共查询到18条相似文献,搜索用时 437 毫秒
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运用NOAA-AVHRR资料估算水稻种植面积,是遥感应用领域中一个新的研究方向,结合国家“八五”攻关项目“太湖地区遥感话产”的要求,在太湖地区进行了初步的尝试:(1)根据估产精度要求和NOAA一AVHRR资料校正精度,探讨了运用NOAA一AVHRR资料估产所需的最小区域范围。(2)针对太湖地区的具休地理环境设计了提取水稻种植曲积的技术方案,并在试验区取得了初步成果。 相似文献
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以浙江省为试验区,在地理信息系统支持下综合利用多种地理信息,探讨丘陵地区大面积提取水稻种植面积信息的可行性。开展了分类识别方法的比较试验及训练样点相对稳定性试验。针对丘陵地区的复杂地形,在数字化地形图的基础上,建立数字地形模型(DTM),并衍生出地面坡度等地貌因子的数字化图像,结合NOAA/AVHRR数据,进行分类。试验结果表明,传统的分类识别方法中,最大似然法的分类精度可满足业务化运行的要求;建立在混合像元分解基础上的模糊监督分类,有较高的分类精度和较好的稳定性,具有较强的适应性;地貌因子参与遥感影像的分类,不仅可以有效地提高丘陵地区水稻种植面积信息的提取精度,而且还可以使面积信息提取精度保持一定的稳定性,提高空间精度;为探讨丘陵地区水稻种植面积信息遥感提取的可靠性和客观性,在训练样点保持相对稳定的前提下,对1996年和1997年浙江省水稻种植面积进行测算,两年的数量精度均在92%以上。 相似文献
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利用洪河湿地2008年5月15日过境的Landsat/TM图像和实测地面数据以及MODIS 地表发射率数据,分别运用大气辐射传输模型、覃志豪的单窗算法和Jimenez\|Munoz & Sobrino 的单波段算法估算洪河湿地的地表温度,并且对比了大气校正前后的NDVI、LSE以及各种算法估算地表温度的差异。分析估算结果表明,覃志豪的单窗算法与实测地面数据估算结果非常一致。指出在没有实时探空数据的情况下,应用只有一个热红外通道的Landsat/TM数据源,采用覃志豪的单窗算法估算的精度是可以接受的。 相似文献
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利用洪河湿地2008年5月15日过境的Landsat/TM图像和实测地面数据以及MODIS地表发射率数据,分别运用大气辐射传输模型、覃志豪的单窗算法和Jimenez—Munoz & Sobrino的单波段算法估算洪河湿地的地表温度,并且对比了大气校正前后的NDVI、LSE以及各种算法估算地表温度的差异。分析估算结果表明,覃志豪的单窗算法与实测地面数据估算结果非常一致。指出在没有实时探空数据的情况下,应用只有一个热红外通道的Landsat/TM数据源,采用覃志豪的单窗算法估算的精度是可以接受的。 相似文献
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以南京市江宁区为研究区域,根据区域特征、作物物候期和水稻的生长特点,采用分层分类的方法提取稻田分布信息。通过比较多时相SAR数据、TM和多时相SAR融合与TM和单时相SAR融合数据识别水稻的精度和提取的水稻种植面积,分析了不同数据对区域多云雨,不同种植方式、面积小且分布破碎的水稻稻田的识别程度,并根据野外实地走访调查分析了主要影响因素。结果表明:多时相SAR数据、TM和多时相SAR数据的水稻识别精度都高于72%,高于TM和单时相SAR融合数据的结果;前两者提取的水稻种植面积和稻田分布接近,主要影响因素是地物分布、不同种植方式水稻物候期和水稻稻田面积小且分布破碎。 相似文献
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NOAA卫星又称TIROS—N系列卫星,是美国国家海洋大气局控制和管理的第三代极轨道业务气象卫星,其主要传感器是高分辨率辐射仪(AVHRR)。AVHRR的通道1和2与陆地卫星MSS5,7吻合,能较好地表达绿色植被的吸收波段和对近红外的特征反射峰。NOAA卫星视场角大,覆盖度宽,又是双星运行,每天可两次过境,获得资料及时。而陆地卫星每16天覆盖一次,若遇阴雨天气,获得资料的周期更长。AVHRR像元面积大,可节省计算机处理时间和费用。所以,近几年来NOAA/AVHRR资料越来越广泛地被应用于植被动态监测和农作物估产。但是AVHRR空间分辨率为1.1公里,远低于MSS,限制了NOAA卫星的应用领域。天津市土地面积只有1731.5万亩,种植混杂,混合像元所占比例较大,致使低分辨率的图像难以反映作物长势。因此,NOAA/AVHRR信息 相似文献
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基于多时相TM影像的冬小麦面积变化监测 总被引:3,自引:0,他引:3
利用北京1992年、2000年、2004年、2009年的多时相Landsat TM5影像数据,结合实际调查数据,分析了近20年来北京冬小麦种植面积的变化趋势及演变特征。采用决策树、PCA、缨帽变换等手段对地物进行分类,利用多时相影像,NDVI组合阈值提取小麦种植区面积。研究结果表明:北京地区1992年、2000年、2004年、2009年冬小麦种植面积分别为:113671ha,84322ha,40410ha,61529ha。北京冬小麦种植面积呈现为明显的先减少后增加的趋势。从1992年到2009年共减少52143ha。其中,从1992年到2000年冬小麦种植面积减少了29349ha,减少的面积中城区扩张占用和转变为裸地的最多,分别为39.7%和42.8%,另外有13.3%变为设施用地,3%成为水体(鱼塘和水田);从2000年到2004年冬小麦种植面积共减少43921ha,减少的面积中转变为裸地和城区扩张占用的最多,分别为39.8%和33.1%;从2004年到2009年冬小麦种植面积共增加了21119ha,其中裸地转变为小麦种植区面积最大。 相似文献
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C. Domenikiotis N. R. Dalezios A. Loukas M. Karteris 《International journal of remote sensing》2013,34(20):4235-4246
Meteorological satellites are appropriate for operational applications related to early warning, monitoring and damage assessment of forest fires. Environmental or resources satellites, with better spatial resolution than meteorological satellites, enable the delineation of the affected areas with a higher degree of accuracy. In this study, the agreement of two datasets, coming from National Oceanic and Atmospheric Administration/Advanced Very High Resolution Radiometer (NOAA/AVHRR) and Landsat TM, for the assessment of the burned area, was investigated. The study area comprises a forested area, burned during the forest fire of 21-24 July 1995 in Penteli, Attiki, Greece. Based on a colour composite image of Landsat TM a reference map of the burned area was produced. The scatterplot of the multitemporal Normalized Difference Vegetation Index (NDVI) images, from both Landsat TM and NOAA/AVHRR sensors, was used to detect the spectral changes due to the removal of vegetation. The extracted burned area was compared to the digitized reference map. The synthesis of the maps was carried out using overlay techniques in a Geographic Information System (GIS). It is illustrated that the NOAA/AVHRR NDVI accuracy is comparable to that from Landsat TM data. As a result NOAA/AVHRR data can, operationally, be used for mapping the extent of the burned areas. 相似文献
