国产卫星遥感数据在电力选线中的适用性研究     

熊宝武  王帅  赵斌彬  谭玉敏  吴春生 《测绘与空间地理信息》2017,(12):34-38

国产卫星遥感数据以其大范围同步观测、综合成本较低等特点在电力选线中具有潜在的应用优势。本文以某220 k V架空输电线路设计为例,对高分二号正射影像进行无控定位精度和有控定位精度分析比较,以及对资源三号影像进行区域网平差,统计分析其在无控制点和有控制点情况下的平差精度。研究表明:高分二号卫星影像在有控制点的情况下其纠正精度完全能够满足1∶10 000全地形比例尺精度要求,利用资源三号影像制作DSM的高程精度能够满足山区1∶10 000地图比例尺要求。综合电力选线相关规程中对选线各阶段的比例尺要求,国产高分二号和资源三号联合应用,完全能够满足山地地区的电力选线的可研性和初设阶段的平面及高程精度需求。  相似文献   

结合风廓线雷达的毫米波衰减特性初步研究          下载免费PDF全文

钟正宇  马舒庆  杨玲  黄书荣  唐英杰 《应用气象学报》2018,29(4):496-504

使用中国气象局大气探测综合试验基地35 GHz毫米波云雷达和L波段风廓线雷达2016年5月1日-7月31日在降水条件下的观测数据,根据不同观测模式下两部雷达得到的数据,计算在一定高度区间内不同下落速度的降水粒子反射率因子变化量,初步分析不同下落速度的降水粒子对毫米波衰减的影响。结果表明:在持续时间较长的层状云降水且降水粒子在雷达观测范围内均匀分布条件下,毫米波衰减与降水粒子下落速度呈近似线性关系,且毫米波经过的路径长度越长,衰减越大;毫米波在经过1110~2430 m,1110~3510 m的高度区间时,下落速度处于3.5~7.5 m·s-1之间的降水粒子对毫米波的衰减作用导致毫米波云雷达所测的等效反射率因子分别减小约1~7 dB和2~11 dB。  相似文献   

CLASSIFYING WESTERN NORTH PACIFIC TROPICAL CYCLONES BY PHYSICAL INDEX SYSTEM     

颜东谊  徐奎  马超  马满仓 《热带气象学报(英文版)》2018,24(2):142-150

The classification of tropical cyclones (TCs) is significant to obtain their temporal and spatial variation characteristics in the context of dramatic-changing global climate. A new TCs clustering method by using K-means clustering algorithm with nine physical indexes is proposed in the paper. Each TC is quantified into an 11-dimensional vector concerning trajectory attributes, time attributes and power attributes. Two recurving clusters (cluster A and E) and three straight-moving clusters (cluster B, C and D) are categorized from the TC best-track dataset of the western North Pacific (WNP) over the period of 1949-2013, and TCs’ properties have been analyzed and compared in different aspects. The calculation results of coefficient variation (CV) and Nash-Sutcliffe efficiency (NSE) reveal a high level of intra-cluster cohesiveness and inter-cluster divergence, which means that the physical index system could serve as a feasible method of TCs classification. The clusters are then analyzed in terms of trajectory, lifespan, seasonality, trend, intensity and Power Dissipation Index (PDI). The five classified clusters show distinct features in TCs’ temporal and spatial development discipline. Moreover, each cluster has its individual motion pattern, variation trend, influence region and impact degree.  相似文献   

天气雷达径向噪声估算及性能测试     

李腾伟  胡广洋  王涛  陈向阳 《气象科技》2018,46(6):1073-1080

雷达天线从外部各种资源中截获热辐射,噪声会随着时间以及天线的不同仰角和方位角位置而变化。传统的天气雷达噪声功率估计方法不能解释噪声在方位上的变化。本文介绍了天气雷达噪声功率估计的研究现状及基于径向的噪声功率估计算法(Radial-Based Noise power Estimation,RBNE),通过仿真实验详细描述了RBNE算法的基本步骤,并利用S波段天气雷达的实测数据对RBNE算法的性能进行了测试。结果表明RBNE算法可以实时地在每个天线位置相对较为准确地估计噪声功率,有利于消除某些类型的径向干扰,有助于提高天气雷达的数据质量。  相似文献   

Fiji,rugby and the geopolitics of soft power. Shaping national and international identity          下载免费PDF全文

