北极新奥尔松地区Austre Lovénbreen冰川温度变化特征

冰川温度是冰川最重要的物理参数之一。2009~2011年间,在北极新奥尔松地区Austre Lovénbreen冰川上B_2、E_2和F点开展了20m浅层冰温监测工作。结果表明,三点冰温曲线在春季5月表现为冷季型,秋季9月属于暖季型。在9m深度以下,E_2点冰温总是要比B_2和F点低。三点处冰温活动层下界的深度都为14m,冰温年平均值分别为-2.76、-3.23和-2.84℃。随着海拔的升高,B_2和E_2点之间20m深处冰温递减率(0.3℃·100m-1)要大于10m深处的(0.15℃·100m-1)。三点在10m深处冰温比近地层气温要高1~4℃,这也显示了冰川融水再冻结释放的潜热导致冰川升温的重要性。     

近30年来喜马拉雅山脉西段纳木那尼峰地区冰川变化的遥感监测研究

本文从1976,1990,1999的Landsat及2003年ASTER系列数字遥感影像上提取了喜马拉雅山脉西段纳木那尼峰地区的4期冰川空间分布数据,在Arc/Info中综合各期数据,建立研究区1976—2003年冰川变化图谱,定量分析了纳木那尼峰地区冰川的空间变化。图谱这种数据集成的方法明显优于直接将各期影像分类结果进行比较的传统研究方法。研究结果表明,纳木那尼峰地区的冰川以广泛退缩为主,但北部也有少量前进冰川存在。自1976年到2003年,冰川面积从84.41km2减少到77.29km2,各时段分别以平均0.17km/a,0.19km/a和0.77km/a的速度在退缩,冰川退缩明显加速。冰川退缩面积占研究区总面积的8.4%,明显比高亚洲冰川平均退缩比例（7%）大,表明西喜马拉雅山脉的冰川退缩比较严重。     

应用于村镇信息自助平台的电子地图构件关键技术研究

从构件化村镇信息自助平台的低成本、易定制的特点出发,针对其中电子地图构件在地图浏览和交互查询中存在的网络负载大、响应速度慢等技术问题,研究了传统We—bGIS空间数据网络发布模式及其不足,探讨了基于AJAX、地图切片、多级缓存技术的电子地图发布解决方案,并实现了在村镇信息自助平台上的应用。     

主要定向技术比较与GNSS快速定位定向仪研制进展

首先介绍了定向的定义、基准和应用背景,总结并比较了目前几种主要定向技术的特点。在此基础上分析了卫星定向技术的优势和改进需求;重点介绍了GNSS快速定位定向仪(臂长1.1 m)研制的基本情况、基本组成和特点。该仪器采用单接收机旋转方式定位定向。经过大量实验鉴定,通过3 min的连续测量可实现优于0.5个密位(108″)的定向精度和优于5 m的定位精度。     

椭球面上真3维坐标系在3维GIS中的应用理论及方法研究

不同于现有的GIS空间坐标参考系 ,本论文提出了地球椭球面上另一种形式的测地坐标系 ,并对其进行了严密的定义和多方面的论证。与大地经纬度相比 ,由于测地坐标以长度为度量单位 ,使椭球面上点位间距离和角度的解算公式形式简单、应用方便 ,从而大大地简化了椭球面上的繁复计算。大量的数据分析证明 ,采用测地坐标计算的距离、方位和面积能够达到相当高的精度。围绕测地坐标系在 3维GIS中的应用理论和方法展开了如下几个方面的研究。1 .冲出传统地图投影的禁锢 ,首次提出了在椭球面上建立DTM的原理和方法。这种椭球面DTM是在区域性椭球…     

GNSS连续运行参考站系统建设关键技术与注意事项浅谈

结合河南省地质信息连续采集运行系统的具体建设,探讨了GNSS连续运行参考站系统建站涉及的几个关键技术和重要环节,可为其他城市建站提供参考.     

