1999～2009年岷江上游干旱河谷聚落区林地变化特征

岷江上游干旱河谷聚落区林地变化情况是检测长江上游生态环境建设好坏的重要指标.本文基于SPOT遥感数据和GIS技术,以聚落生态位为研究单元,分析1999～2009年岷江上游干旱河谷聚落区林地变化特征.结果显示:1)1999 ～2009年,岷江上游聚落生态位内林地面积增加22.58 km2,理县和汶川县增长率较高,分别为87.5％和89.75％;2)岷江上游干旱河谷聚落区林地以2401 ～2600 m为中心呈准正态分布,林地面积增加集中于海拔1 801～2800m地带;3)林地主要分布于15° ～25°之间,不同坡段林地面积均增加,增幅介于36.31％～73.68％之间;4)林地分布呈现北坡与西坡高于南坡与东南坡的特征,受水分与湿度条件影响,北坡和西坡方向上林地增加最多,分别为64.02％和62.78％.因此,由于退耕还林等生态工程的实施,岷江上游干旱河谷聚落区生态环境得到改善.     

四川茂县岷江河谷区段滑坡隐患雷达遥感识别与形变监测

长期以来,中国四川省茂县地区受地质、地形条件和构造活动的影响,滑坡等地质灾害频发,给人民的生命财产和公路等基础设施安全带来了巨大的威胁,因此需要对滑坡隐患区域进行有效识别和监测。以时序哨兵1号A、B卫星(Sentinel-1A/1B)影像为数据源,利用时间序列合成孔径雷达干涉测量(interferometric synthetic aperture radar, InSAR)技术对茂县岷江河谷区段的潜在滑坡隐患开展识别监测,对重点区段进行了分析,同时分析探讨了InSAR滑坡监测中不同轨道数据的视线方向形变测量灵敏度差异。从实验结果中成功探测识别出了茂县岷江河谷沟口乡至石大关乡段的20余处滑坡隐患,现场实地考察验证了识别结果的准确性,证明了时序InSAR方法在高山河谷区滑坡隐患识别监测中的有效性。     

“3S”技术在四川生态环境动态监测中的应用研究

为有效实现四川省生态环境的动态监测,运用RS、GIS和GPS技术,以2004年中巴资源卫星(CBERS-02)遥感影像数据为信息源,2000年TM遥感影像解译的数据为基础,对2004年遥感影像进行解译,修改2000年数据库;手持GPS接收机,在野外对解译成果进行验证,更新数据库;利用GIS技术的空间分析功能,提取出2000～2004年期间土地利用/覆被变化信息,得到2000～2004年期间四川省高精度的土地利用/覆被变化数据库。最后对四川省土地利用/覆被变化信息进行分析,对四川省生态环境的下一步研究指名了方向。     

应用ZY-3监测博斯腾湖地区生态环境变化

通过ArcGIS平台对博斯腾湖地区资源三号卫星高分遥感影像数据进行生态环境因子识别提取,计算出2014年荒漠化土地面积为3 957.27 km2,湿地面积为1 242.93 km2。对比2007年遥感监测成果数据,荒漠化土地面积减少208.60 km2,年变化率为-26.08 km2/a;湿地面积增加12.33km2,年变化率为+1.54 km2/a。综合分析近年来博斯腾湖地区气候变化及人类活动,表明博斯腾湖生态环境的变化受到自然因素和人类活动的共同影响。地表径流的增加促进林草的生长,优化了湿地生态系统,抑制了荒漠化的发生与发展,人类活动的增强使湖泊的自然功能逐渐转成水库功能。加强博斯腾湖水资源及其他自然资源的科学管理与合理利用,对协调、平衡该区域生态环境系统具有重要意义。     

