天空光遮挡法水体光谱测量便携版漂浮式光学浮标研发与应用

离水辐亮度Lw(Water-leaving radiance)是水色遥感现场观测中的关键物理量之一,由其计算获得的遥感反射率Rrs(Remote sensing reflectance)是水色遥感参数反演的最基本参数.天空光遮挡法SBA(Skylight-blocked approach)可以直接测量水体离水辐亮度,作...     

海冰微波辐射传输模式和实验研究

海冰是影响地球热循环的重要因素。以海冰和海水的微波热辐射为源,并通过位于海面遥感海冰的３层分层介质系统的分析,取得中间介质厚度与所接收到的辐射亮温有如下模式：ＴＢ＝Ａ＋Ｂｅ－ＣＤ。其中Ａ,Ｂ,Ｃ与遥感系统的极化,使用角度和角频率有关,可以通过实际地面的海冰测试试验获得。该模式符合电磁场在有损介质中的传播特性,反映出被动微波遥感所接收到的能量与传播距离的关系。近几年来,根据该模式,使用４个频段微波辐射计在地面进行实测（入射角为０°）,在飞行中使用３个频段,结果空中和地面基本符合。实践证明其模式是正确的可行的。文中给出在辽东湾测得航线上的冰厚度分布和亮度温度与冰厚度的统计曲线。最后指出影响测量并限制对厚度识别的几种因素。     

Application and Accuracy of Two Fixed Base Camera Systems

This paper discusses the application of two fixed base non-metric camera systems. The first is a helicopter supported 5m boom carrying two 70 mm Hasselblad cameras, fired simultaneously. The 1;850 scale stereomodels, each covering about 40 ×45 m, were used to measure individual tree characteristics, such as crown closure and size. The second system is a portable camera platform designed for microtopography, which used sequential Minolta 35mm photography (1;80 scale) for generating DEMs and computing volume of soil erosion. In both cases, an analytical plotter was used to collect measurements without ground control. With the helicopter boom system, distances and heights were measured to within 5 per cent of true dimensions. With the portable platform system, volume estimates were within 1 per cent of field measurement values. Particular attention is given to the orientation and scaling of stereopairs. Because the air base is used to scale the model, errors in scale due to non-parallel lines of sight are avoided. Advantages and disadvantages of both systems are discussed.     

Sustainable Utilisation of Water Resource in Watershed Perspective - A Case Study in Alaunja Watershed, Hazaribagh, Bihar

Alaunja watershed, located on ‘Chotanagpur’ plateau of Bihar, is mainly under single cropping. The area receives more than 1000 mm of rainfall but it has not been utilised properly to increase the agricultural output. The remote sensing, geophysical, DBTM (Digital Basement Terrain Model) and GIS (Geographic information System) techniques were used for providing scientific database for sustainable utilisation of water resources in watershed perspective. The landuse, soil and surface water body maps have been prepared using remotely sensed data. DBTM has been generated based on depth of basement information derived from geophysical data to provide information regarding aquifer geometry, fracture zones and sub-surface basins. Analysis indicated that surface and groundwater resources have potential to irrigate 53 per cent of geographical area of the watershed. But at present, this available potential has been utilised only to irrigate 7.03 per cent area of the watershed. Feasibility for large scale development of groundwater through dugwell is possible only in 2 per cent area of the watershed. The available groundwater potential to irrigate 28 per cent area of watershed can not be utilised through dugwells. The surface water potential is also poorly utilised. The present study also helped in prioritising the water resource development activities.     

GNSS-R海面测高现状及其常用方法研究进展

全球卫星导航系统(GNSS)不仅具有导航定位、测速以及授时等功能,且因其反射信号能被接收,可用于海面风场、海面高度反演，由此开辟了一个新的研究领域GNSS反射(GNSS-R)技术，GNSS-R技术用于海洋遥感是一个新的研究领域；文中主要介绍了GNSS-R遥感技术和海面测高的研究进展,并从基于信噪比(SNR)数据测量法、基于 C／A码相位测量法、基于载波相位测量法及基于载波频率测量法等方面分析和总结了GNSS-R在海面高度测量的常用方法.      

