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1.
Alluvial fans are the dominant landforms of the semi-aird and arid environments of the world. Studies on alluvial fans elsewhere suggest that there is a close relationship between the morphology of the fan and the drainage basin area; lithology, mean slope, vegetation, climatic and tectonic environments of the source area. An alluvial fan at Kalanutala village, in Prakasam district of Anthra Pradesh, has been studied in detail in order to analyse it's morphology and arrive at its geomorphic evolution. From a study of fan morphology and it's composition, it has been arrived, at the conclusion that there is a relationship between the fan and it's drainage basin (Kompayasela). Further, this study reveals that the apparent segmentation of the fan is not because of tectonic movement but due to the underlying topography of pediment. The study of fan morphology and its materials suggests that the initial deposition of fan took place in a humid climate, but gradually changed to the present arid climate.  相似文献   

2.
In this study, visible near infrared, shortwave infrared spectral bands of Landsat 8 satellite sensor, two polarisation channel of L band ALOS-PALASAR sensor, SRTM-DEM derived digital elevation data were processed to delineate different geomorphic components of alluvial fans of Tista-Mahanada fan complex. We found image composite of independent components, principal components of Landsat 8 bands were effective in delineating proximal and distal fan segments. Fused images of Landsat 8 and ALOS data were used for enhancing incised distributaries and paleochannels. Field data on depositional sequence of fans, were used to substantiate the image based delineation. Topographic breaks along selected longitudinal profiles (identified with the changes in land use and drainage pattern) of digital elevation data were conjugately analysed using Landsat false colour composites. GPR survey along selected transect highlights the vertical dislocation in the recently deposited sequences of alluvial fan regime indicative of post depositional disturbances.  相似文献   

3.
张霞  吴兴  林红磊  王楠 《遥感学报》2018,22(2):304-312
矿物的种类与含量可限定其形成时特定的地质环境,因此火星表面矿物识别和丰度反演研究对了解火星的地质构造及历史演变过程具有重要意义。Eberswalde撞击坑具有复杂的水文系统,是火星探测的热点地区,而对该地区大范围矿物反演则鲜有研究。基于紧凑型侦查成像光谱仪(CRISM)目标探测模式数据和CRISM光谱库,首先,通过高光谱数据子空间识别算法(Hysime)分析CRISM数据信号子空间,并将光谱库所有矿物光谱投影到子空间上,保留投影误差较小的光谱作为约简后的端元光谱库;然后,使用协同稀疏解混对Eberswalde撞击坑西北部三角洲地区的矿物丰度进行定量反演,得到5种原生矿物:辉石、橄榄石、斜长石、菱铁矿、硬水铝石和1种蚀变矿物透闪石,并从矿物光谱、分布分别对反演结果进行验证;最后,从矿物学的角度对可能成因做出解释,推测该区域存在接触变质作用。  相似文献   

4.
杨树文  刘涛  冯光胜  谢飞 《测绘科学》2013,38(3):166-168
本文在分析冲积扇与其他地物光谱特征差异的基础上,针对Landsat ETM+影像中红光波段与近红外波段的比值能够增大冲积扇与其他地物间差异的特征及地形阴影在蓝绿光波段亮度值降低速率差异较大的特征,基于比值运算、差值运算,构建了冲积扇指数;并利用该模型阈值自动选取算法将冲积扇信息从其他地物及阴影中分离出来,然后根据数学形态学膨胀滤波算法进行空洞填充。经过实验表明,该方法能够高效自动地提取华南山区的冲积扇信息。  相似文献   

5.
Ghagghar river in the alluvial plains of Punjab and Haryana, north-west India exhibits the phenomenon of avulsion in its middle and lower reaches. Study of aerial photographs shows that it has abandoned a 25 km long meander belt between Badshahpur and south of Jaswantpura which lies to the north of the present channel. The present channel course lies at a lower elevation on the flood plain away from the levee deposits which acted as an alluvial ridge.  相似文献   

6.
上黑龙江成矿带主要由早-中侏罗世河流-湖泊-洪积相含煤碎屑岩组成,目前已发现多个中小型矿床,在该区进行成矿预测意义重大。文章利用MORPAS成矿预测系统,采用证据权重法进行了成矿预测工作,在充分研究区内已知矿床的成矿规律基础上,以1：257Y地质图为背景,物化探异常分析子系统对1：20万区域化探数据进行C—A分形确定异常下限,综合现有的找矿标志,提取有利的成矿要素,进行针对处理,制成上黑龙江成矿带MORPAS金成矿预测分析图,提供成矿靶区,为森林高覆盖区提供找矿有利单元。  相似文献   

