Mass Balance Estimation of Dokriani Glacier in Central Indian Himalaya Using Remote Sensing Data

Dokriani Glacier is regarded as one of the important glaciers of Bhagirathi River basin, which fed river Ganges. The length of the glacier is about 4.6 km, and snout elevation is about 4028 m m.s.l. The mass balance of this glacier was calculated using field-based measurements for few years during 1994 to 2000. However, due to remote and poor accessibility, the field-based measurements could not continue; thus, remote sensing-based methods become useful tool to estimate the long-term mass balance of the glacier. In this study, glacier mass balance has been determined using accumulation area ratio (AAR) method. Remote sensing data sets, e.g. Landsat TM, ETM?+?and OLI, have been used to estimate AAR for different years from 1994 to 2014. An attempt has also been made to develop a mathematical relationship between remote sensing-derived AAR and field-observed mass balance data of the glacier. Further, this relationship has been used to estimate mass balance of the glacier for different years using remote sensing-derived AAR. Estimated mass balance was validated from ground-observed mass balance for few years. The field-observed and remote sensing-derived mass balance data are compared and showed high correlation. It has been observed that AAR for the Dokriani Glacier varies from 0.64 to 0.71. Mass balance of the glacier was observed between ??15.54 cm and ??50.95 cm during the study period. The study highlights the application of remote sensing in mass balance study of the glaciers and impact of climate change in glaciers of Central Indian Himalaya.     

Detection of Changes in Glacier Mass Balance Using Satellite and Meteorological Data in Tirungkhad Basin Located in Western Himalaya

Himalayan glaciers and their mass balance are poorly sampled through direct mass balance measurements. Thus, based on Landsat datasets of ETM⁺ (2000), ETM⁺ (2006) and TM (2011), mass balance studies of 32 glaciers was carried out using accumulation area ratio (AAR) method in the Tirungkhad river basin, a tributary of Satluj River, located in western Himalayan region. The overall specific mass balance was negative varying from ?27 cm (2000) to ?41 cm (2011). Out of 32 glaciers, 27 glaciers (81.2 %) showed negative mean mass balance and 5 glaciers (18.7 %) showed positive mean mass balance. Mean of specific mass balance for the year 2000, 2006 and 2011 was found to be ?48 cm, ?55 cm and ?0.61 cm respectively, in case of glaciers with negative mass balance while in case of glaciers with positive mass balance, it was 0.67 cm (2000), 0.56 cm (2006) and 0.47 cm (2011). The investigations suggested a loss of ?0.034 km³ of glacial ice for 2000, 0.036 km³ for 2006 and 0.038 km³ for 2011 respectively. The negative mass balance of the glaciers since 2000 correlates well with the increasing trend of annual mean temperature and decreasing trend of precipitation (snow water equivalent (SWE) and rainfall). Based on Mann Kendall test the temperature and SWE trends were significant at 95 % confidence level, however, the rainfall trend was insignificant.     

青藏高原近30年来现代冰川面积的遥感调查

以1960~1970年间1∶10万比例尺地形图、1975年MSS数据和2000年前后ETM数据为信息源,采用现代遥感技术,按自然山系对青藏高原现代冰川面积进行调查,基本查明了各山系内现有冰川的面积以及近30 a来冰川面积减少的数量:青藏高原现有冰川面积46 887.23 km2,减少了3 941.68 km2,年均减少131.4 km2。     

高山冰川多时相多角度遥感信息提取方法

提出一种多角度遥感影像的冰川信息提取方法。通过"全域—局部"的阈值分割方法获取短时期内不同时相的遥感影像的冰雪边界,结合地形信息和多时相遥感影像的太阳角度信息,联合消除山体阴影对冰川的遮挡,并以多期影像的最小冰雪边界作为最佳冰川边界。以托木尔峰西侧冰川为研究对象,采用2009—2010年4个时相的遥感影像提取冰川信息。结果表明多角度遥感提取的冰川边界效果好,能有效地排除积雪与山体阴影的干扰。     

遥感影像的冰川信息提取方法对比

以林芝地区为例,首先利用2001年10-12月ETM+遥感数据、地质图和DEM数据,经过遥感图像预处理生成冰川信息提取的基础影像。在此基础上采用波段比值法、主成分分析法、光谱角制图法、非监督分类法、监督分类法等进行冰川信息的自动提取,对各种提取方法进行了对比。结果表明,监督分类提取的冰川信息图像清晰、层次分明、分类边界清楚、满足冰川地貌解译的要求。最后通过实例分析得出监督分类法在提取林芝地区冰川信息时获得了较好的应用效果。     

