从地理信息系统到虚拟地理环境的认知转变

自20世纪60年代初以来,地理信息系统引领了地理信息的分析与服务。然而,由于地理学家对于地理过程开展多维模拟的需求,同时许多大型工程需要对于不同方案的后果事先开展模拟评估,为此中国学者们在世纪相交之际开始了对于虚拟地理环境的探索。本文从地理信息系统到虚拟地理环境的认识上的转变着手,分析了虚拟地理环境的演进过程、当前的阶段定位与挑战,着重探讨了虚拟地理环境研究的新态势：基于虚拟地理环境的地理空间认知研究、虚拟地理环境与实验地理学新方向、大数据背景下的虚拟地理认知实验方法和虚拟地理环境与地理知识工程,并给出最新研究思路。     

煤层底板水害防治智能决策支持系统框架构建

煤层底板突水是华北型煤田煤矿生产过程中一种常见的水害类型,为解决水害防治工程的科学决策问题,进一步提高防治水工程的可靠性,提出构建智能决策支持系统的技术思路。智能决策支持系统是传统决策支持系统与人工智能技术相互融合的产物,在分析底板水害防治决策支持功能需求的基础上,提出“数据-模型-方案”一体化设计流程,从数据导入、模型驱动、智能决策等3个层次构建底板水害防治智能决策支持系统的基本框架。将模型驱动层进一步细分为方法库、模型库、知识图谱构建3项专业化服务,模型库包括底板突水空间点预测模型、疏水降压数值模拟模型、注浆改造工程可靠性分析模型、隔离工程设计模型及底板水害监测预警模型。系统最终输出的决策方案包括底板突水危险性分区、疏水降压Q-t-s方案、区域注浆改造设计及工程可靠性评价、隔离工程设计、底板突水监测预警警情发布。系统通过注浆过程的反馈-控制、突水监测预警的深度学习、疏水降压方案的动态优化等实现其智能决策。智能决策支持系统将会在煤层底板水害防治可靠性保障方面提供新的技术支撑。     

黄土沉积与地球圈层相互作用

黄土是地球上分布最为广泛的沉积物之一,黄土的分布区也是旱作农业起源地和古文明的发祥地,养育了地球上数以亿计的人口。作为一种风力搬运的沉积物,黄土也是古气候变化的重要信息载体。长期以来,中外科学家已经对黄土的物理学、地球化学、沉积学、古气候学等开展了多学科的综合研究,取得了瞩目的成就。本文旨在从地球系统科学角度出发,将黄土物质的产生、搬运、堆积及沉积后的成土过程与地球岩石圈、水圈（包括冰冻圈）、大气圈、生物圈的演化联系起来,将黄土作为一个窗口,揭示出看似单一的地质事件（黄土沉积）与地球圈层相互作用之间的内在关联。

     

Possible sources of forecast errors generated by the global/regional assimilation and prediction system for landfalling tropical cyclones. Part I: Initial uncertainties

This paper investigates the possible sources of errors associated with tropical cyclone (TC) tracks forecasted using the Global/Regional Assimilation and Prediction System (GRAPES). The GRAPES forecasts were made for 16 landfalling TCs in the western North Pacific basin during the 2008 and 2009 seasons, with a forecast length of 72 hours, and using the default initial conditions (“initials”, hereafter), which are from the NCEP-FNL dataset, as well as ECMWF initials. The forecasts are compared with ECMWF forecasts. The results show that in most TCs, the GRAPES forecasts are improved when using the ECMWF initials compared with the default initials. Compared with the ECMWF initials, the default initials produce lower intensity TCs and a lower intensity subtropical high, but a higher intensity South Asia high and monsoon trough, as well as a higher temperature but lower specific humidity at the TC center. Replacement of the geopotential height and wind fields with the ECMWF initials in and around the TC center at the initial time was found to be the most efficient way to improve the forecasts. In addition, TCs that showed the greatest improvement in forecast accuracy usually had the largest initial uncertainties in TC intensity and were usually in the intensifying phase. The results demonstrate the importance of the initial intensity for TC track forecasts made using GRAPES, and indicate the model is better in describing the intensifying phase than the decaying phase of TCs. Finally, the limit of the improvement indicates that the model error associated with GRAPES forecasts may be the main cause of poor forecasts of landfalling TCs. Thus, further examinations of the model errors are required.     