基于RSEI的生态环境质量评价及驱动力分析——以闽江流域(福州段)为例

生态环境对社会经济可持续发展至关重要。为了研究闽江流域(福州段)生态环境的变化情况,本文以2010、2015和2021年的遥感影像为基础,通过主成分分析构建遥感生态指数(RSEI),对闽江流域(福州段)近12年的生态环境质量进行评价和监测,并结合地理探测器对其变化原因进行分析。结果表明：(1)闽江流域(福州段)2010、2015和2021年的RSEI指数分别为0.62、0.70和0.68。(2)大部分地区的RSEI指数等级为良和优;生态变好的面积大于生态变坏的面积,生态环境整体向好发展。(3)干度和热度是生态环境质量时空变化的关键驱动因子。     

基于In SAR技术天山乌吐劲河谷同震形变遥感研究

基于ALOS/PALSAR雷达卫星影像,采用合成孔径雷达干涉测量(interferometric synthetic aperture Radar,InSAR)技术,重建地震形变前后的数字高程模型(digital elevation model,DEM),经RTK校验后利用差值算法反演天山乌吐劲河谷地震同震场形变特征。研究结果表明:①去尖三角状崩塌形变面积为104. 47万m2,崩塌量为1 461. 60万m~3,起始端高程为3 225 m,平均坡度为48°,坡向为NNW;②喇叭状堆积形变面积为78. 61万m~2,堆积量为1 424. 27万m~3,掩埋深度为35～80 m;③河道南岸堆积形变将河床向北推进了100 m、向东推进了300 m;④崩塌形变阻塞河道后导致水体形变,形成堰塞湖水面面积在30 d内由原有的0. 039 km~2增大至0. 059 km~2,并在2010年湖面面积出现峰值0. 146 km~2;⑤形变原因不仅是由于其处在地震活动带上,还有石灰岩岩性、地形坡度和断裂构造等综合因素作用的结果。     

基于GIS、RS的野鸭湖及周边湿地资源动态变化分形研究

介绍了分形几何学理论及其特点。首先,基于GIS、RS技术,利用多源遥感影像融合技术和GIS叠置对比分析功能、人机交互解译,得出北京市野鸭湖湿地自然保护区及周边区域在1998年、2000年和2002年湿地资源现状;再利用方正智慧软件统计出各类型湿地图斑的周长和面积,并求出面积、周长的对数,根据二维欧氏空间分形维计算模型,计算出各类型湿地资源的分形维数值和稳定性指数;最后,根据分行维数和稳定性指数的物理意义,揭示了野鸭湖地区湿地资源的动态变化情况。研究表明,沼泽和湖泊是该区域湿地环境的主体,也是最脆弱的湿地要素;湿地资源分形维数(D)和稳定性指数(SK)可以为湿地环境评价、湿地资源的合理利用与可持续发展提供决策依据。     

利用3S技术综合研究新疆塔里木河流域中下游11年生态环境变化与成因

介绍了综合运用RS、GIS和GPS（3S）技术对新疆塔里木河流域中下游土地覆盖与土地利用、植被指数、人口经济等主要生态环境要素的遥感时序信息提取、GIS数据分析和GPS野外定点检测。总结出塔里木河流域中下游地区从1990-2000年的11年间农业用地面积增加了505.433km^2，整个自然/半自然植被的面积减少了943.089km^2，水体面积增加了80.477km^2，塔河中下游天然植被大面积衰败和死亡，尤其是胡杨林面积锐减，致使沙漠化面积不断扩大。初步提出了生态环境修复和治理建议。通过研究还建立了新疆塔里木河流域中下游3S生态环境动态监测系统。     

上海近十年来城市化及其生态环境变化的评估研究

为了了解上海近十年来的变化,应用遥感变化检测方法来评估研究近十年来上海的城市范围及城市生态方面的扩展和变化,即一方面利用从土地覆盖衍生出的城市化面积指数(UAI)来反映城市扩展的速度,另一方面应用植被覆盖率(FVC)变化来评估城市生态环境的演变.研究中,首先对2000～2009年的MOD13Q1影像按照年叠加反演出.N...     

