基于地理实体的基础测绘生产组织模式探索

首先分析了目前我国基础地理信息资源建设存在的主要问题,提出了通过构建地理实体数据库实现基础地理信息资源的共享和深入应用的构想。其次,深入分析了目前国内外地理实体数据库的研究及建设现状。在以上基础上,最后以优先满足国家事权为原则,提出了基于地理实体数据采集的我国基础测绘国家、省、市县任务分工和生产组织模式构想。     

A new method for indentifying the model error of adjustment system

Some theory problems affecting parameter estimation are discussed in this paper. Influence and transformation between errors of stochastic and functional models is pointed out as well. For choosing the best adjustment model, a formula, which is different from the literatures existing methods, for estimating and identifying the model error, is proposed. On the basis of the proposed formula, an effective approach of selecting the best model of adjustment system is given. Project supported by the Open Research Fund Program of the Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University (No. 905276031-04-10).     

应用GeoStar建立数字佛像三维模型的研究

通过使用GeoStar系列软件进行数字三维佛像建模 ,进一步实现佛像的动态漫游 ,从而得出了一种基于等值线图建立数字表面模型并进行空间漫游的可行技术 ;通过研究卧佛的历史资料 ,对数字佛像模型进行修补 ,探讨了实现佛像表面三维可视化复原的方法     

多源卫星重力场模型精度与频谱分析

针对新一代卫星重力探测技术对地球重力场的频谱贡献问题,该文提出了一种基于GPS/水准数据获取多源卫星重力场模型频谱变化特征的方法。采用GPS/水准外符合检验,有效分析评估了多源卫星重力场模型在中国东、西部地区的精度水平。研究结果表明,以CHAMP、GRACE和GOCE卫星为代表的高-低卫星跟踪卫星、低-低卫星跟踪卫星和卫星重力梯度技术,对地球重力场的频谱贡献分别集中在600km以上的长波和中长波、300km以上的中波、200~350km之间的中短波部分。     

冀中拗陷古潜山油田水化学研究

冀中拗陷油气田87%的储量产于海相碳酸盐岩古潜山中,在油气生成、运移、集聚和散失的过程中地下水起了重要作用。本文根据50个试样的水化学分析资料,运用对应分析方法对冀中拗陷古潜山油田水进行了分类并初步探讨了水化学成分演化与油气藏形成的关系。     

Large-scale dune erosion tests to study the influence of wave periods

Large-scale physical model tests were performed to quantify the effects of the wave period on dune erosion. Attention was focussed on 2D cross-shore effects in a situation with sandy dunes and extreme water levels and wave conditions. Besides profile measurements, detailed measurements in time and space of water pressure, flow velocities and sediment concentrations were performed in the near near-shore area. It was concluded that a longer wave period leads to a larger dune erosion volume and to a larger landward retreat of the dune face. Tests with double-peaked wave spectra showed that the influence of the spectral shape on dune erosion was best represented by the T_m − 1,0 spectral mean wave period, better than the peak wave period, T_p. The effect of the wave period on dune erosion was implemented in a dune erosion prediction method that estimates erosion volumes during normative storm conditions for the Dutch coast. More details of the measurements and additional analyses of physical processes are described in an accompanying paper by Van Thiel de Vries et al. [Van Thiel de Vries, J.S.M., van Gent, M.R.A., Reniers, A.J.H.M. and Walstra, D.J.R., submitted for publication. Analysis of dune erosion processes in large scale flume experiments, In this volume of Coastal Engineering.].     

气候变化对黄土碳库效应影响的敏感性研究

中国黄土分布广、厚度大,是古气候变化的良好记录载体,然而黄土在大气CO2循环中到底是源还是汇一直是困扰人们的一个问题.本文利用陆相生态系统中的生物地球化学模型,通过敏感性试验,模拟了土壤有机碳对气候变化的响应.结果表明:1)在各种稳定的气候条件下黄土的土壤有机质都是持续增加的,因此可以认为自然条件下黄土是大气CO2的一个汇;2)温度和降水对黄土中土壤有机质含量的影响正好相反,表明湿度是影响黄土地区生态环境的主要因素,温度和降水都是通过对湿度的影响来影响植被生态的;3)地表植被和土壤有机质是黄土碳库与大气CO2之间的重要媒介.黄土表层的生物地球化学过程是影响黄土碳汇效应的主要过程;4)黄土碳库的主要存在形式以次生碳酸盐为主,其次是土壤有机质,气态CO2只占很小比例.     

碳酸盐岩裂缝型储层最小二乘偏移成像方法研究

碳酸盐岩裂缝型储层是海相油气储层以及西部探区的重要储层类型之一,多表现为缝洞储集体形态,埋藏深度大,地震反射波信号复杂,波场特征分析困难,因而对其进行高分辨成像具有一定的难度.本文推导并实现了基于最小二乘理论的偏移成像(LSM)方法,并将LSM用于西部探区碳酸盐岩裂缝型储层等效地震地质模型的偏移成像工作,成像结果表明:在理论上,LSM方法能够较好地分辨出埋藏深度在3000 m以下的中深部20 m尺度碳酸盐岩裂缝型储层,在西部碳酸盐岩裂缝型储集体地震勘探中,具有较好的适应性.     

A One-dimensional Ensemble Forecast and Assimilation System for Fog Prediction

A probabilistic fog forecast system was designed based on two high resolution numerical 1-D models called COBEL and PAFOG. The 1-D models are coupled to several 3-D numerical weather prediction models and thus are able to consider the effects of advection. To deal with the large uncertainty inherent to fog forecasts, a whole ensemble of 1-D runs is computed using the two different numerical models and a set of different initial conditions in combination with distinct boundary conditions. Initial conditions are obtained from variational data assimilation, which optimally combines observations with a first guess taken from operational 3-D models. The design of the ensemble scheme computes members that should fairly well represent the uncertainty of the current meteorological regime. Verification for an entire fog season reveals the importance of advection in complex terrain. The skill of 1-D fog forecasts is significantly improved if advection is considered. Thus the probabilistic forecast system has the potential to support the forecaster and therefore to provide more accurate fog forecasts.     

Direct observation of complex Tóthian groundwater flow systems in the laboratory

Based on the theory of gravity‐driven groundwater flow systems, we have developed a complex Flow System Sand‐Box Model (FSM). It enables the visual observations of the development and characteristics and temporal evolution of complex Tóthian flow systems in the laboratory. The configuration of the regional, intermediate and local flow systems can be controlled and observed; hydraulic head, flow direction and travel time can be measured; and the scale and shape of the sub‐flow systems as well as the path lines and flow lines can be observed directly. The experiments demonstrate the Tóthian flow systems in a small basin with multiple sources and sinks. Greater local topographic (water table) undulation will lead to larger local flow systems. Greater regional and less local topographic undulation will enhance the development of intermediate and regional flow systems. In homogeneous media, increasing fluid‐potential differences between source and sink increase the spatial scale of the generated flow systems. The FSM is a useful teaching aid and experimental device to study and develop an intuitive insight into gravity‐driven groundwater flow systems. It helps to visualize and understand the hydraulic properties and controlling factors of Tóthian flow systems and may be used to study problems related to the chemical and temperature characteristics of the flow systems as well. Copyright © 2010 John Wiley & Sons, Ltd.