GIS支持下的全球武装冲突数据体系建设评介

地缘环境安全是国家安全的重要组成部分。准确、精细、及时更新的各类地缘冲突信息是全球地缘风险评估和预警的基础。本文全面回顾了以武装冲突为核心的全球地缘冲突数据体系建设的发展历程,剖析了地理时空定位、大数据挖掘等技术的应用进展。在地理信息系统（GIS）技术支持下,对武装冲突内涵和武装冲突事件数据体系总体框架的理解不断深入,生产出一大批高质量的数据集合或数据产品;地缘冲突在主题上逐渐细化,冲突事件记载的空间定位精度从国家发展到更小尺度的地理位置（经纬度）;在网络信息搜索与大数据挖掘技术支持下,武装冲突信息的更新频率从年度更新提高到每小时更新,全球武装冲突数据体系建设初见成效。地缘环境系统科学与地理科学的深度融合、地理大数据与人工智能技术的广泛应用将是推动本学科领域发展的重要动力。     

陆丰凹陷韩江组旋回地层学分析及天文年代标尺的建立

珠江口盆地为新生代典型的海相盆地,也是我国重要的海上油气生产基地。前期已有很多学者对珠江口盆地的地层划分与对比开展了研究,但研究的精度不够。为了提高珠江口盆地陆丰凹陷韩江组地层划分与对比的精度,选择珠江口盆地陆丰凹陷A、B井韩江组的自然伽马数据序列作为古气候替代性指标,使用频谱分析、滤波等方法进行旋回地层学分析。通过深度域频谱分析和小波分析认为,该套地层中保存了米兰科维奇旋回信号,且主要受405 ka长偏心率周期的影响。利用稳定的405 ka长偏心率周期进行天文调谐,结合古生物地层年代框架,建立起陆丰凹陷“绝对”天文年代标尺;结合碳氧同位素变化曲线,估算出2次碳同位素负漂移和1次碳同位素正向偏移事件的持续时间;利用天文旋回周期计算出陆丰凹陷韩江组的沉积速率,发现沉积速率的变化与海平面变化具有相关性。     

A furrow runs through it: An example of sustainable traditional irrigation in Western Cape Province,South Africa

Water and water related matters are important issues in water scarce countries like the Republic of South Africa. This is especially true for the agricultural sector that relies heavily on the availability of water for irrigation to ensure a secure food supply. In South Africa, present day irrigation projects rely on government subsidies and are usually large undertakings beyond the reach of individuals or small communities. The sustainability of such large irrigation projects is still a matter of debate. A 100 years ago a different set of rules applied. Irrigation could only be achieved by hand-dug furrows that supplied water in relatively small quantities to small farming communities. This paper investigated such a small community, the Leeukloof farming community in the Western Cape Province of the Republic of South Africa. For the past 93 years this community has maintained a furrow that supplies water not only to farms bordering the Perdeberg River, which supplies the furrow with water, but also to farms not bordering the river. The authors try to reconstruct the changes in agricultural practices brought about by the furrow, methods of water extraction during each phase, as well as the development and role of the furrow system. The perception by the community of the necessity of this method of water extraction from the river system is also investigated. This revised version was published online in July 2006 with corrections to the Cover Date.     

Model study of the relationship between sediment yield and river basin area

The SHETRAN physically based, spatially distributed model is used to investigate the scaling relationship linking specific sediment yield to river basin area, for two contrasting topographies of upland and more homogeneous terrain and as a function of sediment source, land use and rainfall distribution. Modelling enables the effects of the controls to be examined on a systematic basis, while avoiding the difficulties associated with the use of field data (which include limited data, lack of measurements for nested basins and inability to isolate the effects of individual controls). Conventionally sediment yield is held to decrease as basin area increases, as the river network becomes more remote from the headwater sediment sources (an inverse relationship). However, recent studies have reported the opposite variation, depending on the river basin characteristics. The simulation results are consistent with these studies. If the sediment is supplied solely from hillslope erosion (no channel bank erosion) then, with uniform land use, sediment yield either decreases or is constant as area increases. The downstream decrease is accentuated if rainfall (and thence erosion) is higher in the headwaters than at lower elevations. Introducing a non‐uniform land use (e.g. forest at higher elevations, wheat at lower elevations) can reverse the trend, so that sediment yield increases downstream. If the sediment is supplied solely from bank erosion (no hillslope erosion), the sediment yield increases downstream for all conditions. The sediment yield/basin area relationship can thus be inverse or direct, depending on basin characteristics. There still remains, therefore, considerable scope for defining a universal scaling law for sediment yield. Copyright © 2006 John Wiley & Sons, Ltd.     

