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931.
932.
933.
Aerospace wetland monitoring by hyperspectral imaging sensors: a case study in the coastal zone of San Rossore Natural Park 总被引:1,自引:0,他引:1
The San Rossore Natural Park, located on the Tuscany (Italy) coast, has been utilized over the last 10 years for many remote sensing campaigns devoted to coastal zone monitoring. A wet area is located in the south-west part of the Natural Park and it is characterized by a system of ponds and dunes formed by sediment deposition occurring at the Arno River estuary. The considerable amount of collected data has permitted us to investigate the evolution of wetland spreading and land coverage as well as to retrieve relevant biogeochemical parameters, e.g. green biomass, from remote sensing images and products. This analysis has proved that the monitoring of coastal wetlands, characterized by shallow waters, moor and dunes, demands dedicated aerospace sensors with high spatial and spectral resolution. The outcomes of the processing of images gathered during several remote sensing campaigns by airborne and spaceborne hyperspectral sensors are presented and discussed. A particular effort has been devoted to sensor response calibration and data validation due to the complex heterogeneity of the observed natural surfaces. 相似文献
934.
Identification and mapping of submerged plants in a shallow lake using Quickbird satellite data 总被引:1,自引:0,他引:1
Turkey is a country rich in lakes and wetlands--monitoring of all these will require advances in technology such as remote sensing. In this study, the aquatic plants of the large and shallow Lake Mogan, located in Central Anatolia were identified and mapped using high spatial resolution Quickbird imagery. As Lake Mogan is an important bird area the assessment of submerged plant species is of great value for ecosystem conservation and management. Quickbird multispectral image acquired on August 6, 2005 was geometrically corrected and a water mask was used based on strong absorption of Near Infrared (NIR) wavelengths by calm, clear and deep water. The water mask was applied using band reflectance values for a specific pixel satisfying the conditions of band decreasing property (Green>Red>NIR) and NIR相似文献
935.
Alexandridis TK Lazaridou E Tsirika A Zalidis GC 《Journal of environmental management》2009,90(7):2243-2251
The European Habitats Directive 92/43/EEC has defined the need for the conservation of habitats and species with the adoption of appropriate measures. Within the Natura 2000 ecological network of special areas of conservation, natural habitats will be monitored to ensure the maintenance or restoration of their composition, structure and extent. The European Space Agency's GlobWetland project has provided remotely sensed products for several Ramsar wetlands worldwide, such as detailed land cover-land use, water cycle and inundated vegetation maps. This paper presents the development and testing of an operational methodology for updating a wetland's habitat map using the GlobWetland products, and the evaluation of the extent to which GlobWetland products have contributed to the habitat map updating. The developed methodology incorporated both automated and analyst-supervised techniques to photo-interpret, delineate, refine, and evaluate the updated habitat polygons. The developed methodology was proven successful in its application to the wetland complex of the Axios-Loudias-Aliakmon delta (Greece). The resulting habitat map met the European and Greek national requirements. Results revealed that GlobWetland products were a valuable contribution, but source data (enhanced satellite images) were necessary to discriminate spectrally similar habitats. Finally, the developed methodology can be modified for original habitat mapping. 相似文献
936.
Forest Dynamics in the Eastern Ghats of Tamil Nadu,India 总被引:1,自引:0,他引:1
The primary deciduous forests in the Eastern Ghats (EG) of Tamil Nadu (TN) India have undergone many changes owing to various
need-based forest managements, such as timber extraction for industry, railway sleepers, charcoal, and forest clearance for
hydroelectric projects and agriculture, during preindependence and postindependence periods (i.e., from 1800 to 1980). The
enactment of a forest conservation act during the 1980s changed the perception of forest managers from utilization to conservation.
This study was taken up to assess the forests dynamics in the EG of TN spatially between 1990 and 2003 and nonspatially between
1900 and the 1980s. Landsat Thematic Mapper (TM) and Indian Remote Sensing satellite (IRS) 1D Linear Imaging and Self Scanning
(LISS III) data were used to assess forests during 1990 and 2003, respectively. Field floristic survey and secondary data
(such as published literature, floras, books, and forest working plans) were used to assess the forest dynamics in terms of
forest type and species composition among the preindependence period, the postindependence period, and the present (i.e.,
before and after 1980). The satellite data analysis revealed a considerable amount of changes in all forest types during the
13 years. The comparison of species composition and forest types between the past and present revealed that need-based forest
management along with anthropogenic activity have altered the primary deciduous forest in to secondary and postextraction
secondary forests such as southern thorn and southern thorn scrub forests in the middle [400–900 m above mean sea level (MSL)]
and lower slopes (<400 m MSL). However, the evergreen forests present at the upper slope (>900 m MSL) and plateau seemed not
to be much affected by the forest management. The changes estimated by the satellite data processing in the major forest types
such as evergreen, deciduous, southern thorn, and southern thorn scrub are really alarming because these changes have occurred
after the implementation of a forest conservation act. The dependence of local people on forests for various purposes in this
region is also considerably high, which might be a key factor for the changes in the forests. The results of this study not
only provide an outlook on the present status of the forests and the change trends but also provide the basis for further
studies on forests in the EG of TN. 相似文献
937.
938.
对江苏近 70年的地震观测历程和技术进步作了简要回顾 ;总结了数字化地震台网建设的经验和体会 ;展望了在江苏特定的地理条件下 ,即在第四系覆盖厚、海域地震多而布网均困难的情况下 ,现代地震观测技术的应用前景和研究方向。 相似文献
939.
中国对虾两个不同地理种群遗传结构的RAPD分析 总被引:10,自引:0,他引:10
采用RAPD技术对中国对虾中国黄渤海沿岸种群(HB)和朝鲜半岛西海岸种群(PK)的遗传多样性进行检测。20个随机引物(OPD系列)在二个种群中都扩增出148条DNA片段,其中多态性片段数分别为54条和65条,多态性片段的比例分别为36.49%和43.92%,种群的平均杂合度分别为0.1981和0.2375。实验表明,中国对虾朝鲜半岛西海岸种群的遗传多样性要比中国黄渤海沿岸种群高,但二个种群都处于较 相似文献
940.
基于EOS/MODIS资料的太湖藻类动态模拟 总被引:1,自引:1,他引:0
建立了太湖藻类生长的动态模型,并将其与水动力模型和水质模型相耦合,利用2001年7~8月太湖的实测资料对模型进行了率定。借助该模型,对2004年8月太湖水体中TN、TP的变化以及藻类生长过程进行了模拟。利用中分辨率成像光谱仪EOS/MODIS的数据对太湖叶绿素a浓度进行遥感定量,将遥感监测数据和模型计算结果进行了比较。结果表明:该模型可进行风生湖流、TN、TP的模拟,以叶绿素a浓度描述的藻类浓度的模拟值能较好地拟合遥感监测值,且遥感监测图和模型模拟图所反映的全太湖叶绿素浓度分布基本一致。最后根据遥感和模拟对太湖全区的藻类分布作了具体的分析。 相似文献