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Crop Normalized Difference Vegetation Index (NDVI) time profiles and crop acreage estimates were derived from the application of linear mixture modelling to Advanced Very High Resolution Radiometer (AVHRR) data over a test area in the southern part of the Pampa region, Argentina. Bands 1 and 2 from seven AVHRR scenes (June to January 1991) were combined to produce fraction images of winter crops, summer crops and pastures. A Landsat Thematic Mapper (TM) scene of the region was classified and superimposed to the AVHRR Local Area Coverage (LAC) data by means of a correlation technique. Each class signature was extracted by regressing the AVHRR response on the cover types proportions, estimated from Landsat-TM data, over sets of calibration windows. The crop NDVI profiles were hence derived from the class signatures in bands 1 and 2. These profiles appeared consistent with the cover types, but variability depending on the set of windows was noted. The assessment of the class signatures was indirectly accomplished through the subpixel classifications of the AVHRR data, performed using the different sets of class spectra. Although some discrepancies between AVHRR and Landsat–TM estimates were observed at the individual window level, the classification results compared quite well on a regional scale with Landsat–TM estimates: crop acreage was estimated to an overall accuracy ranging from 89 to 95 per cent according to the spectra used in the classification. Definitely, the proposed methodology should permit a better exploitation of the temporal resolution of AVHRR data in both the areas of yield prediction and vegetation classification. Furthermore, the perational application of such a methodology for crop monitoring will undoubtedlybe facilitated with the coming sensor systems such as the ModerateResolution Imaging Spectroradiometer (MODIS), the SPOT Vegetation Monitoring Instrument or the ‘Satelite Argentino Cientifico’ (SAC–C). 相似文献
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冯学智 《中国图象图形学报》2000,5(10):836-839
着重论述了从卫星遥感资料中提取雪盖信息的一些方法,结果表明,利用积雪阈值参数从NOAA/AVHRR图象中提取雪盖信息方法和利用积雪指数(NDSI)从陆地卫星TM图象中提取雪盖面积的技术,以及利用NOAA/AVHRR和TM信息复合的技术,可提高信息获取的精度,具有实用价值。 相似文献
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The potential of the recent SPOT VEGETATION (VGT) sensor for characterizing boreal forest fires was investigated. Its capability for hotspot detection and burned area mapping was assessed by analysing a series of VGT, NOAA/AVHRR, and Landsat TM images over a 1541 km2 相似文献
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利用LandsatTM、NOAA/AVHRR和中分辨率成像光谱仪(MODIS)三个平台传感器的遥感数据,分别使用训练样本监督分类、阈值数字信号统计、雪盖指数方法制作雪盖图和提取积雪面积。结果表明:不同传感器遥感图像因时相和时空分辨率的差异,提取积雪信息的有效方法有所不同。但基于反射特性的雪盖指数计算法具有普遍的实际操作性意义,即雪盖制图精度高,分类合理,是提取积雪信息的最佳技术手段|当使用监督积雪分类时,只有取得精确的信号文件,分类结果才是可信的|而阈值数字信号统计的雪的阈值确定具有很大的经验性和随机性,但对数据不完整或只有单波段时也不失为有效和简便的途径|山影补偿处理法基本可以消除地形阴影的影响|而去云后其覆盖下的积雪恢复技术值得进一步讨论。 相似文献
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During the last few decades, many regions have experienced major land use transformations, often driven by human activities. Assessing and evaluating these changes requires consistent data over time at appropriate scales as provided by remote sensing imagery. Given the availability of small and large-scale observation systems that provide the required long-term records, it is important to understand the specific characteristics associated with both observation scales. The aim of this study was to evaluate the potentials and limits of remote sensing time series for change analysis of drylands. We focussed on the assessment and monitoring of land change processes using two scales of remote sensing data. Special interest was given to the influence of the spatial and temporal resolution of different sensors on the derivation of enhanced vegetation related variables, such as trends in time and the shift of phenological cycles. Time series of Landsat TM/ETM+ and NOAA AVHRR covering the overlapping time period from 1990 to 2000 were compared for a study area in the Mediterranean. The test site is located in Central Macedonia (Greece) and represents a typical heterogeneous Mediterranean landscape. It is undergoing extensification and intensification processes such as long-term, gradual processes driven by changing rangeland management and the extension of irrigated arable land. Time series analysis of NOAA AVHRRR and Landsat TM/ETM+ data showed that both sensors are able to detect this kind of land cover change in complementary ways. Thereby, the high temporal resolution of NOAA AVHRR data can partially compensate for the coarse spatial resolution because it allows enhanced time series methods like frequency analysis that provide complementary information. In contrast, the analysis of Landsat data was able to reveal changes at a fine spatial scale, which are associated with shifts in land management practice. 相似文献
