基于多尺度资料的体系域划分及其意义——以渤海海域沙垒田凸起东南部东二段为例     

徐春强  郭涛  郑敬贵  王军  宛良伟  赖维成 《海洋地质前沿》2014,30(5):15-21

不同体系域砂体分布和成藏特征存在明显的差别,正确划分体系域对于油气勘探,特别是隐蔽油气藏勘探具有重要意义。相对于海相地层,由于陆相层序本身的复杂性,并不发育明显的坡折带,在进行体系域划分时,不同学者有不同的划分方案,无论在井上还是地震上很难把握各体系域界面的位置。针对这个问题,结合渤海海域沙垒田凸起东南部东二段体系域划分,提出利用多种不同尺度资料层层控制来划分低位域、湖泛域和高位域的思路方法。这种从尺度较大资料到较小尺度资料层层控制来划分体系域的思路方法,可以避免直接从井上来进行划分导致的错误结论,同时相对湖平面变化曲线法的引用,向建立渤海东营组层序划分的标准迈向了坚实一步。  相似文献   

基于曲线特征的等深线自动综合方法研究     

何桂敏  顾锦华  林林 《海洋测绘》2014,34(5):38-41

从等深线的特点及其制图综合的基本原则与方法出发,提出了一种基于曲线特征的Douglas-Peucker改进算法,在此基础上构建了等深线自动综合方法。该方法通过对曲线特征点的提取和弯曲特征的分析,可以自动确定等深线综合的数量指标和最小分界指标,经试验验证取得了较好的综合效果。  相似文献   

Baseline establishment for metals in the western Clarion-Clipperton Zone     

Cai Lin  Yang Liu  Ronggen Jiang  Jinmin Chen  Baohong Chen  Weili Wang  Kaiwen Zhou  Hui Lin 《海洋学报(英文版)》2022,41(11):12-22

Resource exploitation in the Clarion-Clipperton Zone (CCZ) is of major research interest worldwide, but its influence on the environment is poorly understood, especially due to the lack of baseline values for metals in the surrounding sediment. This work aimed to establish the baseline values of 17 metals (Ba, Ca, K, Mg, Mn, Na, Ag, As, B, Cd, Co, Cr, Cu, Hg, Ni, Pb, and Zn) using normalization, the cumulative frequency curve method considering a total of 172 samples taken from 8 multitube cores and 1 box sediment core collected in the western CCZ during the COMRA-45 cruise campaign from August to September 2017. The baseline values of the evaluated metals were as follows: 1 932 mg/kg for Ba, 29 512 mg/kg for Ca, 18 150 mg/kg for K, 17 120 mg/kg for Mg, 6 747 mg/kg for Mn, 28 546 mg/kg for Na, 0.571 mg/kg for Ag, 5.00 mg/kg for As, 94.4 mg/kg for B, 0.626 mg/kg for Cd, 104 mg/kg for Co, 76.1 mg/kg for Cr, 370 mg/kg for Cu, 0.028 mg/kg for Hg, 190 mg/kg for Ni, 27.5 mg/kg for Pb and 156 mg/kg for Zn. Our findings would fill the baseline value gap in the study area and further improve accuracy of environmental impact assessments on the impact of resource exploitation.  相似文献   

Determining crop acreage estimates for specific winter crops using shape attributes from sequential MODIS imagery     

《International Journal of Applied Earth Observation and Geoinformation》2013

There are increasing societal and plant industry demands for more accurate, objective and near real-time crop production information to meet both economic and food security concerns. The advent of the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite platform has augmented the capability of satellite-based applications to monitor large agricultural areas at acceptable pixel scale, cost and accuracy. Fitting parametric profiles to growing season vegetation index time series reduces the volume of data and provides simple quantitative parameters that relates to crop phenology (sowing date, flowering). In this study, we modelled various Gaussian profiles to time sequential MODIS enhanced vegetation index (EVI) images over winter crops in Queensland, Australia. Three simple Gaussian models were evaluated in their effectiveness to identify and classify various winter crop types and coverage at both pixel and regional scales across Queensland's main agricultural areas. Equal to or greater than 93% classification accuracies were obtained in determining crop acreage estimates at pixel scale for each of the Gaussian modelled approaches. Significant high to moderate correlations (log-linear transformation) were also obtained for determining total winter crop (R² = 0.93) areas as well as specific crop acreage for wheat (R² = 0.86) and barley (R² = 0.83). Conversely, it was much more difficult to predict chickpea acreage (R² ≤ 0.26), mainly due to very large uncertainties in survey data. The quantitative approach utilised here further had additional benefits of characterising crop phenology in terms of length of growing season and providing regression diagnostics of how well the fitted profiles matched the EVI time series. The Gaussian curve models utilised here are novel in application and therefore will enhance the use and adoption of remote sensing technologies in targeted agricultural application. With innate simplicity and accuracies comparable to other more convoluted multi-temporal approaches it is a good candidate in determining total and specific crop acreage estimates in future national and global food security frameworks.  相似文献   

矿区观测线的高程拟合程序设计   总被引：1，自引：0，他引：1  

潘申运 《北京测绘》2013,(2):75-77

介绍了GPS高程转换的多项式曲线拟合模型在矿区变形监测观测线中的应用,编制了相应的高程转换程序并以实例加以验证,将拟合高程和水准测量高程进行比较,得出了在矿区一定范围内用GPS测量代替四等水准测量是可行的,从而大大地节省了人力、物力、财力,提高了工作效率。  相似文献   