Gis aided demographic analysis of sub-mountain area of indian punjab-A case study

The present study is an attempt to understand the huge demographic data using GIS at village level. Two blocks from the sub-mountain Siwalik region of Punjabviz. Mahalpur and Garhshankar were selected. Various thematic maps were prepared using this technique. The inequality of distribution between various parameters has been studied using Lorenz curve and Ginni coefficient. Both Mahalpur and Garhshankar blocks are moderately populated blocks with highest population in south western parts. Population density is highest in the areas adjacent to the Garhshankar and Mahalpur towns. Schedule caste population is well distributed in both the blocks. The average sex ratio of the study area is 910 females per thousand males which shows that it is not a female deficit area. There are various villages in these blocks which have sex ratio more than 1000 females per thousand males, which is quite a good sign for these blocks. The literacy rate of the study area is nearly 57 per cent, which is quite low as compared to district Hoshiarpur having 81.4 per cent. Comparatively, Mahalpur block has more literate persons as compared to Garhshankar block. Lorenz curve shows that literate persons are quite evenly distributed. NRI families were around 10 per cent of the total number of families out of which 8 per cent are in Mahalpur block while remaining 2 per cent are in Garhshankar block. The study brings out important inferences at the village level by way of pinpointing the exact location of hot spots where action is needed by the planners and the administration.     

Application of Remote Sensing for Environmental Monitoring in Bijolia Mining Area of Rajasthan

Impact of raining Vindhyan Sandstone, at 3D centres spread over 617 sq kms, by Open cast method in Bijolia area, Rajasthan on the environment, both trataral and social, assessed ever a period of 20 years (1971-91), revealed that it had affected nearly 20 times the area of lease. The study was earried out using Multidate remote sensing date for 1984 and 1991 and topographical maps of 1971, for change detection in land use pattern with the increase in mining activity. Whereas area covered fey mining activity increased by 35.3 times in 20 years, the forest cover decreased by 46.3 per cent The dense forest decreased by 90 per cent and the land under agriculture decreased by 12 per cent Consequently the waste land increased by 67.4 per cent. Hydrologtcal regime was affected by way of blocking the channels and lowering of water table. Solid particulate matter (SPM) values in mining centres were found to be more than double the normal, leading to diseases related to tungs and liver such as Silieosis. Bronchitis, Asthama and T.B. Nearly 25 per cent of workers were found to suffer from one or the other disease. 50 per cent of mine workers suffer from malaria as a consequence of breeding mosquitoes in stagnant waters m mine pits and labour colonies Noise levels at the active zones like drilling, blasting and mine service stations range from 96 to 125 dB as against the permissible limit of 75 dB affecting health and mental facility of mine workers.     

A Study on the Delineation of Coral Reefs in Andaman and Lakshadweep Islands Using RISAT-1 Data

Coral reefs are one of the most diverse of all marine ecosystems and are often referred to as the “rainforests of the sea”. Though they cover less than one per cent of Earth’s surface, they are home to one quarter of all ocean species by providing food and shelter to them. Optical remote sensing has been widely employed for mapping and monitoring coral reefs. But the application of microwave remote sensing has been an alternate domain in this area. This study explores the possibility of utilizing synthetic aperture radar (SAR) data of Radar Imaging Satellite-I, India’s first indigenous microwave satellite to delineate the coral reefs in Andaman and Lakshadweep Islands in the Indian Ocean. The dual polarized data, after reducing the speckle has been classified to delineate the coral reefs in the vicinity of both islands. SAR has a performance comparable with passive optical sensors under favourable conditions of imaging, viz. optimum tidal current and surface winds. The study results are compared with the international coral reef reference map and are found to be highly promising, with an overall accuracy of 98.3% and a Kappa coefficient of 0.944 for fringing reefs in Andaman region. For the atolls in Lakshadweep region, the overall accuracy is found to be 92.99% and the Kappa coefficient is estimated at 0.7377. This study tries to explore a different horizon for microwave remote sensing in coral reef studies. It is seen that, optical and microwave remote sensing can provide a mutually supporting platform in coral reef delineation, in terms of imaging depth as well as climatic conditions.     

Geospatial modelling of biological richness in Sunderbans

The present study attempts to assess the biological richness in Sunderban Biosphere Reserve (SBR) using a three-pronged approach i.e. satellite image (IRS 1D LISS-III) for vegetation/land use stratification, landscape analysis for disturbance regimes assessment and the disturbance regimes together with the ecosystem uniqueness, species richness and importance value for biological richness modelling. The study showed that four mangrove categories, viz., Avicennia, Phoenix, mixed mangroves and mangrove scrub, cover 23.21 per cent of the total geographical area of SBR. The largest area is occupied by mixed mangroves (18.31%). The overall accuracy of the vegetation/land use map worked out to be 91.67 per cent. The disturbance analysis revealed that the vegetation types were not much disturbed. Shannon-Weaver’s index of diversity was highest in case of mixed mangrove. The results revealed that 75 per cent forest area has high biological richness.     

