Application and comparison of two prediction models for groundwater levels: A case study in Western Jilin Province,China     

Z.P. Yang  W.X. Lu  Y.Q. Long  P. Li 《Journal of Arid Environments》2009,73(4-5):487-492

Evaluation and prediction of groundwater levels through specific model(s) helps in forecasting of groundwater resources. Among the different robust tools available, the Integrated Time Series (ITS) and Back-Propagation Artificial Neural Network (BPANN) models are commonly used to empirically forecast hydrological variables. Here, we discuss the modeling process and accuracy of these two methods in assessing their relative advantages and disadvantages based on Root Mean Squared Error (RMSE), Mean Absolute Error (MAE) and coefficient of efficiency (CE). The arid and semi-arid areas of western Jilin province of China were chosen as study area owing to the decline of groundwater levels during the past decade mainly due to overexploitation. The simulation results indicated that both ITS and BPANN are accurate in reproducing (fitting) the groundwater levels and the CE are 0.98 and 0.97, respectively. In the validation phase, the comparison of the prediction accuracy of the BPANN and ITS models indicated that the BPANN models is superior to the ITS in forecasting the groundwater levels time series in term of the RMSE, MAE and CE.  相似文献   

Hydrograph separation for karst watersheds using a two-domain rainfall–discharge model     

Andrew J. Long 《Journal of Hydrology》2009,364(3-4):249-256

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龙木错—双湖—澜沧江缝合带中段双湖地区地球物理特征   总被引：2，自引：1，他引：1       下载免费PDF全文

曾昭发  赵雪宇  李忠雄  李静  王坤  马龙 《地球物理学报》2016,59(12):4594-4602

龙木错—双湖—澜沧江板块缝合带位于青藏高原羌塘中部至藏东一带,相关研究将其厘定为冈瓦纳板块的北界,对探讨青藏高原早期形成与演化历史及区域资源勘查与评价有重要的地质意义.本文结合区域重磁数据、大地电磁数据对该缝合带地球物理特征进行分析论证.首先基于WGM2012全球重力场模型网格化数据,利用垂向一阶导数计算、构造增强滤波等处理方法,推测龙木错—双湖—澜沧江缝合带异常的空间分布.计算的区域莫霍面在缝合带南北两侧深度存在较大差异.重力数据及其处理结果论证了龙木错—双湖—澜沧江缝合带存在的可能性.其次,选取了龙木错—双湖—澜沧江缝合带中段双湖地区的高质量大地电磁数据进行反演解释,电阻率反演结果表明缝合带南北存在较大的电性差异,结合区域地质情况,推测缝合带是不同地质体的分界线.最后,对缝合带地球物理响应特征和地质认识进行了讨论.通过对地球物理数据分析处理,为进一步讨论缝合带形成提供了有利的科学依据.  相似文献   

基于SVG的高速公路横断面交互式可视化研究     

李维  樊文有  柳恒建  戴龙 《测绘通报》2016,(7):110-113

高速公路建成后,养护、管理或改建时快速查看横断面结构、构造物等信息是十分重要的。本文以伊辽高速为例,通过数据提取、处理,实时生成高速公路横断面数据;并通过数据解析,使横断面数据成为SVG绘图的数据源,进而实现了Web下交互式横断面的绘制,从而直观地展现了道路、路基、道路附属设施、道路构造物等信息,便于高速公路管理和养护决策。  相似文献   

CL系统扫描长方体构件的投影计算机仿真     

王雅霄  魏存峰  阙介民  舒岩峰  曹大泉  王燕芳  孙翠丽  史戎坚  魏龙 《CT理论与应用研究》2014,(1):91-100

x射线投影计算机仿真可以排除实际x射线断层扫描过程中的随机因素,更好地验证扫描方式、图像重建方法等的正确性,为实际系统的实现、完善以及重建算法的改进等提供理论依据。本文基于一种典型的计算机分层成像（CL）系统,针对电子线路板大多为长方体薄板的事实,研究了长方体构件的投影仿真计算方法;设计了仿真芯片模体,对其进行投影计算机仿真;并与系统实验结果对比,得到了较为满意的结果。该方法为后续改进图像重建算法、分析误差来源、校正伪影等研究提供了良好的基础。  相似文献   

Petrogenesis and tectonic setting of the Queershan composite granitic pluton,eastern Tibetan Plateau: Constraints from geochronology,geochemistry and Hf isotope data   总被引：2，自引：0，他引：2  

Tao Wu  Long Xiao  Rui Gao  HaiJun Yang  Gang Yang 《中国科学:地球科学(英文版)》2014,57(11):2712-2725