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Abdelgadir A. Abuelgasim Sylvain G. Leblanc 《International journal of remote sensing》2013,34(18):5059-5076
Leaf area index (LAI) is an important structural vegetation parameter that is commonly derived from remotely sensed data. It has been used as a reliable indicator for vegetation's cover, status, health and productivity. In the past two decades, various Canada-wide LAI maps have been generated by the Canada Centre for Remote Sensing (CCRS). These products have been produced using a variety of very coarse satellite data such as those from SPOT VGT and NOAA AVHRR satellite data. However, in these LAI products, the mapping of the Canadian northern vegetation has not been performed with field LAI measurements due in large part to scarce in situ measurements over northern biomes. The coarse resolution maps have been extensively used in Canada, but finer resolution LAI maps are needed over the northern Canadian ecozones, in particular for studying caribou habitats and feeding grounds. In this study, a new LAI algorithm was developed with particular emphasis over northern Canada using a much finer resolution of remotely sensed data and in situ measurements collected over a wide range of northern arctic vegetation. A statistical relationship was developed between the in situ LAI measurements collected over vegetation plots in northern Canada and their corresponding pixel spectral information from Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) data. Furthermore, all Landsat TM and ETM+ data have been pre-normalized to NOAA AVHRR and SPOT VGT data from the growing season of 2005 to reduce any seasonal or temporal variations. Various spectral vegetation indices developed from the Landsat TM and ETM?+?data were analysed in this study. The reduced simple ratio index (RSR) was found to be the most robust and an accurate estimator of LAI for northern arctic vegetation. An exponential relationship developed using the Theil–Sen regression technique showed an R 2 of 0.51 between field LAI measurement and the RSR. The developed statistical relationship was applied to a pre-existing Landsat TM 250 m resolution mosaic for northern Canada to produce the final LAI map for northern Canada ecological zones. Furthermore, the 250 m resolution LAI estimates, per ecological zone, were almost generally lower than those of the CCRS Canada-wide VGT LAI maps for the same ecozones. Validation of the map with LAI field data from the 2008 season, not used in the derivation of the algorithm, shows strong agreement between the in situ LAI measurement values and the map-estimated LAI values. 相似文献
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Kazuhito Ichii Corresponding author Megumi Maruyama Yasushi Yamaguchi 《International journal of remote sensing》2013,34(22):4467-4479
Deforestation in Rondônia state in the south-western part of the Brazilian Legal Amazon was analysed using Landsat Multi-Spectral Scanner (MSS), Thematic Mapper (TM), Enhanced Thematic Mapper Plus (ETM+), National Oceanic & Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer (AVHRR) and hydrological data. The Landsat sensor data coverage was supplemented with Pathfinder AVHRR Land (PAL) Normalized Difference Vegetation Index (NDVI) datasets. The results from the Landsat-based analysis show that more than 30% of the natural vegetation in the study area was subject to deforestation between 1973 and 1999, a finding reinforced by analysis of the PAL NDVI data. In addition, it was established that trends in the PAL NDVI datasets were coincident with the pattern of deforestation. Apart from imagery analysis, time variations in the hydrological data between 1982 and 1988 were used to estimate the evapotranspiration. A decreasing trend was identified in the rate of evapotranspiration, suggesting that deforestation has a significant impact on the local hydrological cycle. 相似文献