地下水化学背景值研究中的异常值判定与处理

根据吉林省地下水化学背景值调查背景值确定出现的水化学异常问题,应用数理统计原理,并结合水文地球化学特征,讨论了判定和处理异常值方法的科学性与适用性。     

Cross-correlation analysis of seismic and volcanic data at Mt Etna volcano,Italy

Seismic data from the MVT-SLN sesmic station located 7 km from the summit area of Mt Etna volcano, which has been operating steadily for the last two decades, have been analysed together with the volcanic activity during the same period. Cross-correlation techniques are used to investigate possible relationships between seismic and volcanic data and to evaluate the statistical significance of the results. A number of significant correlations have been identified, showing that there is an evident relation between seismic events and flank eruptions, and a less clear relation with summit activity, which appears more linked to tremor rather than to the low-frequency events. Particularly interesting are the low-frequency events whose rate of occurrence increases, starting from 17 to 108 days, prior to the onset of the flank activity and are candidates for a useful precursor. On the other hand, a tendency towards the increase in both the duration and the occurrence rate of transients in the volcanic tremor was observed before the onset of summit eruptions. As a result of this study different stages in the volcanic activity of Mt Etna, represented by changes in the characteristics of the recorded seismic phenomena, are identified.     

泾阳Ms4.8地震磁效应的高阶统计量方法研究

以陕西关中地区泾阳、乾陵、周至3个地磁台站的地磁场垂直分量(Z)日均值及3个台站地磁场垂直分量变化与1998年1月5日泾阳Ms4．8地震之间关系为基础,探讨利用高阶统计量分析方法提取与地震活动相关的震磁信息。结果表明,在震前3个月,3个台站的三阶矩(三阶累积量)异常变化幅度在10～20,四阶矩异常幅度在120以上,最高达到260,四阶累积量异常幅度在80～105,与加卸载响应比法结果对比发现,高阶统计量方法在突出震前中长期地磁异常方面具有一定的优越性,提出在震磁效应统计分析研究中引入高阶统计量方法的必要性及其在地震预报中的潜力和良好前景。     

SAR系统不确定性可视化表达及其应用

SAR在成像过程中由于受到外界环境干扰和机载本身的不稳定等不确定因素的影响 ,直接影响 SAR图像的使用。因此 ,对这些不确定因素分析是十分重要的。目前 ,对于 SAR不确定性研究主要是基于统计方法 ,但这种方法不便于揭示 SAR不确定性产生的机理 ,以及不确定性可视化表达。本文首先从机理的角度讨论了 SAR成像系统误差传递函数 ,在确定了 SAR系统误差传递函数之后 ,着重讨论了在误差传递函数基础上利用虚拟现实技术和系统仿真技术进行 SAR成像系统不确定可视化研究 ,最后给出可视化表达的应用实例。     

Temporal and Spatial Characteristics of Mesoscale Eddies in the Northern South China Sea: Statistics Analysis Based on Altimeter Data

Mesoscale eddies are active and energetic in the South China Sea (SCS), and play an important role in regulating the multi-scale circulation and mass transportation in the region, especially for those long-lived strong eddies. Using AVISO altimeter data and outermost closed contour sea level anomaly method, this study identified and tracked mesoscale eddies in the northern SCS during 2011-2018, and focused on the temporal and spatial characteristics of mesoscale eddies in recent years. Similarly to previous results in this region, statistical results show that about 8.6 anticyclonic eddies and 4.5 cyclonic eddies (lifetime > 28 days) were born per year. Among them, about 1/3 of the total number are strong eddies (lifetime > 45 days), showing relatively strong dynamic characteristics, such as strong Eddy Kinetic Energy (EKE) and highly nonlinear feature. Statistics also show significant seasonal variability in mesoscale eddies’ birth places, trajectories and distribution of frequency of occurrence. Specifically, anticyclonic eddies mainly form at the north part of Luzon Strait between autumn and winter, and then move southwestward along isobaths. During this period, the largest value of the frequency of occurrence is over 30%. In summer, most of them form in the west off Luzon Island, and then move westward paralleling to latitude lines. In contrast, cyclonic mainly form in the west off Luzon Strait, and then move westward in winter and spring. During this period, the largest value is about 26%. In addition, observation finds that the strong mesoscale eddy pair could generate off the southwest of Taiwan Island. Analysis of the Kuroshio SCS Index (KSI) implies that loop current caused by Kuroshio intrusion is the most important mechanism for the formation of eddy pair.     