Spatial Technologies in Deriving the Morphotectonic Characteristics of Tectonically Active Western Tripura Region,Northeast India

Employing integrated remote sensing and GIS technology the western most part of Tripura region (Northeast India) and adjoining Bangladesh region has been investigated in the light of its geomorphological characteristics. Nature of fold ridges, several streams and the respective drainage basins are well depicted in satellite images and digital elevation model providing meaningful information. Quantitative parameters such as stream sinuosity, drainage basin asymmetry, basin elongation ratio have been computed. Main rivers of the study area, namely the Gomti and Khowai follows extremely meandering path and crosses through the transversely faulted anticlinal ridges. Fluvial anomalies viz. shift in stream channel and the abandoned meandering loops have been inferred and mapped. The Haora river in the study area exhibits northward shift in some part. Development of drainage system towards north and south from the drainage divide along the latitude 23°45^′N indicated up arching of the region which is also corroborated by the extracted topographic profiles. It has been observed that several tributary streams have gone dry and agricultural fields are developed along the dried up stream. These derived parameters remained useful to understand the nature of topographical modification attributed to the possible tectonic activity.     

On the impact of GNSS ambiguity resolution: geometry,ionosphere, time and biases

Integer ambiguity resolution (IAR) is the key to fast and precise GNSS positioning and navigation. Next to the positioning parameters, however, there are several other types of GNSS parameters that are of importance for a range of different applications like atmospheric sounding, instrumental calibrations or time transfer. As some of these parameters may still require pseudo-range data for their estimation, their response to IAR may differ significantly. To infer the impact of ambiguity resolution on the parameters, we show how the ambiguity-resolved double-differenced phase data propagate into the GNSS parameter solutions. For that purpose, we introduce a canonical decomposition of the GNSS network model that, through its decoupled and decorrelated nature, provides direct insight into which parameters, or functions thereof, gain from IAR and which do not. Next to this qualitative analysis, we present for the GNSS estimable parameters of geometry, ionosphere, timing and instrumental biases closed-form expressions of their IAR precision gains together with supporting numerical examples.     

Creation of DTM with ASTER Data and Statistical Verification of the Accuracy of the Model (Western Peloponnese,Greece)

Abstract

In this paper we present the use of ASTER data for the creation of a Digital Terrain Model (DMT) of high accuracy. Using a stereo pair of ASTER satellite images with 15m resolution we created two DMTs: one with a 30m pixel size and another one with a 15m pixel size. Then we made a statistical verification of the two DTMs accuracy. We created another DTM with 30m pixel size from digitized contours of 1:50000 scale topographic maps. We first made an optical comparison of the two DTMs with 30m pixel size. Then we subtracted the two DTMs and we presented their difference. Finally, we verified the DTMs accuracy using 68 points of a well‐known elevation. All the results demonstrated that DTMs derived from ASTER data have very good accuracy.     

利用重力场模型对中国陆地和岛礁GNSS水准沉降进行分析

利用现势性很强的EGM2008,EIGEN-6C,EIGEN-6C2,GO_CONS_GCF_2_DIR_R4共四个地球重力场模型,对中国沿海近岸陆地和岛礁上16个区域的1 053个GNSS水准点进行了沉降分析,最后发现中国沿海浙江省、辽宁省、上海市、天津市、广西、琼州北(琼州海峡北)、琼州南(琼州海峡南)7个区域存在沉降。     

东南极Amery冰架与陆地冰分界线的重新划定及验证

根据无线电回波测厚(RES)数据对东南极Amery冰架与陆地冰分界线进行了重新划定,指出该冰架的接地线位置最南一直向内陆延伸到73.2°S处,距冰架末端最远距离约500km。并在该流域选取了两条具有代表性的剖面,分别用水面以下的冰厚度与总的冰厚度的比值、流体静力学平衡理论等进行了验证。同时对该地区所在的整个冰流系统用5km ERS-1/DEM数据和1km RAMP/DEM数据,GPS实地测量值等对这一结论进行了验证。最后按流体静力学平衡条件对该流域的漂浮冰部分重新进行了标定。     

Reconstruction of the moraine dammed lake,based on field evidence and paleo-history,Samudra Tapu Glacier,Chandra Basin,Himachal Pradesh

Peri-glacial studies of the Samudra Tapu glacier reveal three stages of well preserved moraines which are also marked by fluvial overprinting. The signatures of fluvial outwashes over the otherwise morainal deposits have been utilized in estimating the extent of palaeo-lake in the valley of Samudra Tapu glacier of the Chandra basin. Distance and thickness of snout of the glacier and its morainal deposits is estimated by the Laser Range Finder. With the change in the position of the snout there is a change in the extent and orientation of the lake. Recent expedition to the glacier confirms this process to be continuing. The study is important in reconstructing formation of the lake with respect to snout position of the glacier. Based on ground truth, fast melting of the snout is confirmed from year 2004 onwards, with the development of fresh end/terminal moraine. The study reveals that the snout region of the Samudra Tapu glacier is thinning and retreating at an alarming rate and is enlarging the lake extent. The development of fresh terminal moraine has the potential to impound the fast melting glacial waters which in turn can pose serious threat to the downstream regions of the Chandra valley.     

