百年尺度东海内陆架风暴事件重建:器测记录与沉积记录耦合

未来全球变化可能带来极端事件的强度增加、频度提高,加之海面上升加快,给海岸带防灾减灾工作带来更新防护标准的课题。由于台风的器测记录时间较短,需要从其他载体寻找替代指标以延长台风记录的时间跨度,这样才能更好地估计极端事件的强度一频率关系。陆架泥质区的风暴事件沉积记录和历史文献中的有关灾害记录,是拓展台风记录的两个方向。本文试图通过台风观测记录与沉积记录的耦合,重建百年尺度东海内陆架泥质区的风暴事件沉积记录,并与气象灾害记载的台风暴潮成灾事件相印证,以期探讨陆架泥对台风事件的保存潜力,及其可能反映的台风信息(如路径和强度)。2018年在浙江温岭近海采集了2 m长的柱样沉积物(J1),通过多指标(粒径分布、D₉₀、Zr/Fe、Sr/Al、Ca)综合识别出台风沉积事件;采用放射性同位素²¹⁰Pb定年法确定沉积物的年代序列,将识别的台风沉积记录与器测台风记录通过时间标尺进行耦合分析。结果显示,J1的沉积速率约为1.1 cm/a,年代跨度大约是1836年至2018年;整根柱样共识别出25次台风沉积事件,其中气象观测时期(1950-2018年)有10次台风...     

激流观测与资料处理若干问题的探讨

随着海洋调查研究的进一步深入 ,海洋激流这一重要的海洋动力现象已越来越引起海洋科学工作者的重视。如何进行激流观测和资料的处理 ,已成为有关人员十分关心的问题。以江苏近海及渤海埕岛海区潮流辐合带流况为例 ,探讨了过去测流和资料分析中的一些问题 ,并提出了若干的建议。     

Potential source and diagenetic signatures of oceanic dissolved and particulate organic matter as distinguished by lipid biomarker distributions

Potential biogenic sources of ultrafiltered dissolved and suspended particulate organic matter (UDOM and POM, respectively) from the Sargasso Sea (SS) and North Central Pacific (NCP) Ocean were investigated using lipid biomarker compounds. Organic carbon (OC) concentrations were ~ 20–40 times greater in UDOM than POM and decreased with depth. However, total OC-normalized lipid concentrations were 2–3 orders of magnitude higher in POM than in UDOM. Particulate total lipids decreased 3–10-fold with depth, compared to 10–20% for dissolved total lipids. Total fatty acids (FA), the most abundant lipids, showed similar patterns as total lipids, comprising ~ 62–88% of the total lipids analyzed in UDOM and ~ 57–84% in POM.FA were dominated by straight-chain saturated compounds followed by monounsaturated, polyunsaturated, and branched FA. Polyunsaturated FA were enriched in POM vs. UDOM and in surface vs. deep waters for both UDOM and POM, likely reflecting the algal origins and greater reactivity of surface-derived materials. In both UDOM and POM, sterols of planktonic origin dominated, including cholest-5-en-3β-ol (C₂₇Δ⁵), 24-methylcholesta-5,24(28)E-dien-3β-ol (C₂₈Δ^5,24(28)) and 24-ethylcholest-5-3β-ol (C₂₉Δ⁵), with varying contributions from cholesta-5,22E-3β-ol (C₂₇Δ^5,22), 24-methylcholesta-5,22E-3β-ol (C₂₈Δ^5,22) and 24-ethylcholesta-5,22E-3β-ol (C₂₉Δ^5,22).Factor analysis of lipid biomarkers showed major differences between the UDOM and POM pools and for each pool as a function of depth, but not between the SS and NCP. While UDOM and POM biomarkers were both dominated by autochthonous sources, differences between the two pools suggest potential effects from some combination of source and diagenetic factors. The lipid biomarker data are further evaluated relative to previous studies of radiocarbon (¹⁴C) and elemental (C:N:P) characteristics of UDOM and POM in the SS and NCP.     