7.
A comparative study has been made of the usefulness of Landsat and airborne radar images. The study area is situated in the Middle Magdalena Valley of Colombia. It consists of a folded sedimentary sequence of Upper Cretaceous to Lower Tertiary rocks, partially covered by extensive volcanic lahar and alluvial fan material.To obtain the full benefit of the spectral information from Landsat and the textual and pattern information from radar, a combined image was produced using the hue and saturation information from Landsat data and the intensity values from radar data.A clear differentiation between old lahar deposits and the recent one caused by the Nevada del Ruiz eruption of 1985 was possible on SAR images. The synergistic radar imagery, particularly used in stereo, is very useful for prediction of future lahar routes and volcanic risk evaluation.  相似文献   

8.
Rajaji National Park in U.P. is a protected area where large number of nomad population live within the park area. Their dependence on the forest for cattle rearing and firewood has caused degradation of the forests. Proximity to settlements outside the park further adds to the problems. In the present study, forest cover and river, bed changes have been attempted by using temporal aerospace data of the year 1960 and 1993. Subsequently, PAMAP GIS package has been used for the change detection analysis. The study indicates that the land cover changes are mainly due to biotic factors. Some of the important changes in forest cover are: (i) transformation of mixed forest to scrub forest in 67 ha (ii) the sal mixed and mixed sal forest categories have replaced sal forest in 262 ha (iii) significant increase in forest plantation i.e. 2075 ha in the year 1960 to 3793 ha in 1993 (iv) eighteen times increase in Chirpine area, it increased from 13 ha in 1960 to 230 ha in 1993. The land cover changes in 6663 ha (45%) out of 14962 ha of the study area. The consequential changes in the river beds due to the change in the forest cover was also analyzed. During this period river beds with boulders have increased by 87 ha. These river bed changes include lengthening and broadening of river and change in river course.  相似文献   

9.
Haryana-Punjab plain (Yamuna-Sutlej interfluve) is part of the Indo-Gangetic foreland basin and makes the eastern part of the Indus River system. It is characterized by southwestern regional slope and is made up of sediments derived from the Himalayan front. The southern part of the Haryana-Punjab plain has a narrow northeast sloping surface, made up of sediments derived from the Rajasthan craton, making the peripheral bulge of the basin. The area of interaction of these two opposing slopes is marked by a rather flat region of poor drainage with a number of water bodies. This interactive zone of the two slopes has a constricted belt of westerly outlet merging in the Indus alluvial plain. The excessive sediments derived from the Himalayan front formed mega-fans, which in Late Pleistocene, extended down to 200 m altitude close to the southern limit of Haryana-Punjab plain. There are geomorphic evidence of punctuations in reduction in fan building activity during Late Quaternary with terminations at 225 and 300 m altitude, prominently seen in satellite imagery and Digital Elevation Model (DEM). The Haryana-Punjab plain also exhibits undulations with prominent highgrounds around Bhatinda, Hissar, and Sonipat-Jind. During the Late Quaternary, the streams of Yamuna-Sutlej interfluve region, viz., Dangri (sometimes referred as Tangri), Ghaggar-Saraswati, Markanda and Chautang, drastically reduced their carrying capacity due to reduced monsoon activity and neotectonic block movements. These streams abort within their terminal fans. Yamuna River is confined within its valley having prominent flood plain (T0) and well-developed Newer Alluvial plain (T1); as such it has not been a part of Indus system, at least during Holocene.  相似文献   

10.
Parts of Indogangetic alluvial plain and southern part of Simla-Himalayas were studied to evaluate the ground water potential zones through hydromorphogeological mapping using various remotely sensed data. Black and white panchromatic aerial photographs were mainly used to differentiate different lithounits whereas MSS and TM FCC were used to delineate the major trends of lineaments. IRS LISS-II CCT was used for digitally generating enhanced False Colour Composite, Principal Component and Filtered products for better correlative studies. Different rocks of Subathu and Siwalik groups form the structural hills of high to low relief which are mainly runoff zones. The alluvial fan forming piedmont zone has been further subdivided into upper and lower piedmont zones. In order to ascertain ground water movement and occurrence, the infiltration and discharge zones were established. Other local potential discharge zones were also considered. Ground water occurs under semi-confined to confined conditions and good prospects of potable water are present in the area.  相似文献   

