当代云计算发展研究现状     

龚强 《东北测绘》2013,(5):1-4,8

地理信息技术和地理信息产业作为信息产业的重要组成部分,一直与其同步发展或紧随其后。目前,第三次信息化浪潮和未来技术的代表云计算正在迅速兴起,全球各大IT公司竞相进入云计算领域,抢占制高点;我国也高度重视这一战略性新兴产业,呈现出科研先行,政府推动,企业参与,风起"云"涌的态势。全球学术界和企业界密切协作,有力推动了云计算技术的发展。测绘地理信息界需要了解国际国内云计算研究发展现状。  相似文献   

一种新的全球海量地形实时绘制算法     

汪荣峰  廖学军 《测绘科学》2013,38(1):130-132

本文为实现全球海量地形数据的实时可视化,提出了一种新算法。算法不使用几何数据而是利用球面特征进行地形多分辨率模型初建,然后基于视锥与节点关系对初建结果进行扩展来得到完整的地形网格。此外设计了能消除具有复杂邻接关系的节点间裂缝的拼接方式,构造了简洁的方法消除GPU32位浮点精度导致的"wob-bling"现象。实现的算法在普通微机上平均漫游速度达每秒95帧以上。  相似文献   

MapGIS点文件数据分析与读取实验     

王星捷 《测绘科学》2013,38(1):112-115

本文以研究MapGIS点文件为重点,全面详细剖析了点文件数据格式,并利用程序实现了MapGIS点文件的读取实验,减少数据转换中的数据失真,实现了自动成图。实验结果证明了点文件数据格式分析的准确性和数据的精确性。  相似文献   

一种提高大比例尺航测精度的方法试验研究     

谢建春  潘宝玉  苏国中  林宗坚 《测绘科学》2013,38(5):5-7,21

针对现有规范关于1∶500与1∶1000平坦地形测图必须采用全野外高程控制测量的规定,本文的试验采用装载组合宽角相机的无人飞艇低空航测系统,通过空中三角测量内业方法,突破了此技术限制。文中详述了三个试验测区的地理状况,以及采用的控制网布设方法,尤其是新设计的标志点之优点。成果表明,用航测内业加密方法所成图的高程和平面精度均超过现有规范标准。说明利用无人飞艇低空航测系统可以实现1∶500和1∶1000测图的全部航测任务,符合"允许采用新技术以更高质量的成果突破现有规范限制"的规定。  相似文献   

基于组合罗德里格矩阵的异常特征点探测     

陈西江  花向红  鲁铁定 《测绘科学》2013,38(4)

特征点是点云配准的基础,针对异常特征点对点云配准精度的影响,本文给出了一种异常特征点探测方法,即根据罗德里格矩阵的性质,对特征点进行向量组合,对比分析不同向量组合的点云配准精度,确定配准误差超限的向量组合,此向量组合中含有而其他向量组合中不合有的特征点,便是异常特征点.通过实例验证了该方法的可行性.  相似文献   

三维激光扫描技术在数字矿山领域的应用     

白立飞  潘宝玉  张兰 《测绘科学》2013,38(5):178-179

随着数字矿山概念的提出,矿山管理对空间三维信息的需求也显得更加迫切,三维可视化的管理模式已经成为数字矿山的主要内容之一,而目前常规的测量方式所获取的数据很难满足三维数字矿山的需要。三维激光扫描技术具有高分辨率、高采样率以及非接触式测量优势,非常适用于获取矿山的复杂表面和高危区域的空间三维信息。本文结合三维激光扫描的技术优势探讨该技术在数字矿山中的应用和方法,总结了三维激光扫描技术在数字矿山领域的应用方向。  相似文献   

A Comprehensive Observational Analysis for the Effects of Gas Cannons on Clouds and Precipitation     

吴彬  王丹丹  李艳芳  尹浩  杜爽  黎朋红 《热带气象学报(英文版)》2022,28(2):237-251

To analyze the effects of gas cannons on clouds and precipitation, multisource observational data, including those from National Centers for Environmental Prediction (NCEP) reanalysis, Hangzhou and Huzhou new-generation weather radars, laser disdrometer, ground-based automatic weather station, wind profiler radar, and Lin''an C-band dual polarization radar, were adopted in this study. Based on the variational dual-Doppler wind retrieval method and the polarimetric variables obtained by the dual-polarization radar, we analyzed the microphysical processes and the variations in the macro - and microphysical quantities in clouds from the perspective of the synoptic background before precipitation enhancement, the polarization echo characteristics before, during and after enhancement, and the evolution of the fine three-dimensional kinematic structure and the microphysical structure. The results show that the precipitation enhancement operation promoted the development of radar echoes and prolonged their duration, and both the horizontal and vertical wind speeds increased. The dual-polarization radar echo showed that the diameter of the precipitation particles increased, and the concentration of raindrops increased after precipitation enhancement. The raindrops were lifted to a height corresponding to 0 to -20 ℃ due to vertical updrafts. Based on the disdrometer data during precipitation enhancement, the concentration of small raindrops (lgNw) showed a significant increase, and the mass-weighted diameter Dm value decreased, indicating that the precipitation enhancement operation played a certain“lubricating”effect. After the precipitation enhancement, the concentration of raindrops did not change much compared with that during the enhancement process, while the Dm increased, corresponding to an increase in rain intensity. The results suggest the positive effect of gas cannons on precipitation enhancement.  相似文献   