近10年连云港海域紫菜养殖区遥感监测与分析

近年来连云港海域紫菜养殖面积不断增大,为监测其发展趋势,本文利用Landsat-5、Landsat-7和Landsat-8卫星遥感影像为数据源,结合GIS空间分析方法,同时采用2017、2018年海域无人机影像对同期卫星影像目视解译结果开展精度验证,得出紫菜养殖区目视解译精度,以此获取近10年连云港海域紫菜养殖范围、面积和分布变化情况。结合等深线数据,开展不同深度区紫菜养殖面积增加和减少情况分析。该研究从宏观的角度掌握了连云港海州湾海域紫菜养殖的动态变化情况,对连云港市海域使用现状监管和海洋生态环境监测起到一定的技术支撑作用。     

利用国产GF-1卫星数据实现山区细小河流河宽的自动提取

以国产GF-1卫星影像为数据源，选取皇甫川流域内山区细小河流密集的上游1421 km²作为研究区域，针对因山区河流河道狭窄、形态复杂等导致的河流边界提取难度大、精度差、河宽无法自动提取的难题，首先利用改进的变异系数法筛选水体指数，再采用改进的决策树法结合DEM河网精确获取河流边界，最后通过自动化河宽提取算法实现对山区细小河流及其河宽的自动提取。结果表明，本文方法对山区河流判别的总体精度为89.5%，有效地排除了山体阴影等地物的干扰。对河宽为0~10 m的极细河流，本文方法提取河宽的误差为18.54%；10~30 m的细小河流，提取误差为12.07%。     

Remote sensing and GIS application in change detection of the Barak River channel,N.E. India

Rivers flowing through the alluvium invariably have very low gradient forcing the river to flow slowly in a meandering and zigzag path. Nature and intensity of meandering is governed by the geological and tectonic conditions of the river basin. Barak River in tectonically active south Assam (Northeast India) exhibits intense meandering and shifting of the river course. Topographic data of two different years and satellite images of 4 different years covering a section of the Barak River have been investigated to verify the nature of changes undergone by the river through times. This study reveals active northward shift of the river and a prominent neck-cut off in the initial part of the study area. Northward shift of the river also occurred in the area west of Silchar. But, in the western part the river has shifted both towards north and south. Oscillatory shifting in the river channel has also been noticed. The river has shown a overall northward shift which is probably due to uplift of the southern part of the Barak River valley.     

Mapping and Change Detection Study of Nepal-2015 Earthquake Induced Landslides

The devastating earthquake that struck Nepal in 25 April (Mw7.8) and 12 May (Mw7.3) 2015 have triggered numerous landslides and reactivated existing landslides extending over large areas. These two shocks mostly affected the northwest and northeast region of Kathmandu which accelerated large region along with southward up thrusting in the region. To detect the event of the landslides in time and space satellite images have been analysed using space remote sensing techniques like pseudo colour transformation technique and was employed to pre and post-earthquake images of the event to bring out only landslide affected areas from the image by masking the remaining part, where field based survey of the landslides provided information on real nature of it, slope and rock type. Surprisingly the observed mass movements are mostly belong to debris flow and rock fall types beginning from the top part of the ridge slope with south-westerly faces i.e. sun facing. Further, satellite images of different dates could be gathered which facilitated analysis on development of landslide with time. This study also revealed that the NE–SW trending geological faults have controlled the landslide occurrence especially in Ramche area and along the Bagmati river valley near Shital-chowk village on Kathmandu-Hetauda road.     

Use of multitemporal remote sensing data for mapping the Alfios River network changes from 1977 to 2000

Alfios is the biggest river of the Peloponnese and the ninth longest river in Greece. It drains an area of almost 2575 km² in Western Peloponnese and discharges at Kiparissiakos Gulf. Due to its extent, the Alfios basin presents complex physiography and geomorphology.

