混沌分析在水文预测中的应用和展望

简述了将混沌理论应用于水文预测中需要解决的三个关键问题:(1)水文系统重建相空间技术;(2)水文系统混沌性识别;(3)水文混沌预测方法。分析了现有的研究成果和最新进展,并指出今后需要开展的工作及存在的问题。     

流域降雨径流时间序列的混沌识别及其预测研究进展

混沌和随机在本质上是两种不同的特征,对这两种特征的描述方法各不相同,确定流域降雨径流时间序列的混沌性和随机性是对其进行模拟和预测的重要基础。近10多年来,许多学者相继开展了流域降雨径流时间序列的混沌识别及其预测研究。着重回顾其中最为重要的相空间重构、混沌识别和混沌预测方法,对将混沌理论应用于降雨径流时间序列的限制条件(序列的数据量大小和数据噪声)也进行了探讨。     

对水文时间序列混沌特征参数估计问题的讨论

水文过程到底是不是低维混沌过程一直是个有争议的问题。相关文献在混沌特征参数估计中存在不少问题,包括:时延量估计的主观性很强,不同研究者的估计值差别很大;在关联维估计中,很多研究者有意无意地忽略了一个基本原则,即只有在关联维估计图上存在明确的标度区的情况下才能准确判断存在有限关联维;很多研究者在计算水文时间序列的关联维时仍采用原始的G-P计算公式,而没有采用Theiler提的修正公式,从而可能误将相点在时序上的相关性当做一种状态空间几何特征,造成关联维估计错误;国内相关研究中还普遍存在序列长度偏短的问题,对这些问题进行了讨论并给出了相应的结论。     

混沌时间序列预测的局域法在边坡变形分析中的应用

边坡作为一个复杂系统,其本身的各种参量是不确定的和随机的,在其演化过程中,表现出复杂的非线性行为,发生一系列的混沌现象。本文运用现代混沌理论,对边坡变形的预测问题进行探索性研究,把混沌时间序列理论引入到边坡工程研究中,对该理论的建立及预测方法进行系统地讨论,为该领域的研究提供完整的技术方法。通过对新滩滑坡的研究结果表明,混沌时间序列方法对混沌序列的预测较线性时间序列具有较高的精度。     

矿井涌水量混沌时间序列分析与预测

矿井地下水系统是个非线性系统,由于地下水系统的复杂性,很难完全确定影响矿井涌水量的因素,因此传统的矿井涌水预测表现出较大的局限性。而混沌时间序列分析能够利用单变量处理方法,分析矿井地下水系统中,由于多因素耦合作用所产生的矿井涌水量时间序列。通过对某矿区1985年9月至2005年2月矿井涌水量时间序列资料的分析,显示矿井涌水量时间序列具有混沌特征;通过对比预测值和实测值,表明预测精度高。因此,混沌时间序列分析方法用于矿井涌水量预测是可行的。     

时间序列分解模型在水文要素中长期预报中的应用

基于时间序列分解法，建立了降雨、水库来水的中长期预报模型。引入灰色系统理论来分离趋势项，并应用反馈模拟校正技术对预报结果作出实时校正，从预报结果可以看出，所建模型具有较好的适应性和预报精度。     

基于经验模态分解的水文时间序列预测研究

径流预报是一类经典的水文问题,对水资源的调配管理和防洪减灾的决策有着重要的意义.本文利用近年来刚刚提出的经验模态分解理论和方法对水文序列进行分解,然后对不同成分分别建立回归预测模型,最后将这些模型的预测结果进行组合,得到最终预测结果.以南京下关站次日高潮位预测为例,取得了令人满意的预报精度,表明本文提出的方法具有一定的创新性和较高的实用价值.     

基于混沌神经网络理论的城市地面沉降量预测模型

通过分析城市地面沉降量时间序列的非线性动力学系统,认为该时间序列具有混沌特性。在此基础上,通过相空间重构的方法建立了用于城市地面沉降量预测的混沌神经网络模型;并利用此模型对高桥地面沉降量进行了预测,并和实际监测沉降量进行了比较,最大绝对预测误差为1. 7,预测的平均误差为0. 0833,研究结果表明,应用混沌神经网络模型进行城市沉降预测是可行、精确的。     

混沌时间序列支持向量机模型及其在径流预测中应用

以重构相空间理论为基础,探讨了混沌时间序列的支持向量机预测模型建模的思路、特点及关键参数的选取。利用饱和关联维数法进行相空间重构,并运用改进小数据量法计算最大Lyapunov指数,对宜昌站月径流时间序列进行混沌特性识别。在运用混沌时间序列的支持向量机模型对月径流预测的应用中,引入了径向基核函数,简化了非线性问题的求解过程。实例表明,该模型能较好地处理复杂的水文序列,具有较高的泛化能力和很好的预测精度。     

矿井涌水量混沌特征与预测

由于受到水文地质、矿井开采等因素的影响, 矿井地下水系统的演化不仅具有确定性也具有随机性, 采用单一的确定性方法或随机性方法都难以揭示矿井地下水系统演化的两面性.混沌理论将确定性分析方法和随机性分析方法两者实现了统一.矿井涌水量时间序列是地下水系统中各要素相互作用的结果, 它包含着该动力系统的信息.基于刘桥二矿水文地质背景分析, 采用混沌时间序列分析方法对该矿的矿井涌水量时间序列进行建模、分析, 得出了其Lyapunov指数为0.1427, 表明刘桥二矿涌水量具有混沌特征.利用建立的模型, 选择2004年4月至2005年2月间的矿井涌水量时间序列进行验证, 结果表明, 利用混沌时间序列分析方法预测矿井涌水量是可行的且具有较高的精度.      

