河流网络的分形与自组织及其物理机制

扼要地评述近年来国内外在流域、水系等方面的分形及自组织研究的有关成果,指出其中存在的问题和可能的改进途径.从地球内外营力及河网系统的开放性、非线性、随机性、耗散性等角度探讨河网系统自组织及分形结构产生的物理机制.在流域侵蚀与生态环境恢复、流域产流与汇流、泥沙产生与输移、河床形态演变等方面提出了进一步的研究方向及有关课题.     

Towards a new view of earthquake phenomena

Recent advances in the theory of fracture and fragmentation are reviewed. Empirical laws in seismology are interpreted from a fractal perspective, and earthquakes are viewed as a self-organized critical phenomenon (SOC). Earthquakes occur as an energy dissipation process in the earth's crust to which the tectonic energy is continuously input. The crust self-organizes into the critical state and the temporal and spatial fractal structure emerges naturally. Power-law relations known in seismology are the expression of the critical state of the crust. An SOC model for earthquakes, which explains the Gutenberg-Richter relation, the Omori's formula of aftershocks and the fractal distribution of hypocenters, is presented. A new view of earthquake phenomena shares a common standpoint with other disciplines to study natural complex phenomena with a unified theory.     

岩石中自组织现象的成因：对传统地质理论的挑战及其对策

从岩石中自组织现象出发,举例阐明了传统地质理论的局限性;回顾了自组织现象的研究历史和现状,提出了岩石中自组织现象的初步分类;阐明了自组织现象研究的意义,并指出:随着自组织现象研究的广泛开展和成果的不断积累,正在孕育着“非线性岩石学”这样一门新兴的边缘学科。     

神经网络方法识别测井曲线形态

随着油田勘探开发程度的不断提高,要找到有利的油气聚集带以及在开发阶段提高油田采收率,都必须进行储层沉积相分析。这里介绍一种利用自组织神经网络识别曲线形态的方法。采用将测井曲线网格化,再利用自组织神经网络识别曲线形态,进而去判别沉积相。此方法可以对测并曲线形态进行识别,且消除了测井曲线中的不确定因素,运用该方法对实际测井曲线形态的识别基本正确。     

地球地质历史中非生物成因的自组织耗散结构(英文)

自从地球上有水出现,就持续存在水-岩体系的平衡-不平衡。这一体系内部是不协调的,这就决定了它在地质历史的长河中自发地连续发展的可能性,并导致完全新的矿物相和水的不同地球化学类型的生成。在地壳中这一体系持续在一个热力学分支的线性域中,远离平衡而发育。它积聚太阳能,形成非生物成因耗散结构。它在连续发育惯性中起特殊作用,然后发育为一种生命物质。前进自组织将向该体系倾斜的趋向,定义为无机物质发育的基础之一。还有其他的一组体系都从这个体系中继承了它大多数的性质。水-岩体系的演化导致了次生矿物相和水的地球化学新类型的形成。随着演化程度加深,体系在成分上、结构上逐渐变得复杂,形成新的地球化学介质,它们又反过来控制新矿物相的生成从而对自身的性质产生影响。这一过程在地质历史上是永恒的。这便是矿物界自组织的要点,即包括发生、生长及新结构形体的时-空弥散以及矿物、地球化学介质的形成,最后是新的有机物质和生命的起源。     

气象条件与 SARS发生的关系分析

根据 2 0 0 3年北京、香港SARS高发期间逐日确诊发病人数序列 ,运用数理统计和幂律关系方法 ,分析了不同地区SARS与气象条件之间的关系。结果表明 :京港两地SARS高发期的波动量与确诊前 7～ 1 0天的最高气温、最低气温、气温日较差、日照时数呈显著负相关 ,与相对湿度、云量呈正相关 ;气象条件与SARS发病人数呈显著的幂律关系 ,为自组织临界态理论在大气科学中的应用提供了观测证据。     

Possible causes of the variation in fractal dimension of the perimeter during the tropical cyclone Dan motion

We calculated the fractal dimensions Db of the perimeter of tropical cyclone(TC)Dan based on the satellite GMS-5 infrared sensor images from 1800 UTC,1 October 1999 to 1200 UTC,9 October 1999.The fractal dimensions Db were used to characterize objectively the temporal change of TC complex structure.Our results show that the change of fractal dimension during TC Dan motion can be divided into three stages.The statistically significant difference does not exist either between Dm1 and DL or between Dm3 and DL,but it exists between Dm2 and DL,where Dmi denotes the mean value of Db in i-th stage(i=1,2 and3);DL denotes Lovejoy’s fractal dimension calculated based on satellite and radar data within the size range(1–1.2×106 km2),which is used as a"normal value"of the fractal dimension of the cumulus cloud perimeter for the global tropical region.TC Dan turns to the north from the west abruptly at the end of the second stage.The emergence of the second stage with high fractal dimensions may be viewed as a possible premonition for the track turning.Our results also show that there are two kinds of processes resulting in the translation from the first stage to the second stage.One is the interaction of TC circulation and an adjacent small scale convective cloud cluster,causing to the complexity increase of a local segment of the perimeter.The other includes the fragmentation of a strong convective area within the TC inner region,the self-organization of the small strong convective cloud clusters,the emergence,development,and merger of the small scale non-convective holes,and the formation of a gap of the perimeter,causing to the complexity increase of the whole TC perimeter.     

绿洲边缘人工固沙植被自组织过程

在对植被自组织过程研究进展评述的基础上,研究了河西走廊荒漠绿洲边缘人工固沙植被格局40年来自组织及种群自疏过程,发现在干旱区,特别是降水量200mm以下的荒漠区,绿洲边缘雨养或者降水和地下水共同维系的沙丘人工植被也会发生自组织过程,原来基本均匀栽植的植被出现斑块化,最大斑块面积、斑块密度、斑块聚集度在20~30a出现,但种群自疏过程并未遵循随植被发育年龄变化的规律,而与生境与绿洲的距离及生境地下水埋深显著相关。未来应加强在气候变化和人类干扰条件下植被格局发生突变的阈值范围的研究,也应加强干旱区人工植被自组织过程及其变化等的研究。