谱模式在美国国家气象中心应用一年的统计性能

一、引言美国国家气象中心(NMC)于1980年8月12日开始使用谱模式,结束了舒曼(Shuman)和赫韦曼尔(Hovermale)于1968年提出的、长期以来较受重视的原始方程(PE)模式。这个新的谱模式是1980年由 Sala 提出的。本文并不涉及谱模式本身的详细情况,只对它作简单的描述。     

Linking historical smelter emissions across Humberside （UK） to enhanced soil metal concentrations using geostatistics and preserved environmental samples

Background： Analysis of human malignancies on Humberside （UK） in 1984 showed an increased risk close to the site of the local smelter. Geochemical survey data for Pb and Sn in soil collected soon after the smelter closed showed elevated concentrations relative to local background levels, and a strong spatial trend related to the prevailing wind direction. No historical emission data existed and evidence associating the smelter with the putative soil contamination plume was considered equivocal. In this work we test the hypotheses that： a） historical data can be used to estimate the excess quantities of Pb and Sn in the soil; b） tree bark ＆ attic dust can act as historical archives of particulate deposition; c） geochemical and mineralogical information assist in linking the source of the metal and the historical contamination plume.     

Is environmental antimony a potential health problem？

Antimony has long been recognized as a non-essential, potentially toxic element. It has recently been suggested, on the basis of measured elemental profiles in peat bogs, that natural levels of Sb in the environment have been overestimated by a factor of 10 and that anthropogenic Sb deposition from the atmosphere has closely followed that of Pb. The implication is that the health effects of environmental Sb may have been seriously underestimated. To examine these propositions, we have compared new data for Sb and Pb in dated cores from four Scottish ombrotrophic peat bogs, Carsegowan Moss, Flanders Moss, Red Moss of Balerno and Turclossie Moss, in southwest, west-central, east-central and northeast Scotland, respectively. Dried peat sections, 1 to 2 cm thick, were subjected to microwave-assisted digestion in nitric/hydrofluoric acid and subsequently analyzed for a range of elements （including Sb, Pb, and the conservative elements Sc, Ti） and Pb isotopic composition by ICP-OES and ICP-MS as appropriate. Three certified reference materials, including NIMT/UOE/FM/001 Peat, were used for quality control purposes. Radiometric dating of upper and lower sections of the cores was carried out using gamma spectrometry for ^21-Pb and accelerator mass spectrometry for ^14C, respectively Some 2000 years ago, in Roman times, both Sb and Pb were clearly elevated in Scottish peat but typically at concentrations below 0.1 mg/kg and 5 mg/kg, respectively, with an average anthropogenic Sb/Pb ratio of-0.01.     

Determining depleted uranium （DU） contamination in soils and salt marsh sediments in the vicinity of DU munitions testing sites in SW Scotland and NW England, UK

In its natural state uranium has three isotopes; ^238U （99.27 atom % abundance）, ^235U （0.72%） and ^234U （0.0055%）, with the ^235U ： ^238U activity ratio having a constant value of 0.045 and the ^234U：^238U activity ratio commonly ranging 0.8-1.2 for soils and sediments （e.g. Fisenne 1996）. Uranium enrichment, the process by which the fissile isotope ^235U is concentrated for the production of nuclear fuel, generates a waste product that is depleted in both ^235U and ^234U. Depleted uranium （DU） therefore has a distinct isotopic signature that can be used to monitor contamination arising from the use of munitions containing it （i.e., DU weapons and armour）. The UK Ministry of Defense has tested such munitions at coastal locations in SW Scotland and NW England, resulting in possible contamination of the surrounding terrestrial and marine environments. We examined the U isotope distribution in surface soil （top 10 cm） and salt marsh sediment samples from these locations using alpha spectrometry to determine the extent of any DU contamination from the munitions testing programme. Despite 〉30 t of DU shells having been fired into the sea in this region there was no evidence of deviation from the natural ^234U ： ^238U activity ratio range in salt marsh samples. The ^235U ： ^238U activity ratio could not be used to assess these salt marsh samples because ^235U activities were at the limit of detection for alpha spectrometry.     

