多维植被信息系统及其应用前景

3S(地理信息系统GIS、遥感RS、全球定位系统GPS)及其相关技术的发展，使得植被信息系统的构建和应用成为可能。早期的植被图没有涉及到高度维和时间维，其应用受到很大的限制。因此有必要建立一种基于时空的多维植被信息系统，它的组成包括地理信息系统GIS、数据处理模块DPM、数据存取模块DAM、植被分析模块VAM和交互显示模块IDM，可用于植被的时空分析、三维景观显示、植被—地形—气候关系研究以及植被综合管理等方面，特别适合于山地植被的研究。多维植被信息系统具备立体直观的用户友好界面和强大的时空数据处理能力，并可通过数据库和网络进行资源共享，使植被研究和管理自动化、无纸化，其应用前景广阔。     

多右端非对称位移方程组的GMRES种子投影方法

考虑用GMRES方法求解多右端非对称位移方程组(A-σjI)x^(j)=b^(j)，1≤j≤p。基于Smith的求解多右端方程组的种子投影思想，提出了求解上述位移方程组的GMRES种子投影方法，利用种子方程组产生的Krylov子空间来求近似解。本文给出了近似解的误差界，最后数值结果显示了该方法的有效性。     

Identification of soil degradation during earthquake excitations by Bayesian inference

A Bayesian inference approach is introduced to identify soil degradation behaviours at four downhole array sites. The approach of inference is based on a parametric time‐varying infinite impulse response filter model. The approach is shown to be adaptive to the changes of filter parameters and noise amplitudes. Four sites, including the Lotung (Taiwan), Chiba (Japan), Garner Valley (California), and Treasure Island (California) sites with downhole seismic arrays are analysed. Our results show two major types of soil degradation behaviour: the well‐known strain‐dependent softening, and reduction in stiffness that is not instantaneously recoverable. It is also found that both types of soil degradation are more pronounced in sandy soils than in clayey soils. The mechanism for the second type of soil degradation is not yet clear to the authors and suggested to be further studied. Copyright © 2003 John Wiley & Sons, Ltd.     

Seismic risk assessments and GIS technology: applications to infrastructures in the Friuli–Venezia Giulia region (NE Italy)

This paper illustrates the seismic risk preliminary estimates of two different groups of structures located on the territory of the Friuli–Venezia Giulia region (NE Italy) : the first group includes some special industrial plants, and the second group includes bridges and tunnels belonging to the regional highway network. The part of the study on special industrial plants tries to evaluate the degree of expected damage, taking into account their structural typology and ground shaking expressed in terms of macroseismic intensity. The second part of the study is an application of the HAZUS methodology to the tunnels and bridges of a highway network: the combination of expected ground shaking and the construction characteristics lead to very different risk levels, especially when considering the bridges. The resulting damage levels to bridges and tunnels are still only indicative because of the fragility curves used in the evaluations: they were developed for existing bridge and tunnel structural typologies in the U.S.A. Moreover, both examples show the power of GIS technology in storing, elaborating, and mapping spatial data. Copyright © 2003 John Wiley & Sons, Ltd.     

论层序地层学与含油气系统在油气勘探中的联系——以鄂尔多斯中生代盆地为例

虽然层序地层学与含油气系统理论的各自研究对象和研究方法不同，但由于层序地层学研究对象(沉积岩)是含油气系统研究对象(油气)的载体，二者可以由含油气盆地分析有机的结合起来。层序地层分析包含了对含油气系统的地质要素及成藏作用载体的分析，因而沉积层序的组成单元与含油气系统的地质要素有必然的联系：在一个沉积盆地的数个沉积层序中，成熟烃源岩往往是地史中具一定埋深、分布广、厚度大、有机质含量高的凝缩层，这个凝缩层往往是一个构造超层序的最大海(湖)泛面；储集岩往往是成熟烃源岩之上层序的低水位体系域或紧邻成熟烃源岩的高水位体系域；有效盖层为储集岩之上层序的水进体系域及凝缩层；成熟烃源岩之上的沉积层序为上覆岩层；低水位体系域储集岩有可能沿上倾方向尖灭，被层序界面及其上层序的水进体系域岩性圈闭；除构造裂缝外，低水位体系域下切谷可作为油气向上运移通道；一个含油气系统往往跨越不同的沉积层序甚至构造超层序。     

东北大部旱情缓解 粤闽局地暴雨成灾──1997年5月

东北大部旱情缓解粤闽局地暴雨成灾—１９９７年５月—徐良炎（国家气候中心，北京１０００８１）５月份，东北大部、华北北部及黄淮等地普降喜雨，旱情缓解；西北东部、华北西部等地降水偏少，旱情持续或发展。南方大部地区雨水比较调匀，无大范围旱涝发生，但华南局地遭...     

Generating fracture networks using iterated function systems

In order to model flow and transport in fractured rocks it is important to know the geometry of the fracture network. A stochastic approach is commonly used to generate a synthetic fracture network from the statistics measured at a natural fracture network. The approach presented herein is able to incorporate the structures found in a natural fracture network into the synthetic fracture network. These synthetic fracture networks are the images generated by Iterated Function Systems (IFS) as introduced by Barnsley (1988). The conditions these IFS have to fulfil to determine images resembling fracture networks and the effects of their parameters on the images are discussed. It is possible to define the parameters of the IFS in order to generate some properties of a fracture network. The image of an IFS consists of many single points and has to be suitably processed for further use.     

Genesis and distribution of mineral waters as a consequence of recent lithospheric dynamics: the Rhenish Massif,Central Europe

Three major, interdependent processes control the genesis and distribution of mineral and thermal waters in the Rhenish Massif, Central Europe: (a) Magmatic processes in the upper mantle provide most of the CO₂ to produce bicarbonate waters in shallow aquifers. (b) Extension of the brittle upper crust enables the ascent of sodium chloride waters. (c) Uplift and erosion shape the massif's relief, which determines the extent of flow systems and the distribution of thermal springs. The chemistry of mineral waters further depends on the aquifers' mineral composition. A comprehensive set of hydrological, chemical, tectonic and geophysical data on the Rhenish Massif has been compiled. It was used to classify the mineral waters and to map the spatial distribution of water properties. The composition of cuttings from several representative wells producing different water types shows that the hydrothermal alteration of the aquifer rocks consists mainly of kaolinization of chlorite and dissolution of feldspar. Numerical transport simulations favour two modes of groundwater flow: topography-driven flow and the pressure-driven ascent of basement brines along active faults. Thermal convection is less important.     

A physical statistical approach to erosion

Erosion is a complex process consisting of many components such as surface runoff, impact of raindrops, wind forces, soil and rock mechanics, etc. Trying to integrate all these processes into a physical model seems to be hopeless. In order to understand the variety of natural shapes and patterns produced by erosion we present an integrated statistical approach. Our model is based on simple physical constraints for the separation of amalgamated particles (abrasion) and for the movement of loose particles (denudation) and on the laws of statistics. After some simplifications, we obtain a nonlinear system of partial differential equations which is solved using finite volume techniques. The model is suitable for the formation of different types of rill systems and the episodic behaviour of erosion processes, a kind of self-organized criticality. Besides effects of inhomogeneities, e.g. the formation of terraces can be investigated.     

瞬变电磁场的奇点展开法

在分析电磁系统自然谐振现象的基础上,简述了瞬变电磁场奇点展开法的物理基础、基本理论、极点提取方法,并考查了奇点展开法在地球物理中的应用可能性。