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161.
对9216号热带风暴在9月1日02时中心分裂的原因,作了初步探讨,认为东南低空急流使热带风暴倒槽区的气旋性环流加强,以及低涡的吸引合并,是产生新中心的原因。青岛产生大暴雨的条件,是充沛的水汽,强烈的上升运动和长波槽东移影响。 相似文献
162.
利用主成份分析和非整数波功率谱分析研究了1991年初夏亚洲季风区逐日500 hPa环流的时空分布特征。结果表明,主成份分析得到的前5个特征向量的空间分布与各个季风系统的活动有关,其时间系数存在显著的12—22天准周期振荡和28—31,43—65天的低频振荡周期,它们与长江下游暴雨形成有密切联系。当第一主成份从谷点上升且第二主成份稳定地增大(减小)时,长江下游出现持续暴雨。亚洲副热带海洋加热异常和海陆热力差异产生的不均匀加热分布激发的各种低频波及其相互作用导致向热带外能量频散的异常,是引起长江下游持续暴雨的 相似文献
163.
文章根据对萨拉乌苏河地区第四纪地层中的碎屑矿物分析结果,将重矿物按其抗化学风化的能力不同分为不稳定、较稳定、稳定和极稳定四种类型,不同层位的重矿物类型的百分含量不同,从而可求出重矿物的风化系数HW。不同时期地层的HW不同,而HW的大小变化与化学风化的程度有很大关系,一般来说,化学风化作用强,HW相应变小。而化学风化作用的强弱又主要受气候的影响,从而可推测该时期气候环境的变化。 相似文献
164.
分析了淮河上游大暴雨过程的水汽来源和暴雨区的水分平衡。结果说明,暴雨区除有大量水汽净通量外,还有相当数量的水分来自云的净输送,尤其是大暴雨中心附近,积雨云团的净通量决定降水量的大小。因此,分析云的移动和变化是暴雨预报的重要课题。 相似文献
165.
Data from the super-deep wells(PS10,PS14 and YS1)led to the discovery of widespread met-al-bearing hydrothermal fluids (or hot brines) related to basic magmas in the Lower Tertiary clastic sequence in the Dongpu Depression .In terms of SEM and EDAX analyses, pore-casting thin section examination of sandstone ,the composition and forming temperature of fluid inclusions ,the trace ele-ment composition of mustone and kerogen and organic geochemical analyses, it is demonstrated that the hydrothermal fluids existing in the area studied are ejecting fluids, which have a close bearing on diagenesis and sedimentation, rather than intrusive veins along the tectonic fractures.The main indicators of hydrothermal activity are:(1)abnormal alteration of kerogen;(2) high-temperature altered mineral assemblage;(30abnormal distribution of hydrocarbons;(4) specific assemblages and abnormal contents of heavy metals in mudstone and kerogen;(5) specific composi-tion of complex compounds and assemblages of fluid inclusions in sandstone;(6) periodic basaltic magma activity.Results of geological observations and laboratory simulating experiments demonstrated that the hydrothermal fluids have a close bearing on hydrocarbon generation in the Dongpu Depression. Two aspects of the effect of hydrothermal fluids are noticed:hydrothermal hydrocarbon production and strong metal catalysis in oil and gas generation. 相似文献
166.
R. A. Crichton 《Geotechnical and Geological Engineering》1994,12(3):183-212
Summary The legislative framework within which the disposal of sewage sludge is managed in England and Wales and the methods employed are outlined. Those factors which affect management decisions are analysed and consideration is given to the environmental implications of those decisions. Sewage processes and sludge disposal are considered, and the problems, especially those of heavy metal contamination, are addressed. An indication is given as to how the Water Services Companies are likely to implement the more stringent controls on disposal. Finally, the future of sludge management in England and Wales is discussed.Abbreviations BAT
Best available technology
- BATNEEC
Best available technology not entailing excessive cost
- BOD5
Biochemical oxygen demand
- BPEO
Best practicable environmental option
- CBI
Confederation of British Industry
- CEST
Centre for Exploitation of Science and Technology
- COD
Chemical oxygen demand
- CSC
Customer Services Committee
- DAF
Dissolved air flotation
- DG
Director General
- DoE
Department of the Environment
- DS
Dried solids 相似文献
167.
