Quality Assessment Of Digital Surface Models Generated From IKONOS Imagery

The growing applications of digital surface models (DSMs) for object detection, segmentation and representation of terrestrial landscapes have provided impetus for further automation of 3D spatial information extraction processes. While new technologies such as lidar are available for almost instant DSM generation, the use of stereoscopic high-resolution satellite imagery (HRSI), coupled with image matching, affords cost-effective measurement of surface topography over large coverage areas. This investigation explores the potential of IKONOS Geo stereo imagery for producing DSMs using an alternative sensor orientation model, namely bias-corrected rational polynomial coefficients (RPCs), and a hybrid image-matching algorithm. To serve both as a reference surface and a basis for comparison, a lidar DSM was employed in the Hobart testfield, a region of differing terrain types and slope. In order to take topographic variation within the modelled surface into account, the lidar strip was divided into separate sub-areas representing differing land cover types. It is shown that over topographically diverse areas, heighting accuracy to better than 3 pixels can be readily achieved. Results improve markedly in feature-rich open and relatively flat terrain, with sub-pixel accuracy being achieved at check points surveyed using the global positioning system (GPS). This assessment demonstrates that the outlook for DSM generation from HRSI is very promising.     

基于CryoSat-2数据的海冰厚度估算算法比较

以北极为研究区,使用CryoSat-2数据,利用现有海冰厚度卫星测高研究中4种主流算法(Laxon03算法、Kurtz09算法、Yi11算法和Laxon13算法)分别对北冰洋海冰厚度进行估算,并将估算结果与研究区IceBridge机载激光测高冰厚数据进行了比较,探索各算法海冰厚度估算的差异,寻找最优的估算算法,为估算长时序海冰厚度提供基础和参考。结果表明,4种算法估算的海冰厚度空间分布较为一致,但不同算法估算的结果差异较大,可达0.476 m;4种算法估算结果大小依次为Laxon03算法、Yi11算法、Laxon13算法、Kurtz09算法;4种算法估算的平均海冰厚度差异,在北极波弗特海海域最大,其次是北极中心海域、格陵兰和挪威海;Laxon13算法估算结果相对于IceBridge观测结果与其他算法相比,具有最小的平均偏差和均方根误差,是卫星测高估算海冰厚度的最优算法。     

利用Lageos 1 SLR资料解算1990-2001年的地球定向参数

利用 12年的Lageos 1卫星激光测距资料 (1990 - 2 0 0 1)解算得到了地球定向参数 (EOP) ,将该序列的结果与同期的EOP(IERS)C0 4进行比较 ,其外符精度为 :极移XP— 0 .4 0mas,YP— 0 .4 2mas ,日长变化Dr— 0 .0 35ms。     

双波长卫星激光测距

双波长卫星激光测距不必借助大气改正模型，利用双波长往返时间差就可以进行大气折射改正，采用皮秒级事件计时器等技术测量往返时间差，修正精度可以达到毫米量级，介绍了这一领域的研究进展、双波长大气改正的基本原理，分析了双波长激光测距的精度，最后对双波长卫星激光测距前景进行了展望。     

地震-电离层扰动探测技术的研究进展

回顾了地震-电离层扰动机理的研究进展和主要的数据观测方法,总结了地震电磁卫星观测电离层扰动的应用发展情况以及基于卫星测量数据对异常辐射源定位的研究进展,介绍了无线电探测方法的实验情况和数据分析方法,为未来中国探测电离层扰动进行短临地震预测工作提出了建议.     

基于GF-2影像西藏桑耶地区岩性-构造遥感解译

西藏桑耶地区位于青藏高原中南部,区内切割强烈,地势陡峻,属于高山峡谷区。为提高区域地质调查野外工作效率,在调查中率先开展了遥感解译研究。在充分收集已有资料的基础上,通过对GF-2卫星数据进行预处理和影像增强,结合野外验证建立了各地质要素的遥感解译标志,实现了区内不同地层岩性、侵入岩、断裂和褶皱等地质要素的提取,最终编制了研究区1:5万遥感地质解译图,为区域地质调查提供了数据支撑。结果表明: 各地质要素在GF-2数据上均有良好反映,完全满足1:5万尺度的遥感地质解译和编图的需要,充分显示出该卫星数据在区域地质调查等工作中具有良好的应用前景。     

苏州城郊土地利用变化对土壤的影响

1IntroductionThe conversion of natural systems to agricultural production has been the primary basis for the successful growth of human populations for the last 9,000 years (Kates etal., 1990). The conflict between urban and agricultural land use, however…     

卫星云图、雷达回波在人工增雨时机选择中的应用

概述了干旱期间选择飞机和高炮人工增雨作业时机的方法，以2000年6～7月哈尔滨地区特大干旱期间进行的飞机和高炮人工增雨作业为例，利用卫星云图和雷达回波资料选择的作业时间和作业区域应是比较有利的。因为从卫星云图中的水汽图、红外和可见光云图上可分析出云系中的含水量、云顶温度、云系强度，在此基础上利用天气雷达跟踪订正，可直接指挥飞机和高炮在有利的区域和时间内进行作业，获得了明显的效果。     

Mechanisms controlling the temporal variation of the sea ice edge in the Southern Ocean

This paper examines the mechanism controlling the short time-scale variation of sea ice cover over the Southern Ocean. Sea ice concentration and ice velocity datasets derived from images of the Defense Meteorological Satellite Program (DMSP) Special Sensor Microwave Imager (SSM/I) are employed to reveal this mechanism. The contribution of both dynamic and thermodynamic processes to the change in ice edge location is examined by comparing the meridional velocity of ice edge displacement and sea ice drift. In the winter expansion phase, the thermodynamic process of new ice production off the ice edge plays an important role in daily advances of ice cover, whereas daily retreats are mostly due to southward ice drift. On the other hand, both advance and retreat of ice edges in the spring contraction phase are mostly caused by the dynamic process of the ice drift. Based on the above mechanism and the linear relation between the degree of ice production at the ice edge and northward wind speed, the seasonal advance of ice cover can be roughly reproduced using the meridional velocity of ice drift at the ice edge.     

GOCE Gravity Field Processing Strategy

A processing strategy and the corresponding software architecture for the processing of GOCE (Gravity field and steady-state Ocean Circulation Explorer) observables is presented and described, with the major objective to compute a high-accuracy, high-resolution spherical harmonic model of the Earth's gravity field. The combination of two numerical solution strategies, i.e. the rigorous solution of the corresponding large normal equation systems applying parallel processing (on a PC cluster) as the core solver, and the fast semianalytic approach as a quick-look gravity field analysis (QL-GFA) tool, is proposed. Such a method fusion benefits from the advantages of the individual components: the rigorous inversion of the system providing also the full variance-covariance information, and the quickness enabling the consecutive production of intermediate gravity field solutions, for the purpose to analyse partial and incomplete data sets and to derive a diagnosis of the performance of the GOCE measurement system. The functionality and operability of the individual components are demonstrated in the framework of a closed loop simulation, which is based on a realistic mission scenario both in terms of the orbit configuration and the coloured measuring noise. Special concern is given to the accuracy of the recovered coefficients, the numerical behaviour, the required computing time, and the particular role of the individual modules within the processing chain. In the case of the core solver, it is demonstrated that the assembling and rigorous solution of large normal equation systems can be handled by using Beowulf clusters within a reasonable computing time. The application of the quick-look tool to partial data sets with short-term data gaps is demonstrated on the basis of several case studies. Additionally, the spectral analysis of the residuals of the adjustment is presented as a valuable tool for the verification of the noise characteristics of the GOCE gradiometer.