Predicting agricultural drought in eastern Rajasthan of India using NDVI and standardized precipitation index

In the present study, prediction of agricultural drought has been addressed through prediction of agricultural yield using a model based on NDVI-SPI. It has been observed that the meteorological drought index SPI with different timescale is correlated with NDVI at different lag. Also NDVI of current fortnight is correlated with NDVI of previous lags. Based on the correlation coefficients, the Multiple Regression Model was developed to predict NDVI. The NDVI of current fortnight was found highly correlated with SPI of previous fortnight in semi-arid and transitional zones. The correlation between NDVI and crop yield was observed highest in first fortnight of August. The RMSE of predicted yield in drought year was found to be about 17.07 kg/ha which was about 6.02 per cent of average yield. In normal year, it was 24 kg/Ha denoting about 2.1 per cent of average yield.     

高速公路线路放样中长度投影变形的影响和对策

高速公路中平面坐标系需纳入到国家高斯平面坐标系,由于高速公路施工的线路比较长而不可避免地出现长度变形,并导致公路测量放样产生很大的误差。通过分析长度变形的原因以及长度变形对测量放样的影响,提出了减少长度变形对高速公路测量放样的对策。     

空中基线标定与量测

简要介绍用高精度测距系统,结合周日观测和实时基线校准来完成1.86 km,605 m,311 m 3条空中基线边的量测过程,并精确测定出此组空中基线边的长度,测边误差分析后的结果表明空中基线边长度达亚毫米级测距精度.     

Medical photogrammetric measurement: overview and prospects

Since the earliest days of photogrammetry, there have been photogrammetrists who have directed research effort towards medical measurement. Although the specific motivation for these studies has not always been disclosed, it is probably because of the various benefits that photogrammetry can offer to humanity as a painless and non-invasive means of providing medical practitioners with spatial measurement relating to the human body. The intention of this paper is to reflect on the place of the many medical developments within the photogrammetric world. The various photogrammetric applications in medicine are summarised to identify the characteristics of medical photogrammetry, and it becomes evident that medical photogrammetrists have developed a range of body measurements using widely varying photogrammetric techniques, in response to the demands for specialised spatial measurement tools for a wide variety of medical ends. This volume of research activity has made medical measurement a substantial and varied sector of non-mapping photogrammetry. It is also clear that there are numerous challenges to the design of medical photogrammetric systems. They must give paramount consideration to the human patients and their comfort; they must yield not simply spatial data about the body but rather specific medical information. At the same time, it is of concern that non-photogrammetric scientists and engineers have developed medical measurement systems based on both photogrammetric and other optical techniques. Fortunately, photogrammetrists can also contribute to medical problems through their spatial data experiences. It is concluded that the many distinctive challenges mean that medical photogrammetry has not yet been as successful at changing the world as the extensive efforts applied to it suggest, but nevertheless, medical photogrammetry deserves to be recognised as a category of close range photogrammetry which remains a valuable pursuit which should not be abandoned because of any difficulties.     

A comparative evaluation of IRS-1A LISS-II and landsat MSS images using computer-aided lineament data analysis

Lineament patterns detected from remotely sensed data provide useful information to geoscientists, specially in the study of basement tectonics, groundwater targetting and mineral exploration. Improvements in the spatial resolution of satellite images have resulted in the detection of short and faint lineaments which have hitherto gone unnoticed The IRS-1A LISS-II data offers a significant improvement in spatial resolution as compared to the Landsat MSS. A set of computer programmes developed for analysis of lineaments were used to study the parameters such as lineament frequency, length and density in order to quantify the added information derived using IRS-1A LISS-II images. The incremental contribution of LISS-II images are of the order of 100 per cent for lineament frequency and about 60 per cent for total line kilometers of lineaments detected.     

