地震信息网络数据的动态存储方法研究          下载免费PDF全文

龚明明  叶伦强 《地震工程学报》2020,42(4):1043-1048

为了提高地震信息网络数据存储的效率和稳定性,本文提出一种地震信息网络数据的动态储存方法。首先,设计和分析地震信息网络数据的动态存储系统中的硬件部分,基于Hadoop的分布式集群大数据动态存储系统,整合多台存储服务器,为一个集群系统,并平衡存储服务器负载情况,获取性能指标的比例值,通过加权公式获取综合性能参数,根据综合负载指标和服务器综合指标参数获取最佳存储服务器。对本文系统、高速数据存储系统和网络编码云存储系统进行大数据动态存储对比实验。实验结果表明:地震信息网络数据的动态存储耗时最短,存储效率最快;具有较高存储稳定性,且不会出现过载问题。  相似文献   

Assessing basin storage: Comparison of hydrometric- and tracer-based indices of dynamic and total storage     

Ciara D. Cooke  James M. Buttle 《水文研究》2020,34(9):2012-2031

Storage is a fundamental but elusive component of drainage basin function, influencing synchronization between precipitation input and streamflow output and mediating basin sensitivity to climate and land use/land cover (LULC) change. We compare hydrometric and isotopic approaches to estimate indices of dynamic and total basin storage, respectively, and assess inter-basin differences in these indices across the Oak Ridges Moraine (ORM) region of southern Ontario, Canada. Dynamic storage indices for the 20 study basins included the ratio of baseflow to total streamflow (baseflow index BFI), Q ₉₉ flow and flow duration curve (FDC) slope. Ratios of the standard deviation of the streamflow stable isotope signal relative to that of precipitation were determined for each basin from a 1 year bi-weekly sampling program and used as indicators of total storage. Smaller ratios imply longer water travel times, smaller young water fractions (F _yw, < ~2–3 months in age) in streamflow and greater basin storage. Ratios were inversely related to BFI and Q ₉₉, and positively related to FDC slope, suggesting longer travel times and smaller F _yw for basins with stable baseflow-dominated streamflow regimes. Inter-basin differences in all indices reflected topographic, hydrogeologic and LULC controls on storage, which was greatest in steep, forest-covered headwaters underlain by permeable deposits with thick and relatively uniform unsaturated zones. Nevertheless, differential sensitivity of indices to controls on storage indicates the value of using several indices to capture more completely how basin characteristics influence storage. Regression relationships between storage indices and basin characteristics provided reasonable predictions of aspects of the streamflow regime of test basins in the ORM region. Such relationships and the underlying knowledge of controls on basin storage in this landscape provide the foundation for initial predictions of relative differences in streamflow response to regional changes in climate and LULC.  相似文献   

Mapping 3D visibility in an urban street environment from mobile LiDAR point clouds     

Yi Zhao  Jianping Wu  Song Shu  Handong Liang  Min Liu 《地理信息系统科学与遥感》2020,57(6):797-812

ABSTRACT

Visibility determination is a key requirement in a wide range of national and urban applications, such as national security, landscape management, and urban design. Mobile LiDAR point clouds can depict the urban built environment with a high level of details and accuracy. However, few three-dimensional visibility approaches have been developed for the street-level point-cloud data. Accordingly, an approach based on mobile LiDAR point clouds has been developed to map the three-dimensional visibility at the street level. The method consists of five steps: voxelization of point-cloud data, construction of lines-of-sight, construction of sectors of sight, construction of three-dimensional visible space, and calculation of volume index. The proposed approach is able to automatically measure the volume of visible space and openness at any viewpoint along a street. This approach has been applied to three study areas. The results indicated that the proposed approach enables accurate simulation of visible space as well as high-resolution (1 m × 1 m) mapping of the visible volume index. The proposed approach can make a contribution to the improvement of urban planning and design processes that aim at developing more sustainable built environments.  相似文献   

基于无人机遥感和面向对象法的简单地物分类研究     

袁慧洁 《测绘与空间地理信息》2020,(3):113-117,123

近年来,全国各地进行了大范围的土地利用调查,随着无人机遥感技术越来越成熟,无人机影像分析技术已深入应用到土地利用调查中,其中最多的用途是地物分类。本文选择昭通市昭阳区某乡镇区域为研究区,对采集到的无人机影像进行预处理,生成对应的正射影像;基于多种可见光植被指数,计算每3种指数合并得到影像的OIF指数,确定最佳波段组合;采用基于规则和基于样本两种面向对象分类方法,提取房屋、道路、植被等简单地物及背景。分析结果:两种方法的提取精度均达到90%以上,基于规则的面向对象分类方法精度较高,但耗时较长;基于样本的面向对象方法耗时较短,精度相对较低。两种方法相结合的全自动分类提取是下一步研究的目标。  相似文献   