During the last 50 years, major direct human activities have had an important impact on the river network shape and on the valley floor morphology. The most important human activities were the channel straightening caused by meander cut-offs in 1950, the construction of two dams: the Ladonas dam in 1955 and the Flokas dam in 1968 and the illegal in-stream gravel extraction that started in the 1960s and continues until today. As a result, the Alfios riverbed has presented very rapid vertical and horizontal (lateral) erosion and significant changes to its network shape. The drainage network follows a straighter course, the number of meanders has been reduced and the seventh order branch is deeply incised. Besides the morphological impacts to the river network shape there are also serious economic damages caused by human activity. During the winter of 1999, the Flokas dam bridge was closed for a long period due to damages at its foundation caused by the heavy rain and illegal gravel extraction. Transportation between the villages in the area became extremely difficult and time consuming and the cost of the repairs was estimated at 500 000 euros. In this study, there is an effort to map the network shape transformation for the period 1977–2000 using multitemporal and multisensor satellite images. One Landsat MSS image, three Landsat TM images, two Landsat ETM images, and one Terra ASTER image have been orthorectified and processed in order to cover the specific period. Principal Component Analysis (PCA) method and Geographical Information System (GIS) techniques have been applied to map the changes in the Alfios River channel. The drainage network straightening and the cut-off of five big meanders were detected and mapped. These changes occurred between 1986 and 2000.     

多源高分辨率卫星影像监测黑臭水体的适用性研究

高分辨率卫星的幅宽一般很小,受云雨和轨道回访周期影响,单颗卫星的短时段内覆盖能力有限,因此,单一高分辨率卫星常常无法满足一定时段内的黑臭水体监测需求,需要多源卫星协同监测黑臭水体。为了分析多源高分辨率影像对黑臭水体遥感监测的适用性,本文基于地物光谱仪实测的水体遥感反射率数据,以GeoEye-1、WorldView-2、北京二号(DMC3)、高景一号SV1(SuperView-1)以及GF-PMS系列(GF-1/1B/1C/1D、GF-2、GF-6)传感器波段进行等效计算,结果表明:(1)采用反射率比值模型——BOI(Black and Odorous water Index)模型,GeoEye-1、WorldView-2、SuperView-1和GF-1/1B/1C/1D/2/6影像识别黑臭水体正确率均较高,分别为89.5%、89.5%、92.1%和92.1%。(2)BOI模型不适用于DMC3,这里采用了归一化水体指数NDWI≤0.55判别黑臭水体,识别正确率为89.5%。(3)BOI模型应用于仅有的2景同步卫星影像——GF-2影像,经实测数据验证,识别精度为83.3%,精度较高。针对通州区内的某重叠区,2016年—2021年10颗多源卫星影像协同观测的结果一致性较好,表明了多源遥感影像监测黑臭水体的适用性较好。综合考虑卫星影像空间分辨率和采购成本,给出了合理的协同观测建议。     

Identification of palaeochannels around Cauvery river near Talakad, Karnataka using remote sensing data

Visual interpretation of satellite images could help in the identification of present and past landforms. An attempt has been made to identify the palaeochannels of the Cauvery river in Karnataka state through visual interpretation of IRS-1C, LISS III False Colour Composites (FCC). In order to assess their inter-relationship with other hydrogeomorphic elements, various geomorphic units have been mapped. Major geomorphic units like alluvial plain, pediplain, valley fill. residual hill, ridges, meander scar, channel bars and water bodies have been demarcated. Considering the hydrogeomorphic setup of the palaeochannels. it is inferred that the disposition of palaeochannels of the area are controlled by the geology and structure and the prevailing geomorphic process.     

2004年印度洋海啸印尼亚齐省灾情遥感监测与分析

2004年12月底印尼苏门答腊岛西北海岸发生里氏9.0级地震,引发印度洋沿岸的印尼、斯里兰卡、泰国、印度等国家先后遭受强烈海啸。印度尼西亚亚齐省是遭受海啸灾害最严重的地区之一。为了评估海啸灾害造成的严重影响,应用遥感和地理信息系统技术,以2005-01-07英国DMC小卫星遥感影像为基础数据源,结合收集到的该地区灾前(2001年)LandsatETM 遥感影像,对亚齐省进行了监测和快速评估。监测结果表明距离震中位置较近的亚齐省苏门答腊岛西海岸遭受影响较严重,亚齐省苏门答腊岛西海岸由于距离震中位置较近遭受严重影响,而苏门答腊岛东海岸则影响较轻,受灾最严重的地区是亚齐省首府班达亚齐市附近。经统计,整个亚齐省遭受海啸严重影响的地区面积约为483km2,其中城市建成区受淹面积约为26·2km2,乡村(镇)地区受淹面积约为430·5km2。文章的最后还结合数字高程模型对海啸灾情的结果进行了分析。结果表明,绝大多数因海啸而受淹地区高程低于20m。     

