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1.
The oiling rate (oiled birds/total birds) has become the international standard to analyze beached bird survey data. However, this index may not reliably track long-term changes in marine oil pollution in regions where other activities that kill seabirds vulnerable to oil, such as hunting and gill-netting, are also changing. We compare the oiling rate from beached bird surveys conducted in southeastern Newfoundland between 1984 and 2006 to an alternative approach, namely trends derived from a model examining the linear density of oiled birds (birds/km). In winter, there was no change in the oiling rate since 1984, while in summer oiling rates significantly increased. In contrast, the number of oiled birds/km showed a significant decline in both winter and summer. The discrepancy in these trends was attributed to steep declines in the number of unoiled birds found in both seasons. In winter, the decline in unoiled birds/km was related to a reduction in the legal murre hunt and less onshore winds, while in summer a reduced cod fishery resulting in fewer murres drowning in nets and warming summers may have lead to the decline. The significant declines in oiled birds/km over the past three decades are hopefully an indication of less oil being present in the marine environment. Although oiled bird densities since 2000 have remained relatively low for the region (winter: 0.58 birds/km, summer: 0.27 birds/km), they still exceed densities reported elsewhere in the world.  相似文献   

2.
Lagrangian passive tracer transport simulations covering the 46-year period 1958-2003 were utilized to compare the exposures of different parts of the German North Sea coast to ship-related chronic oil pollution. Assuming the spatial distribution of oil releases to be proportional to estimated ship traffic density, detailed drift reconstructions allowed for the reconstruction of wind-induced inter-annual variations in coastal pollution. For the winter months, a statistical relationship between simulated advective transports and prevailing sea surface pressure fields was established via Canonical Correlation Analysis. Wind effects were found to be more important for the northern (Schleswig-Holstein) than for the southern (Lower Saxony) part of the German North Sea coast. For Schleswig-Holstein, simulations showed consensus with beached bird survey data from this region. Proper identification of weather-driven inter-annual and spatial variations in monitoring data helps to avert misjudgments with regard to trends in the general level of chronic oil pollution.  相似文献   

3.
基于广义S变换的大地电磁测深数据处理   总被引:2,自引:7,他引:2       下载免费PDF全文
S变换是一种优于短时傅里叶变换和小波变换的时频分析方法.采用广义S变换进行大地电磁场时间序列频谱分析,一方面能够提高对电磁噪声成分的时间定位能力,便于实现电磁噪声的滤波处理;另一方面可以增加频谱系数的个数,从而改善大地电磁阻抗张量元素的统计特性.本文从广义S变换和大地电磁测深数据处理方法的原理出发,给出了采用叠加窗函数的离散广义S变换形式,讨论了广义S变换窗口宽度比例因子、窗口宽度与可提取频谱系数个数之间的关系,定义了利用离散广义S变换时频谱计算大地电磁场分量功率谱公式;在此基础上,研究了基于S变换时谱频的大地电磁测深数据ROBUST处理方法.最后,通过实测资料进行方法检验,结果表明本文方法比短时傅里叶变换处理效果更好,并且有利于识别和压制电磁噪声.  相似文献   

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Liability and compensation for pollution damage caused by oil spills from laden tankers is governed by two international conventions: the 1969 Civil Liability Convention and the 1971 Fund Convention. The Civil Liability Convention established a system of strict liability for tanker owners and introduced compulsory liability insurance. The Fund Convention created a system of supplementary compensation administered by an intergovernmental organization, the International Oil Pollution Compensation Fund (IOPC Fund), which at present has 56 member states (August 1993). The IOPC Fund pays compensation to victims of oil pollution in member states when the compensation from the shipowner and his insurer is insufficient. Over the years (up to August 1993), the IOPC Fund has been involved in 66 incidents and has paid US$92 million to victims. Only three of these incidents have been taken to court, whereas in all other cases claims have been settled out of court. The IOPC Fund has developed a policy on the admissibility of claims covering clean-up costs, measures to prevent pollution, damage to property and economic loss suffered by fishermen, hotel-owners and others who depend directly for their livelihood on sea-related activities.  相似文献   