新疆艾比湖流域枯、丰水期三维荧光光谱特性及其与水质的关系     

王迪  张飞  张兆永  张海威  朱世丹  张贤龙 《湖泊科学》2020,32(2):483-495

以艾比湖流域主要入湖河流为研究对象，在5月（丰水期）和8月（枯水期）分别沿博尔塔拉河（博河）和精河进行采样，采用平行因子模型（PARAFAC）和三维荧光区域积分法对水体三维荧光特性进行研究并对其与水质的关系在枯、丰水期下的变化进行探讨.结果表明①河流DOM在枯水期与丰水期都含有C1（240、425 nm） UVC类腐殖质，C2（225、290 nm）紫外区内络氨酸类有机物，C3（230/280、330 nm）蛋白类有机物，C4（265、260 nm）腐殖质类共4种组分.通过对水体三维荧光进行区域积分可以看出DOM荧光成分的占比在不同时期的变化.博河在枯水期时EEM光谱中的区域Ⅲ富里酸含量低于丰水期，枯水期时区域Ⅱ芳香类蛋白质、区域Ⅳ可溶性微生物代谢物以及区域Ⅴ类腐殖质酸高于丰水期；对于精河来说，区域Ⅱ芳香类蛋白质和区域Ⅳ可溶性微生物代谢物在枯水期的含量高于丰水期，区域Ⅲ富里酸和区域Ⅴ类腐殖质酸的含量枯水期低于丰水期，这表明水体腐质化程度较高.②本研究选取了一些常规的荧光指数来描述枯、丰水期水体的荧光指数特性.经研究发现，精河的荧光指数、自生源指数和腐殖化指数在不同时期的变化幅度较小，而博河的变化幅度较大.③将荧光指数与水质参数进行相关性分析并建模，结果表明枯水期自生源指数（BIX）与化学需氧量呈显著正相关，相关系数R=0.688；丰水期时BIX与铵态氮浓度呈显著负相关，相关系数R=-0.493.通过对比分析艾比湖主要入湖河流的三维荧光光谱特性与水质在枯、丰水期时的关系进一步表明水体中DOM的特性以及在枯、丰水期下的差异，为艾比湖流域的治理改善提供一定的理论支持和参考依据.  相似文献   

基于水利益共享的跨境流域水资源多目标分配研究——以澜沧江-湄公河为例   总被引：2，自引：1，他引：1  

刘艳丽  赵志轩  孙周亮  王国庆  金君良  王高旭  鲍振鑫  刘翠善  贺瑞敏 《地理科学》2019,39(3):387-393

以水利益共享代替分水的理念有利于充分发挥水资源效益和减少区域矛盾冲突,但由于缺乏具体可实施的分配模式一直停留在设想阶段。基于水利益共享理念,建立跨境流域水资源多目标分配指标体系,并结合澜沧江-湄公河流域跨境水资源利用现状及需求,提出澜沧江-湄公河流域跨境水资源多目标分配模型。为基于水利益共享的跨境水资源多目标分配提供了具有充分可操作性的指标体系和分配模型,有助于推进跨境流域水利益共享的实施,实现区域双边或多边在水资源利用上的共赢和发展目标。  相似文献   

可见光下Li+/CNTS-TiO2光催化剂降解海洋柴油污染的研究          下载免费PDF全文

于晓彩  王力萍  刘京华  郭美岑  朱婉婷  廖佳琪  吴云英 《海洋学研究》2019,37(1):52-58

通过溶胶-凝胶法,以CNTS-TiO₂为前驱物制备了Li⁺掺杂CNTS-TiO₂的纳米复合光催化剂(以下均称为Li⁺/CNTS-TiO₂),采用X射线衍射(XRD)、扫描电镜(SEM)等测试手段对光催化剂进行表征,结果表明制得的催化剂为纳米材料且在TiO₂的基础上增大了比表面积。利用掺杂量为3%的Li⁺掺杂CNTS-TiO₂复合光催化剂(以下均称为3%Li⁺/CNTS-TiO₂)光催化降解海洋柴油污染,在可见光条件下考察了Li⁺掺杂量、煅烧温度、光催化剂投加量、柴油初始质量浓度、光催化反应时间、H₂O₂质量浓度等条件对光催化实验的影响。进行正交实验,确定最优化工艺条件为:Li⁺掺杂量为3%,光催化剂的煅烧温度为600 ℃,3%Li⁺/CNTS-TiO₂的投加量为0.1 g/L,降解柴油初始质量浓度为0.4 g/L,光催化反应时间为3 h,H₂O₂质量浓度为0.6 g/L,降解率可以达到95%以上。同时对此光催化剂进行应用试验,试验结果表明光催化剂去除效果优异,去除率可达91.87%。  相似文献   