Research Status and Prospect of the Subsurface Hydrology and Ecological Effect in Arid Regions

Centering on the scientific problems faced by subsurface hydrology in arid regions and ecological effect, the urgency of national ecological civilization and the Belt and Road construction towards the research of groundwater discipline, this article analyzed the formation and evolution mechanisms of groundwater and studied the groundwater function of arid regions. Based on the analysis and research, this article discussed domestic and overseas research status, existing problems and developing trend from six aspects, raised key and scientific problems which urgently need to be addressed, aiming at the existing bottlenecks of subsurface hydrology and ecological effect in arid regions and national requirement, so as to make some contribution to the innovative development of China’s groundwater science and national economic construction.     

湿地水文研究进展综述

湿地是地球上一种重要的生态系统,具有巨大的环境功能和环境效益。水文是湿地中最重要的过程,是决定产生和维持湿地典型类型和湿地过程的重要因素。因此,湿地水文过程的研究是湿地研究的核心内容,是当前国内外湿地研究的热点。本文介绍了湿地水文及其对湿地功能等的重要性,综述了当前国内外在湿地水文状态与生态环境的关系、水流运动、水文模型与水文观测等方面的研究进展,并提出了今后我国亟待加强的湿地水文研究领域。     

中国煤田构造研究现状与展望

中国煤田地质的显著特点是煤盆地类型多样、煤系后期改造明显、构造样式丰富,从而在很大程度上决定了煤炭资源开发利用的价值。进入新世纪以来,我国煤田构造研究取得的主要成果包括：①煤田构造的区域地质背景研究取得重大进展;②中国东部盆地动力学与构造控煤作用受到关注;③煤田滑脱构造研究的继续——控煤构造样式的划分;④煤变形-变质作用的构造控制研究愈加深入;⑤以三维地震技术为代表的煤田构造高精度探测技术全面推广应用;⑥矿井构造定量评价和预测已成为煤田构造研究的亮点。通过回顾总结我国煤田构造研究历史和主要成就,分析了当前面临的挑战和机遇,提出了今后一段时期的重点攻关目标。     

基于混沌理论的煤与瓦斯突出前兆时序预测研究

煤与瓦斯突出的预测研究通常是通过监测对煤与瓦斯突出的启动比较敏感的指标来进行,指标监测数据的大小和变化规律是进行预测的基础。首先介绍了一步预测和多步预测的基本原理,然后对2组瓦斯浓度数据序列利用全域法、零阶局域法和一阶局域法进行了对比计算;计算结果表明,加权一阶局域法的预测精度相对较高,该方法对混沌性强的数据序列的预测精度高于混沌性弱的数据序列的预测精度。     

当前国际水文学科技术领域的研究方向

根据联合国有关机构发布的公报和世界各国近年来的学术研究情况，整理出了近期水文学科在地表水、地下水、水质、水资源系统、大气～土壤～植被、大陆侵蚀、冰雪、遥感技术和示踪技术等领域的热门研究课题，在一定程度上反映了当前国际上水文学科的研究和发展方向，对国内同行有一定的参考价值。     

Current Research Status and Prospect of Tectonically Deformed Coal

A number of studies have shown that development areas of weak deformation brittle series of tectonically deformed coal are often the favorable areas for coalbed methane development, and the distribution area of the mylonitic coal of ductile deformation is a danger zone of mine gas outburst. Therefore, faced with solving the key scientific issues and technical problems of the coal bed methane exploration and development and gas outburst prediction and evaluation, more and more attention has been paid to the research on tectonically deformed coal. This paper first systematically elaborated the main research progress on the concept and classification of tectonically deformed coals, their deformation characteristics, and the pore fissure structure and chemical structure. Then, it pointed out that there was a lack of research on the ductile deformation mechanism of coal, and this key scientific problem needs further research in the future. It seemed that the structural and geochemical process of chemical elements migration and accumulation during coal deformation was a new field which is worth exploring. Through refining stress sensitive elements, their distribution and evolution patterns in different stress-strain environments and different types of tectonically deformed coals might be revealed, and then they could become a predictive index which indicates the significance of distribution of tectonically deformed coals and gas outburst prediction. It was thought that geophysical response characteristics and research of detection theory and interpretation method of different types of tectonically deformed coal and gas enrichment area should be an important development direction in the future.     