第24章：监测执行《全面禁止核试验条约》的地震学方法

1996年9月，经过近40年期间遭遇许多次失败的协商谈判之后，对《全面禁止核试验条约》（CTBT）的文本最终达成了一致并在联合国开放供各国签署，随即由5个声称拥有核武器的国家（美、俄、中、英、法）进行了签署。在签字仪式上，克林顿总统称该条约为“最长久的追求、最艰苦的战斗、核武器控制的收获”。     

孔隙弹性介质中的震后流体流与库仑应力变化

一般认为地震序列的发生意味着不同断层段之间的一种相互作用。每次位错产生的同震应力的传递则是这种相互作用最显著的成分。然而，一个地震系列中各个后续事件之间的时间间隔却表明，同震应力尚不足以单独引发其他的地震。我们研究了同震应力场可能诱发孔隙流体流，改变了所在区域的孔隙压力分布情况。鉴于地壳在很多地区都是一种流体饱和介质，故将地壳视为一种孔隙弹性固体。由于孔隙物质所表现的应力场依赖于时间，所以我们将验证这种性质能否解释余震的触发。我们考察了一些现有的半无限平面断层的解析方法。对可渗透的和不可渗透的位错面均作了考虑。我们将孔隙弹性介质的解法与孔隙介质的解法作了对比，计算了变形与流体扩散之间的耦合效应。结果发现主震产生的库仑应力变化在某些区域初始时可能表现为负值，但尔后随着孔隙流体的重新分布而变为正值。这种变化意义重大。如果地壳确如我们所假定的表现为一种各向同性、充满流体的孔隙弹性介质的话，那么，通过孔隙流体扩散的库仑应力触发作用则很可能是余震产生的重要机制，余震发生的范围分别为长约2．5个断层长度，宽约0．5个断层长度。这个范围小于以前模型的预测值，以前的这些模型都忽略了弹性变形和孔隙流体扩散之间的力学相互作用。对于典型的孔隙结构，流体流引起的应力变化在主震发生后约一年内会有很大程度的衰减。     

《地震活动图像动力学及地震触发》专辑介绍

由于地震对人类生活、基础设施和区域经济造成巨大损失，因此地震危险性的计算和评估十分重要。即使在1906年灾难性的旧金山大地震发生100年之后的今天，我们对地震破裂及其时空成核过程的认识仍然极其有限。原因之一是对于地下地震过程中重要状态变量（如地表下部压力及物性）的认识不足，这与天气预报等相关领域是不同的。对地下进行直接观测，仅在少数几个进行了昂贵的地壳深井钻探的地方才有可能。     

中亚金-汞矿床:矿床类型分布规律成因模式

金-汞矿化代表一种新的有前途的矿床类型，可划分四种成因模式：Au—As—Hg，Au—Sb—Hg，Au—Te-Hg和Au-Cu-Hg，与不同金矿化有成因联系，由不同的成矿系列产生。四类金。汞矿床广泛存在于东亚和东南亚。越南是最有希望发现这一工业类型矿床的地区之一。     

预测地震破裂的终点

发生地震的活断层的迹线通常间断分布(Wesnousky,1988),一般会被间断面隔断,由一个个的分段组成,在视图中出现类似阶跃的迹线。在这些间断面上由滑动产生的应力集中可能减缓或停止破裂的传播,因此对地震破裂长度产生控制作用(Segall and Pollard,1980)。在本文中,我调查了破裂     

在某些热水矿物中稀土元素的分配结晶的控制证据

稀土元素丰度在硬石膏(CaSo_4)、重晶石(BaSo_4)、菱铁矿(FeCo_3)和方铅矿(Pbs)中用中子活化分析测定了。一种简单的结晶化学模式定性的描述了在硬石膏、重晶石和菱铁矿中稀土元素代替的相对亲合力。当地壳的丰度正常化时(近似热液稀土元素模式),三个热水矿物个别的和集体的对数稀土元素丰度是一种惊人地线形函数。(大阳离子离子半径——稀土元素的离子半径)。然而,重要的例外是Eu,相对于稀土元素的邻近原子序数和三价离子的半径,Eu在重晶石中异常富集而在菱铁矿中缺失。原则上,共生热水矿物的成对稀土元素分析,结合适当的实验资料,能得到稀土元素含量和原始热液的温度。 稀土元素仅有微弱的亲铜倾向,反映在方铅矿上有很低的丰度——La 0.6P Pb,Sm 0.06P Pb;其余的稀土元素含量低于侦查极限。