浅论县（市）级土地利用数据库系统建设

随着经济的迅猛发展,各地土地利用情况多种多样,采用手工管理土地资料更新周期长,综合利用率低,各种查询统计要耗费大量的人力物力,而且统计计算的数据结果精度不高。因此仅仅依靠传统的手工管理模式已经远远不能满足土地管理工作的需要,为保质保量按时完成全国土地利用现状更新调查,加强地籍规范化管理,利用成熟的计算机技术辅助进行土地调查已势在必行。     

Weathering features of the Erzhe gold deposit, Sichuan, China

Based on the analysis and study of mineral composition, structure, and major and trace elements, this paper deals with element geochemical characteristics and transformation from primary ore into oxidized ore in the Erzhe gold deposit, Sichuan. Some grounds are provided to constrain the transformation of primary ore to oxidized ore.     

频率测深的拟地震解释法

电磁波和弹性波的复反射函数无论从数学表达形式上,还是从物理意义上都有一定的相似性。通过对拟地震解释法中反射系数q_n的求取,将频率测深曲线转换成v_p－t₀曲线及时间剖面,并对均匀介质及2层、3层、4层断面的理论模型和实例做了正反演计算。结果表明,频率测深拟地震解释法作为一种新的解释手段具有较好的应用前景。     

Deciphering the Variscan tectonothermal overprint and deformation partitioning in the Cadomian basement of the Teplá–Barrandian unit, Bohemian Massif

The Teplá–Barrandian unit (TBU) has long been considered as a simply bivergent supracrustal ‘median massif’ above the Saxothuringian subduction zone in the Variscan orogenic belt. This contribution reveals a much more complex style of the Variscan tectonometamorphic overprint and resulting architecture of the Neoproterozoic basement of the TBU. For the first time, we describe the crustal-scale NE–SW-trending dextral transpressional Krakovec shear zone (KSZ) that intersects the TBU and thrusts its higher grade northwestern portion severely reworked by Variscan deformation over a southeastern very low grade portion with well-preserved Cadomian structures and only brittle Variscan deformation. The age of movements along the KSZ is inferred as Late Devonian (~380–370?Ma). On the basis of structural, microstructural, and anisotropy of magnetic susceptibility data from the KSZ, we propose a new synthetic model for the deformation partitioning in the Teplá–Barrandian upper crust in response to the Late Devonian to early Carboniferous subduction and underthrusting of the Saxothuringan lithosphere. We conclude that the Saxothuringian/Teplá–Barrandian convergence was nearly frontal during ~380–346?Ma and was partitioned into pure shear dominated domains that accommodated orogen-perpendicular shortening alternating with orogen-parallel high-strain domains that accommodated dextral transpression or bilateral extrusion. The synconvergent shortening of the TBU was terminated by a rapid gravity-driven collapse of the thickened lithosphere at ~346–337?Ma followed by, or partly simultaneous with, dextral strike-slip along the Baltica margin-parallel zones, driven by the westward movement of Gondwana from approximately 345?Ma onwards.     

Microstructure characteristics and forming environment of late Quaternary Period loess in the Loess Plateau of China

Since the late Quaternary Period, the rapid rising of the northeastern Qinghai-Tibetan Plateau has greatly changed the East Asian climate and formed different regional monsoon climates. Various microstructures of the loess in northern China have formed under a variety of climatic conditions. The scanning electron microscope (SEM) and energy spectrum analysis are used in this paper to study the relationship between the indexes of loess microstructures and the forming climates, and the indexes include the diameter of sand grains, Ca/Fe value and the characteristic shapes of the loess from SEM microstructures pictures. In terms of their respective climatic circumstances, the major microstructures of regional loess may be classified into nine categories according to their forms and particle sizes, such as loess formed in near-sand source, loess of granule sand dropping, and loess formed in hot and rainy places, i.e. with the loess SEM pictures, climates of about 15 ka b.p. in different places may be evaluated. In conclusion, the clear and distinguishable loess microstructures and their indexes in the Loess Plateau of China can also deduce the evolution of climate, such as warm or cold and wet or dry, and even sandstorm activities when the loess is deposited.     

