一种地物关系约束下的线阵影像坐标反投影计算方法

坐标反投影计算是线阵影像基于严格模型几何校正的关键步骤。本文在分析线阵摆扫式影像的成像方式及其特点的基础上,针对传统基于像方的顺序或迭代搜索方法效率低下的问题,提出了一种利用地物关系约束的坐标反投影计算方法。首先将当前相邻点的最佳扫描行作为先验值,估算其与当前点最佳扫描行的距离,定位初始最佳扫描行;然后以初始最佳扫描行为中心构建搜索窗口,进行最佳扫描行精确搜索;最后根据最佳扫描行对应的外方位元素进行坐标反投影计算。通过对机载线阵摆扫式模拟影像数据和推扫式真实影像数据的试验,验证了该方法的可行性、准确性和高效性。     

塔里木盆地海相油藏具有高热稳定性的地球化学条件探讨

塔里木盆地在埋深超过8000 m、油藏经历200℃以上高温改造仍然发现液态烃类流体稳定存在,目前勘探工作正在面向深层-超深层拓展,塔里木盆地海相原油具有的高热稳定性来自其较好的保存条件。本文总结了近年来塔里木盆地海相油藏研究进展,结合宏观地质背景演化,主要从微观过程入手探讨塔里木盆地海相油藏热稳定性的地球化学特征。认为宏观上塔里木盆地目前的低地温梯度有利于油藏的稳定保存;而油藏储层中普遍缺乏氧化性矿物,石膏类等含硫矿物也贫乏,使得油藏储层中的烃-水-岩相互作用(包括热化学硫酸盐还原反应)发生的程度有限;同时,塔里木盆地海相油藏中地层水广泛发育、分布复杂,这对油藏中的液态烃类,特别是大分子烃类的热裂解具有抑制作用,从而有利于油藏的稳定保存。有必要进一步开展针对塔里木盆地海相原油热稳定性的微观地球化学特征探讨,特别是烃-水-岩相互作用中有利于原油烃类流体稳定保存的物理化学机理分析,研究成果将有助于深化塔里木盆地深层-超深层油气藏的勘探研究工作。     

ERA-Interim���Ϻ�NeQuick�����ģ������D-InSAR�������Ŀɿ����о�

????ROI_PAC????????????????ALOS PALSAR 474?????4?????????ERA-Interim?????NeQuick?????????????ж?????????????????????????????λ???????5??GPS?????????????????б????????????????????????????D-InSAR???ó?????λ????侭????????????????????????λ?????GPS??????????????????0.104 m?????????????0.057 m,???????????????????????????????D-InSAR?????????????     

中小学最优避难疏散模型与选址应用

本文以区位-配给模型理论为指导,以路网疏散距离最短、场地服务容纳量最大为目标,构建最优避难疏散模型,以解决中小学避难场地选址问题。本文从保障学生避难疏散场地的安全性和适宜性角度出发,通过建立环境制约因素模型,对地形坡度、断裂带、河流湖泊、易燃易爆站点、高层建筑物倒塌范围和文物古迹保护范围6大因素进行空间叠加分析,计算了实际的避难需求和供给容量。为减少利用直线距离直接作为疏散道路产生的误差,本文通过对不受影响的路网信息进行网络分析,计算最短疏散道路,以获取实际的路网距离。本文将该方法应用于北京市西城区中小学避难场地选址的优化方案,有效地解决了中小学避难场地选址问题。     

Modeling the impacts of drying trend scenarios on land systems in northern China using an integrated SD and CA model

Climate-induced drought has exerted obvious impacts on land systems in northern China. Although recent reports by the Intergovernmental Panel on Climate Change (IPCC) have suggested a high possibility of climate-induced drought in northern China, the potential impacts of such drying trends on land systems are still unclear. Land use models are powerful tools for assessing the impacts of future climate change. In this study, we first developed a land use scenario dynamic model (iLUSD) by integrating system dynamics and cellular automata. Then, we designed three drying trend scenarios (reversed drying trend, gradual drying trend, and acceleration of drying trend) for the next 25 years based on the IPCC emission scenarios and considering regional climatic predictions in northern China. Finally, the impacts of drying trend scenarios on the land system were simulated and compared. An accuracy assessment with historic data covering 2000 to 2005 indicated that the developed model is competent and reliable for understanding complex changes in the land use system. The results showed that water resources varied from 441.64 to 330.71 billion m³ among different drying trend scenarios, suggesting that future drying trends will have a significant influence on water resource and socioeconomic development. Under the pressures of climate change, water scarcity, and socioeconomic development, the ecotone (i.e., transition zone between cropping area and nomadic area) in northern China will become increasingly vulnerable and hotspots for land-use change. Urban land and grassland would have the most prominent response to the drying trends. Urban land will expand around major metropolitan areas and the conflict between urban and cultivated land will become more severe. The results also show that previous ecological control measures adopted by the government in these areas will play an important role in rehabilitating the environment. In order to achieve a sustainable development in northern China, issues need to be addressed such as how to arrange land use structure and patterns rationally, and how to adapt to the pressures of climate change and socioeconomic development together.     