Distribution analysis of salt affected soils under canal and non-canal command area in a part of Etah district,U. P., using remote sensing technique

A World Bank-aided project on sodic land reclamation in Uttar Pradesh is being executed by U.P. Bhumi Sudhar Nigam, Lucknow, and Remote Sensing Applications Centre, U.P., Lucknow has the responsibility of sodic land mapping for the execution of land reclamation programme at the cadastral level. Sodic lands are mainly concentrated in the Gangetic alluvial plains but the problem of sodicity is particularly acute in the canal-irrigated areas. A study of the distribution pattern of sodic lands in canal and noncanal command areas in a reclamation site (covering 60 villages out of which sodic lands were mapped in 51 villages) of Etah district in Uttar Pradesh, indicates that 18.39 per cent area of the canal command villages was barren sodic which was 13.41 per cent of the total geographical area of the site (15417 ha), however, 11.69 per cent area was recorded to be barren sodic in the non-canal command villages which was only 3.16 per cent of the geographical area of the site. The results of soil chemical analysis indicate that barren sodic lands of canal command area are saline-sodic with higher concentration of soluble salts (pH₂ >8.5, EC₂ >4 dSm⁻¹), however, those of non-canal command area are sodic (pH₂ >8.5, EC₂ <4 dSm⁻¹). The post-monsoon ground level in the canal-irrigated areas was in the critical and semicritical zone (< 3.0 mbgl) whereas it was well below the semi-critical zone in the non-canal command area, which indicates that the high ground water level is a major factor to higher the area under sodicity.     

黄河三角洲Sentinel-3高精度时空连续海陆表面温度反演

海陆表面温度是理解全球变化与人类活动的关键参数。针对已有温度反演产品海陆边界时空不连续的问题,本文采用Sentinel-3海陆表面温度辐射计(SLSTR)光学与热红外影像,通过植被指数阈值法逐像元计算陆表与海表发射率,基于分裂窗算法反演得到黄河三角洲陆海表面时空连续温度产品。结合地面温度观测和欧洲中期天气预报中心提供的全球中等分辨率数值大气再分析产品,验证了本文陆海温度产品(均方根误差优于1.1K)反演精度高于现有公开的全球产品,可为全球时空连续温度产品反演提供参考。     

无源微波遥感技术在海冰测厚中的应用研究

　In recent years, microwave radiometry has been developed as a powerful technique for remote Sensing of Sea ice in China. Since 1986 the thermal emission from sea ice in Liaodong Bay and Bohai Bay has been measured by multi-frequency microwave radiometers designed by Changchun Institute of Geography, Academia Sinica.     

全站仪测量过程中仪器高改正问题分析

全站仪,即全站型电子速测仪（Electronic Total Station）。它是一种集光、机、电为一体的高技术测量仪器,是集水平角、垂直角、距离（斜距、平距）、高差测量功能于一体的测绘仪器系统。因其一次安置仪器就可完成该测站上全部测量工作,所以称之为全站仪,并广泛用于地上大型建筑、地下隧道施工等精密工程测量、变形监...     

Thermal Conditions in the Aral Sea (1982-2000) from Satellite Data

This paper presents the results of a study of the seasonal and interannual variability of Aral Sea sea surface temperature (SST) during the contemporary period (1982-2000) using sea-surface-temperature data obtained from NOAA satellites. A comparison was made between present-day temperature conditions in the sea and observations for 1950-1980, as well as with known predictions of its change due to a sea level reduction. Special aspects of temperature conditions in three Aral Sea (northern, western, and central) regions are examined separately.     

Long-term vertical land motion from double-differenced tide gauge and satellite altimetry data

We present a new approach to estimate precise long-term vertical land motion (VLM) based on double-differences of long tide gauge (TG) and short altimetry data. We identify and difference rates of pairs of highly correlated sea level records providing relative VLM estimates that are less dependent on record length and benefit from reduced uncertainty and mitigated biases (e.g. altimeter drift). This approach also overcomes the key limitation of previous techniques in that it is not geographically limited to semi-enclosed seas and can thus be applied to estimate VLM at TGs along any coast, provided data of sufficient quality are available. Using this approach, we have estimated VLM at a global set of 86 TGs with a median precision of 0.7 mm/year in a conventional reference frame. These estimates were compared to previous VLM estimates at TGs in the Baltic Sea and to estimates from co-located Global Positioning System (GPS) stations and Glacial Isostatic Adjustment (GIA) predictions. Differences with respect to the GPS and VLM estimates from previous studies resulted in a scatter of around 0.6 mm/year. Differences with respect to GIA predictions had a larger scatter in excess of 1 mm/year. Until satellite altimetry records reach enough length to estimate precise VLM at each TG, this new approach constitutes a substantial advance in the geodetic monitoring of TGs with major applications in long-term sea level change and climate change studies.