现代遥感技术在地震灾害中的应用

现代遥感技术是非常重要的数据获取手段,为了研究现代遥感技术与地震灾害之间的关系,结合512汶川大地震实例,分别从灾前、灾中和灾后三个阶段进行了分析,阐述了现代遥感技术在地震灾害中的广泛应用。     

Modeling Urban Growth Using GIS and Remote Sensing

Based on remote sensing and GIS, this study models the spatial variations of urban growth patterns with a logistic geographically weighted regression (GWR) technique. Through a case study of Springfield, Missouri, the research employs both global and local logistic regression to model the probability of urban land expansion against a set of spatial and socioeconomic variables. The logistic GWR model significantly improves the global logistic regression model in three ways: (1) the local model has higher PCP (percentage correctly predicted) than the global model; (2) the local model has a smaller residual than the global model; and (3) residuals of the local model have less spatial dependence. More importantly, the local estimates of parameters enable us to investigate spatial variations in the influences of driving factors on urban growth. Based on parameter estimates of logistic GWR and using the inverse distance weighted (IDW) interpolation method, we generate a set of parameter surfaces to reveal the spatial variations of urban land expansion. The geographically weighted local analysis correctly reveals that urban growth in Springfield, Missouri is more a result of infrastructure construction, and an urban sprawl trend is observed from 1992 to 2005.     

海量遥感影像的存储与快速调度显示方法

随着计算机技术的发展,计算机的存储和处理的功能越来越强大,但是仍然无法满足日益增加的海量信息处理的需要。因此研究如何利用有限的计算机内存,处理无限大小的数据,成为研究的重点。本文根据海量遥感影像数据的特点以及对海量遥感图像进行处理的需要,研究了实现海量图像数据快速显示的方法以及其数据库存储结构。主要包括图像重采样、影像金字塔生成技术、图像快速显示技术等。     

Using Thermal Remote Sensing in Environmental Studies

Thermovision is a relatively new method of remote sensing with applications in areas such as military operations, residential monitoring, technological process control and emergency management. Surprisingly, it has not seen much application in environmental studies. The article presents a method of using thermovision for topoclimatic studies. The method is based on the spatial distribution of land surface temperature (LST). The LST distribution indicates the amount of solar energy reaching the Earth surface and depends primarily on terrain shape and land cover types. By analyzing the LST distribution, one can determine spatial topoclimatic variability. The LST derived topoclimatic classification was compared with the theoretical topoclimatic classification based on heat balance. New classes of topoclimates were created and some of the existing types were diversified into more detailed subtypes. The analysis of selected lowland areas in north‐western Poland revealed that both land cover and terrain shape characteristics had a significant impact on the LST distribution, contrary to the expectation of land cover characteristics being more important than terrain shape. The article demonstrates the possibilities of using thermovision in environmental research and presents a new method of topoclimate delimitation based on thermal remote sensing data and geographical information systems (GIS) techniques comparing. The LST classification method with conventional methods based on DEM and land cover analysis.     

遥感图像准无损压缩技术的研究

提出了一种基于图像恢复技术的遥感图像压缩技术,在提高遥感图像压缩比的同时,使压缩后的重建图像质量达到准无损的技术要求。对SRTF、TM图像的试验结果表明,该技术是可行的。     

遥感技术在泥石流沟调查中的应用效果

本文结合成昆铁路泥石流沟的遥感调查工作,归纳了利用遥感图像判别泥石流沟的工作步 骤；介绍了宏观定性判别和统计分析判别两种判别方法,着重说明利用遥感图像判别泥石流沟, 较常规方法不仅大大提高了判别的准确性,而且可以节省大量财力、物力和人力,具有很好的经 济效益和技术效益。     

遥感自动提取海岸线方法

利用遥感技术确定海岸线位置的问题受到关注由来已久,就其在国内外的研究现状做了介绍,利用小波边缘检测算子提取出黄河三角洲河口区2004年Landsat TM图像的海岸线位置;在分析小波算子与传统边缘提取方法相比的优点的同时,并就其存在的不足提出了今后的研究重点。     

遥感技术在城市研究方面的应用探讨

遥感技术是二十世纪快速兴起的一门技术学科．目前在城市研究中得到了广泛的应用。本文介绍了城市典型地物(水体、植被、道路以及工矿建筑等)的波谱特性，在此基础上探讨了遥感技术在城市规划与城市环境方面的应用。     