非平稳标准化降水蒸散指数构建及中国未来干旱时空格局   总被引：3，自引：0，他引：3  

温庆志  孙鹏  张强  姚蕊 《地理学报》2020,75(7):1465-1482

旱灾是一种致灾因子与成害机理均非常复杂的自然灾害,也是目前对其检测与风险防御最为困难的自然灾害种类之一。随着全球气候变化,干旱的变化逐渐趋于非平稳化,水文气象序列的非平稳性已有广泛研究,但在干旱检测指标中却鲜有考虑。基于标准化降水蒸散指数（SPEI）和非平稳性理论,构建非平稳性标准化降水蒸散指数（NSPEI）并进行适用性评价,利用NSPEI评估未来不同排放情景下中国气象干旱时空格局演变规律。结果表明：① 非平稳性站点集中在东北平原、黄淮海平原、长三角地区、青藏高原及周边区域,NSPEI拟合最优的站点占中国气象站点的88%（2177个站点）。② SPEI对温度较为敏感,在评估未来干旱变化时会高估干旱强度和持续时间性,而NSPEI能够克服这一弱点,较SPEI可更好的检测中国气象干旱,且能很好的刻画中国未来干旱变化。③ 低、高排放情景下中国北方干旱加剧,南方呈湿润化趋势;中排放情景下中国北方湿润化趋势明显,而中国南方则呈干旱化。基于NSPEI干旱检测结果,中高排放情景下中国未来极端干湿历时与发生频率均呈增加趋势。  相似文献   

顾及空间非平稳特征的遥感干旱监测     

朱欣然  黄长平  吴波  苏华  焦文哲  张立福 《遥感学报》2019,23(3):487-500

遥感技术具备实时快速、时空连续、广覆盖尺度等独特优势,在全球气候恶化大背景下,利用遥感干旱监测方法相比于传统地面监测手段,能够提供实时、准确、稳定的旱情信息,辅助科学决策。目前常用遥感旱情监测方法大多依赖全域性数学模型建模,假定了旱情模式的空间平稳特性,因而难以准确反映旱情模式的局部差异特征。本文提出利用地理加权回归模型GWR (Geographically Weighted Regression),考虑旱情模式的空间非平稳特性,综合多种遥感地面旱情监测指数,以实现传统全域旱情监测模型的局部优化。以美国大陆为研究区,监测2002年—2011年共10年的旱情状态。研究表明,GWR模型能够提供空间变化的局部最佳估计模型参数,监测结果更加吻合标准美国旱情监测USDM (U.S Drought Monitor)验证数据,且与地面实测值的最高相关系数R达到0.8552,均方根误差RMSE达到0.972,显著优于其他遥感旱情监测模型。GWR模型具备空间非平稳探测优势,实现了旱情模式的局部精细探测,能够显著提升遥感旱情监测精度,具备较好的应用前景。  相似文献   

Geographical information system-based groundwater quality index assessment of northern part of Kolkata,India for drinking purpose     

Suranjana Banerji  Deblina Mitra 《国际地球制图》2019,34(9):943-958

Groundwater is a resource under stress. In both developed and developing countries, it has been found that increasing human influence has led to the contamination of the groundwater resource. To understand the magnitude of this problem, a study was conducted in 58 wards within Northern part of Kolkata, India, where water samples from tube wells were collected and analysed on essential drinking water quality parameters, prescribed by WHO. Using Principal component analysis, and Water quality index mapping, the aforementioned results have been interpreted. This has helped to depict that not only is the groundwater unsuitable for drinking, but that the parametric values have a tendency to increase abruptly within the shortest of ranges, indicating urban pollution as the root cause of contamination. This paper shall thus discuss the spatial change in groundwater quality in northern Kolkata and suggest measures which might be implemented to secure a sustainable future for the city.  相似文献