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41.
Sediment samples were collected from the lower channel of the Yangtze River and the Yellow River and the contents of rare
earth elements (REEs) were measured. In addition, some historical REEs data were collected from published literatures. Based
on the δ EuN-ΣREEs plot, a clear boundary was found between the sediments from the two rivers. The boundary can be described as an orthogonal
polynomial equation by ordinary linear regression with sediments from the Yangtze River located above the curve and sediments
from the Yellow River located below the curve. To validate this method, the REEs contents of sediments collected from the
estuaries of the Yangtze River and the Yellow River were measured. In addition, the REEs data of sediment Core 255 from the
Yangtze River and Core YA01 from the Yellow River were collected. Results show that the samples from the Yangtze River estuary
and Core 255 almost are above the curve and most samples from the Yellow River estuary and Core YA01 are below the curve in
the δEuN-ΣREEs plot. The plot and the regression equation can be used to distinguish sediments from the Yangtze River and the Yellow
River intuitively and quantitatively, and to trace the sediment provenance of the eastern seas of China. The difference between
the sediments from two rivers in the δEuN-ΣREEs plot is caused by different mineral compositions and regional climate patterns of the source areas. The relationship
between δEuN and ΣREEs is changed little during the transport from the source area to the river, and from river to the sea. Thus the original
information on mineral compositions and climate of the source area was preserved.
Supported by National Natural Science Foundation of China (Grant Nos. 40506016, 40576032, and 90411014) 相似文献
42.
lINTR0DUCTIONSoiler0si0ncanbeaseriousproblemonsl0pinguplands0fthes0uthemUnitedStatesthatareintensivelycr0pped.Conservati0nprovisionsofthel985U.S.FarmBillmandateddevelopmentofaconservati0nplanonhighlyer0diblelands.Researchwasinitiatedinl9870na28-haareaattheA-E.Nels0nFarrninn0rthernMississippit0determineiftheconservati0nprovisionscouldbeachievedwhileprofitablygr0wingrowcropsincludingcott0n(GosSyPiumhirsutumL.),soybean(GlyciDemax(L.)Merr.),sorghum(SOrghumbicolor(L.)Moench),c0rn(Zeam… 相似文献
43.
Ch. Venkateswara Rao K.M.M. Rao P. Shasidhar Reddy Girish Pujar 《International Journal of Applied Earth Observation and Geoinformation》2008,10(2):165-1
The Resourcesat-I satellite is equipped with different types of sensors with varied characteristics. For the effective utilization of the available multi-sensor, multi-temporal, multi-spectral and multi-radiometric data from these sensors, fusion of digital image data has become a valuable technique. Image fusion enhances the information content and helps in better discrimination of various land cover types. The Resourcesat-1 has equipped with three sensors, AWiFS, LISS-III and LISS-IV, which are having identical spectral resolutions, with different spatial, radiometric and temporal resolutions. The spatial resolutions ratio of the data set for merging are required to be maximum of 1:6, where as the data sets (AWiFS and LISS-III) that are used in the current study are having the ratio of 1:2.5 approximately. A novel merging technique is designed, which retains the multi-spectral response of the input data in the output data. The merged data set provides the higher spatial and radiometric resolutions. In order to evaluate the fusion merits quantitatively, all the data sets are digitally classified and studied the output classes for homogeneity and clear discrimination. A comprehensive comparative study is carried out between the fused image and the LISS-III image based on the contingency matrix and the scatter plots, which demonstrates the strength of fused image for discriminating the object classes at 23.5 m spatial and 10-bit radiometric resolutions. The merged data set gives the improved classification accuracy. 相似文献
44.
清帝玄烨(即康熙帝)重视农业气象。亲自在北京培育出高产早熟品种的水稻——御稻米。而且还在生长季较长的江浙以双季稻方式推广成功,大大增加了当时的稻产量。 相似文献
45.
Journal of Geographical Sciences - The study of multi-dimensional expansion of urban space (MEUS) addresses the laws of urban spatial expansion from all directions and angles. Using Nanjing as an... 相似文献
46.
47.
机载LiDAR数据估算样地和单木尺度森林地上生物量 总被引:2,自引:0,他引:2
利用机载激光雷达点云数据,结合大量实测单木结构信息,分别从样地和单木尺度估算了森林地上生物量AGB。首先,利用局部最大值单木提取算法提取了每个样地内的单木结构参数,并针对样地和单木尺度分别计算了一组激光雷达变量。然后,利用激光雷达变量和地上生物量及其两者的对数形式,从样地和单木尺度分别构建了估算模型。最后,针对两种尺度估算过程中存在的不确定性进行了详细讨论。结果表明:(1)样地和单木尺度模型估算的森林地上生物量与地面实测值都具有明显的相关性,且对数模型估算效果要优于非对数模型;(2)样地尺度模型估算效果(R2=0.84,rRMSE=0.23)明显优于单木尺度模型(R2=0.61,rRMSE=0.46);(3)按树木类型分别进行估算可以提高单木地上生物量的估算精度;(4)不论是样地还是单木尺度地上生物量估算都存在一定的不确定性,与样地尺度相比,单木尺度估算过程的不确定性更大,这种不确定性主要来自单木识别过程。 相似文献
48.
应用有序样方聚类法,把普陀山旅游区32个样方分为5个群落类型,分别是马尾松-青冈+檵木群丛、马尾松-青冈+檵木+红楠+窄基红褐柃群丛、马尾松+枫香+檵木-青冈+檵木群丛、马尾松+青冈-青冈+檵木群丛、马尾松+青冈-青冈+檵木+石栎群丛,并运用TW INSPAN对上述样方进行聚类分析。两种分类方法的结果具有极显著的关联,说明有序样方聚类法很好地揭示了旅游干扰和群落类型之间的关系,它更适合于旅游干扰分析中的聚类研究,在旅游干扰的研究中是一个有益且有效的尝试。 相似文献
49.
气象观测数据等值线自动绘制系统 总被引:7,自引:2,他引:5
基于气象观测数据的自动等值线系统采用IDL作为开发工具,通过对自动气象站数据的处理和分析,自动生成等值线图(包括温度,降水等值线图,风矢量图等)并发布到WEB页面,提供动画播放功能和图像查询功能.该系统不仅为天气预报提供必要的决策支持,也是监视天气变化的有效工具.系统在北京第29届奥运会气象服务中得到了广泛使用,是气象预报人员进行个例分析和预报服务的重要支撑平台. 相似文献
50.
从分析绘制异常型直方图的观测误差出发,讨论了直方图区间的模糊化问题,给出了计算模糊频数的公式和绘制模糊直方图的方法,并结合实例,说明了模糊直方图的优越性。 相似文献