中国东西部平原区湖泊近期变化之比较   总被引：2，自引：1，他引：2  

王晓峰 《干旱区地理》1994,17(2):16-21

本文通过对中国部湖泊近期演化及其对环境影响的比较研究，认为导致东西部湖泊近期大面积退缩的主要原因都是人类活动。平原区湖泊的许多传统功能正逐渐被水利工程所取代，今后湖区资源的开发应充分注意这一趋势。  相似文献   

矿物热力学数据的获取     

殷辉安 《地球科学进展》1993,8(2):33-39

简介矿物热力学数据获取方法发展现状,重点评述量热法和相平衡法的近期发展状况。  相似文献   

土地系统研究的几个问题   总被引：4，自引：0，他引：4  

史华 《地球科学进展》1993,8(5):75-80

对土地系统研究的形成背景、研究现状及发展趋势进行了综述,并在此基础上,就土地系统研究的对象、理论基础和体系等进行了探讨。  相似文献   

贵州丹寨汞矿方解石的微观特征及其与构造成矿关系初探     

吴为民  王子江 《矿物岩石》1993,13(3):48-54

鉴于方解石是研究低温碳酸盐型汞矿床构造应力作用的良好对象,作者对贵州丹寨汞矿床中24件方解石样品进行构造形变及构造成矿模拟试验,经光学显微镜及透射电子显微镜对比观察指出:多种应力作用叠加及微观构造形变的先后生成关系,可视为多期次构造动力作用的结果;汞矿的成矿作用和构造作用的相关和同步性,说明构造作用既可提供成矿的空间,又是促进成矿的动力。  相似文献   

La sismicité en corse: Revue historique et etude macrosismique de quelques evénéments récents     

F. Marillier  A. Gauthier  J. Vogt 《Pure and Applied Geophysics》1982,120(1):167-185

Résumé L'étude des documents (archives, presse et catalogues sismiques) que nous avons consultés, nous a permis de remonter jusqu'à la fin du XVIIIe siècle dans l'histoire sismologique corse. Le nombre des séismes ressentis (épicentres en mer ou sur l'île) recensés pendant ces deux siècles et demi est relativement faible. Les intensités maximales ont parfois atteint le degré VI, plus rarement VII. L'activité sismique touche principalement une région située au Nord-Est de la Corse, au voisinage de failles au rejeu récènt et séparent le domaine de la Corse schisteuse (alpin) du domaine de la Plaine Orientale (Quaternaire, Néogène). Une crise sismique récente (1978–1979) a de nouveau secoué cette même région où on a suggéré l'activité actuelle de certaines de ces failles. Les plus importants de ces séismes (I _max=VI et V) ontifait l'objet d'enquêtes macrosismiques qui permettent d'en préciser les épicentres. Deux d'entre-eux ont été étudiés en détail (3 avril 1978 et 27 mars 1979); en utilisant la relation de Kövesligethy, les hypocentres se situent respectivement à 4,5±0.5 km et vers 5 km, pour des coefficients d'absorption de 0,020 et 0,031. Ces profondeurs indiquent que ces deux séismes ont mis en jeu des éléments superficiels de la croûte corse (30 km).

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The documents that we have compiled (archives, newspaper reports and seismic catalogues) enabled us to go back to the end of the 18th century in the seismic history of Corsica. The number of felt earthquakes (epicentres off shore or on the island) which were documented during the two and a half centuries is relatively low. Maximum intensities have reached VI or rarely VII. The seismic activity is mainly located in the North-East of Corsica, near faults which have recently been active between the Corse schisteuse (Alpine domain) and the Plaine Orientale (Quaternary, Neogene). A seismic crisis happened recently (1978–1979) in this area where present activity of some of these faults has been suggested. Macroseismic studies have been conducted for the main shocks (I _max=VI and V) in order to locate them accurately. Two among them (April 3, 1978 and March 27, 1979) are studied here in detail. Using the Kövesligethy formula hypocenters are respectively found at 4.5±0.5 km and around 5 km, whereas the corresponding absorption factors are 0.020 and 0.031. Such depths show that the two events affected the upper crust of Corsica (30 km).