基于时空棱柱的人员搜寻范围优化

在人员搜寻过程中,地理信息技术的应用能帮助缩小搜寻的空间范围、合理分配搜救资源,从而提高搜救效率、节约时间和资金投入。本文首先探讨了户外搜救过程中,地理信息技术在协助划定搜寻的空间范围和分配应急资源方面的应用;在此基础上,将时间作为连续变化的因素进行分析,以时间地理学对人员搜寻的时空范围进行优化;利用时空棱柱工具表达失踪对象和搜救资源各自的时空约束,继而确定他们各自随着时间变化的潜在活动范围;通过求解搜救资源和失踪对象的时空交集,来确定每个搜救资源最优的搜寻范围的外边界;通过将各资源的最优搜索范围的外边界进行综合分析,来求解在多个资源协作情况下的最小搜寻范围和各资源对应的搜索起点,实现对搜救资源的合理分配;最后,在ArcGIS平台上对该方法进行了实现和模拟。搜救案例展示该方法划定的人员搜寻范围在空间上更小,时间上更为精确,有助于分配救援资源和提高搜救效率。     

A recipe for why and how to set up and sustain an experimental catchment

Experimental catchments are fundamental elements in hydrological sciences as they provide key data for putting forward and testing hypotheses, developing theories, constraining models, and making predictions. Significant progress in catchment hydrology stemmed from field measurements but increasing costs and risks associated with field work and the availability of big data based on remote sensing, machine learning, and a plethora of models, as well as observations deriving from previous and current sites, raises questions on whether running an experimental catchment still provides individual and community benefits as in the past. In this commentary, I highlight the advantages of keeping experimental catchments alive and propose a personal 10-step “recipe” to set up a new experimental catchment and manage and sustain it in the long term. These suggestions can be useful both to young and less young researchers who are open to facing the challenge of measuring processes in the field and are willing to offer the scientific community new experimental evidence for advancing our current knowledge in catchment hydrology.     

InSAR技术及其在沧州地面沉降监测中的应用

随着城市建设的飞速发展,地面沉降危害日益显著,常规的测量方法尽管精度高,但是成本高、采样精度低、测量时间周期长,已经无法满足当今社会的要求。合成孔径雷达干涉测量(InSAR)已成为测量地球表面变化极具潜力的技术,它可以大面积的采样、测量时间短,同时成本也很低。沧州地区至2001年沉降中心累计沉降量已达2236mm。文中介绍用合成孔径雷达干涉测量进行沧州地区地面沉降监测的试验,最后利用InSAR的差分技术得到的沧州地区的地面沉降监测结果,并据此得到一些初步认识。     

LATE HOLOCENE AVERAGE RECURRENCE INTERVAL OF GREAT EARTHQUAKES OF SHANGZHI PART OF THE YILAN-YITONG FAULT ZONE,NE CHINA: CONSTRAINTS FROM PALEO-EARTHQUAKES AND HISTORICAL WRITTEN RECORDS

Although the kinematics and mechanics of the Yilan-Yitong fault zone (YYFZ) since the Mesozoic-early Cenozoic were studied very well in the past decades,few results about the average recurrence interval of great earthquakes in late Quaternary,which is the most important parameter for us to understand the active tectonics and potential seismic hazard of this crucial structure,were obtained because of its unfavorable work environments.Based on interpretations of high-resolution satellite images and detailed geologic and geomorphic mapping,we discovered that there exist linear fault scarp landforms and troughs in the Shangzhi part of YYFZ with a length of more than 25km.Synthesized results of trenches excavation and differential GPS measurements of terrace surfaces indicate two paleo-events EⅠ and EⅡ occurring in Shangzhi part during the late Holocene,which resulted in ca.(3.2±0.1) m accumulated vertical coseismic displacement with strike-slip motion accompanied by thrusting and shortening deformation.¹⁴C samples dating suggests that event EⅠ might occur at (440±30) and (180±30) a BP and event EⅡ might happen between (4 090±30) and (3 880±30) a BP,and the average recurrence interval of major earthquakes on the YYFZ is around (3 675±235) a.Historical written records discovered from Korea show that the event EⅠ may correspond to the earthquake occurring in AD 1810(Qing Dynasty in Chinese history) in Ningguta area with magnitude 7.0.     

The constrained politics of the Svalbard offshore area

This study identifies some mechanisms through which external factors constrain state behavior. Examining Norwegian governance for the disputed Svalbard offshore area, it finds the behavior of Norway to be constrained in multiple ways by the conflicting policies of foreign powers toward the area. When shaping the management regime of the controversial maritime zones of the former terra nullius Svalbard, Norwegian authorities cautiously consider the possible international ramifications of their actions. Norway's behavior—not only manifested in policy but also in the exercise of contested legislative and enforcement jurisdiction—is curbed amid international disagreements over Norwegian rights in the area.