Research Status and Application Prospect of Shelf-Edge Trajectory Analysis

Trajectory analysis is the hotspot and research frontier of sedimentology and sequence stratigraphy. Compared with conventional analytical methods, trajectory analysis is aiming at identifying sedimentary systems and predicting sandstone reservoirs more directly. The definition of trajectory analysis has been made by Helland-Hansen as “The study of the lateral and vertical migration of geomorphological features and associated sedimentary environments, with emphasis on the paths and directions of migration”. Based on current research progress, the basic concepts and methods of trajectory analysis, types of basinward-migrating trajectories (ascending, flat and descending), quantitative parameters and the application in predicting deep-water sandstone reservoirs were introduced. Trajectory analysis mainly centers on two scales: Shoreline trajectories and shelf-edge trajectories. The formation of basin-floor fans has close relation with shelf-edge trajectories, and multiple case studies have confirmed that large-scale basin floor fan usually form under flat or descending shelf-edge trajectories. As research advances, trajectory analysis theory, which developed in continental margins, is believed to have been influenced by multiple factors. Thus, the accurate prediction of sandstone reservoirs requires the comprehensive consideration of the influence of sediment supply, accommodation spaces, past climate and so on. In addition, the problems and extensions of trajectory analysis were also introduced, including ①the along-strike lateral differential evolution; ② trajectory analysis theory in hydrological-closed sedimentary basins; ③the application of trajectory analysis in carbonate settings. As a developing theory, the terminology of trajectory analysis still needs standardization, and the coupling between shelf-edge trajectories and the development and distribution of deep-water sandstones also needs further understanding. The next research focus could be placed on interpreting the evolution of three-dimensional sedimentary systems, and the extension of shelf-edge trajectory theory to hydrologically-closed basin and carbonate sedimentary environments. The research methods of trajectory analysis should also follow the newest trends to allow researchers to better study the evolution of shelf-edge trajectories, for instance, integrating high-resolution seismic data and logging data, core samples, outcrops and high-resolution dating techniques to describe ancient sedimentary environment and geomorphology, combining satellite imaging, ground penetrating radar to portray the modern morphology of continental margins, and utilizing remote sensing to construct more precise three-dimensional models for outcrops.     

Status of Stratigraphy Research in China

Scientific research and productive practice for earth history are inseparable from the accurate stratigraphic framework and time framework. Establishing the globally unified, precise and reliable chronostratigraphic series and geological time series is the major goal of the International Commission on Stratigraphy(ICS). Under the leadership of the ICS, the countries around the world have carried out research on the Global Standard Stratotype-section and Points(GSSPs) for the boundaries of chronostratigraphic systems. In the current International Chronostratigraphic Chart(ICC), 65 GSSPs have been erected in the Phanerozoic Eonothem, and one has yet been erected in the Precambrian Eonothem. Based on the progress of research on stratigraphy especially that from its subcommissions, the ICS is constantly revising the ICC, and will publish a new International Stratigraphic Guide in 2020. After continual efforts and broad international cooperation of Chinese stratigraphers, 10 GSSPs within the Phanerozoic Eonothem have been approved and ratified to erect in China by the ICS and IUGS. To establish the standards for stratigraphic division and correlation of China, with the support from the Ministry of Science and Technology, the National Natural Science Foundation of China and the China Geological Survey, Chinese stratigraphers have carried out research on the establishment of Stages in China. A total of 102 stages have been defined in the "Regional Chronostratigraphic Chart of China(geologic time)", in which 59 stages were studied in depth. In 2014, the "Stratigraphic Chart of China" was compiled, with the essential contents as follows: the correlation between international chronostratigraphy and regional chronostratigraphy of China(geologic time), the distributive status of lithostratigraphy, the characteristics of geological ages, the biostratigraphic sequence, the magnetostratigraphy, the geological events and eustatic sea-level change during every geological stage. The "Stratigraphical Guide of China and its Explanation(2014)" was also published. Chinese stratigraphers have paid much attention to stratigraphic research in south China, northeast China, north China and northwest China and they have made great achievements in special research on stratigraphy, based on the 1:1000000, 1:250000, 1:200000 and 1:50000 regional geological survey projects. Manifold new stratigraphic units were discovered and established by the regional geological surveys, which are helpful to improve the regional chronostratigraphic series of China. On the strength of the investigation in coastal and offshore areas, the status of marine strata in China has been expounded. According to the developing situation of international stratigraphy and the characteristics of Chinese stratigraphic work, the contrast relation between regional stratigraphic units of China and GSSPs will be established in the future, which will improve the application value of GSSPs and the standard of regional stratigraphic division and correlation. In addition, the study of stratigraphy of the Precambrian, terrestrial basins and orogenic belts will be strengthened, the Stratigraphic Chart of China will be improved, the typical stratigraphic sections in China will be protected and the applied study of stratigraphy in the fields of oil and gas, solid minerals, etc. will be promoted. On the ground of these actions, stratigraphic research will continue to play a great role in the social and economic development of China.