Contribution n^o 321 de l'Institut de Géophysique, Ecole Polytechnique Fédérale de Zürich.  相似文献   

A two-way nested-grid ocean-circulation model for the Meso-American Barrier Reef System   总被引：2，自引：0，他引：2  

Jinyu?ShengEmail author  Liqun?Tang 《Ocean Dynamics》2004,54(2):232-242

A two-way nested-grid ocean-circulation model is developed for the Meso-American Barrier Reef System (MBRS), using a newly developed two-way interactive nesting technique. The unique feature of this new nesting technique is its use of the semi-prognostic method (Sheng et al. 2001) to exchange information between different grids through the model momentum equations. The nested-grid model for the MBRS has a fine-resolution inner model embedded in a coarse-resolution outer model. The outer model is the western Caribbean Sea model developed by Sheng and Tang (2003), with a horizontal resolution of roughly 19 km. The inner model domain covers the northwest Caribbean Sea (NWCS) between 79°W and 89°W and between 15.5°N and 22°N, with a horizontal resolution of roughly 6 km. The nested-grid ocean model is initialized with the January mean temperature and salinity and forced by the monthly mean COADS (comprehensive ocean-atmosphere data set) wind stress and surface heat flux. The model sea-surface salinity is restored to the monthly mean climatology. The nested-grid model is integrated for 2 years and the second-year model results are presented in this paper. The model-calculated annual-mean near-surface currents over the NWCS agree reasonably well with the time-mean near-surface currents inferred by Fratantoni (2001) from trajectories of the satellite-tracked 15-m drogued drifters in the 1990s. The two-way nested model is also used to quantify the role of local wind stress, local density gradients and boundary forcings of the outer model in driving the annual-mean circulation in the region.Responsible Editor: Phil Dyke  相似文献   

海洋生态预报的复杂性与研究方法的讨论   总被引：1，自引：1，他引：0  

吴增茂  谢红琴  张志南  万小芳 《地球科学进展》2004,19(1):81-086

海洋生态动态预报预测研究已经成为海洋科学乃至地球系统科学领域中的热点问题。比较深入地分析了海洋生态预报的复杂性、不确定性和实况监测资料严重不足等问题,为促进海洋生态预报研究的快速发展,借鉴中期数值天气预报的一些有效方法,提出以下建议：①加深理解海洋生态系统的非线性动力学特征,深入开展随机-动力耦合的海洋生态系统模型研究;②加强海洋生态集合（ensemble）预报和综合预报方法研究;③大力促进卫星遥感信息的海洋生态应用研究,加强资料同化研究和反问题研究方法的应用,努力发掘各种信息资料的预报应用。  相似文献   

NOAA/AVHRR影像中红外波段信息提取研究     

黄鹏  郭德方  陈建裕  宋志超 《国土资源遥感》2004,15(2):65-67

对多景NOAA/AVHRR影像的研究发现:CH3波段不仅可以提取高温信息,而且还可以提取常温状态下的物类信息,并且在很多情况下优于CH4波段。文章给出了具体分析,并进行了原因探讨。  相似文献   

The thermal regime of the Northeastern-German Basin from 2-D inversion   总被引：2，自引：0，他引：2  

Hans-Dieter Vosteen  Volker Rath  Andreas Schmidt-Mumm  Christoph Clauser   《Tectonophysics》2004,386(1-2):81-95

The thermal regime and the distribution of heat flow at the base of sedimentary basins is fundamental to the understanding of the process of basin evolution and the associated mobilization and migration of hydrocarbon and other fluids. For the Northeastern-German sedimentary basin, available information on structure, temperature, and thermal properties along a seismic DEKORP reflection profile allow high resolution 2-D forward and inverse simulations. This approach is attractive in situations where much information is available, if only with considerable uncertainty. In particular, this allows to introduce “soft” information into the analysis. In our case, forward simulations yield initial a priori estimates of the parameters while inversion calculations yield a posteriori estimates of the parameters and their uncertainty. The a priori parameters as well as their assumed uncertainty are input for a Bayesian parameter estimation scheme. In respect to the Northeastern-German sedimentary basin, the inverse analysis postulates a significant and characteristic a posteriori variation of thermal conductivity of the Zechstein unit along the entire profile as well as a generally large a posteriori thermal conductivity of the (pre-Permian) basement in the northern part of the basin. For inverse calculations, we used two alternative scenarios: One assumes the thermal conductivity of the Zechstein unit to be homogeneous along the profile while the other allows a lateral variation. A posteriori heat flow across the base of the model varies from 40 to 60 and 50 to 65 mW m⁻² for models in which values for thermal conductivity and radiogenic heat generation rate were either based on literature values or direct measurements, respectively.  相似文献   

旅游地形象研究管窥   总被引：1，自引：3，他引：1  

赵飞羽  陈桂林 《云南地理环境研究》2004,16(2):39-43

旅游业的发展呈迅猛之势，越来越多的研究者发现，旅游地的形象因素已成为吸引游客的关键性因素之一，对旅游地的开发规划工作和市场营销工作都有重要意义。国内外旅游界对旅游地形象进行了深入而广泛的研究，其发展历程可概括为：(1)“自然”旅游地形象研究阶段，(2)“人为”旅游地形象研究阶段，(3)不同学科理论对供求双方的互动效应的探索阶段；其主要内容概括为：旅游地形象定义及其效应等理论研究、旅游地形象设计及其传播等实践研究。  相似文献