基于GIS的海域定级系统研究     

路文海  陈戈  金继业 《海洋通报》2007,26(3):72-80

为提高海域定级工作的效率和成果的精度与质量,在海域定级原理研究的基础上,基于GIS技术和数据库技术设计开发了海域定级系统。该系统的主要功能模块包括:因素因子体系的建立;语言型、域值型、数值型、点扩散型和线扩散型影响因子的量化方法;层次分析法计算影响因素因子权重值;海域定级及结果显示。  相似文献   

Ionospheric tomography based on GNSS observations of the CMONOC: performance in the topside ionosphere     

Zhe Yang  Shuli Song  Wenhai Jiao  Guangming Chen  Junchen Xue  Weili Zhou  Wenyao Zhu 《GPS Solutions》2017,21(2):363-375

This study carries out a quantitative analysis of the performance of ionospheric tomography in the topside ionosphere, utilizing data of October 2011 collected from 260 Global Navigation Satellite System (GNSS) stations in the Crustal Movement Observation Network of China. This tomographic reconstruction with a resolution of 2° in latitude, 2° in longitude and 20 km in altitude has more than 70 % of voxels traversed by GPS raypaths and is able to provide reliable bottom parts of ionospheric profiles. Compared with the observations measured by the Defense Meteorological Satellite Program (DMSP) satellites (F16, F17 and F18) at an altitude of 830–880 km, the results show that there is an overestimation in the reconstructed plasma density at the DMSP altitude, and the reconstruction is better during daytime than nighttime. In addition, the reconstruction at nighttime also indicates a solar activity and latitudinal dependence. In summary, with respect to DMSP measurements, the daytime bias is on average from ?0.32 × 10⁵/cm³ to ?0.28 × 10⁵/cm³, while the nighttime bias is between ?0.37 × 10⁵/cm³ and ?0.24 × 10⁵/cm³, and the standard deviation at daytime and at nighttime is, respectively, 0.082 × 10⁵/cm³ to 0.244 × 10⁵/cm³ and 0.086 × 10⁵/cm³ to 0.428 × 10⁵/cm³. This study suggests that vertical ionospheric profiles from other sources, such as ionosondes or GNSS occultation satellites, should be incorporated into ground-based GNSS topside tomographic studies.  相似文献   

传统村落农户乡村旅游适应性评价与影响因素研究——基于湘西州6个村落的调查   总被引：8，自引：3，他引：5  

吴吉林  周春山  谢文海 《地理科学》2018,38(5):755-763

基于传统村落农户乡村旅游适应性分析框架构建适应性评价指标体系,以湘西州6个传统村落327户农户为研究对象,通过参与式农村评估法获取数据,运用主成分分析等方法分析传统村落农户乡村旅游适应类型、程度和影响因素。结果表明： 农户适应类型可划分为全面适应型、认知缺失型、生态主导型、政策缺失型、文化主导型和发展滞后型6种,各类型特点不一; 农户总体适应程度从高到低依次为全面适应型、文化主导型、认知缺失型、政策缺失型、生态主导型和发展滞后型,全面适应型为比较适应,其他均为一般适应; 每种适应类型在6类因子适应程度上表现有内部差异,除全面适应型外,其他适应类型在社会、文化、经济三类因子的适应程度上普遍较低; 政策、社会、生态、经济和心理5类因子中有13个影响因素对农户乡村旅游适应性有影响,影响程度不一。最后,从农户、社区和政府3个层面提出传统村落农户乡村旅游适应性提升建议。  相似文献   

浅析我国海洋环境监测数据公开的现状及建议          下载免费PDF全文

李潇  路文海  杨翼  王秋璐  刘捷 《海洋开发与管理》2016,33(7):97-101

文章通过互联网对环保、水利、农业(渔业)、林业、国土、气象、中科院、国家海洋局等部委的政府网站、技术支撑单位门户网站或数据共享平台中涉及的环境数据共享情况进行搜索、整理和汇总归纳,形成相关部委环境数据信息公开情况报告,并对海洋环境监测数据的共享发布提出建议。  相似文献   

Site dependence of far-source ground motions during the Wenchuan earthquake          下载免费PDF全文