John Connell 《New Zealand geographer》2018,74(2):92-100

In this century, sport has steadily become a more visible and marketable part of everyday life and of global political significance. States have consequently used sport as a means of soft power in order to develop a positive international presence and, usually to a lesser extent, affirm national identity. Sport diplomacy is usually associated with mega‐events and large states, but Fiji has used its prowess in rugby, and its Sevens victory in the 2016 Olympic Games, to promote itself globally, strengthen its national image and support government claims to legitimacy. The government emphasised Fijian values to construct a banal nationalism, in the face of ethnic divisions, and external concerns over repression of civil society. At least ephemerally, Fiji acquired new international recognition, and the government gained national legitimacy, indicating the expanding role of sport in geopolitics.  相似文献   

积尘对光伏电站发电功率的影响研究综述     

崔永琴  冯起  孙家欢  李芳  肖建华 《中国沙漠》2018,38(2):270-277

概述了积尘对光伏电站发电功率的影响,提出积尘通过影响辐照度、温度来影响短路电流、开路电压和最大功率(包含最大电流和最大电压),并分析了降尘量、降雨量、降雨强度和频率、风速和风向、湿度、地表植被与空气污染、光伏组件表面封存材料的材质、光伏组件放置的倾角和方位角等因素对光伏组件积尘的影响。最后提出:(1)从微观角度深入研究各种因素对光伏组件积尘的影响;(2)加强研究空气质量、气候特点与光伏组件积尘的关系;(3)建立光伏组件发电数据和积尘状况长期远程监测系统;(4)就积尘对光伏组件功率的影响进行专项评估,并考虑清洁积尘系统的设计。  相似文献   

双星串飞编队卫星测高模式下高度计相对定标     

管斌  孙中苗  刘晓刚  翟振和 《测绘学报》2017,46(1):44-52

提出了一种新型双星串飞编队卫星测高模式下高度计之间的相对定标方法,给出了计算高度计相对偏差的完整公式;采用Jason-2卫星数据,对相对偏差计算公式中的各误差项进行了功率谱分析以及差分序列的统计分析;以厘米级定标精度为前提,简化了相对偏差计算公式并进行了误差预估。结果表明,相对偏差中各误差项均呈现低频特性,相对偏差误差主要与两颗卫星的相对径向轨道误差、测距误差、海况偏差及两星下比较点间的水准面高差相关,单次飞行高度计之间相对偏差的精度约为1.99cm。  相似文献   

Embracing Informality – A Commentary     

Liora Bigon  Ambe J. Njoh 《The Cartographic journal》2017,54(2):181-184

This short commentary surveys an international exhibition entitled ‘The cartography of the unseen’, presented at HIT's Faculty of Design Research Gallery, Israel, February 2015. For a better understanding of this exhibition and its implications, also theoretically, we intervened with a further interpretation on one of the exhibited projects, that is, Map Kibera.  相似文献   

Finding meaningful participation in volunteer geographic information and citizen science: a case comparison in environmental application     

Mu-Ning W. Brandeis  Maria Isabel Carrera Zamanillo 《制图学和地理信息科学》2017,44(6):539-550

ABSTRACT

Volunteer geographic information (VGI) and citizen science (CS) have been used as a way to promote a form of democratization of knowledge. Crowdsourcing facilitates the massive collection of data through nonexpert volunteers. This study compares 57 VGI and CS projects through a cross-case comparison method to explore the level of involvement of participants, based on three main analytic dimensions (project rationale, actor interaction, and data flow) and 12 sub-variables. The primary goal of this research is to analyze the purpose and the role of technology in VGI and CS projects, using three matrices to explore emerging trade-offs. Finally, we synthesized the workflow of VGI and CS project and compared based on project purposes. At the end of this study, five main purposes were found among the selected projects, uncovering that data collection is the most common purpose. A general workflow can be conceptualized, but detail implementation will involve various trade-offs, especially between local involvement and large-area expert-oriented protocol implementations. By exploring diverse relationships among selected variables of analysis in VGI and CS projects, this study pretends to build a foundation for larger, global meta-analysis that can bring some transparency in the epistemic interactions between experts and nonexperts.  相似文献   

水下无线电能传输研究进展     

牛王强 《南京气象学院学报》2017,9(1):46-53

首先对水下无线电能传输技术进行了分类,然后给出了磁感应式水下无线电能传输的基本结构和工作原理,讨论了该技术的最优工作频率、传输距离、线圈结构选择、涡流损耗与频率分裂现象.随后简要给出了磁谐振式水下无线电能传输技术和电场耦合式水下无线电能传输的研究现状.最后对水下无线电能传输技术有待研究的问题进行了展望.  相似文献