6.
The European Water Framework Directive (WFD) establishes a framework for the protection and improvement of estuarine (transitional) and coastal waters, attempting to achieve good water status by 2015; this includes, within the assessment, biological and chemical elements. The European Commission has proposed a list of priority dangerous substances (including metals such as Cd, Hg, Ni and Pb), with the corresponding list of environmental quality standards (EQS), to assess chemical status, but only for waters. In this contribution, a long-term (1995–2007) dataset of transitional and coastal water and sediment trace elements concentrations, from the Basque Country (northern Spain), has been used to investigate the response of these systems to water treatment programmes. Moreover, the approach proposed in the WFD, for assessing water chemical status (the ‘one out, all out’ approach), is compared with the integration of water and sediment data, into a unique assessment. For this exercise, background levels are used as reference conditions, identifying the boundary between high and good chemical status. EQS are used as the boundary between good and moderate chemical status. This contribution reveals that the first approach can lead to misclassification, with the second approach representing the pattern shown by the long-term data trends. Finally, the management implications, using each approach are discussed.  相似文献   

7.
Marine mammals are probably frequently exposed to floating oil but little is known about the effect oil pollution has on them. Oil stranded on the shore in Pembrokeshire, West Wales in September 1974 coincided with the start of the Grey Seal breeding season there. Observations have been made on the effect the oil had on the newborn pups and their mothers.  相似文献   

8.
Many studies have indicated that structural strain will be significantly influenced by temperature variations, and a good understanding of the effect of temperature on structural strain is essential. A structural health monitoring system has been installed in a typical Tibetan timber building to measure the structural strains and ambient temperature since 2012. This paper presents the correlation between temperature and strain data from the monitored structure. A method combining singular spectrum analysis and polynomial regression is proposed for modeling the temperature induced strains in the structure. Singular spectrum analysis is applied to smooth the temperature data, and the correlation between the resulting temperature time series and the measured strains is obtained by polynomial regression. Parameters of the singular spectrum analysis and the regression model are selected to have the least regression error. Results show that the proposed method has both good reproduction and prediction capabilities for temperature induced strains, and that the method is accurate and effective for eliminating the effect of temperature from the measured strain. A standardized Novelty Index based on the residual strain is also used for the condition assessment of the structure.  相似文献   

9.
A consolidated picture of oil pollution for the northern Indian Ocean is presented. Oil slicks were sighted on 5582 observations, about 83.5% of the total observations of 6689. The range of concentrations, of the floating tar balls, is 0–6.0 mg/m2 in the Arabian Sea. Similarly, the oil tanker route in the Bay of Bengal has the range of 0–69.75 mg/m2. North of this route, the Bay of Bengal is comparatively free from this floating tar. Mean concentrations of dissolved and dispersed hydrocarbons for 0–20 m are 32.5 and 24.1 μg kg?1, respectively, in the Arabian Sea and the Bay of Bengal.  相似文献   

10.
构造油藏开发中后期含水上升快,稳产技术措施必须进行合理调整,开展好精细地质研究,尤其是充分利用现有常规测井资料开展油水界面识别和油藏剖面特征研究十分重要.本文基于文献调研,结合研究区(Z区)地质资料、测井资料和动态生产资料,开展了油水界面识别方法研究,并对现有测井资料按照测井时间进行合理分段研究,提出基于时间推移的油水界面确定方法和油藏剖面动态特征研究方法,得到了工区油水界面动态变化特征.研究表明,基于自然伽马、自然电位和感应测井方法可以较好地识别工区目的层油水界面,按照测井时间合理分段可以更准确地实现对油水界面变化的动态分析,基于时间推移的油水界面研究方法简单有效.本文研究成果对邻区具有一定的参考作用.  相似文献   

11.
Shock recovery experiments on olivine single crystals (mineralogical composition: forsterite~80) have been carried out in a pressure range from~200up to~ 575kbar. Infrared spectroscopic investigations indicate a transformation of the mineral within a pressure interval from~420to~575kbar. Exposure to dynamic pressures of~575kbar yielded complete decomposition of the former olivine into an X-ray amorphous material upon pressure release. The infrared investigations suggest the post-shock products to consist essentially out of short-range-ordered (Mg,Fe)O and SiO2.  相似文献   

