A groundwater-based, objective-heuristic parameter optimisation method for a precipitation-runoff model and its application to a semi-arid basin     

K. Mazi  A. D. Koussis  P. J. Restrepo  D. Koutsoyiannis 《Journal of Hydrology》2004,290(3-4):243-258

A hydrologic model calibration methodology that is based on groundwater data is developed and implemented using the US Geological Survey's precipitation-runoff modelling system (PRMS) and the modular modelling system (MMS), which performs automatic calibration of parameters. The developed methodology was tested in the Akrotiri basin, Cyprus. The necessity for the groundwater-based model calibration, rather than a typical runoff-based one, arose from the very intermittent character of the runoff in the Akrotiri basin, a case often met in semi-arid regions. Introducing a datum and converting groundwater storage to head made the observable groundwater level the calibration indicator. The modelling of the Akrotiri basin leads us to conclude that groundwater level is a useful indicator for hydrological model calibration that can be potentially used in other similar situations in the absence of river flow measurements. However, the option of an automatic calibration of the complex hydrologic model PRMS by MMS did not ensure a good outcome. On the other hand, automatic optimisation, combined with heuristic expert intervention, enabled achievement of good calibration and constitutes a valuable means for saving effort and improving modelling performance. To this end, results must be scrutinised, melding the viewpoint of physical sense with mathematical efficiency criteria. Thus optimised, PRMS achieved a low simulation error, good reproduction of the historic trend of the aquifer water level evolution and reasonable physical behaviour (good hydrologic balance, Reasonable match of aquifer level evolution, good estimation of mean natural recharge rate).  相似文献   

Radiocarbon calibration beyond 20,000 C yr B.P. by means of planktonic foraminifera of the Iberian Margin     

Edouard Bard  Frauke Rostek  Guillemette Ménot-Combes 《Quaternary Research》2004,61(2):204-214

We present a new set of ¹⁴C ages obtained by accelerator mass spectrometry (AMS) on planktonic foraminifera from a deep-sea core collected off the Iberian Margin (MD952042). This site, at 37°N, is distant from the high-latitude zones where ¹⁴C reservoir age is large and variable. Many independent proxies — alkenones, magnetic susceptibility, ice-rafted debris, foraminifera stable isotopes, abundances of foraminifera, pollen, and dinoflagellates — show abrupt changes correlative with Dansgaard-Oeschger and Heinrich events of the last glacial period. The good stratigraphic agreement of all proxies — from the fine to the coarse-size fractions — indicates that the foraminifera ¹⁴C ages are representative of the different sediment fractions. To obtain reliable ¹⁴C ages of foraminifera beyond 20,000 ¹⁴C yr B.P., we leached the shells prior to carbonate hydrolysis and subsequent analysis. For a calendar age scale, we matched the Iberian Margin U₃₇^K′ profile with that of Greenland Summit δ¹⁸O. Both are proxies for temperature, which in models varies synchronously in the two areas. The match creates no spurious jumps in sedimentation rate and requires only a limited number of tie points. Except for ages older than 40,000 ¹⁴C yr B.P., Greenland's GISP2 and GRIP records yield similar calendars. The ¹⁴C and imported calendar ages of the Iberian Margin record are then compared to data — from lacustrine annual varves and from corals and speleothems dated by U-Th — previously used to extend the calibration beyond 20,000 ¹⁴C yr B.P. The new record follows a smooth pattern between 23,000 and 50,000 cal yr B.P. We find good agreement with the previous data sets between 23,000 and 31,000 cal yr B.P. In the interval between 33,000 and 41,000 cal yr B.P., for which previous records disagree by up to 5000 cal yr, the Iberian Margin record closely follows the polynomial curve that was previously defined by an interpolation of the coral ages and runs between the Lake Suigetsu and the Bahamian speleothem data sets.  相似文献   

基于GIS的地下水信息管理系统分析   总被引：5，自引：0，他引：5  

戴长雷  迟宝明  高淑琴  林岚 《世界地质》2004,23(2):158-162

GIS支持下的地下水信息管理系统开发是当前水资源管理研究的热点之一，它能够根据用户的触发指令，借助基础软件和特定的功能模块，将离散的数据整合为符合用户需求的知识信息以辅助决策。通过对地下水信息的内容、组成及其特征的分析，刻画了系统内部的数据流、信息流和知识流。在分析系统用户类型及层次的基础上，抽象出系统用户一功能规约表。基于对开发原则、开发工具和开发模式的分析和讨论，给出一种可行的基于GIS的地下水信息管理系统逻辑模型。  相似文献   