Martin Wessels Angela Lenhard Federico Giovanoli Andreas Bollhöfer 《Aquatic Sciences - Research Across Boundaries》1995,57(4):291-304
Sediments in Lake Constance have been dated by radiometric methods and lamination counting. Investigations into the concentrations of lead and zinc in the sediments were carried out to get detailed information about environmental history. Maximum concentrations were found at the beginning of the 1960's. The lead maximum contamination occurred 3 years before the zinc maximum and has an unidentified source. The use of coal, leaded gasoline or the remobilization within the sediment could be excluded to result in the lead maximum. The fluctuations in zinc contamination could be explained with increasing and decreasing pollution (industry, coal burning, building of sewage plants). The greatest fluctuations of both metals occur during periods of great change in the economic history of Germany. 相似文献
168.
Christine Franke Thomas Frederichs Mark J. Dekkers 《Geophysical Journal International》2007,170(3):1053-1066
Low-temperature rock magnetic measurements have distinct diagnostic value. However, in most bulk marine sediments the concentration of ferrimagnetic and antiferromagnetic minerals is extremely low, so even sensitive instrumentation often responds to the paramagnetic contribution of the silicate matrix in the residual field of the magnetometer. Analysis of magnetic extracts is usually performed to solve the problems raised by low magnetic concentrations. Additionally magnetic extracts can be used for several other analyses, for example electron microscopy or X-ray diffraction. The magnetic extraction technique is generally sufficient for sediments dominated by magnetite. In this study however, we show that high-coercivity components are rather underrepresented in magnetic extracts of sediments with a more complex magnetic mineralogy. We test heavy liquid separation, using hydrophilic sodium polytungstenate solution Na6 [H2 W12 O40 ], to demonstrate the efficiencies of both concentration techniques. Low-temperature cycling of zero-field-cooled, field-cooled and saturation isothermal remanent magnetization acquired at room temperature was performed on dry bulk sediments, magnetic extracts, and heavy liquid separates of clay-rich pelagic sediments originating from the Equatorial Atlantic. The results of the thermomagnetic measurements clarify that magnetic extraction favours components with high spontaneous magnetization, such as magnetite and titanomagnetite. The heavy liquid separation is unbiased with respect to high- and low-coercive minerals, thus it represents the entire magnetic assemblage. 相似文献
169.
Measurements of topsoil magnetic susceptibility are often used for quick assessment of soil contamination of anthropogenic
origin, with heavy metals or other pollutants. However, because of complicated correlations between low-field magnetic susceptibility
(shortened to magnetic susceptibility) of topsoil and soil pollution, the outcome of a field magnetometry survey can not be
related directly to soil pollution. For each case study, the results should be interpreted on their own taking into account
not only the type of pollution but also pedogenic, biogenic and environmental factors. In practice, it is very difficult to
measure and consider all these factors. Here we illustrate the merit of geostatistical methods, which are focused on the spatial
variability of a phenomenon, in the interpretation of soil magnetometry results.
This article presents the analysis of spatial variability of top soil layers magnetic susceptibility-within the Upper Silesia
Industrial Region (USIR)-using semivariance analysis. It also explains how to adjust the sampling density of field magnetometry
measurements to spatial variability of the soil pollution as well as to the spatial scale of the investigated area. For this
purpose, the values of magnetic susceptibility have been measured by using various sampling densities at areas of different
size located within USIR. This enabled to determine the main scales of magnetic susceptibility spatial variability of soils
within USIR using semivariance. A few distinct scales of variability were found from the site scale to a more regional scale.
Variability ranges of 30 km, 12 km, and 5 km refer to the large regional scale, whereas smaller ranges of few hundreds down
to a few tens of meters, can be attributed to the local (site) scale. In addition, the precision of the measuring campaigns,
performed within USIR with different sampling densities, was compared through the analysis of the spatial variability of the
soil magnetic susceptibility signal by using ordinary kriging.
jarek97@yahoo.com, piotr.fabijanczyk@is.pw.edu.pl 相似文献
170.