large, with feedback. Viscous forces limit the smallest turbulent eddy size to the Kolmogorov scale. In stratified fluids, buoyancy forces limit large vertical overturns to the Ozmidov scale and convert the largest turbulent eddies into a unique class of saturated, non-propagating, internal waves, termed fossil-vorticity-turbulence. These waves have the same energy but different properties and spectral forms than the original turbulence patch. The Gibson (1980, 1986) theory of fossil turbulence applies universal similarity theories of turbulence and turbulent mixing to the vertical evolution of an isolated patch of turbulence in a stratified fluid as its growth is constrained and fossilized by buoyancy forces. Quantitative hydrodynamic-phase-diagrams (HPDs) from the theory are used to classify microstructure patches according to their hydrodynamic states. When analyzed in HPD space, previously published oceanic datasets showed their dominant microstructure patches are fossilized at large scales in all layers. Laboratory and field measurements suggested phytoplankton species with different swimming abilities adjust their growth strategies by pattern recognition of tur-bulence-fossil-turbulence dissipation and persistence times that predict survival-relevant surface layer sea changes. New data collected near a Honolulu waste-water outfall showed the small-to-large evolution of oceanic turbulence microstructure from active to fossil states, and revealed the ability of fossil-density-turbulence patches to absorb, and vertically radiate, internal wave energy, information, and enhanced turbulent-mixing-rates toward the sea surface so that the submerged waste-field could be detected from a space satellite (Bondur and Filatov, 2003).     

Future Benefits of Time-Varying Gravity Missions to Ocean Circulation Studies

A summary is offered of the potential benefits of future measurements of temporal variations in gravity for the understanding of ocean dynamics. Two types of process, and corresponding amplitudes are discussed: ocean basin scale pressure changes, with a corresponding amplitude of order 1 cm of water, or 1 mm of geoid height, and changes in along-slope pressure gradient, at cross-slope length scales corresponding to topographic slopes, with a corresponding amplitude of order 1 mm of water, or a maximum of about 0.01 mm of geoid. The former is feasible with current technology and would provide unprecedented information about abyssal ocean dynamics associated with heat transport and climate. The latter would be a considerable challenge to any foreseeable technology, but would provide an exceptionally clear, quantitative window on the dynamics of abyssal ocean currents, and strong constraints on ocean models. Both options would be limited by the aliassing effect of rapid mass movements in the earth system, and it is recommended that any future mission take this error source explicitly into account at the design stage. For basin-scale oceanography this might involve a higher orbit than GRACE or GOCE, and the advantages of exact-repeat orbits and multiple missions should be considered.     

不同海潮模型对中国大陆构造环境监测网络GNSS数据解算的影响

选取2018年中国大陆构造环境监测网络GNSS基准站及中国周边IGS站数据,基于CSR4、FES2004、GOT00、NAO99b等海潮负荷改正模型,采用单一变量的解算方式,分析不同海潮模型对我国GNSS基准站基线、三维坐标、时间序列等造成的影响。结果表明：利用不同海潮模型解算基线精度,水平方向相差不大于1 mm,垂向相差不大于3 mm;各测站NEU坐标精度均在毫米级以下,以耿马站时间序列为例,与其他模型相比,基于FES2004模型解算的各向偏差趋势波动较弱,其年序列图的精度及连续性、稳定性更佳。简言之,利用FES2004海潮模型解算GNSS站点位置,效果较好。     

国土空间类型划分与主要特征分析

国土空间类型的综合划分是其后续规划、开发利用与保护的基石。首先,基于现有国土空间的主要类型及其深入划分的现实需求,选取空间维度、空间性质、使用用途、矿产资源价值/矿业空间规模和地下工程/空间规模作为文中对国土空间类型进行进一步划分的主要依据;其次,基于上述主要依据提出了较为完善的国土空间类型划分方案与体系,其涵盖了包括二维平面视角和三维立体视角的29类和45亚类陆域和海域国土空间;最后,简要分析了以上提出的不同类型国土空间的主要特征和规划开发要点,为其实现良性四维规划开发利用与保护提供了重要依据。     

山西新太古界柏芝岩组条带状铁建造中的菱铁矿:成因机制与古环境意义

菱铁矿是前寒武纪条带状铁建造(BIF)中重要的矿物组分和古海洋信息载体,但它可能具有原生、早期成岩和晚期成岩多种成因,这在一定程度上限制了其在古海洋条件分析中的应用。虽然前人对菱铁矿开展了广泛的地球化学分析,但在岩相学研究方面相对薄弱。为进一步揭示BIF中菱铁矿的成因机制,以山西代县羊角沟矿区新太古界柏芝岩组的BIF为研究对象,开展了系统的岩相学工作。研究表明,该BIF主要由厘米级交互的富铁与富硅条带构成,其中普遍缺少水体扰动沉积构造,偶见交错层理和风暴碎屑,表明主要沉积于风暴浪基面之下。菱铁矿的主要产出形式有3种:(1)亚毫米级条带,其内"悬浮"有风暴成因碎屑颗粒,具有水柱或沉积物/水界面的原生成因特征;(2)在富铁条带中的晶体间隙充填,可能为早期成岩成因;(3)富硅条带中存在绿泥石层间脉状充填或截切石英和铁白云石的脉体,具有晚期成岩成因。原生菱铁矿的产出,表明新太古代在风暴浪基面之下的海水强烈缺氧、富铁并具有低硫酸盐浓度的特征。尽管原生菱铁矿条带的产出表明菱铁矿具有反映海洋化学条件的潜力,但多种成因菱铁矿的同时产出,也要求在应用菱铁矿分析古海洋条件时应当分组构进行。     