The Queershan composite granitic pluton is located in the north of the late Paleozoic Yidun arc collision-orogenic belt, eastern Tibetan Plateau. The main rock types are coarse-grained porphyritic alkalic-monzonite granite with minor fine-grained porphyritic monzogranite and granodiorite distributed in the eastern and southwestern regions. Here we report their zircon U-Pb ages and geo- chemical data. The intrusive contact relations indicate that granodiorite was formed earlier than the alkalic-monzonite granite(105.9±1.3 Ma) and monzogranite(102.6±1.1 Ma). These suggest that the Queershan composite granitic pluton was formed through three-stage magmatic events. The alkalic-monzonite granite(105.9±1.3 Ma) and monzogranite(102.6±1.1 Ma) are characterized by high SiO2(73.5%–77.7%), K2O+Na2O(6.9%–8.5%), Ga/Al ratios(2.6–3.4) and low Al2O3(11.8%–14.5%), CaO(0.25%–1.5%), MgO(0.18%–0.69%), negative Ba, Sr and Eu anomalies, showing A-type granite affinities. The granodiorite exhibits lower SiO2, P2O5 and K2O+Na2O contents, but higher Al2O3, CaO and MgO contents than alkalic-monzonite granite and monzogranite, showing I-type granite affinity. 176Hf/177 Hf ratios of the alkalic-monzonite granite and the monzogranite are 0.282692–0.282749 and 0.282685–0.282765, respectively, and with similar ?Hf(t) values(?0.56 to 1.43 and ?0.87 to 1.90 respectively). They also present similar TDM2 model ages(1.04–1.22 and 1.07–1.2 Ga respectively), indicating they may be sourced from a similar rock source, mostly like Kangding Complex. The homogeneity of the Hf isotopic compositions and the absence of the MMEs demonstrate that little depleted mantle materials have contributed to the source. We propose that the Mesoproterozoic crust materials of the Yangtze Craton exist beneath the Yidun arc terrane and support it was a dismembered part of the Yangtze Craton. The A-type granites of Queershan composite granitic pluton are most probably related to the closure of the Bangong-Nujiang Tethys ocean.  相似文献   

Eichhornia crassipes Cleans Wetlands by Enhancing the Nitrogen Removal and Modulating Denitrifying Bacteria Community          下载免费PDF全文

Neng Yi  Yan Gao  Xiao‐hua Long  Zhi‐yong Zhang  Jun‐yao Guo  Hong‐bo Shao  Zhen‐hua Zhang  Shao‐hua Yan 《洁净——土壤、空气、水》2014,42(5):664-673

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珠江口小榄镇—万顷沙地区晚更新世以来的海侵层序          下载免费PDF全文

谢叶彩  王强  龙桂  周洋  郑志敏  黄雪飞 《古地理学报》2014,16(6):835-852

依据广东省中山地区3个标准孔岩心材料的AMS(加速器质谱)¹⁴C测年、微体古生物有孔虫、介形类、硅藻分析,海相双壳类、腹足类鉴定,沉积构造、沉积物颜色特征,结合已经报道的万顷沙钻孔研究成果,确定小榄镇—万顷沙地区东西向4个钻孔揭露了珠江河口地区LGM(末次盛冰期)河间地与古河谷区两类古地貌单元。由于处在较闭塞的地理位置,下切河谷从9 ka BP(¹⁴C 日历年龄)开始接受泥质沉积物充填,不同于长江三角洲和中国北方沿海平原古河谷充填的砂质沉积;大约7 cal ka BP 出现最大海侵,导致在古河间地LGM风化层之上发生海侵超覆,随后三角洲开始形成。按照河流层序与海面变化对应关系,没有发现海相微体生物的完整河流旋回应该对应MIS(深海氧同位素阶段)3海侵。基于对埋藏阶地的考虑,以及30年来测年技术对这段地层无法取得突破,认为存在着这样的可能性:即区域自上而下第2厚层富铝质红色风化层属于MIS4低水位域沉积,最底部见少量海相双壳类、腹足类的富有机质河口湾沉积单元可能属于MIS5晚期。  相似文献   

基于DLG信息的重点要素变化自动检测技术     

齐中华  刘达  张俊  房龙 《测绘与空间地理信息》2012,35(11):158-159,164,168

结合国家基础地理信息数据库动态更新工程,本文采用基于DLG信息的重点要素快速变化发现技术,对省(市)级基础测绘成果与国家1∶50 000地形数据库进行了变化检测,达到了项目更新的技术要求,提高了更新工作效率。  相似文献   

大连市大范围快速地形3维建模的探索     

李婷  郭林凯  孙龙  张琛 《测绘与空间地理信息》2012,(Z1):6-8

结合大连市地形图的实际生产过程及大范围快速地形3维建模的经验,提出了在地形图生产环节,注重地形要素3维信息的采集;在编辑环节保留地形要素的3维信息;对入库后的3维数据,通过在GIS3维展示平台下进行简单的设置,快速生成大范围3维地形模型,解决城市地形图更新快、常规3维建模较慢,不能满足现势性要求的问题。  相似文献