边坡挡墙变形监测新技术研究

三维激光扫描技术的出现,为边坡挡墙变形监测提供了新的监测手段,本文选用在测量领域中使用较广的脉冲式扫描仪,以监测某立交桥的边坡挡墙变形为实例,进行了点云数据采集。根据边坡挡墙变形监测的特点及数据处理的要求,使用机带软件RIEGL VZ-1000进行了点云数据预处理之后,再引入第三方点云处理软件Geomagic Studio和Geomagic Qualify,进行了数据处理及变形分析。通过研究,提出了基于三维激光扫描技术的边坡挡墙变形监测新方法。     

Strategies for High Precision Processing of GPS Measurements with Application to the Amery Ice Shelf,East Antarctica

A number of statistic Global Positioning System (GPS) measurement campaigns have been made on a floating Antarctic ice shelf, the Amery Ice Shelf, as part of ongoing glaciological studies designed to investigate the ice shelf dynamics, grounding zone definition, and ice shelf strain. Such studies ar fundamental to improving out knowledge of the Antarctic ice-sheet mass balance and dynamical models of ice sheet/ocean interaction. This article describes two techniques used to process the statistic GPS data. One approach uses a segmented version of the classical static methodology, and the other approach adopts a new sequential processing technique. Both approaches yield similar results for the station coordinates and demonstrate the potential of GPS for extracting the tidal signal on the ice shelves and giving information on the dynamical motion of the ice sheet. To verify our results for the vertical component, we compare the ice shelf GPS tidal signal with a tidal model derived from tide gauge measurements at nearby Beaver Lake. Comparison of the GPS results with the tide model give good agreement in amplitude at the few cm level (GPS results always larger) but clearly shows evidence of phase propagation of the ocean tidal wave under the ice shelf. Improving the resolution of the tides over the ice shelves will be of tremendous benefit for future satellite missions, such as Ice, Cloud and Land Elevation Satellite (ICESAT), and the integrated use of GPS and satellite data will be fundamental for any on-going Antarctic ice sheet mass balance studies. ? 2000 John Wiley & Sons, Inc.     

Integration of Remote Sensing and GIS to Detect Pockets of Urban Poverty: The Case of Rosario, Argentina

The advent of high spatial resolution, multispectral satellite imagery has allowed analysis of remotely sensed images of urban land cover to become more useful to urban planning and decision making than in the past. The addition of radar imagery at relatively high spatial resolution (6 metres at best), with the advantages that it is not affected by cloud and diurnal light conditions and that it is sensitive to the target's geometric shape, surface roughness and moisture content offers additional capability in this regard. This paper incorporates analysis of Canadian RADARSAT-1 and American Landsat TM satellite imagery and ground-based GIS data to identify known pockets of urban poverty. Poverty is defined, based on a limited number of census variables related to dwelling construction materials and per household overcrowding. The objective is to provide a proof of concept that remote sensing data, especially from synthetic aperture radar, and ground-based GIS data can be successfully integrated for urban planning purposes. The results suggest that the approach used is reasonable and that, with future refinement, it offers planners and decision makers a timely and cost effective means to locate and monitor poverty pockets in urban areas. This is especially important in large, rapidly urbanising areas in the developing world.     

Modelling the Spatial Extent of Franz Josef Glacier,New Zealand from Environmental Variables Using Remote Sensing and GIS