1999年11月29日辽宁省岫岩—海城5.6级地震震害统计和损失评估

在岫岩－海城５．６级地震中,震中区遭受到ＶＩＩ度地震破坏,同时震区又遭受多次强余震,总直接经济损失８４８８．８万元,１６２９户房屋发生严重破坏,５７３４人家可归,由于震前成功预报,无人员伤亡发生。本次地震震区为农村,其中农村砖房大１我数为基本完好和轻微破坏,而大量的石砌房层则破坏较重,在重建粗园中应采取必要的抗震措施。     

Comments on FAO's State of Fisheries and Aquaculture, or ‘SOFIA 2010’

Comments are provided on a few sections of the FAO's 2010 edition of the bi-annual ‘State of the World's Fisheries and Aquaculture’ (SOFIA), i.e., its characterization of the present as a period of ‘stability’, the peculiar role of China's fisheries statistics, the under-reporting of much of the small-scale fisheries catch from developing countries as a key aspect of the deteriorating quality of statistical data submitted to the FAO by member countries, and some other minor topics (but not aquaculture). Overall, this SOFIA report, like its predecessors, provides an excellent starting point for debates about the status of global fisheries, rather than settling them, and a few vignettes are presented, which illustrate this. Moreover, this debate should be broader, e.g., involve more university- and civil society-based researchers, to provide the wide variety of views and analyses required to strengthen FAO in its laudable mission of providing dependable information on the state of global fisheries.     

对海峡两岸地震系统震级测定差异的统计研究

本文利用海峡两岸地震系统对台湾花莲、台东等六个地区近几年的地震资料进行震级差异的统计,得出台湾的地震系统记录的震级一般都比福建台网的大。它与福建台网的震级差最大1.2级,最小为0级。平均结果在0.4级左右。(本文利用的是福建台网中心编目室的资料与台湾中央气象局的资料进行统计对比得出结论)。     

怀柔太阳观测基地数据流量统计系统设计与实现

基于数据流量的统计功能是评判数据产地应用服务的一项指标;统计不同类型观测数据的使用、共享情况,可为分析数据的使用需求提供参考。因此,设计观测数据流量统计系统具有较强的应用价值。基于中国科学院国家天文台怀柔太阳观测基地的数据服务,以LAMP为开发环境,设计了数据流量实时统计及定时入库、数据流量查询功能、流量可视化功能(包括直方图显示和饼状图显示)等功能模块,以流量统计层、数据层、业务层及用户层4个层次为结构框架,实现了统计及查询任意时段内多种仪器观测的多种数据传输至各用户单位的流量功能,系统具有统计精确、多个关键字进行完整查询、显示直观、扩展性强等优点,能够满足当前及未来应用需求,对其它数据产地的多类型数据的流量统计具有可用性。     

40Ar/39Ar ages of flood basalt provinces in Russia and China and their possible link to global faunal extinction events: A cautionary tale regarding alteration and loss of 40Ar1

The hypothesis that the Permo–Triassic boundary (PTB) mass extinctions were caused by flood basalt volcanism in Russia (Siberian Traps) and/or China (the Emeishan Traps) is investigated from the point of view of time of occurrence (⁴⁰Ar/³⁹Ar ages). Numerous published ages in the literature are rejected as good estimates of the time of crystallization. The filters applied in this respect are (a) statistical reliability of plateau/isochron sections of stepheating data and (b) the alteration state of the material that was dated. Alteration appears to be ubiquitous, unsurprising since most of the material dated was used without acid leaching – a procedure that is effective in yielding fresh(er) samples. Of ∼70 ages in the literature for the main pulse of Siberian Trap volcanism, less than ten prove to be reliable ages. Similar techniques applied to ⁴⁰Ar/³⁹Ar for the Emeishan Traps, leaves only a single reliable age for the magmatic episode. These ages are compared to both published and new ⁴⁰Ar/³⁹Ar ages for the PTB as based on analysis of minerals from critical ash beds in China. There is good overlap in the ages (PTB – 250.0 ± 0.1 Ma, Siberian Trap lavas – 250.1 ± 0.4 Ma), lending credence to a genetic link between the formation of the Siberian Traps and the faunal extinction event at the PTB. A similar link for the formation of the Viluy Traps (Russia) and the Late Devonian extinction event is investigated; only a single reliable ⁴⁰Ar/³⁹Ar age is available for the Viluy Traps, and falls close to the interpolated age for the Frasnian–Fammenian boundary. The use of the unspiked K–Ar technique to yield accurate ages for such (altered) samples is questioned.A review of U–Pb data pertinent to these problems suggests a close temporal link between the formation of the Siberian Traps and the PTB. Comparison of U–Pb and ⁴⁰Ar/³⁹Ar ages for the PTB, raises questions about the accuracy of high precision sanidine ages, possibly resulting from very slow leakage of ⁴⁰Ar¹ from this mineral.