A fair E-cash scheme based on elliptic curve cryptography     

Wang Changji  Wu Jianping  Duan Haixin 《地球空间信息科学学报》2013,16(3):231-234

A new fair off-line electronic cash scheme on elliptic curve cryptography was presented. The new scheme is more efficient than those by extending fair off-line electronic cash scheme from finite field into elliptic curve cryptography and introducing a new elliptic curve discrete logarithm assumption. The expiry date and denomination are embedded into the blindly signed coin by integrating partially blind signature with restrictive blind signature. A bank need not use different public keys for different coin values, shops and users need not carry a list of bank's public keys to verify in their electronic wallet. At the same time, the bank just needs to keep undue electronic coins for double spending check in his database, thus bank's database can be dramatically reduced.  相似文献   

Determination of water requirements of the Gavkhuni wetland,Iran: A hydrological approach     

《Journal of Arid Environments》2013

This study compared three hydrological methods – low flow frequency analysis, flow duration curve (FDC), and concentration-discharge (C-D) modeling – to determine the water requirement of the Gavkhuni wetland located in an arid region of Iran. Due to the effects of water impounding upstream on the hydrological regime of the Gavkhuni's inflow after construction of the Zayandehrud dam, none of the methods produced satisfactory results.Consequent modification of the hydrological regime of the wetland's inflow using a scaling process allowed all the methods except low flow frequency analysis to dependably estimate the base flow for the wetland. The results of the C–D method revealed that this method can provide a minimum health condition from the water quality point of view, while the results of the FDC demonstrated that not only the inflow estimated using this method can supply minimum conditions in terms of water quality parameters, but it also covers most areas of the wetland, based on the results of hydraulic modeling.The results reveal that the hydrological methods implemented in this study can dependably estimate environmental water allocation for wetlands in arid and semi-arid regions when there is no detailed knowledge about the biological requirements of the wetlands' biota.  相似文献   

Geographic approaches to resolving environmental problems in search of the path to sustainability: The case of polluting plant relocation in China     

《Applied geography (Sevenoaks, England)》2013

This paper applies a spatial perspective to environmental problems in search for the paths to sustainability, using polluting plant relocation in China as a case study. It examines how environmental improvement in one place may lead to environmental degradation in another place, how geographic concepts such as location, distance, spread and backwash effects, and land use models can help understand such phenomenon, and what the implications are for the environmental Kuznets curve (EKC) and development policies. Field research was conducted from 2006 to 2012 in Chinese cities of Beijing, Dalian, Shanghai, Guangzhou, Wuxi, Hangzhou, and Ningbo. It involved intensive site observations and in-depth interviews with government officials of environmental protection, economic development, and business recruitment, and grassroots environmentalists. The results indicate that environmental improvement in all these cities has led to environmental degradation in their suburbs and rural areas due to relocation of polluting plants. Environmental spread and backwash effects may help explain the severe intra-regional environmental and economic disparities and environmental injustice. The powerful and wealthy may achieve rapid economic growth and environmental recovery at the expenses of the powerless and poor, leading to environmental poverty and sustainability disparities.  相似文献   

Maximum observed floods in China     

Chaoqun Li  Guoan Wang  Rongrong Li 《水文科学杂志》2013,58(3):728-735

Abstract

Maximum observed floods (MOF) and their envelope curves are useful to hydrological engineers when estimating probable maximum floods or design floods. The World MOF and its envelope curve were developed originally in 1967 and modified in 2009 by our team. Based on MOF concepts and observed hydrological data in China, the China MOF and its envelope curve are presented, and their characteristics analysed. The results will be useful for flood design, for example for dam spillways, in China and in similar regions, in particular where no data are available, but cannot be used without modification and comparative analyses.

Editor Z.W. Kundzewicz

Citation Li, C., Wang, G., and Li, R., 2013. Maximum observed floods in China. Hydrological Sciences Journal, 58 (3), 728–735.  相似文献   

Optimization of cumulative trapped sediment curve for an arid zone reservoir: Foum El Kherza (Biskra,Algeria)     

F.Z. Tebbi  H. Dridi  G.L. Morris 《水文科学杂志》2013,58(7):1368-1377

Abstract

Reservoir silting is one of the principal problems affecting the performance of dams in Algeria from the standpoint of reservoir capacity for storage. Foum El Kherza Reservoir (also known as Foum El Gherza), near Biskra Town, Algeria, is subject to dredging operations with the intent of recovering 70% of its initial storage capacity of 47 hm³ (million cubic metres). The forecasting of sediment volume trapped in the reservoir is essential to plan the future use of this resource and to sustain irrigation for the palm groves characteristic of the region. However, there are currently no sediment data, nor a sediment rating curve, for predicting sediment inflow based on hydrological data. This paper describes the optimization of a cumulative trapped sediment curve for Foum El Kherza Reservoir based on 44 years of daily inflows, by using a spreadsheet optimization tool, Microsoft Excel® Solver to calibrate the cumulative sediment load against the cumulative sediment inflow as documented by eight bathymetric surveys since the dam construction.

Editor D. Koutsoyiannis; Associate editor A. Montanari

Citation Tebbi, F.Z., Dridi, H., and Morris, G.L., 2012. Optimization of cumulative trapped sediment curve for an arid zone reservoir: Foum El Kherza (Biskra, Algeria). Hydrological Sciences Journal, 57 (7), 1368–1377.  相似文献