北斗卫星导航系统双差动力法精密定轨及其精度分析

针对GEO卫星切向轨道分量与双差模糊度强相关的问题,对经典双差动力法进行了改进,提出联合使用载波相位和相位平滑伪距实现北斗系统精密定轨,并从理论上分析了以上处理策略的可行性及对模糊度固定的影响,然后结合北斗系统精密定轨特点,推导给出了利用QIF方法实现北斗卫星双差模糊度固定的基本原理,实测数据分析表明:联合载波相位和相位平滑伪距,既可降低相关性,又可兼顾精度,定轨效果优于经典双差动力法;利用QIF方法能够取得一定的模糊度固定效果,但受观测条件限制,北斗卫星双差模糊度固定成功率整体不高,双差模糊度固定之后对轨道的改进作用有限。     

Landfill site selection based on reliability concepts using the DRASTIC method and AHP integrated with GIS – a case study of Bengaluru city,India

The selection of landfill sites for municipal solid waste (MSW) disposal involves consideration of geological, hydrological and environmental parameters which exhibit large spatial variability. Therefore, it is necessary to define, to what extent the chosen sites are reliable such that the probability of environmental pollution and health risks to population is minimal. In the present study, groundwater vulnerability to contamination has been assessed using the standard DRASTIC method. The results showed that the study region has 9.45% of very less, 32.94% of less, 25.47% of moderate, 22.79% of high and 9.35% of very high vulnerable zones. The study also revealed that none of the landfills are located in safe zones. This suggests that it requires proper remedial measures to avoid environmental pollution. A landfill site selection process has been carried out using the Analytical Hierarchy Process integrated with Geographical Information System tools. The obtained results showed that only 3.59?km² (0.08%) of the total area is suitable for landfills. The reliability analysis of the site suitability revealed that landfills are located at unreliable locations where the probability of risk to environmental pollution is high. The presented approach assists decision-makers in selecting reliable locations for the safe disposal of MSW.     

Comparative Study of Acid and Alkaline Stimulants with Granite in an Enhanced Geothermal System

The Enhanced Geothermal System (EGS) is an artificial geothermal system that aims to economically extract heat from hot dry rock (HDR) through the creation of an artificial geothermal reservoir. Chemical stimulation is thought to be an effective method to create fracture networks and open existing fractures in hot dry rocks by injecting chemical agents into the reservoir to dissolve the minerals. Granite is a common type of hot dry rock. In this paper, a series of chemical stimulation experiments were implemented using acid and alkaline agents under high temperature and pressure conditions that mimic the environment of formation. Granite rock samples used in the experiments are collected from the potential EGS reservoir in the Matouying area, Hebei, China. Laboratory experimental results show that the corrosion ratio per unit area of rock is 3.2% in static acid chemical experiments and 0.51% in static alkaline chemical experiments. The permeability of the core is increased by 1.62 times in dynamic acid chemical experiments and 2.45 times in dynamic alkaline chemical experiments. A scanning electron microscope analysis of the core illustrates that secondary minerals, such as chlorite, spherical silica, and montmorillonite, were formed, due to acid-rock interaction with plagioclase being precipitated by alkaline-rock interactions. Masking agents in alkaline chemical agents can slightly reduce the degree of plagioclase formation. A chemical simulation model was built using TOUGHREACT, the mineral dissolution and associated ion concentration variation being reproduced by this reactive transport model.     

应用分布式存储技术优化省级CIMISS数据服务能力

随着气象数据量的不断增长,进一步提升CIMISS数据管理和服务能力的需求变得日益迫切。为解决存储系统动态扩展能力不足、并行计算与吞吐效率低下等限制CIMISS继续发展的问题,采用分布式文件系统和NAS技术替代GPFS建设共享文件系统,实现非结构化气象数据的存储功能;采用分布式数据库替代Oracle RAC建设关系数据库管理系统,实现结构化气象数据的存储功能和非结构化气象数据的索引功能。实践证明,该方案能够有效地改善CIMISS的数据存储能力、并发响应能力,适应未来气象业务对数据存储和应用的需求。     

全球寒武系四统划分框架正式确立

国际地层委员会最近陆续发布了2005和2006年版《国际地层表》(http://www.stratigraphy.org/cheu.pdf),这两张新表较以往各版最为突出的变动是将寒武系分为四个统和十个阶,不再采用国际地学界沿用了近一百七十年的上、中、下3统的传统划分方法。这一改写是全球地层学的重大事件     

重要信息系统的灾难恢复刍议

现代社会和生活越来越依赖于IT系统,信息系统遭到灾难和毁灭性打击将是社会公众的灾难和噩梦。美国“9.11”事件中纽约交易所成功实施了信息服务灾难恢复计划,使得全球对于“业务连续和灾难恢复”有了重新的认识。在我国,信息安全也日益成为政府部门管理层、企业和公众关注的重要话题。企业的弹性、系统的健壮性,信息系统的抗毁性与灾难恢复日益深入人心,风险管理越来越为业界所重视。地震部门在政府应急联动系统中具有重要作用,其本身的信息系统安全已逐步引起重视。