11.
Changes brought in habitat conditions due to increasing human influences on natural areas have posed serious threat to wildlife. Remote Sensing has probably omerged as one of the most viable techniques to assess and monitor habitat conditions. Comparative analysis of maps of two-time period can provide authentic data with respect to changes brought in the habitat conditions. Chandaka Wildlife Sanctuary, covering an area of 213.71 sq. km in Orissa is one of the natural reserves of elephants which has undergone serious changes brought in through anthropogenic activities of urban areas of Cuttack and Bhubaneshwar lying within the proximity of the sanctuary. The natural reserve, an ideal habitat for elephants, was connected to neighbouring extensive forest belts. These connections have been either degraded or deforested over the years. The present study analyses the types of habitat available in the sanctuary using remote sensing data (aerial and satellite). Vegetation-type maps of 1975 have been prepared from B/W aerial photographs of 1:25,000 scale. For assessing the current vegetation types, maps have been prepared from Indian Remote Sensing Satellite (LISS II) false colour composite on 1:50,000 scale. Comparative evaluation of the maps indicates changes in the vegetation pattern, increase in mining and agriculture areas within the sanctuary. Stratified field sampling of vegetation types provide structural characteristics of the vegetation. Bamboo has been found to extend in the valleys and side slopes of the sanctuary area during past 15 years. An analysis on response of vegetation in all major vegetation types mapped have been made in the context of the invasion of Eupatorium odoratum. Finally, bamboo biomass has been assessed through stratified random sampling as it constitutes a major elephant food source.  相似文献   

12.
The 2001 Bhuj earthquake (Mw 7.7), one of the most severe earthquakes in the recent history of India, reactivated various existing active faults. It is manifested in the form of coseismic ground fissures/cracks and upheaval of land in the form of bumps. Identification and reactivation of Loriya Fault is established by 1—Geomorphic changes with the help of digital imagery (LISS III images). 2—Coseismic changes through ground checks and 3—Geophysical signatures through magnetic and gravity survey. A lineament cutting the north-western part of the Pur River alluvial fan has been revealed by satellite imagery. The streams flowing along the lineament add to the evidences of a weak plane, while the occurrence of coseismic ground fissures confirms the existence of an active fault. No dip slip movement is recorded in the trenches made across the Loriya active fault while the en-echelon pattern of ground fissures suggest strike slip movement along the fault due to 2001 earthquake.  相似文献   

13.
The present study aims to estimate the long term changes in sea ice areal extent (SIAE) around Antarctica using Special Sensor Microwave Imager (SSM/I) satellite data (1988–2011). Daily, weekly and monthly brightness temperature (TB) maps of Antarctica have been generated. Temporal variation in monthly averaged TB values of sea ice have been analyzed and an increasing trend is observed in TB. Sea ice concentration (SIC) values are estimated and the concentration class 0.85–0.95 is observed as the main contributor in sea ice areal extent during the Antarctic peak winter month i.e. September and October. SIC changes rapidly from October onwards and shows fast melting of sea ice, however, from April start of freezing has been observed. Continuous increase in SIAE is observed from February to September in all the analyzed years (1988–2011) data. In this observation period maximum SIAE is observed in September 1989 and minimum in February 1993. The Moderate Resolution Imaging Spectroradiometer (MODIS) data is used for the validation of SIAE values. SSM/I and MODIS estimated SIAE values are compared (R2?=?0.98) and a relation between them is established by performing regression analysis. This relation is further used for the estimation of corrected SIAE values. The monthly average sea ice extent maps of last three decades have been analyzed and a shift in onset of freezing of sea ice has been observed. The period of frozen sea has also been observed as decreased.  相似文献   

14.
Singrauli Coalfield spreading over an area of about 300 sq km along Uttar Pradesh and Madhya Pradesh border in the central part of India, is witnessing rapid industrialisation due to a large number of open pit coal mining projects and Super Thermal Power Station (STPS). Large scale mining activities along with operation of STPS have generated a great deal of environmental stress not only on the landuse pattern but also on various ecosystems in this region. An integrated remote sensing study was conducted to assess the impact of industrialisation on landuse pattern in the area under reference. The multispectral, multi-temporal data (1975, 1986 & 1991) of LANDSAT MSS and TM duly supplemented with ground truth were studied for generation of multidate landuse maps. Data base for landuse for the years 1975, 1986 and 1991 was created using PAMAP GIS for landuse analysis and change detection for optimal utilisation, planning and management of land resources. The study has revealed that the areas under built-up land, mining and fly ash pond have increased substantially from 1975 to 1991. Loss in forest cover and agricultural land has occurred due to rapid industrialisation in this region. It has been observed from the comparison of 1986 and 1991 data that the wasteland generated due to deforestation for initiating coal mining projects has gradually been reclaimed under operation “Green Gold” launched by Northern Coalfields Ltd. Further the wastelands have been effectively utilised for establishing the STPS, townships as well as other infrastructures in this area.  相似文献   