Fengyun-4 Geostationary Satellite-Based Solar Energy Nowcasting System and Its Application in North China     

Chunlin HUANG  Hongrong SHI  Ling GAO  Mengqi LIU  Qixiang CHEN  Disong FU  Shu WANG  Yuan YUAN  Xiang′ao XIA 《大气科学进展》2022,39(8):1316-1328

Surface solar irradiance (SSI) nowcasting (0–3 h) is an effective way to overcome the intermittency of solar energy and to ensure the safe operation of grid-connected solar power plants. In this study, an SSI estimate and nowcasting system was established using the near-infrared channel of Fengyun-4A (FY-4A) geostationary satellite. The system is composed of two key components: The first is a hybrid SSI estimation method combining a physical clear-sky model and an empirical cloudy-sky model. The second component is the SSI nowcasting model, the core of which is the derivation of the cloud motion vector (CMV) using the block-matching method. The goal of simultaneous estimation and nowcasting of global horizontal irradiance (GHI) and direct normal irradiance (DNI) is fulfilled. The system was evaluated under different sky conditions using SSI measurements at Xianghe, a radiation station in the North China Plain. The results show that the accuracy of GHI estimation is higher than that of DNI estimation, with a normalized root-mean-square error (nRMSE) of 22.4% relative to 45.4%. The nRMSE of forecasting GHI and DNI at 30–180 min ahead varied within 25.1%–30.8% and 48.1%–53.4%, respectively. The discrepancy of SSI estimation depends on cloud occurrence frequency and shows a seasonal pattern, being lower in spring–summer and higher in autumn–winter. The FY-4A has great potential in supporting SSI nowcasting, which promotes the development of photovoltaic energy and the reduction of carbon emissions in China. The system can be improved further if calibration of the empirical method is improved.  相似文献   

Aerosol-Cloud-Precipitation Interactions in a Closed-cell and Non-homogenous MBL Stratocumulus Cloud     

Xiaojian ZHENG  Xiquan DONG  Dale M. WARD  Baike XI  Peng WU  Yuan WANG 《大气科学进展》2022,39(12):2107-2123

A closed-cell marine stratocumulus case during the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA) aircraft field campaign is selected to examine the heterogeneities of cloud and drizzle microphysical properties and the aerosol-cloud-precipitation interactions. The spatial and vertical variabilities of cloud and drizzle microphysics are found in two different sets of flight legs: Leg-1 and Leg-2, which are parallel and perpendicular to the cloud propagation, respectively. The cloud along Leg-2 was close to adiabatic, where cloud-droplet effective radius and liquid water content linearly increase from cloud base to cloud top with less drizzle. The cloud along Leg-1 was sub-adiabatic with lower cloud-droplet number concentration and larger cloud-droplet effective, but higher drizzle droplet number concentration, larger drizzle droplet median diameter and drizzle liquid water content. The heavier drizzle frequency and intensity on Leg-1 were enhanced by the collision-coalescence processes within cloud due to strong turbulence. The sub-cloud precipitation rate on Leg-1 was significantly higher than that along Leg-2. As a result, the sub-cloud accumulation mode aerosols and CCN on Leg-1 were depleted, but the coarse model aerosols increased. This further leads to a counter-intuitive phenomenon that the CCN is less than cloud-droplet number concentration for Leg-1. The average CCN loss rates are ?3.89 \begin{document}$\mathrm{c}{\mathrm{m}}^{-3}\;{\mathrm{h}}^{-1}$\end{document} and ?0.77 \begin{document}$\mathrm{c}{\mathrm{m}}^{-3}\;{\mathrm{h}}^{-1}$\end{document} on Leg-1 and Leg-2, respectively. The cloud and drizzle heterogeneities inside the same stratocumulus can significantly alter the sub-cloud aerosols and CCN budget. Hence it should be treated with caution in the aircraft assessment of aerosol-cloud-precipitation interactions.  相似文献   

A Machine Learning-based Cloud Detection Algorithm for the Himawari-8 Spectral Image     

Chao LIU  Shu YANG  Di DI  Yuanjian YANG  Chen ZHOU  Xiuqing HU  Byung-Ju SOHN 《大气科学进展》2022,39(12):1994-2007

Cloud Masking is one of the most essential products for satellite remote sensing and downstream applications. This study develops machine learning-based (ML-based) cloud detection algorithms using spectral observations for the Advanced Himawari Imager (AHI) onboard the Himawari-8 geostationary satellite. Collocated active observations from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) are used to provide reference labels for model development and validation. We introduce both daytime and nighttime algorithms that differ according to whether solar band observations are included, and the artificial neural network (ANN) and random forest (RF) techniques are adopted for comparison. To eliminate the influences of surface conditions on cloud detection, we introduce three models with different treatments of the surface. Instead of developing independent ML-based algorithms, we add surface variables in a binary way that enhances the ML-based algorithm accuracy by ~5%. Validated against CALIOP observations, we find that our daytime RF-based algorithm outperforms the AHI operational algorithm by improving the accuracy of cloudy pixel detection by ~5%, while at the same time, reducing misjudgment by ~3%. The nighttime model with only infrared observations is also slightly better than the AHI operational product but may tend to overestimate cloudy pixels. Overall, our ML-based algorithms can serve as a reliable method to provide cloud mask results for both daytime and nighttime AHI observations. We furthermore suggest treating the surface with a set of independent variables for future ML-based algorithm development.  相似文献