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991.
全数字摄影测量主要应用于生产数字地形图及数字地面高程模型(DEM)和数字正射影像图(DOM)。某市及周边地区1:l000地形图航测项目,利用DMC一110摄影仪进行摄影获取的影像数据,使用VirtuoZo数字摄影测量工作站,阐述进行航测内业绘制地形图的全面流程。DMC技术将发挥更大的优势,在数字摄影测量中得到越来越广泛的应用。 相似文献
992.
《International Journal of Digital Earth》2013,6(6):582-603
ABSTRACTPublic understanding of climate and climate change is of broad societal importance. However, misconceptions regarding reasons for the seasons abound amongst students, teachers, and the public, many of whom believe that seasonality is caused by large variations in Earth’s distance from the Sun. Misconceptions may be reinforced by textbook illustrations that exaggerate eccentricity or show an inclined view of Earth’s near-circular orbit. Textbook explanations that omit multiple factors influencing seasons, that do not mesh with students’ experiences, or that are erroneous, hinder scientifically valid reasoning. Studies show that many teachers share their students’ misconceptions, and even when they understand basic concepts, teachers may fail to appreciate the range of factors contributing to seasonal change, or their relative importance. We have therefore developed a learning resource using Google Earth, a virtual globe with other useful, weather- and climate-related visualizations. A classroom test of 27 undergraduates in a public research university showed that 15 improved their test scores after the Google Earth-based laboratory class, whereas 5 disimproved. Mean correct answers rose from 4.7/10 to 6/10, giving a paired t-test value of 0.21. After using Google Earth, students are helped to segue to a heliocentric view. 相似文献
993.
《International Journal of Digital Earth》2013,6(5):449-468
Abstract To investigate geological mining hazards using digital techniques such as high-resolution remote sensing, a semi-automatically geological mining hazards extraction method is proposed based on the case of the Shijiaying coal mine, located in Fangshan District, Beijing, China. In the method, the vegetation is first removed using the normalized difference vegetation index (NDVI) on the GeoEye-1 data. Then, geological mining hazards interpretation features are determined after color enhancement using principal component analysis (PCA) transformation. Bitmaps mainly covered by geological mining hazards are isolated by masking operation in the environment for visualizing images software. Next, each bitmap is classified into a two-valued imagery using support vector machine algorithm. In the two-valued imagery, 1 denotes the geological mining hazards, while 0 denotes none. Afterwards, the two-valued imagery is converted into a vector graph by corresponding functions in the ArcGIS software and no geological mining hazards regions in the vector graph are deleted manually. Finally, the correlation between factors (such as mining activity, lithology, geological structure, and slope) and geological mining hazards is analyzed using a logistic regression and a hazardous-area forecasting model is built. The results of field verification show that the accuracy of the geological mining hazards extraction method is 98.1% and the results of the hazardous-area forecasting indicate that the logistic regression is an effective model in assessing geological hazard risks and that mining activity is the main contributing factor to the hazards, while geological structure, slope, lithology, roughness of the surface, and aspect are the secondary. 相似文献
994.
A long-term Global LAnd Surface Satellite (GLASS) data-set for environmental studies 总被引:1,自引:0,他引:1
《International Journal of Digital Earth》2013,6(6):5-33
Recently, five Global LAnd Surface Satellite (GLASS) products have been released: leaf area index (LAI), shortwave broadband albedo, longwave broadband emissivity, incident short radiation, and photosynthetically active radiation (PAR). The first three products cover the years 1982–2012 (LAI) and 1981–2010 (albedo and emissivity) at 1–5 km and 8-day resolutions, and the last two radiation products span the period 2008–2010 at 5 km and 3-h resolutions. These products have been evaluated and validated, and the preliminary results indicate that they are of higher quality and accuracy than the existing products. In particular, the first three products have much longer time series, and are therefore highly suitable for various environmental studies. This paper outlines the algorithms, product characteristics, preliminary validation results, potential applications and some examples of initial analysis of these products. 相似文献
995.
利用川西地区2010-2012年期间的流动重力观测资料,系统分析了区域重力场变化及其与2013年4月20日四川芦山7.0级地震发生的关系.结果主要表明:①区域重力场异常变化与北东向龙门山断裂带南段和北北西向马尔康断裂带在空间上关系密切,反映沿该两断裂带(段)在2010-2012年期间发生了引起地表重力变化效应的构造活动或变形.②芦山7.0级地震前,测区内出现了较大空间范围的区域性重力异常,而震源区附近产生了局部重力异常,沿龙门山断裂带南段形成了重力变化高梯度带,其中,宝兴、天全、康定、泸定、石棉一带重力差异变化达100×10-8m·s-2以上;这些可能反映芦山地震前,区域及震源区附近均产生与该地震孕育、发生有关的构造运动或应力增强作用.③重力场差分动态演化图像和重力场累积变化动态图像均反映芦山7.0级地震孕育过程的最后2~3年出现较显著的流动重力异常变化,可视为该地震的中期前兆信息;本文第一作者等也曾基于该流动重力异常变化在芦山7.0级地震前做过一定程度的中期预测,尤其是地点预测.本文的例子再次证明流动重力观测能较好地捕捉到强震孕育发生过程中,特别是该过程最后阶段的重力异常变化信息.因此,区域流动重力场观测对未来强震的中-长期预测,尤其是在发震地点的判定上具有优势. 相似文献
996.