A new global ocean hydrographic climatology

This report describes the main features of the recently published World Ocean Experiment–Argo Global Hydrographic Climatology. This climatology is based on profile data from ships, Argo floats, and sensors attached to marine mammals. As an important deviation from the widely used climatologies produced previously by the National Oceanographic Data Center, the spatial interpolation was performed on local potential density surfaces, so that no ‘artificial water masses’ were created. In addition to monthly fields of temperature and salinity, gridded maps of the upper mixed layer depth are now provided.     

Review and Prospect of Global Operational Ocean Forecasting

The marine environmental forecast plays an increasingly important role in economic growth and infrastructure development, and touches upon many fields and aspects, including marine security, energy resources development and protection, ocean shipping and fisheries. Global Ocean Data Assimilation Experiment (GODAE) OceanView supports the national research groups providing them with coordination and technical support among the partners. Forecasting centers develop and establish global operational ocean forecast systems. The global operational ocean forecasting system uses the ocean dynamic numerical model as the dynamic framework, and the near real-time high-quality observation input field is integrated into the model by data assimilation to realize the future environmental forecasts of the marine conditions covering the multi-time scale. The products are routinely validated with observations in order to assess their quality. This paper briefly introduced and reviewed the development process and current situation of the global ocean forecasting system covered by GODAE OceanView, and outlined the future development of global ocean forecasting.     

西藏松多地区晚白垩世末期弧岩浆岩岩石成因及构造意义

新特提斯洋在晚白垩世末期(68Ma左右)的构造演化一直饱受争议。西藏松多地区晚白垩世末期弧岩浆岩包括花岗斑岩和二长花岗岩。锆石定年结果显示,二长花岗岩和花岗斑岩年龄均为68Ma。松多花岗斑岩和二长花岗岩的Si O_2含量为68.5%~80.6%,K_2O含量为4.1%~6.5%,P2O5含量为0.011%~0.058%。花岗斑岩Mg#值较低,为11.3~19.0,二长花岗岩Mg~#值为24.2~43.5。花岗斑岩和二长花岗岩样品均显示轻稀土元素富集、重稀土元素亏损和明显的Eu(δEu=0.15~1.21)负异常。两者均富集大离子亲石元素Rb、Th、U、K、Pb等,亏损高场强元素Nb、Ta、Ti。花岗斑岩εHf(t)值为-0.9~+2.9,二阶段模式年龄T_(DM)~C在955~1196Ma之间;二长花岗岩εHf(t)值为-17.1~+7.9(只有1个点为负值),二阶段模式年龄在633~2219Ma之间。最终认为,松多地区晚白垩世末期二长花岗岩和花岗斑岩岩浆源区为新生下地壳,但花岗斑岩更靠近古老下地壳。结合区域资料,认为新特提斯洋在晚白垩世末期68Ma左右属于洋脊俯冲结束阶段。     

利用全球海潮模型确定海图深度基准面

比较并分析了FES99潮汐模型和NAO.99Jb潮汐模型在浙江近海的精度;利用调和分析法计算了浙江近海的8个主要分潮和3个浅水分潮的调和常数;研究了浙江近海海图深度基准面的计算方法;利用长期验潮站资料验证了本文方法的可靠性与准确性;利用径向基函数方法格网化了经验潮站海图深度基准值加密后的数据,最终得到了浙江近海分辨率为2.5'×2.5'的海图深度基准面模型.     

沉积岩型层状铜矿床研究进展

沉积岩型层状铜矿床是全球第二重要的铜矿类型,重要性仅次于斑岩型铜矿床。并且,它们常伴生一定规模的钴、银、铅、锌、铀、金、铂族元素等其他金属资源。其矿体通常呈层状、似层状发育在沉积盆地的还原性岩石或地层中。大多数沉积岩型层状铜矿床形成于围岩的成岩作用或者成岩晚阶段,但也经常会受到成矿后变质作用、变形作用的改造,发生成矿物质的活化一再沉淀。原生成矿作用的发生通常要经历成矿流体(低温、中—高盐度、含硫)在矿体下盘的红层中持续、长期的循环,萃取铜等金属元素,随后沿着盆地边界断裂迁移至盆地还原性地层中或者被迁移的还原性物质(石油、天然气)还原而发生铜等成矿物质的沉淀。超大规模的层状铜矿化可能对应地球地质历史时期特殊的地质事件和地质条件,其中包括超大陆裂解、炎热干旱的古气候、大氧化事件以及冰期和富镁的海洋等。