基于多源卫星遥感的暴雨灾情时空动态信息的提取     

苏亚丽  郭旭东  雷莉萍  汪晓帆  吴长江 《地球信息科学学报》2018,20(7):1004-1013

强暴雨淹没耕地形成灾害的同时,对耕地作物的生长也产生着极大的影响,而暴雨灾害对耕地作物生长的影响是一个渐变过程,需要由时空动态的观测进行监测。多源卫星遥感观测技术具有捕捉地面瞬间状态和刻画过程的优势。论文利用Terra/MODIS、Landsat和Sentinel卫星观测数据,挖掘多源卫星遥感观测数据,提出了一种利用NDVI变化的特征值进行灾情动态信息提取方法;并以2016年发生暴雨灾害的巢湖地区为实验区进行了方法的应用和讨论。结果表明,基于MODIS多时相NDVI变化结果提取的信息能够获得受灾害影响开始时期和持续时长等丰富的时空动态信息,根据这些信息可以统计得出大范围区域中受灾害影响的面积。另外,结合利用30 m和10 m的Landsat和Sentinel观测数据提取的水淹区,可为在暴雨致灾范围方面提供准确的参考信息。多源遥感作为评估灾情信息的依据之一,其获取的灾情动态信息能够为灾后耕地的恢复情况以及国家灾后损失评估和救助决策提供科学的数据依据。  相似文献   

Geochronology and geochemistry of Baicaogou tuff in Yanji,NE China and its tectonic implications for Early Cretaceous     

WANG Yingchao  SUN Fengyue  LI Liang  XIN Wei  YAN Jiaming  TIAN Lidan 《世界地质(英文版)》2018,(1):14-25

The authors studied zircon U-Pb age and geochemical data of Baicaogou tuff in Yanji,Jilin Province.The results indicate that the rocks formed in Early Cretaceous( 125. 6 ± 2. 3 Ma). Geochemically,these tuffs have high Si O2 and total Na2 O + K2 O,low Mg O and Fe O,and they belong to metaluminous series,the rock are enriched in LREEs and LILEs,depleted in HREEs and HFSEs such as Nb,Ta,Ti,and P,exhibiting an affinity to I-type granite. All these characteristics implied that the volcanic rocks were derived from partial melting of lower crust. Combined with the geochronology and geochemical features of the coeval igneous rocks within NE China,it is concluded that Yanji area was in a back-arc extensional setting in response to the subduction of the Paleo-Pacific Plate beneath the Eurasian Plate.  相似文献   

珊瑚环礁区侧扫声呐图像中的目标物识别方法     

韩孝辉  刘刚  薛玉龙  王雪木  李亮 《海洋技术学报》2019,(5)

为研究西沙宣德环礁海底地貌特征及珊瑚分布情况,采用舷挂侧扫拖鱼的方式对环礁区域海底进行地貌扫测,从采集的侧扫声呐图像上可以识别出环礁区域珊瑚分布情况及珊瑚礁区地貌特征,利用侧扫声呐图像识别方法结合实物样品比对可以圈定出珊瑚分布范围、暗礁区域及环礁区域底质类型分布,采用基本的数学处理方法定量分析了水下珊瑚礁体的海底高度及疑似沉船的大小,分析了侧扫声呐图像显示的调查船转向效应。  相似文献   

新工科理念下的实验课程教学改革与实践探索     

蔡剑红  霍亮  朱凌 《测绘通报》2019,(2):147-152

近年来为适应创新人才的培养，"卓越计划"开启了全新教学模式。基于新工科理念，为了更好地进行实验课程教学，以"3ds Max软件三维建模"为例，笔者从课程内容安排、教学方式、考核机制等方面进行了教学探索和实践。本文以应用软件实验类课程项目教学的实践经验为基础，注重学生团队合作和交流能力、实践能力、创新能力培养，以及多渠道快速学习新事物的能力，通过与测绘新技术下多软件融合，使学生拥有知识整合能力，为提高实践教学提供参考和借鉴，以更好地适应新工科理念下的创新人才培养。  相似文献   

GPS静态精密单点定位算法精度分析   总被引：1，自引：0，他引：1  

符华年  张旭东  胡玉坤 《测绘通报》2019,(2):95-98

采用精密轨道和钟差，利用Bernese软件解算得到亚洲地区13个IGS跟踪站的站坐标、对流层ZTD和接收机钟差，将解算的结果与CODE发布的结果对比发现：静态PPP算法解算的N方向收敛精度明显优于E方向和U方向，4~6 h后，坐标偏差在1 cm左右；NEU RMS均值分别为0.45、0.29、0.69 cm，ZTD RMS均值为0.85 cm，接收机钟差RMS均值为0.14 ns。试验表明：精密单点定位算法具有较高的精度和可靠性，可为实际工程测量及相关地球物理信号研究提供理论依据。  相似文献   

Characteristics of Sulfide Removal by Hydrogenovibrio thermophilus Strain TT in Mariculture System     

WANG Xiaoqiong  ZHAO Yangguo  WANG Junpeng  ZHANG Mo  BAI Jie  GUO Liang  GAO Mengchun 《中国海洋大学学报(英文版)》2019,(5)

