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131.
Groundwater study using remote sensing and geographic information systems (GIS) in the central highlands of Eritrea 总被引:3,自引:1,他引:3
Remote sensing, evaluation of digital elevation models (DEM), geographic information systems (GIS) and fieldwork techniques were combined to study the groundwater conditions in Eritrea. Remote sensing data were interpreted to produce lithological and lineament maps. DEM was used for lineament and geomorphologic mapping. Field studies permitted the study of structures and correlated them with lineament interpretations. Hydrogeological setting of springs and wells were investigated in the field, from well logs and pumping test data. All thematic layers were integrated and analysed in a GIS. Results show that groundwater occurrence is controlled by lithology, structures and landforms. Highest yields occur in basaltic rocks and are due to primary and secondary porosities. High yielding wells and springs are often related to large lineaments, lineament intersections and corresponding structural features. In metamorphic and igneous intrusive rocks with rugged landforms, groundwater occurs mainly in drainage channels with valley fill deposits. Zones of very good groundwater potential are characteristic for basaltic layers overlying lateritized crystalline rocks, flat topography with dense lineaments and structurally controlled drainage channels with valley fill deposits. The overall results demonstrate that the use of remote sensing and GIS provide potentially powerful tools to study groundwater resources and design a suitable exploration plan.The online version of the original article can be found at 相似文献
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133.
Decision-support systems for groundwater protection: innovative tools for resource management 总被引:1,自引:0,他引:1
Stefan Kollarits Gerhard Kuschnig Miran Veselic Ante Pavicic Corrado Soccorso Marina Aurighi 《Environmental Geology》2006,49(6):840-848
Governmental authorities are forced by law to make decisions within the framework of European, national and regional directives
in the fields of spatial planning, groundwater and environmental protection. These tasks can be supported by a decision-support
system, which integrates data from various sources and helps to make decision processes more effective and transparent. Basic
work for such a decision support system has been done in a transnational and interdisciplinary project (Interreg II C: KATER),
including metadata definition, metadata system, cartographic tools and GIS tools. The direct integration of these tools and
information in the decision process will be implemented in the next few years (project KATER II). 相似文献
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136.
对河北省昌黎县闫庄铁矿床的磁铁石英岩型铁矿石261件样品进行了光谱反射率测量,并与其铁含量进行了相关关系研究,目
的是对钻孔岩芯编录的新方法即高光谱岩芯编录在此类矿床中的可行性进行分析。研究结果表明,铁矿石反射率较低,一般为5%~20%
,铁离子的吸收峰主要表现在400~1 100 nm范围内,铁矿石中铁含量与850~900 nm的反射率均值呈现显著指数负相关关系,为高光谱
岩芯编录在此类矿床中的可行性提供了理论依据和技术途径。 相似文献
137.
利用和田地区4个代表站1961~2000年的气温资料,对和田地区近40a来的气温变化作了分析。得出近40年来和田地区年平均气温呈上升趋势,春季气温和于田县的年平均气温却呈下降趋势。特别是上世纪90年代增温十分明显,1999年是近40a来和田地区最暖的一年。 相似文献
138.
梅雨锋云系的结构特征及其成因分析 总被引:7,自引:9,他引:7
利用逐时卫星遥感观测资料和地面测站的降水资料,分析了江淮流域2003年6月22~26日暴雨过程中梅雨锋云系的演变、结构特征和形成原因。结果表明,梅雨锋云系为一条TBB的低值带,稳定少动,其上分布着中尺度对流系统(MCS),而中尺度对流系统是由不同尺度、不同强度.的对流单体(包括中β和中γ尺度对流单体)组成的,从而使得梅雨锋云系产生不均匀的降水分布(包括时间上和空间上)。在该暴雨过程中,梅雨锋云系充分体现了中尺度对流系统中所包括的3类组织结构形式。梅雨锋云系与中高纬度云系或热带辐合带云系之间的相互作用与暴雨过程关系密切,梅雨锋云系的维持和发展与强大的黄淮气旋云系直接相关,它是江淮流域上空冷暖气流交汇的结果。 相似文献
139.
Trevor Quinn A.-Xing Zhu James E. Burt 《International Journal of Applied Earth Observation and Geoinformation》2005,7(4):324-338
Hydro-ecological modelers often use spatial variation of soil information derived from conventional soil surveys in simulation of hydro-ecological processes over watersheds at mesoscale (10–100 km2). Conventional soil surveys are not designed to provide the same level of spatial detail as terrain and vegetation inputs derived from digital terrain analysis and remote sensing techniques. Soil property layers derived from conventional soil surveys are often incompatible with detailed terrain and remotely sensed data due to their difference in scales. The objective of this research is to examine the effect of scale incompatibility between soil information and the detailed digital terrain data and remotely sensed information by comparing simulations of watershed processes based on the conventional soil map and those simulations based on detailed soil information across different simulation scales. The detailed soil spatial information was derived using a GIS (geographical information system), expert knowledge, and fuzzy logic based predictive mapping approach (Soil Land Inference Model, SoLIM). The Regional Hydro-Ecological Simulation System (RHESSys) is used to simulate two watershed processes: net photosynthesis and stream flow. The difference between simulation based on the conventional soil map and that based on the detailed predictive soil map at a given simulation scale is perceived to be the effect of scale incompatibility between conventional soil data and the rest of the (more detailed) data layers at that scale. Two modeling approaches were taken in this study: the lumped parameter approach and the distributed parameter approach. The results over two small watersheds indicate that the effect does not necessarily always increase or decrease as the simulation scale becomes finer or coarser. For a given watershed there seems to be a fixed scale at which the effect is consistently low for the simulated processes with both the lumped parameter approach and the distributed parameter approach. 相似文献
140.
通过引人泊松括号,分析了无限维Hamilton的性质,并将其推广到广义Hamilton系统,且从理论和实用角度讨论了这类广义Hamilton系统的辛格式构造问题,从而为辛几何算法在一般的时间发展方程的数值求解提供新的具体途径。 相似文献