Longjun Xu  Haiying Yu  Wenhai Cao  Lili Xie 《地震科学（英文版）》2009,22(5):531-537

This paper aimed to examine the site dependence and evaluate the methods for site analysis of far-source ground motions. This was achieved through the examination of frequency content estimated by different methods based on strong ground motions recorded at twelve far-source stations in Shandong province during the Wenchuan earthquake. The stations were located in sites with soil profiles ranging from code classes Ⅰ to Ⅲ. Approaches used included the Fourier amplitude spectrum (FAS), the earthquake response spectrum (ERS), the spectral ratio between the horizontal and the vertical components (H/V), the spectral ratio between the spectra at the site and at a reference site (SRRS), and coda wave analysis (CWA). Results showed that major periods of these ground motions obtained by FAS, ERS and H/V ratio methods were all evidently larger than site dominant periods; the periods were also different from each other and mainly reflected the frequency content of long period components. Prominent periods obtained by the SRRS approach neither illuminated the long period aspect nor efficiently determined site features of the motions. The CWA resulted in a period close to site period for stations with good quality recordings. The results obtained in this study will be useful for the evaluation of far-source effect in constructing seismic design spectra and in selecting methods for ground motion site analysis.  相似文献   

VALIDATION STUDY ON THE EAST ASIAN CLIMATE SIMULATED BY CCM2     

Dong Min  Li Yuefeng  Shen Wenhai 《Acta Meteorologica Sinica》1999,13(3):291-303

The NCAR community climate model was run for 20 years and the simulated East Asianclimate was analyzed and checked against the observation data.It is found that the large-scalefeatures of the East Asia climate were simulated pretty well by the model,though there are stillsome discrepancies between the model output and the observation.The simulated geopotentialheight,wind and temperature fields are very close to the observations.The large scale systemssuch as subtropical high.Mongolia high,Indian low which have important influence on the EastAsia monsoon also simulated pretty well.It is also found that the moisture field is not simulated sowell as those fields mentioned above.The simulated precipitation is rather different from theobservations.These suggest that some physical processes in the CCM2 need to be improved.  相似文献   

基于多变量LSTM神经网络模型的风暴潮临近预报     

刘媛媛  张丽  李磊  刘业森  陈柏纬  张文海 《海洋通报》2020,39(6):689-694

台风的风暴潮是台风引发的一种重要次生灾害，对沿海城市带来的威胁是多方面的。及时准确地预报风暴潮，对沿海地区采取合理措施减少人员伤亡和经济损失具有重要意义。本文利用长短期记忆神经网络 （LSTM） 模型，综合考虑风速、 风向、气压等气象因素和前时序的潮位数据，建立了风暴潮的临近预报模型。结果表明，基于 LSTM 的临近预报模型具有相当的预报技巧，利用前时序的风速和风向数据以及潮位数据建立的模型可对风暴潮潮位进行准确地预测。研究还表明，仅考虑前时序潮位的预测模型误差最大，考虑气压后的模型预测能力有一定进步，而考虑风的要素以后，预测的效果提升更为明显。  相似文献   

基于轨道根数的LEO广播星历参数设计     

关梅倩  焦文海  贾小林  高生阳 《大地测量与地球动力学》2018,38(9):948-952

对LEO轨道摄动变化进行分析，在原有16、18广播星历参数的基础上提出适用于LEO卫星的22、24广播星历参数。500~1 500 km仿真及实测卫星轨道数据实验结果表明，22参数20 min星历拟合URE优于6 cm。  相似文献   

长江经济带城市网络结构与空间格局 ——基于高速铁路流数据的分析     

孙建平  胡文海  傅妍芳 《地域研究与开发》2022,41(3):75-81

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螺栓孔特征点云支持下的地铁盾构隧道环缝识别与环间错台量分析     

卢建军  李文海  燕樟林  鲍艳  吴旭  倪树新 《测绘通报》2022,(9):6

管片错台是地铁盾构隧道全生命周期中常见的一种隧道病害。错台量过大,可能会使成型的隧道发生大面积的破损和渗漏,对地铁隧道的耐久性和安全性产生极大的威胁。基于三维激光扫描技术的错台检测通过确定环缝位置提取环缝两侧的断面,继而分析错台量。目前的环缝位置识别需要将点云数据转化为正射影像,再采用人工标注的方法,该方法效率低,精度极易受作业人员的影响。本文提出了一种基于螺栓孔特征点云的地铁盾构隧道环缝识别方法,无需生成正射影像,充分利用盾构隧道既有特征点云,能够准确、快速地识别环缝位置,并在此基础上结合杭州市实际地铁工程进行环间错台检测以验证该方法。结果表明,相较于传统的隧道检测手段,该方法效率高,检测全面且监测结果能够达到工程应用的精度要求。  相似文献