RUSSIAN DOLLS OR SCALE SKIPPERS? TWO GENERATIONS IN STRASBOURG*

ABSTRACT. Over the past quarter‐century academic geographers have interrogated the concept of “scale.” It had previously been conceived as an unproblematic and mechanical item in geographical representation, a device for moving “up” from the finely detailed to the general. Regular, commonsensical steps were supposed to move one from the corporeal scale to the global scale, each scale nested into the next higher. Such is the “Russian‐dolls” mode, whereby an individual considering his or her geographical identity—as in this study—would proceed hierarchically in scale from self, to city, to region, to nation, to continent. Ethnographic evidence from Strasbourg, France, however, reveals another mode: “scale skipping.” Here an individual, musing upon her or his identity, can plausibly make the leap from the individual to the supranational scale in one sentence. Instructive examples of both modes are furnished from two fifteen‐strong groups of Strasburgers, selected for their presumed attachment to the supranational‐scale ideal of “Europe.” The older group comprises professional Eurocrats; the younger group, college students returning to complete their studies in Strasbourg after attending universities elsewhere in the European Union through the Erasmus Program of study abroad.     

ANALYSIS OF THE RELATIONSHIP BETWEEN THE CHINA ANOMALOUS CLIMATE VARIATION AND ENSO CYCLE ON THE QUASI-FOUR-YEAR SCALE

1 INTRODUCTION Much work has been done addressing the relationship between anomalous climate changes and ENSO in China and the results vary much. For instance, Li et al. (1987) [1] think that the Mei-yu (sustained rain) starts later, lasts shorter and pre…     

基于大比例尺数字高程模型DEM制作方法的经验和体会

大比例尺DEM更能够清晰详细地表述地面高程信息,它在测绘、水文、气象、地貌、地质、土壤、工程建设、通讯、气象、军事等国民经济和国防建设以及人文和自然科学领域有着广泛的应用。针对大比例尺DEM的制作精度要求比较高、制作成本高的特点,本文提供大比例尺数字高程模型DEM制作方法的一些经验和体会。     

大范围网络RTK基准站间整周模糊度实时快速解算

网络RTK是目前实现高精度实时动态定位的重要手段之一,而网络RTK高精度定位的关键问题是基准站间整周模糊度的实时快速准确固定。对于大范围网络RTK,由于基准站间距离的增加,电离层延迟误差、对流层延迟误差和卫星轨道误差相关性降低,导致基准站间整周模糊度不能快速准确地固定,因此本文提出了一种大范围网络RTK基准站间整周模糊度固定算法。该算法首先利用L1、L2载波相位观测值和P1、P2伪距观测值解算基准站间的双差宽巷模糊度;然后采用Saastamoinen模型和Chao映射函数模型相结合解算双差对流层延迟误差,并将双差宽巷模糊度作为L1、L2双差载波相位整周模糊度的约束关系来确定L1、L2双差载波相位整周模糊度;最后采用CORS站的实测数据进行试验,并将本文的试验结果同GAMIT软件的解算结果进行比对,结果表明该算法可以快速准确地实现单历元双差载波相位整周模糊度的固定。     

北大西洋涛动位相转换的数值研究

借助一个非线性准地转正压模型,模拟了基本西风气流的强弱、不同空间分布的天气尺度扰动涡对北大西洋涛动(NAO)位相转换的作用,以及大尺度双波地形对其的影响.通过一系列的对比试验发现,适当弱的基本西风气流有利于下游系统西退使NAO由正(负)位相转换为负(正)位相;振幅强、活动范围大的天气尺度扰动波是NAO由负位相转换为正位...