Dleineation and characterization of geomorphological features in a part of lower maharahstra metamorphic plateau using IRS-ID LISS-III Data

In the present study, an attempt has been made to delineate and characterize the different geomorphic units of Tundiya river catchment in a part of Lower Maharahstra Metamorphic Plateau, north-eastern part of Nagpur district, Maharashtra. The drainage, contour and delineated geological units have been overlaid on IRS-ID LISS III satellite imagery (bands 2,3 and 4) in EASI/PACE analysis system to delineate and characterize different geomorphological units and analysis of their processes based on the field observations. The study area is basically of metamorphic in origin with different geological formations and is influenced by the various fluvio-morphological processes. Based on the satellite data analysis, the distinct geomorphological units viz., table top summits, structural hills, subdued plateau, linear ridges, shallow, moderate and deeply buried foot slopes, shallow valley fills and deep valley fills have been delineated and characterized. The information generated from satellite data in the form of vector layers has been used in GIS to generate geological and geomorphological maps of the study area. The present study demonstrates that IRS-ID LISS-III data in conjunction with geology, drainage and contour parameters to enable detailed evaluation of different geomorphological units and analysis of their processes based on the field observations. The delineated geomorphological units can be utilized for evaluation and management of natural resources and geo-environment on sustainable basis at river catchment level.     

Tectonic activity classes along the nahan thrust (NT) in nw sub-himalaya

Morphotectonic analysis using remote sensing images and GIS techniques have been utilized to identify areas experiencing rapid tectonic deformation and to estimate relative variations of tectonic activity along the mountain front in the Morni Hills, marked by the Nahan Thrust (NT) zone. The NT separates the Upper Morni Hills (UMH) from the highly dissected Lower Morni Hills (LMH). The digital elevation model (DEM) of the area draped with the satellite image was used to identify different geomorphic zones mainly based on altitude and dissection by streams. The NT is also marked by incising streams on the hanging wall block that become braided on the footwall block, across the NT, which can be very well picked on the satellite image. The topographic profiles drawn across the NT, using DEM show a sharp break in slope at the mountain front. Morphometric analysis of the mountain front was carried out determining mountain front sinuosity (S_mf) derived from remote sensing images and valley floor/valley width ratio (V_f) indices obtained from topographic profiles using the DEM. The S_mf values vary from 1.1 to 2.4 that are characteristic of low sinuosity mountain fronts. On the other hand, V_f values (0.1 to 0.33) are quite low. Both these indices indicate active uplift of the mountain front and consequent downcutting by streams in the hanging wall block. Further, using the S_mf and V_f indices, two tectonic activity classes: 1 (active) and 2 (moderately active) are identified from the study area.     

Morphometric analysis using remote sensing techniques in the chaka sub-basin, purulia district, West Bengal

Remote sensing techniques using satellite imagery have proved to be an indispensible tool in morphometric analysis and groundwater studies. In the present area, morphometric analysis using temote sensing techniques have been carried out in Chaka river sub-basin of Manbazar Block, Purulia district, West-Bengal, which is one of the most drought affected area in West-Bengal. The parameters worked out include Bifurcation ratio (R_b), Stream length (L_u). Form factor (R_f), Circulatory ratio (R_c), and Drainage density. The morphometric analysis suggests that the area is covered by fractured, resistant, permeable rocks, the drainage network not so affected by tectonic disturbances. Using satellite imageries of LANDSAT and IRS, different hydrogeomorphological units have been delineated. The study shows that moderately weathered pediplains and valley fills are good prospective zones for groundwater exploration.