Within the confines of Earth Observation Scientific Knowledge and Technology Transfer in Hungary (EKAT) titled ESA PECS project we gained forum for utilization of our earth observation (EO) knowledge and possibility for further development of experiences. The project aims the horizontal preparation of Hungary for ESA membership – for a dynamically developing sphere in the common part of science, technology and business. For the efficient transfer and dissemination, we preconceived target groups and principles to reach main take-up points and to open new forums of information exchange. Nowadays, user-friendly service, complex supply and real-validation process all have great importance. Joining units of suitable data choice, entire ingestion–processing chains and ergonomic interfaces can only offer a timely and professional solution for the challenges of industry and business sectors. It has to be clearly seen, that information and communication technologies (ICT) and information control becomes a more and more significant part of EO services. 相似文献
997.
It is still not well understood if subseasonal variability of the local PM2.5 in the Beijing-Tianjin-Hebei (BTH) region is affected by the stratospheric state. Using PM2.5 observations and the ERA5 reanalysis, the evolution of the air quality in BTH during the January 2021 sudden stratospheric warming (SSW) is explored. The subseasonal variability of the PM2.5 concentration after the SSW onset is evidently enhanced. Stratospheric circumpolar easterly anomalies lasted for 53 days during the January–February 2021 SSW with two evident stratospheric pulses arriving at the ground. During the tropospheric wave weakening period and the intermittent period of dormant stratospheric pulses, the East Asian winter monsoon weakened, anomalous temperature inversion developed in the lower troposphere, anomalous surface southerlies prevailed, atmospheric moisture increased, and the boundary layer top height lowered, all of which favor the accumulation of pollutant particulates, leading to two periods of pollution processes in the BTH region. In the phase of strengthened East Asian winter monsoon around the very beginning of the SSW and another two periods when stratospheric pulses had reached the near surface, opposite-signed circulation patterns and meteorological conditions were observed, which helped to dilute and diffuse air pollutants in the BTH region. As a result, the air quality was excellent during the two periods when the stratospheric pulse had reached the near surface. The increased subseasonal variation of the regional pollutant particulates after the SSW onset highlights the important role of the stratosphere in the regional environment and provides implications for the environmental prediction. 相似文献
998.
基于旋翼无人机开展大气边界层观测可为气象要素和大气污染物垂直结构的研究提供具有高时空解析能力的新方法,有助于深入理解低层大气物理化学变化机制。本文详述了旋翼无人机在开展大气边界层环境气象垂直观测实验的应用及优势。基于自主研发的旋翼无人机环境气象观测平台,通过开展传感器在无人机上不同的搭载位置,以及旋翼无人机与探空气球、高塔的对比观测实验,明确了旋翼无人机对气象环境观测的影响及合理的搭载方式。研究进一步在湖北重污染天气条件下开展了0—1000 m的大气边界层垂直观测,并研发了基于旋翼无人机姿态数据的大气边界层气象要素及污染物垂直观测的订正方法。结果表明:实验获取了2—10 m垂直分辨率的高质量大气廓线数据,可精细捕捉大气边界层及其逆温层高度和污染物浓度等要素的垂直变化特征。本文旨在为无人机观测的科研应用提供一种技术可行且数据可靠的观测手段。 相似文献
999.
Zhaoliang ZENG Zemin WANG Minghu DING Xiangdong ZHENG Xiaoyu SUN Wei ZHU Kongju ZHU Jiachun AN Lin ZANG Jianping GUO Baojun ZHANG 《大气科学进展》2021,38(9):1497-1509
Long-term,ground-based daily global solar radiation (DGSR) at Zhongshan Station in Antarctica can quantitatively reveal the basic characteristics of Earth’s surface radiation balance and validate satellite data for the Antarctic region.The fixed station was established in 1989,and conventional radiation observations started much later in 2008.In this study,a random forest (RF) model for estimating DGSR is developed using ground meteorological observation data,and a highprecision,long-term DGSR dataset is constructed.Then,the trend of DGSR from 1990 to 2019 at Zhongshan Station,Antarctica is analyzed.The RF model,which performs better than other models,shows a desirable performance of DGSR hindcast estimation with an R~2 of 0.984,root-mean-square error of 1.377 MJ m~(-2),and mean absolute error of 0.828 MJ m~(-2).The trend of DGSR annual anomalies increases during 1990–2004 and then begins to decrease after 2004.Note that the maximum value of annual anomalies occurs during approximately 2004/05 and is mainly related to the days with precipitation (especially those related to good weather during the polar day period) at this station.In addition to clouds and water vapor,bad weather conditions (such as snowfall,which can result in low visibility and then decreased sunshine duration and solar radiation) are the other major factors affecting solar radiation at this station.The high-precision,longterm estimated DGSR dataset enables further study and understanding of the role of Antarctica in global climate change and the interactions between snow,ice,and atmosphere. 相似文献
1000.
对雅安市两个基层台站(区站号56287和56278)在运行质量管理体系前后的业务管理方式、业务运行情况和业务质量进行对比分析,延伸到市级、省级,探讨质量管理体系运行效果。结果表明:1)气象台站在气象观测质量管理体系运行后,各类气象观测业务质量均有所提升。2)气象观测质量管理体系的建设,有效解决了传统业务管理存在的问题,提高了各级气象观测站运行质量,促进了各级气象观测业务的发展,大大提高了气象观测工作效率和成效。 相似文献