金属成矿省等级体制成矿   总被引：4，自引：2，他引：4  

裴荣富  李进文  梅燕雄 《矿床地质》2004,23(2):131-141

基于成矿“时间维”造就“空间维”的活动论新思维，提出了金属成矿省等级体制成矿概念，即成矿构造背“景”、成矿构造聚敛“场”、金属成矿“相”和矿“床”4个成矿等级在1个金属成矿省内的成矿作用，及其随着地质历史演化进程，通过在一定地质时期的一定地质事件，促发4个不同等级的成矿组成以一定规律发生耦合。不耦合者不成矿，一般耦合仅成一般规模矿床，最佳耦合导致巨量金属堆积，形成特大型矿床。文章以华北板块北缘及其北侧金属成矿省为例，通过成矿等级体制的有序耦合、耦合程度及其巨量金属堆积机制的研究，发现巨量金属的堆积是在一定的地质历史时期内，由一定的地质事件激发常规成矿作用发生异常“引潮共振”的结果。  相似文献   

Optimising the accuracy of a low-cost photogrammetric motion study system     

Albert K. Chong 《The Photogrammetric Record》2004,19(108):296-310

Generally, a low-cost image-based motion study system consists of a set of two or more video imaging cameras and a set of object space control targets. The control targets are required to provide for the computation of exterior parameters of the video frames of objects in motion. Subsequently, the computed exterior orientation parameters are used to compute the position of the motion targets. In general, the accuracy of the motion data is dependent largely on the accuracy of the 3D coordinates of the control targets, the computed camera and lens parameters and the frame rate of the camera. Obviously, it is difficult to improve the frame rate of a low-cost camera; however, the other factors may be optimised analytically. Optimising the accuracy of the control targets is a straightforward process and is discussed briefly in the paper. Optimising the computed camera and lens parameters was the main focus of the research. Consequently, the paper provides the detail of the developed optimising technique. The results show that an optimal principal distance and other lens parameters can be determined by analysing the error of a set of highly accurate object distances. The evaluation shows that the accuracy of the video motion study system can be improved by as much as six times or a reduction of scaling error from 1·06 to 1·01.  相似文献   

Development of a Robust Photogrammetric Metrology System for Monitoring the Healing of Bedsores     

Abbass  Malian  Ali  Azizi  Frank A.  van den Heuvel  Mahmoud  Zolfaghari 《The Photogrammetric Record》2005,20(111):241-273

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广义点摄影测量及其应用   总被引：28，自引：3，他引：28  

张祖勋  张剑清 《武汉大学学报(信息科学版)》2005,30(1):1-5

将传统的点摄影测量与当代发展的线摄影测量以及无穷远点理论综合升华为广义点摄影测量理论。论述了广义点摄影测量理论。介绍了其应用。包括由灭点计算影像参数及单像建模。由矢量与影像的匹配确定影像的参数，钣金件的检测与由轮廓线匹配确定飞机的姿态等。  相似文献   

Daybreak厚源α-计数仪的标定及测量影响因素的初步研究   总被引：2，自引：0，他引：2       下载免费PDF全文

王同利  陈杰  杨传成 《地震地质》2005,27(4):633-644

年剂量测量是释光和电子自旋共振测年的关键之一。厚源α-计数仪(简称TSAC)是年剂量测量中的常用仪器。通过不同标准源的标定对比实验,对美国Daybreak公司582,583型低本底厚源α-计数仪的高压值(HV)和积分甄别器阈值(DISC)进行了标定。同时,对测量过程中的诸多影响因素如被测样品的氡逃逸、粒度、含水量、颜色以及ZnS闪烁屏的密度、测量时间等开展了初步的实验研究,并根据实验结果提出了针对本型号仪器在实际测量时的改进措施,以提高厚源α-计数仪的测量精度  相似文献   

双频道激电法在我国西部特殊地貌景观条件下的应用   总被引：3，自引：2，他引：3  

白宜诚  佟铁钢  罗维斌  郭军 《矿产与地质》2005,19(1):72-77

简要介绍了双频道激电法的原理和SQ-3双频道轻便型激电仪的特点，研究了双频道激电法在我国西部地形陡峭的高寒山区、沙漠戈壁等特殊地貌景观环境下进行普查找矿的方法技术及其地质效果。实践证明，该方法具有高效、快速、观测精度高等优点，适合在西部地区特殊地貌景观条件下开展普查找矿工作。  相似文献   

环渤海海岸带¹⁴C数据集（Ⅱ）   总被引：10，自引：2，他引：10       下载免费PDF全文

王宏  范昌福 《第四纪研究》2005,25(2):14-156

作为晚更新世与全新世地层年代测定的一种重要手段,¹⁴C测年被广泛应用于地质样品的年代测定。但对于¹⁴C数据的系统校正,迄今未得到应有的重视。文章在环渤海海岸带¹⁴C数据集(Ⅰ)的基础上,对所收集的421个由其他研究者获得的环渤海海岸带¹⁴C数据进行了系统校正。并讨论了百年、千年与万年尺度的¹⁴C数据校正效果。结果表明,直接测定值与系统校正值之间的差值常有数百年至两千年的差别。经统一校正的¹⁴C年龄,最大限度地接近样品太阳历纪年的“真实”年龄,从而有助于更加准确地重建该地区的晚更新世晚期以来的地质年代史,并可与考古纪年及其他测年方法获得的绝对年龄直接对比。  相似文献