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31.
Comparison Between Four Methods for Data Fusion of ETM+ Multispectral and Pan Images 总被引:2,自引:0,他引:2
PouranBehnia 《地球空间信息科学学报》2005,8(2):98-103
Four data fusion methods, principle component transform (PCT), brovey transform (BT), smoothing filter-based intensity modulation(SFIM), and hue, saturation, intensity (HSI), are used to merge Landsat--7 ETMq- multispectral bands with ETM panchromatic band. Each of them improves the spatial resolution effectively but distorts the original spectral signatures to some extent. SFIM model can produce optimal fusion data with respect to preservation of spectral integrity. However, it results the most blurred and noisy image if the coregistration between the multispectral and pan images is not accurate enough. The spectral integrity for all methods is preserved better if the original multispectral images are within the spectral range of ETM pan image. 相似文献
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标准卵磷脂氢过氧化物(PC-OOH)与亚油酸甲酯氢过氧化物(ML-OOH)制备 总被引:1,自引:0,他引:1
报道了用自由基引发剂(AAPH)引发氧化,反相高效液相色谱法分离卵磷脂(Phos-phatidylcholine,PC)及其氢过氧化物(PC-OOH),获得纯品PC-OOH,以及50℃自动氧化后,用硅胶柱层析分离亚油酸甲酯(MethylLinoleate,ML)及其氢过氧化物(ML-OOH),而获得标准ML-OOH的方法。 相似文献
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极轨气象卫星大气垂直探测(TOVS)资料微机处理系统可实时接收处理TOVS/HRPT资料,生成空间分辨率约75(或50)km的大气温度和湿度廓线、位势高度、热成风、大气中水汽总含量、射出长波辐射(OLR)、臭氧总含量等大气参数以及TOVS水汽图象等产品。其中,大气温度的平均相对误差为2.5K,大气湿度的平均相对误差为25%。由于气象卫星覆盖范围广,观测频次多,因此,TOVS产品可弥补海洋、高原、沙漠等地区常规探测资料之不足。 相似文献
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Masoomeh Alaibakhsh Irina Emelyanova Olga Barron Neil Sims Mehdi Khiadani Alireza Mohyeddin 《水文研究》2017,31(4):800-810
A deficiency in crucial digital data, such as vegetation cover, in remote regions is a challenging issue for water management and planning, especially for areas undergoing rapid development, such as mining in the Pilbara, Western Australia. This is particularly relevant to riparian vegetation, which provides important ecological services and, as such, requires regional protection. The objective of this research was to develop an approach to riparian vegetation mapping at a regional scale using remotely sensed data. The proposed method was based on principal component analysis applied to multi‐temporal Normalized Difference Vegetation Index datasets derived from Landsat TM 5 imagery. To delimit the spatial extent of riparian vegetation, a thresholding method was required and various thresholding algorithms were tested. The accuracy of results was estimated for various Normalized Difference Vegetation Index multi‐temporal datasets using available ground‐truth data. The combination of a 14‐dry‐date dataset and Kittler's thresholding method provided the most accurate delineation of riparian vegetation. 相似文献
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Andrew Bunker Joanna Smith Hyron Spinrad Daniel Stern Stephen Warren 《Astrophysics and Space Science》2003,284(2):357-360
We have discovered extended Lyman-α emission around a z=4.5 QSO in a deep long-slit spectrum with Keck/LRIS at moderate spectral resolution (R≈ 1000). The line emission extends 5 arcsec beyond the continuum of the QSO and is spatially asymmetric. This extended line
emission has a spectral extent of 1000km/s, much narrower in velocity spread than the broad Lyman-α from the QSO itself and
slightly offset in redshift. No evidence of continuum is seen for the extended emission line region, suggesting that this
recombination line is powered by reprocessed QSO Lyman continuum flux rather than by local star formation. This phenomenon
is rare in QSOs which are not radio loud, and this is the first time it has been observed at z>4. It seems likely that the QSO is illuminating the surrounding cold gas of the host galaxy, with the ionizing photons producing
Lyman-α fluorescence. As suggested by Haiman and Rees (2001), this `fuzz' around a distant quasar may place strong constraints
on galaxy formation and the extended distribution of cold, neutral gas.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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The aim of this work is to compare macroturbulent coherent structures (MCS) geometry and organization between ice covered and open channel flow conditions. Velocity profiles were obtained using a Pulse‐Coherent Acoustic Doppler Profiler in both open channel and ice‐covered conditions. The friction imposed by the ice cover results in parabolic shaped velocity profiles. Reynolds stresses in the streamwise (u) and vertical (v) components of the flow show positive values near the channel bed and negative values near the ice cover, with two distinctive boundary layers with specific turbulent signatures. Vertically aligned stripes of coherent flow motions were revealed from statistics applied to space‐time matrices of flow velocities. In open channel conditions, the macroturbulent structures extended over the entire depth of the flow whereas they were discontinued and nested close to the boundary walls in ice‐covered conditions. The size of MCS is consequently reduced in scale under an ice cover. The average streamwise length scale is reduced from 2.5 to 0.4Y (u) and from 1.5 to 0.4Y (v) where Y is the flow depth. In open channel conditions, the vertical extent of MCS covers the entire flow depth, whereas the vertical extent was in the range 0.58Y–1Y (u) and 0.81Y–1Y (v) in ice‐covered conditions. Under an ice cover, each boundary wall generates its own set of MCS that compete with each other in the outer region of the flow, enhancing mixing and promoting the dissipation of coherent structures. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
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