湖泊自生碳酸盐碳同位素在环境变化中的应用

湖泊自生碳酸盐碳同位素组成(δ13Cc)在区域气候与环境变化方面的应用研究近年来进展迅速,成果显著,保存在各类湖泊沉积物柱芯中的δ13Cc记录揭示了湖表水体与大气CO2的交换程度、暖季降水量的多少、流域C3和C4植被变化情况、水生生物光合作用或呼吸作用强弱、湖泊生产力大小、湖泊水体化学特征、湖水不同深度层的有机质变化过程等重要的气候和环境信息;对此进行归纳和述评。     

Modeling of environmental influence in structural health assessment for reinforced concrete buildings

One branch of structural health monitoring (SHM) utilizes dynamic response measurements to assess the structural integrity of civil infrastructures. In particular,modal frequency is a widely adopted indicator for structural damage since its square is proportional to structural stiffness. However,it has been demonstrated in various SHM projects that this indicator is substantially affected by fluctuating environmental conditions. In order to provide reliable and consistent information on the health status of the monitored structures,it is necessary to develop a method to filter this interference. This study attempts to model and quantify the environmental influence on the modal frequencies of reinforced concrete buildings. Daily structural response measurements of a twenty-two story reinforced concrete building were collected and analyzed over a one-year period. The Bayesian spectral density approach was utilized to identify the modal frequencies of this building and it was clearly seen that the temperature and humidity fluctuation induced notable variations. A mathematical model was developed to quantify the environmental effects and model complexity was taken into consideration. Based on a Timoshenko beam model,the full model class was constructed and other reduced-order model class candidates were obtained. Then,the Bayesian modal class selection approach was employed to select the one with the most suitable complexity. The proposed model successfully characterizes the environmental influence on the modal frequencies. Furthermore,the estimated uncertainty of the model parameters allows for assessment of the reliability of the prediction. This study not only improves the understanding about the monitored structure,but also establishes a systematic approach for reliable health assessment of reinforced concrete buildings.     

地震监测中环境因素对精密水准观测影响分析

区域精密水准测量在地震监测中发挥了重要的作用,但是由于其作业范围广、观测周期长,容易受外界复杂多变的环境因素影响。目前对环境因素的影响分析大多是定性描述,缺乏实验观测数据的支撑。针对这一问题,选取大约2000km区域精密水准观测数据,结合观测环境资料,统计分析不同环境因素对观测成果的影响程度,并提出了相应的改进措施。     

地质环境容量与评价研究

本文系统总结了当今地质环境容量研究存在的主要问题及发展趋势,应用地质环境容量评价指标体系,初步建立了地质环境容量评价理论框架.在此基础上结合上海市主要环境地质问题,分析其主要影响因素,分层次选取合适的评价指标,对上海市地质环境容量进行实证分析.     

环境水力学研究中的预报模型的研究现状

主要介绍目前世界上环境水力学研究中,湍流模式下,预报模型的发展、现状及种类。并简单分析了模型的原理以及模型的适用性与非适用性,来说明实际工程中对瑞流模式研究的重要性和可行性。     

Green Costs,Red Ink: Determinants of Municipal Defensive Expenditures inOntario

Book reviews are in these Articles.

Understanding Peasant Agriculture: An Integrated Land-Use Model for the Punjab Joseph H. Astroth, Jr. Chicago: University of Chicago, Committee on Geographical Studies, 1990. (Geography Research Paper No. 223). ix and 173 pp., maps, photos, figs., apps., biblio., and index; $12.00 paper (ISBN 0-89065-127-2).

National Integration in Indonesia: Patterns and Policies Christine Drake. Honolulu: University of Hawaii Press, 1989. xvi and 354 pp., maps, diags., tables, index, and biblio. $35.00 cloth ISBN 0-8248- 1229-8).

Urban Economic Theory: Land Use and City Size. Masahisa Fujita. New York: Cambridge University Press, 1989. x and 366 pp., diag., graphs, biblio. notes, append, biblio., index. $65.00 cloth (ISBN 0-521-34662-2).