Gravitational Waves and Gravitational-wave Sourcestwo

The recent discovery of gravitational-wave burst GW150914 marks the coming of a new era of gravitational-wave astronomy, which provides a new window to study the physics of strong gravitational field, extremely massive stars, extremely high energy processes, and extremely early universe. In this article, we introduce the basic characters of gravitational waves in the Einstein's general relativity, their observational effects and main generation mechanisms, including the rotation of neutron stars, evolution of binary systems, and spontaneous generation in the inflation universe. Different sources produce the gravitational waves at quite different frequencies, which can be detected by different methods. In the lowest frequency range (f < 10^?15 Hz), the detection is mainly dependent of the observation of B-mode polarization of cosmic microwave background radiation. In the middle frequency range (10^?9 < f < 10^?6 Hz), the gravitational waves are detected by analyzing the timing residuals of millisecond pulsars. And in the high frequency range (10 ? 4 < f < 10⁴ Hz), they can be detected by the space-based and ground-based laser interferometers. In particular, we focus on the main features, detection methods, detection status, and the future prospects for several important sources, including the continuous sources (e.g., the spinning neutron stars, and stable binary systems), the burst sources (e.g., the supernovae, and the merge of binary system), and the stochastic backgrounds generated by the astrophysical and cosmological process. In addition, we forecast the potential breakthroughs in gravitational-wave astronomy in the near future, and the Chinese projects which might involve in these discoveries.     

金成矿多样性与矿床谱系

金成矿多样性在成矿地质环境、成矿时代和矿化类型上非常明显,这种多样性具有规律性变化,并在成矿时间、空间及矿床成因等方面构成了矿床谱系.进一步研究金成矿多样性和矿床谱系对阐明金成矿规律、指导找矿具有十分重要的意义.     

纳米探矿——用地气携带的纳米物质勘查隐伏矿

矿体周围广泛赋存着纳米物质,其可在地球排气的作用下从深部向地表迁移。在地表或地表附近可俘获这些纳米物质,这些纳米物质与矿体发出的直接信息密切相关。通过对其成分或聚集态等进行分析,可勘查隐伏矿。本文介绍了纳米探矿的应用现状和一些实例,探讨了该技术所存在的问题,并对今后的研究工作进行了展望。     

Factors affecting runoff and sediment yield on the semiarid loess area in Northern Shaanxi Province,China

The semiarid loess area in north Shaanxi Province is one of the most serious areas of water erosion in China. The Chinese government initiated the project “Grain-for-Green” for soil erosion control in 1999, with significant effect. Vegetation, rainfall, soil, and topography are the most dominant natural factors affecting soil erosion; therefore, the aim of this research was to investigate the effects of these four factors on runoff and soil loss at the runoff-plot scale over five years and use the Gray relational analysis methods to compare the impacts of these factors. Five runoff-measuring sites were established in five different vegetation types. The results show that the relative impacts of the four factors on runoff were: rainfall > soil > topography > vegetation, and the relative impacts of the factors on sediment yield were soil > runoff > rainfall > topography > vegetation. We also analyzed the weights of these four factors on runoff and sediment yield during the wettest year alone. For that year, the relative weights of the factors on runoff were topography > rainfall > soil > vegetation, and the relative weights of the factors on sediment yield were runoff > soil > rainfall > topography > vegetation.     

海洋沉积物标准物质应用功能探析

海洋沉积物标准物质是标准的重要组成部分，在海洋科学研究中起着重要作用。本文根据海洋沉积物标准物质研制的具体实际及海洋沉积物标准物质的特殊情况，从海洋沉积物标准物质的基本功能出发，提出了海洋沉积物标准物质的另外4种扩展功能，即：对历史资料的同化开发功能、背景值功能、沉积物标本功能、对外交流功能，从而使沉积物标准物质在科研中发挥更大的作用。最后介绍了在东海海洋沉积物标准物质研制过程中所采用的一些措施及该标准物质的一些基本情况。     

太阳宁静区的高分辨率像复原

本文介绍在怀柔６０ｃｍ多通道太阳望远镜上运用斑点干涉像复原方法所取得的一些初步结果,对用短暴光方法（暴光时间不大于１０毫秒）获得的一系列“冻结”大气后的目标像用斑点干涉像复原方法进行处理,即可获得消除了地球大气影响的目标复原像,斑点掩模法即为斑点干涉像复原方法的一种,我们用它对日面中心的宁静区米粒进行处理,复原出了分率不劣于０．〃５的白光米粒象。