Long-term polar motion prediction using normal time–frequency transform

This paper presents normal time–frequency transform (NTFT) application in harmonic/quasi-harmonic signal prediction. Particularly, we use the normal wavelet transform (a special NTFT) to make long-term polar motion prediction. Instantaneous frequency, phase and amplitude of Chandler wobble, prograde and retrograde annual wobbles of Earth’s polar motion are analyzed via the NTFT. Results show that the three main wobbles can be treated as quasi-harmonic processes. Current instantaneous harmonic information of the three wobbles can be acquired by the NTFT that has a kernel function constructed with a normal half-window function. Based on this information, we make the polar motion predictions with lead times of 1 year and 5 years. Results show that our prediction skills are very good with long lead time. An abnormality in the predictions occurs during the second half of 2005 and first half of 2006. Finally, we provide the future (starting from 2013) polar motion predictions with 1- and 5-year leads. These predictions will be used to verify the effectiveness of the method proposed in this paper.     

Visualization and damage assessment for flooded area

A practical method for visualizing flood area and evaluating damage is presented, which consists of two technical approaches: self-programming and adapting commercial GIS platforms. The low-cost and easy-to-use GIS-Based model developed by self-programming can meet current requirements of most local authorities, especially in developing countries. In this model, two cases, non-source flood and source flood, are distinguished and the Seed-spread algorithm suitable for source-flood is discussed; The flood damage is assessed by overlaying the flood area range with thematic maps and other related social and economic data. and all thematic maps are converted to raster format before overlay analysis. Two measures are taken to improve the operation efficiency of speed seed-spreed algorithm. The accuracy of the model mainly depends on the resolution and precision of the DEM data, and the accuracy of registering all raster layers and the quality of attribute data.     

FY-3A/MERSI数据在典型大城市热环境监测预报中的应用——以上海市为例

以上海市为例,探索中国新型自主的FY-3A/MERSI数据在典型大城市热环境研究中的应用模式,包括实时监测与同化数值预报两个方面。结果表明:FY-3A/MERSI反演的250 m地表温度及其他衍生指标能够客观呈现城市热场格局及热岛效应,精细揭示出上海市区—近郊—远郊的地温明显分异,热岛由中心城区呈放射性面状过渡到远郊以乡镇为中心的团块状,其形成与下垫面介质关系密切。同化FY-3A/MERSI数据产品的中尺度数值模式,耦合城市冠层参数化方案,可实现250 m格网0～48 h城市近地层气温空间精细化预报,提取1 h间隔的热环境日演变特征将有助于在不同天气形式下进行热环境灾害潜式预报及机理分析。预报结果在时空分辨率方面明显优于常规数值预报,并避免了卫星云污染的影响,说明FY-3A卫星探测资料能有效改善模式背景场与初始场。     

GIS专业的Java程序设计教学改革初探

Java语言的独特优势促使其在GIS专业教学中起到越来越重要的作用。本文分析了GIS专业教学中Java程序设计课程教学存在的问题,结合武汉理工大学GIS专业的Java程序设计课程的改革实践,提出了总体的改革思路,并从教学、实践、考核等几个方面提出了具体的改革要求和内容。该门课程的教学改革能推动GIS专业的Java程序设计语言的学习,提高学生的实践动手能力和解决GIS专业问题的能力。同时,该教学改革模式对兄弟院校的GIS专业程序设计语言方面的教学实践能起到相应的借鉴作用。     

测绘生产管理信息化建设应用研究

国家测绘地理信息局在2007年开展了信息化测绘体系研究,测绘地理信息领域的信息化获得长足进步。信息化测绘时代的到来,对测绘生产管理提出了更高的要求。本文设计了以测绘生产管理为核心内容的信息系统,经过近三年时间的应用,其管理功能模块能够满足测绘生产信息化管理需要。     

Global morphology of ionospheric F-layer scintillations using FS3/COSMIC GPS radio occultation data

We report on the FormoSat-3/Constellation Observing System for Meteorology, Ionosphere and Climate (FS3/COSMIC) limb-viewing observations of GPS L-band scintillations since mid-2006 and propose to study global F-layer irregularity morphology. The FS3/COSMIC has generally performed more than 1000 ionospheric radio occultation (RO) observations per day. We reprocess 1-Hz amplitude data and obtain complete limb-viewing profiles of the undersampling (sampling frequency lower than Fresnel frequency) S4 scintillation index from about 80% of the RO observations. There are a few percent of FS3/COSMIC RO observations having greater than 0.09 undersampling S4max values on average. However, seven identified areas, Central Pacific Area (?20° to 20° dip latitude, 160°E–130°W), South American Area (?20° to 20° dip latitude, 100°W–30°W), African Area (?20° to 20° dip latitude, 30°W–50°E), European Area (30°–55°N, 0°–55°E), Japan Sea Area (35°–55°N, 120°–150°E), Arctic Area (>65° dip latitude), and Antarctic Area (<?65° dip latitude), have been designated to have a much higher percentage of strong limb-viewing L-band scintillations. During the years in most of the last sunspot cycle from mid-2006 to the end 2014, the scintillation climatology, namely, its variations with each identified area, season, local time, magnetic activity, and solar activity, have been documented.     

基于光谱分析的MODIS云检测算法的研究

在总结云、陆地、植被、水体等目标光谱特性以及云和不同目标间光谱差异的基础上,改进了一种下垫面多光谱云检测算法,并采用MODIS影响进行了试验.试验结果表明,此改进方法行之有效.     

浅谈城市地下管线普查成果数据的质量检查

本文阐述了对城市地下管线普查成果数据进行质量检查的必要性,并结合工作实际,介绍了质量检查的内容和方法.     

基于ArcScene的建筑物日照分析模块的设计与实现

介绍了利用ArcObjects开发、基于ArcScene的建筑物日照分析模块的研制,对各个子模块作了介绍。特别对涉及到的日照分析技术、阴影动态显示、3维建筑设计等技术做了详细的说明。最后对该模块的应用做了简要演示。     

便携式电子地图设计中需解决的几个问题

软性显示器和投影技术超微型化的发展,使得电子地图有足够的空间满足便携式电子地图的设计需求,本文通过介绍几种便携式材质的特性,提出便携式电子地图设计中需解决的几个硬件技术问题。