Water Balance Study for a Basin Integrating Remote Sensing Data and GIS

Water balance of a basin involves estimation of input precipitation, runoff, infiltration and evapotranspiration (ET). Although ET may have large variations over a big basin, it is commonly estimated using a few point measurements and this makes the estimation error prone. Satellite based remote sensing data provides few parameters for estimation of energy fluxes, at the land surface and atmosphere interaction in a distributed manner using the meteorological parameters. These parameters through surface energy balance equation have been used for the estimation of ET in this study. Various spatially distributed variables required for ET estimation; viz. NDVI, surface albedo, surface temperature etc. have been derived using remote sensing and ancillary data for Tapi basin located in western India. Beside this field data such as rainfall, air temperature, relative humidity, sunshine hours etc. have been used. For computation of runoff, Soil Conservation Services (SCS) approach has been considered. Tapi basin up to Ukai dam has been selected as the study area. Satellite data from National Oceanic and Atmospheric Administration (NOAA), Polar Orbiting Environmental Satellite, which carries the Advanced Very High Resolution Radiometer (AVHRR), have been used for preparation of various maps required for runoff and ET analysis. The results of runoff and ET have been compared with observed data for 2 years, 2002–2003 and the results have been found in good agreement with observed data.     

Mapping the Extent of Agroforestry Area in Different Altitudes of Tehri District,North Western Himalaya,India Through GIS and Remote Sensing Data

Assessment of area under agroforestry in Tehri district of North Western Himalaya, Uttarakhand, India has been done using GIS and remote sensing technology. The study district characterized by hilly terrain with varying elevations from 288 m to more than 2800 m and generally gentle slopes, valleys, flat land covers and agricultural terraces. High-resolution satellite imageries (spatial resolution 5.8 m) were used in this study for land uses and land covers classification. According to unsupervised classification, highest area was found under forest class (65.22%) followed by cropland (20.41%). Considerable area was also found under snow cover (9.45%) in the district. Area under agroforestry was estimated to be 5572.26 ha (1.53%) by this method, whereas it was estimated to be 7029.06 ha (1.93%) by supervised classification. Estimated cropland area comes out to be about 20.0%. An accuracy of 86.5% was found in this classification for agroforestry class. Highest area under agroforestry of 3707.36 ha was obtained in 1200–2000 m elevations followed by 2231.26 ha in 288–1200 m elevations. Negligible area was found on high elevation zones of more than 2800 m. The major agroforestry systems of dominated by Grewia oppositifolia (Bhimal), Celtis australis (Kharik) and Quercus leucotrichophora (Banj) were identified and mapped and remaining systems were grouped as others class. Estimated area under G. oppositifolia, C. australis and Q. leucotrichophora based systems come out to be 2330.82, 1456.80 and 1129.10 ha, respectively. These systems are multiple usufructs are food, fuelwood, fodder, fiber and small timber. It has been observed from the accuracy assessment that the estimates of area under agroforestry obtained under this study are reliable.     

基于ENVI的高分辨率遥感图像应用试验研究

介绍了高分辨率遥感图像用于城市土地利用信息提取的主要过程,应用ENVI软件作为试验研究平台对试验区进行了遥感图像分类处理。试验表明,遥感技术是进行城市土地利用信息提取的有效手段之一,针对遥感图像中出现的水体和建筑混杂的现象,提出了应用监督分类与矢量操作相结合的处理方法,可得到较好的分类结果。     

藏西地区多幅ETM遥感影像的镶嵌方法

利用现有遥感图像镶嵌技术,基于ENVI遥感图像处理软件,以藏西多幅ETM遥感的镶嵌为例,利用色调调整,以及边缘羽化等方法,研究出一套简单易行且效果较好的镶嵌方案,为大量遥感影像的镶嵌工作节约时间和工作量。     

遥感技术在土地利用现状调查中的应用

土地利用现状调查是土地管理的一项重要基础工作,是搞好土地管理工作的前提条件。及时、精确的掌握土地利用现状不仅关系到土地利用规划的编制和政府对土地的科学、有效的管理,还关系到政府对房地产市场的调控和我国国民经济的发展。遥感影像具有探测范围大,资料实时新颖,获取的信息丰富等优点,已经普遍应用于土地利用现状调查中。本次调查利用Mapgis和Envi软件,对安义县精度较高的遥感影像进行几何校正并矢量化,获得了准确的2008年度安义县土地利用现状数据,同时也为安义县土地利用管理及规划的编制奠定了良好的基础。     

遥感技术在考古界的应用进展

遥感技术视野广阔,能使我们对古代遗址蕴涵的古地理、古环境以及古代社会的信息有更深入的了解,成为考古学的新手段。近年来,我国通过介绍遥感技术,普及了遥感知识;遥感技术应用于考古,推动了我国考古事业的发展。本文对遥感考古在我国的应用成果进行了综述。