不同模式模拟的降水稳定同位素效应的比较和评估

利用引入水稳定同位素循环的ECHAM4、GISS E、HadCM3、MUGCM以及iAWBM的模拟数据,分析了全球降水中稳定同位素效应的空间分布特征,对不同模式的模拟结果之间以及模拟结果与GNIP（Global Network of Isotopes in Precipitation）的实际监测结果之间进行了比较,旨在对稳定同位素大气环流模式的模拟有效性进行评价,改善对水循环中水稳定同位素效应的理解和认识。结果显示,5个模式均很好地再现了全球降水中平均δ18O和平均δ18O季节差的空间分布特征,降水中稳定同位素的温度效应、降水量效应的分布特点以及全球大气水线GMWL（Global Meteoric Water Line）均被很好地模拟出。比较而言,ECHAM4模拟的降水中的平均δ18O以及δ18O平均季节差的空间分布与GNIP的实际分布最接近,拟合水平也最高;ECHAM4、GISS E、MUGCM和iAWBM再现全球温度效应空间分布的能力较强,拟合水平大致相当;由iAWBM模拟的降水量效应空间分布与实际分布之间的相关性最强,5个模式模拟的与实测的δ18O/P相关系数符号相同的站点数大致位于同一水平;GISS E和iAWBM模拟的全球大气水线与实测的GMWL最接近。     

Geomorphological site classification for the Fujian province

Geomorphological classification of the Fujian province was done based on remote-sensing imaging, digital elevation maps, and slope gradient data acquired by ArcGIS 9.2. The engineering geological units in the Fujian province were divided into five types by the geomorphologic shape and genesis. The relationship among geomorphological type, engineering geological unit, and site category was determined using engineering geological data and site category data. Then, after making a preliminary site classification adjusted by drill hole data, the site was classified into four types: I₀, I₁, II, and III according to site classification standards of equivalent shear-wave velocity and overburden thickness. The results showed that the site categories in the Fujian province mainly consist of type II, which accounts for 85.26 % of the land area. The percentage of I₀ was the smallest, which accounts for only 2.44 % of the total area.     

Application of data assimilation for improving forecast of water levels and residual currents in Singapore regional waters

Hydrodynamic models are commonly used for predicting water levels and currents in the deep ocean, ocean margins and shelf seas. Their accuracy is typically limited by factors, such as the complexity of the coastal geometry and bathymetry, plus the uncertainty in the flow forcing (deep ocean tide, winds and pressure). In Southeast Asian waters with its strongly hydrodynamic characteristics, the lack of detailed marine observations (bathymetry and tides) for model validation is an additional factor limiting flow representation. This paper deals with the application of ensemble Kalman filter (EnKF)-based data assimilation with the purpose of improving the deterministic model forecast. The efficacy of the EnKF is analysed via a twin experiment conducted with the 2D barotropic Singapore regional model. The results show that the applied data assimilation can improve the forecasts significantly in this complex flow regime.     

5•12汶川地震中山区公路桥梁震害及启示

桥梁结构的振动特性受场地条件及土—结相互作用影响显著,为提高桥梁结构的抗震性能,减少因结构破坏而产生的经济损失,进一步开展考虑场地土体非线性以及土—结相互作用对桥梁结构地震反应影响的研究工作十分必要。本文以一典型桥梁结构为例,着重介绍了美国太平洋地震工程研究中心基于性能的桥梁有限元模拟平台BridgePBEE应用中所涉及的地震动选取、桥梁结构建模、土体本构选择以及基于构件的桩—土—桥梁结构体系损伤评估方法,为研究震后桥梁结构经济损失分析方法提供可行性方案。