Abstract

This study attempts to model the spatial extent of Franz Josef Glacier in the Southern Alps of New Zealand from environmental variables. Glacier tongue length, area, and equilibrium line altitude were measured in ArcView after 15 end‐of‐summer glacier termini were demarcated from a diverse source of remotely sensed materials that had been geometrically rectified. These tongue parameters were correlated with and regressed against mean winter (June to September) precipitation, summer (December to February) temperature, and terminal gradient. The regressed length model was used to simulate the spatial extent of the glacier tongue in ArcInfo. Modelling of the spatial extent was implemented in a two‐stage approach using Arc Macro Language. The terminus end of the glacier tongue was simulated with an empirical parabolic curve. It is found that the averaging duration of climatic variables plays a significant role in exploring their impact on the glacier tongue. Tongue area has a Pearson correlation coefficient of 0.70 and 0.60, respectively, with mean monthly winter precipitation and averaged monthly summer temperature. The underlying topography exerts a significant effect on tongue morphometry that is most reliably predicted from slope gradient (β) but less so from precipitation (PPT) and temperature (T). The best models for tongue length and area are Length=4100.779?1.2346×PPT+91.9162×T?29.30×β (R²=80.77%) and Area=308.3207?0.0342×PPT+3.3100×T?0.9893×β (R²=81.51%). Through its horizontal shifting and rotation, the empirical parabolic curve enabled the terminal end of the glacier tongue to be accurately and realistically modelled from the environmental variables.     

应用FY－1B气象卫星监测1991年江淮洪水的研究

本文研究了ＦＹ－１ＢＶＨＲＳＲ的三个可见光通道和一个近红外通道监测１９９１年夏天中国江淮地区洪水的能力。分析该区域不同水体的各个通道的光谱状况表明，ＶＨＲＳＲ第二通道区别水、陆（植被）边界十分显著，ＶＨＲＳＲ第一通道有感应洪水泥沙含量信息的能力，ＶＨＲＳＲ的第三、四通道（海洋通道）则可以获得水深信息。文中针对ＦＹ－１Ｂ的波段的特点设计了几种信息增强方法，从而有效地识别出水陆边界，计算了洪水深度及洪水浑浊度的相对等级，精确地统计出洪水的面积。结果表明ＦＹ－１Ｂ在洪水监测中大有潜力。     

Variations in the Ice Phenology and Water Level of Ayakekumu Lake,Tibetan Plateau,Derived from MODIS and Satellite Altimetry Data

The alpine lakes on the Tibetan Plateau (TP) are highly sensitive to variations in climate changes, and the lake ice phenology and water level are considered to be direct indicators of regional climate variability. In this study, we first used 14 years of moderate resolution imaging spectroradiometer snow cover products to analyse the freeze dates, ablation dates, and ice coverage durations. The lake level changes during 2002–2015 were estimated, derived from satellite altimetry and Hydroweb data. Unexpectedly, the freeze dates of lake ice greatly advanced, and the ablation dates were markedly delayed. The complete freezing duration lengthened by approximately 77 days. As a result of the warm-wet climate in the northern TP, the lake area expanded from 770 to 995 km² during 2002–2015, and the water levels rose by 4.2 m in total, at a rate of 0.3 m/year. The progressive expansion of Ayakekumu Lake profoundly affected the ice phenology. Larger water volume with larger thermal capacity likely led to the delaying of ablation dates, with the freezing point depression caused by decreasing salinity. Some new narrow and shallow bays located in southern and eastern Ayakekumu Lake were conducive to early freezing of ice. Additionally, the changes in air temperature, precipitation, potential evaporation, and sunshine duration may be related to the prolonged ice cover duration since 2002. In sum, accurate measurements of lake ice and water levels are critical for understanding the water resource balance and hydrologic cycle in arid or semi-arid regions of China.     

Systems and Technologies for the Reception,Processing, and Dissemination of Remote Sensing Data at the Russian Aerospace Agency (Rosaviakosmos)

A number of key problems relating to the collection, storage, processing, and dissemination of data from operational remote sensing systems of the Russian Aerospace Agency are examined. More specifically, methods and strategies of Rosaviakosmos are described in the areas of data reception and registry; verification and metrological certification of information; cataloguing, storage, and servicing of users; and the generation of informational products.     

利用矢栅混合数据模式解决WebGIS技术难题——浏览器调阅空间数据速度问题

空间数据库是比一般的数据库要复杂,尤其在WebGIS中更是如此。因为网络传输和带宽的限制,因此如何有效地进行空间数据的调度和显示就成为WebGIS的技术难点。通过构造矢量和栅格混合WebGIS系统数据结构,并在服务端和客户端建立各自的多级缓冲,采用多线程调度方法,解决一直影响WebGIS系统运行速度瓶颈即网络带宽所带来WebGIS运行速度慢问题,提高WebGIS软件调阅空间数据的调度速度,加快页面响应时间。试验表明,利用矢栅混合数据模式能够有效提高WebGIS系统的空间数据调阅速度。