15.
In the present study analysis of Landsat MSS, TM and SPOT imagery and digital analysis of IRS LISS-1 data of Doon Valley was carried out. Various geomorphic features were identified and classified, morphostratigraphy of the area has been established. Main geomorphic units of the area are Mussoorie Hill Range (Denudational), Siwalik Hills (Structural), Remnant Hills (Residual). Siwalik Piedmont. Doon Piedmont, River Terraces and Flood Plain. Three large fan lobes are identified on Doon Piedmont deposits, viz., Western fan lobe, Central fan lobe and Eastern fan lobe. Average slope of these three fan lobes are 2°21′, 2°3′, and 1°24′ for the western, central and eastern fan lobes respectively. Western and central fan lobes have been affected by neotectonic activity which is reflected in transverse profiles.  相似文献   

16.
The study deals with making land evaluation for sugarcane, wheat and paddy cultivation in the semi-arid central alluvial plains in district Rohtak, Haryana. The special feature of this study is the use of soil survey data obtained from the interpretation of aerial photographs (1∶25,000) with limited field checks for making soil classification. Methodology of land evaluation is based on F.A.O. frame work and an attempt has been made to extricate land qualities from the information contained in the texa of soil Taxonomy identified in the surveyed are. The study successfully demonstrates a systematic, fast and economic way of making land evaluation for sound landuse planning in an area for agriculture development. On the basis of this study, highly suitable (S1), moderately suitable (S2), marginally suitable (S3) and currently not suitable (N1) land mapping units for the cultivation of sugarcane, wheat and paddy have been identified and their respective percentage area calculated for the study area.  相似文献   

17.
Digital image processing on IRS-1C-LISS-III data acquired on October 13, 1998 has been carried out to map the land use classes in part of the Kandi belt, the submontane tract lying in the Outer Himalaya of Jammu region of Jammu and Kashmir. Supervised classification has been combined with rule-based classification to delineate various land use classes. The various categories of land use in the area recognized are forest, agriculture, riverbed, urban, fallow, wasteland and water. Forest is dominant along the upper boundary of the Kandi belt (along Siwalik) and on ridges, whereas, agriculture land is mainly along the lower boundary (along Sirowal) of the study area.  相似文献   

18.
The studies on forest cover change can reveal the status of forests and facilitate for its conservation planning. Idukki is the largest district in the state of Kerala having a total geographical area of 5019 km2. The objectives of the present study are to map forest cover in Idukki district using multi-temporal remote sensing data (1975, 1990, 2001 and 2012) and topographical maps (1925), to analyze the trends in deforestation and land use changes. Overall statistics for the period of 1925 indicate that about 4675.7 km2 (93.2 %) of the landscape was under forest. The forest cover in 2012 was estimated as 2613.4 km2 (52.1 %). Recently, due to the implementation of policies and protection efforts, the rate of deforestation was greatly reduced. The commencement of hydroelectric projects during 1925–1990 responsible for an increase of area under water bodies by inundating other land uses. The long term analysis shows agricultural area been decreasing and commercial plantations been increasing in the district. There has been a significant increase in the area of plantations from 1236.2 km2 (1975) to 1317.3 km2 (2012).  相似文献   

19.
Mangroves of the Marine National Park constitute the second largest patch of mangroves in Gujarat, extending up to 11,000 ha, comprising six species of mangroves. Earlier studies carried out using remote sensing data pertained to baseline data generation and mapping and monitoring the mangroves (density-wise) of the Park from 1975 to 1993. Using IRS IC/ID LISS III data (1998–2001) supported by ground data, the distribution of different mangrove communities in the Park has been attempted. Amongst various image-processing techniques, band ratioing followed by supervised classification gave the best result (classification accuracy was 92%).Avicennia community is the most dominant community accounting for more than 70% of the area. TheRhizophora community occupies the inward margins of the creeks and theCeriops community is present in the interior regions. The ecotone between the marsh and mangrove communities has been identified as the transitional mangroves (Avicennia alba, Sueada), representing the transition from the less saline mangrove to the highly saline marsh community. The zoning of the mangroves has also helped in assessing the diversity of the region. Based on the richness of species, three areas, namely Bhains Bid, North-east Dide Ka Bet and South-east Chhad Island have been identified as highly diverse (most suitable area for preservation).  相似文献   

20.
香宝  刘纪远 《遥感学报》2003,7(3):316-320
对1982—1993年气候年际变化的强信号——ENSO进行了确认及再分类。以美国地质调查局EROS中心提供的AVHRR 8km NDVI为数据源，应用地理信息系统技术，计算了1982—1993年每年夏季(5—9月)NDVI平均影像。在此基础上用数据断面分析法对ENSO年东亚地区土地覆盖的空间分布进行了分析，再用主成分分析法对同一时间序列NDVI平均影像进行了运算，发现其第7主成分影像所反映的土地覆盖分布与数据断面分析法所反映的结果是一致的。对此，进一步分析了第7主成分的特征向量与代表ENSO变化特征的南方  相似文献   

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