The Sugar Cane Industry: An Historical Geography from Its Origins to 1914. J. H. Galloway. Cambridge, MA: Cambridge University Press, 1989. xiii and 266 pp., maps, tables, diags., index, and biblio. $44.50 cloth (ISBN 0-521-24853-1).

Government Policy and Industrial Change. David Gibbs, ED. New York: Routledge, 1989. xvi and 317 pp., 15 figs., 53 tables, index, and biblio. $59.95 cloth (ISBN 0-415-01032-2).

English Agriculture: An Historical Perspective. David Grigg. New York: Basil Blackwell, 1989. vii and 256 pp. $60.00 cloth (ISBN 0-631-16033-7).

London 2001. Peter Hall. London: Unwin Hyman, 1989. xii and 226 pp., maps, diags., index, and biblio. $34.95 cloth (ISBN 0-04-4451 61 -X).

The Land that Became Israel: Studies in Historical Geography. Ruth Kark, ED. Translated from the Hebrew by Michael Gordon. Jerusalem: The Magnes Press, The Hebrew University and New Haven and London: Yale University Press, 1990. x and 332 pp., maps, diags., plates. $27.50 cloth (ISBN 0-300- 04718-5).

Die Farmer-Genossenschaften in den USA – Eine agrargeographie Untersuchung. Werner Klohn. Vechta, Federal Republic of Germany: Vechtaer Druckerei, 1990. Vechtaer Arbeiten zur Geographie und Regionalwissenschaft, Band 9. 285 pp., maps, photos, diags., and biblio. 39.80 DM paper (ISBN 3-88441-083-0).

Agricultural Development in Japan: The Land Improvement District in Concept and Practice. Gil Latz. Chicago, IL University of Chicago Press, 1989. vii and 135 pp., maps, diags., index, and biblio. $12.00 paper (ISBN 0-89065-129-9).

Land Use Planning Made Plain. Hok Lin Leung. Kingston, Ontario: Ronald P. Frye &; Company, 1989. xv and 237 pp., maps, diags., tables, append., index, and refs. $19.95 paper (ISBN 0-919741-98-3).

Computers in Geography. David J. Maguire. New York: Halsted Press, 1989. xv and 248 pp., maps, photos, diags., index, and biblio. $31.95 paper (ISBN 0-470-21 194-6).

Maps with the News: The Development of American Journalistic Cartography. Mark Monmonier. Chicago: The University of Chicago Press, 1989. xii and 331 pp., maps, illus., index, and biblio. $24.95 cloth (ISBN 0-226-53411-1).

Geographic Information Systems and Cartographic Modeling. C. Dana Tomlin. Englewood Cliffs, NJ: Prentice Hall, 1990. xviii and 249 pp., maps, diags., review questions, selected readings, appendix, index, $44.20 cloth (ISBN 0-13-350927-3).     

COUNCIL MEETING,CHICAGO, ILLINOIS November 3-4, 1972

This paper questions the validity and relevance of the application of procedures of classical statistical inference to population data in geography. Arguments for such procedures include the notions of temporal and spatial samples, measurement error, modifiable areal units, data vetting and stochastic processes. It is concluded that such arguments cannot be justified in terms of statistical theory.     

Data structures for three-dimensional spatial information systems in geology

Abstract

The accumulation of geological information in digital form, due to modern exploration methods, has introduced the possibility of applying geographical information system technology to the field of geology. To achieve the benefits in information management and in data analysis and interpretation, however, it will be necessary to develop spatial models and associated data structures which are specifically designed for working in three dimensions. Some progress in this direction has already been demonstrated, with the application of octree spatial subdivision techniques to the storage of uniform volume elements representing mineral properties. By imposing octree tessellations on more precisely-defined geometric data, such as triangulated surfaces and polygon line segments, it may now be possible to combine efficient spatial addressing with topologically-coded boundary representations of geological strata. The development of storage schemes capable of representing such geological boundary models at different scales poses a particular problem, a possible solution to which may be by means of hierarchical classification of the vertices of triangulated surfaces according to shape contribution.