To biologically inhibit the production of highly toxic sulfide in the aquaculture area, one bacterium, designated as Hydrogenovibrio thermophilus strain TT, was isolated from sediment in Jiaozhou Bay, China. The strain was found to be microaerobic mixtrophic, employing both carbon dioxide and organic carbons, e.g. citrate, lactate, glucose, and peptone as carbon sources. When it oxidized the sulfide and thiosulfate, oxygen was the optimal electron acceptor, followed by nitrite and nitrate, which benefited to removal of sulfide under low-oxygen mariculture environment. In addition, the strain TT exhibited remarkable tolerance of sulfide and thiosulfate in seawater, and it was able to oxidize 18.52 mmol L~(-1) S~(2-) in 12 h or 45 mmol L~(-1) S_2O_3~(2-) in 24 h at initial pH 7.0-9.0, 30-40℃. Therefore, this strain showed a quite promising application for biological remediation of sulfide-contaminated mariculture system.  相似文献   

PHoToNs–A parallel heterogeneous and threads oriented code for cosmological N-body simulation     

Qiao Wang  Zong-Yan Cao  Liang Gao  Xue-Bin Chi  Chen Meng  Jie Wang  Long Wang 《天文和天体物理学研究(英文版)》2018,(6)

We introduce a new code for cosmological simulations, PHo To Ns, which incorporates features for performing massive cosmological simulations on heterogeneous high performance computer(HPC) systems and threads oriented programming. PHo To Ns adopts a hybrid scheme to compute gravitational force, with the conventional Particle-Mesh(PM) algorithm to compute the long-range force,the Tree algorithm to compute the short range force and the direct summation Particle-Particle(PP) algorithm to compute gravity from very close particles. A self-similar space filling a Peano-Hilbert curve is used to decompose the computing domain. Threads programming is advantageously used to more flexibly manage the domain communication, PM calculation and synchronization, as well as Dual Tree Traversal on the CPU+MIC platform. PHo To Ns scales well and efficiency of the PP kernel achieves68.6% of peak performance on MIC and 74.4% on CPU platforms. We also test the accuracy of the code against the much used Gadget-2 in the community and found excellent agreement.  相似文献   

Study of the interaction between dry granular flows and rigid barriers with an SPH model          下载免费PDF全文

Xuzhen He  Dongfang Liang  Wei Wu  Guoqing Cai  Chenggang Zhao  Shun Wang 《国际地质力学数值与分析法杂志》2018,42(11):1217-1234

This study uses an incompressible smoothed‐particle hydrodynamics model to investigate the interaction between dry granular material flows and rigid barriers. The primary aim is to summarise some practical guidelines for the design of debris‐resisting barriers. The granular materials are modelled as a rigid‐perfectly plastic material where the plastic flow corresponds to the critical state. The coupled continuity equation and momentum equation are solved by a semi‐implicit algorithm. Compared with flows in controlled flume experiments, the model adequately reproduces both the kinetic of the flows and the impact force under various conditions. Then the numerical simulations are used to study the detailed interaction process. It is illustrated quantitatively that the interaction force consists of two parts, ie, the earth pressure force caused by the weight of the soil and a dynamic force caused by the internal deformation (flowing mass on top of a dead zone). For the estimation of impact load, this study suggests that an increased earth pressure coefficient depending on the Froude number should be incorporated into the hydrostatic model.  相似文献   

同步改正法平均海面传递应用于海南岛礁测绘的探讨     

张亮  车志伟  张景凯 《海洋技术学报》2019,38(5)

同步改正法因其特点和优势被广泛应用于平均海面传递,文中从平均海面的理论定义和实际计算两方面出发,对同步改正平均海面传递法原理进行了论述。利用海南岛周边的长期验潮站数据,按单站传递和多站组网传递分别分析了同步改正平均海面传递的规律。结果表明,单站传递同步观测10 d能满足岛礁测绘对垂直基准面精度的要求,采用多站组网传递能较明显地减少同步时长较短时的极限误差。当采用多站组网平均海面传递同步观测5 d,其极限误差可达10 cm以内,建议在同步观测时间有限时采用该方法。结合海南岛验潮站和岛礁分布情况,同步改正平均海面传递法应用于海南岛礁测绘是可行的。  相似文献   

基于高分遥感影像的建筑物侧面信息提取及其高度计算     

宋旭东  曹文峰  冯德俊  张星星 《北京测绘》2020,(3):296-300

本文选取成都市某一区域建筑物A、B为研究对象,采用分辨率为0.61 m的Quick bird影像,运用图像分割法和LVQ神经网络算法,提取建筑物侧面信息,根据假设法原理,构建高度计算物理模型,求取建筑物高度。对比实测数据,结合可能影响实验结果的实地因素、遥感影像因素进行精度分析与评价,探讨基于高分遥感影像的建筑物侧面信息提取和高度计算的方法。结果表明,LVQ神经网络算法在建筑物侧面提取和高度计算中有更好的应用价值,精度高达94%。  相似文献