Research on scale effect of histogram

To describe the spatial relationship among the earth objects compactly, in this paper, we raised the concept of histo-variogram based on the analysis of the characteristics of other spatial analyzing methods such as variogram, information entropy. And we also raised a new spatial analysis method of histogram decomposition based on the definition of standing pixel and contour pixel. At the end of this paper, we demonstrated the characteristics of histo-variogram by two experiments, one for spatial analysis, the other for image fusion.     

Experimental investigation of drag coefficients of gobi surfaces

The response of gobi surfaces to the near-surface air flow can be characterized quantitatively by drag coefficients. By using wind tunnel tests, an attempt is made to define the relationship between the drag coefficients of gobi surfaces and gravel size and coverage. It is concluded that the drag coefficients of gobi surfaces tend to be constants when gravel coverage is over 40%-50%. Consequently, we think that the gobi deflation planes expanding vastly in the arid Northwestern China are aerodynamically stable, at least not the supplying sources of current dust storms, and therefore the emphasis on dust storm control should be paid on the so-called "earth gobi" that has low gravel coverage. The prediction model for drag coefficients of gobi surfaces has been developed by regressing drag coefficients on gravel size and coverage, the predicted results are in reasonably good agreement with wind tunnel results (R 2 = 0.94). The change of drag coefficients with gravel friction Reynolds number implies that the development extent of drag effect increases with gravel size and coverage.     

Matrix expression of thermal radiative characteristics for an open complex

The directionality of thermal radiance of a homogeneous isothermal non-black plane surface is totally decided by its directional emissivity, which depends on the complex dielectric constant and roughness of surface. It can be expressed by This paper proves that it is necessary to express emissivity by a matrix when a target becomes an inhomogeneous non-isothermal open complex with complicated inner geometric structure. The matrix describes the inner radiative interaction among components accurately and also expresses its thermal radiative directionality and structural characteristics completely. Advantages of matrix expression are as follows: first, the physical mechanics of effective emissivity of an open complex is described in a simple and perfect way; second, it becomes easy to understand the principle and method to retrieve components temperature from multi-angle thermal remotely sensed data; and third, the differences of directionalities between an open complex and a homogeneous isothermal non-black plane body are expressed by just using an effective emissivity matrix instead of an emissivity vector. Formula in classic physics is only the special case of matrix expression; therefore, the matrix is a universal unconditional expression to describe the directionality of thermal radiance.     

中南半岛影响南海夏季风建立和维持的数值研究

利用美国大气研究中心研制的第三代公共气候模式(CCM3)模拟了中南半岛对南海夏季风的建立和维持的影响,数值试验结果表明,中南半岛对南海夏季风的建立和维持起了非常重要的作用.同时还就中南半岛影响南海夏季风建立和维持的机制进行了讨论.     

Bedded jaspers of the Ordovician Løkken ophiolite,Norway: seafloor deposition and diagenetic maturation of hydrothermal plume-derived silica-iron gels

Sedimentary beds of jasper (red hematitic chert) in the Ordovician Løkken ophiolite of Norway are closely associated with volcanogenic massive sulphide (VMS) deposits. The jaspers occur in the immediate hangingwall and laterally peripheral to the large Løkken (25–30 Mt) and small Høydal (0.1 Mt) VMS deposits, and are exposed discontinuously for several kilometres along strike. Massive or laminated types predominate; jasper-sulphide debris-flow deposits are also abundant near VMS deposits. The jaspers contain hematite-rich laminae showing soft-sediment deformation structures and microtextural evidence that record the presence of a colloidal precursor and an origin as gels. Early textures include: (1) straight or curved chains of hematitic filaments 3–10 µm in diameter and 20–100 µm long; (2) branching networks of 15–25 µm-thick, tubular structures surrounded by cryptocrystalline hematite and filled with quartz and euhedral hematite; (3) small (up to 10 µm) spherules composed of cryptocrystalline hematite and silica; and (4) up to 50 µm silica spherules with hematitic cores. The small filaments seem to have been deposited in varying proportions in the primary laminae, possibly together with hematitic and siliceous microspheroids. Diagenetic changes are represented by polygonal syneresis cracks, and the presence of cryptocrystalline (originally opaline) silica, chalcedony, quartz, carbonate and cryptocrystalline hematite and/or goethite forming botryoidal masses and spheroids <10 µm to 5 mm in diameter. Coarser euhedral grains of quartz, carbonate, and hematite are integral parts of these textures. Bleached, silica-rich jaspers preserve only small relics of fine-grained hematite-rich domains, and locally contain sparse pockets composed of coarse euhedral hematite±epidote. The jaspers are interpreted to record colloidal fallout from one or more hydrothermal plumes, followed by maturation (ageing) of an Si-Fe-oxyhydroxide gel, on and beneath the Ordovician sea floor. Small hematitic filaments in the jaspers reflect bacteria-catalysed oxidation of Fe ²⁺ within the plume. The larger tubular filaments resulted from either microbial activity or inorganic self-organized mineral growth of Fe-oxyhydroxide within the Si-Fe-oxyhydroxide gel after deposition on the sea floor, prior to more advanced maturation of the gel as represented by the spheroidal and botryoidal silica-hematite textures. Bleaching and hematite±epidote growth are interpreted to reflect heat and fluids generated during deposition of basaltic sheet flows on top of the gels.     

Editors

Editorial Board

Editors     

Effect of near-fault earthquake on bridges: lessons learned from Chi-Chi earthquake

The objective of this paper is to describe the lessons learned and actions that have been taken related to the seismic design of bridge structures after the Chi-Chi, Taiwan earthquake. Much variable near-fault ground motion data was collected from the rupture of Chelungpu fault during the Chi-Chi earthquake, allowing the seismic response of bridge structures subjected to these near-fault ground motions to be carefully examined. To study the near-fault ground motion effect on bridge seismic design codes, a two-level seismic design of bridge structures was developed and implemented. This design code reflects the near-fault factors in the seismic design forces. Finally, a risk assessment methodology, based on bridge vulnerability, is also developed to assist in decisions for reducing seismic risk due to failure of bridges. Director of Center for Research on Earthquake Engineering. Supported by: the Science Council, Chinese Taipei, under grant no. SC 90-2211-E-002-028.     

Paleoenvironmental evolution of the Paratethys in the Slovenian Basin during the Late Paleogene

Several sections from the uppermost Eocene and Oligocene of northern Slovenia have been investigated with respect to sedimentary facies, foraminiferal assemblages, stable isotopes, carbonate microfacies, and palynology. The main objective was to reconstruct the paleoenvironmental history of the Paleogene Paratethys in this region of the eastern Alpine realm. The sediments exhibit a transgressive succession beginning with conglomerates, sandstones, and mudstones of fluvial and lacustrine origin followed by carbonates and muddy marls indicating marine conditions. The foraminiferal faunal changes from brackish to shallow marine to deeper marine assemblages and the distribution of the palynofloras corroborate the sedimentological results. Microfacies analysis of the limestones shows a wide variation of shallow water, generally mud-rich facies dominated by coralline algae, foraminifera, and corals. Microfaunas adapted to low-oxygen conditions indicate temporal sluggish bottom-water circulation which can be associated with high fresh-water fluxes. These results are discussed as reflecting both the global sea-level rise during the Early Oligocene and the regional tectonic and climatic evolution.     

Contents To Volume 88

Volume Contents

Contents To Volume 88     

积极推动“数字海南”建设

海南省具有得天独厚的发展优势,“数字地球”是实现整体可持续发展的重要保障,将有力推进全省信息化的进程,促进经济发展。