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14.
颜蕊  王兰炜  胡哲  刘大鹏 《地震学报》2017,39(4):549-557
本文采用散点图、趋势线、相关系数及观测偏差等统计方法,利用COSMIC卫星和SPIDR提供的垂测仪观测的F2层峰值电子密度数据,开展了综合统计及按季节、地方时和纬度的分类统计.统计结果显示:地基垂测仪与卫星观测到的相应的F2层峰值电子密度数据具有很高的相关性,两者之间的相关系数高达0.95,相对偏差的平均值为-3.38%,标准差为19.54%.基于上述研究结果,提出了利用地面垂测仪观测数据验证卫星观测的电离层结构参数的方法,并给出了定性的判别依据和定量的判别标准,可在我国电磁监测试验卫星发射后,为F2层峰值电子密度观测数据的真实性和有效性提供检验方法和保障.   相似文献   

15.
The biological damage caused by the large oil spill in Bantry Bay and the clean-up measures adopted to deal with it (already reported in the Marine Pollution Bulletin) has been followed up in the months following the oil spill. This report refers to damage to algae and lichens.  相似文献   

16.
Observation of oiled sandy beaches showed the fate of oil released by a tanker collision. The amount of oil extracted depended on timing in the beach erosion and depositing cycle. The recovery of the beaches took about 8 months, but deteriorated again after the arrival of unaccounted oil batches. It is this unaccountable oil which is responsible for chronic oil pollution on the South African coast and possibly other beaches around the world.  相似文献   

17.
以洛阳地震台地电数字化观测资料为基础,阐述了地电场数据测量原理及其在分析中的应用,并通过对地电暴、避雷装置和电极故障3个地电场数据异常案例研究分析,得出当出现故障时应该遵循“替换法”和“逐步逼近法”原则.  相似文献   

18.
The currently available experimental data, among which the series of particle flux measurements on satellites are of crucial importance, have revealed a number of regularities pertaining to solar cosmic rays (SCRs). Based on these regularities, we have developed a probabilistic model of particle fluxes. This model not only provides a basis for determining radiation conditions in space flights and space weather impacts but also allows such situations as the occurrence of extreme SCR events in the quiet-Sun period in 2005–2006 to be predicted.  相似文献   

19.
Petroleum pollution is a problem for seabirds along the Southwest Atlantic coast. Twenty-five groups from Salvador, Brazil (12 degrees 58'S) to San Antonio Oeste, Argentina (40 degrees 43'S) survey or rehabilitate sick or oiled seabirds. Four groups, one each in Brazil and Uruguay, and two in Argentina, kept counts of birds found alive and in need of rehabilitation. An average of 63.7% of the seabirds found were Magellanic penguins (Spheniscus magellanicus), with 3869 reported since 1987. Mainly adult penguins were found in Argentina (1605 of 2102 penguins of known age class) and Uruguay (158 of 197). Juveniles were most common in Brazil (234 of 325). Oil fouling was the most frequent cause of injury or sickness. The number of oiled penguins reported in their wintering range has greatly increased since the early 1990s and is strongly correlated with petroleum exports from Argentina. Our results show that chronic petroleum pollution is a problem for wildlife from Southern Brazil through Northern Argentina, and regulations and enforcement are failing to protect living resources.  相似文献   

20.
编码源地电阻率观测试验   总被引:1,自引:0,他引:1       下载免费PDF全文
地电阻率的高精度观测是实现地震预测预报的前提之一.面对日益严重的电磁干扰,提出了基于编码源循环互相关辨识技术的地电阻率观测方法,其实质是将待测地质体视为待辨识系统,利用编码源信号激励供电电极A和B产生的电流信号作为系统输入信号,测量电极M与N之间的电压信号作为系统响应输出,将输入和输出信号严格同步采样为时间序列,分别与参考信号进行循环互相关运算并转换至频率域计算获得待探测地电阻率谱(幅度和相位).由于系统环境的干扰和随机噪声与编码源信号不相关,通过循环互相关运算可以达到抑制环境随机噪声和干扰的目的.这种地电阻率观测体系在环境干扰较大的甘肃省兰州观象台和陇南汉王地震台站利用现有的观测场地和线路进行了观测试验,测量结果显示,数据的一致性好、均方差小,说明该方法在强干扰环境下具有较好的抗电磁干扰能力,观测频带较以往直流电法测量有较大的扩展.该方法为现有地面地电阻率台站持续发展提供了技术保障,可为地震预报与科学研究提供高质量的地电阻率观测数据.   相似文献   

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