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121.
采用对照反演比法对比分析了青藏高原地区相同时空条件下的MODIS反照率当量反演结果和全反演结果的差异。利用2002—2004年青藏高原地区Terra MODIS数据开展的对照反演试验表明:(1)黑空反射率BSA两种反演结果的绝对偏差小于0.03,白空反射率WSA两种反演结果的绝对偏差约为0.04;BSA两种反演结果绝对偏差的标准差约为0.05,而WSA的则更大。(2)BSA两种反演结果和WSA两种反演结果的绝对偏差及其标准差均存在一定的年际差异。(3)可见光区反照率两种反演结果的绝对偏差及其标准差一般大于红外光区两种反演结果的绝对偏差及其标准差。(4)两种地表反照率反演结果的绝对偏差及其标准差在青藏高原地区三种主要地表类型的差异不大。 相似文献
122.
油砂作为21世纪以来世界能源的重要组成部分,已经有大量的地质工作者对其形成的地质特征、成矿带分布特征等进行了详细研究,并取得一定成果,但是对于遥感在油砂勘探中的应用少有研究。遥感技术识别不同地物的理论基础是同一波长位置处的反射率差异及反射率随波长的变化规律,因此本文通过分析油砂的实测光谱数据,得到其反射光谱的特征及规律。为实现在Landsat 8OLI卫星遥感影像上对油砂的识别,根据油砂实测光谱的研究,分别提出基于油砂光谱特征和相关性分析的Landsat 8遥感影像油砂识别模式,并将其应用在柴达木盆地冷湖和马海两个研究区。结果表明:利用遥感影像进行油砂找矿靶区圈定是可行的;本文总结出的基于相关性分析的油砂提取模式优于光谱特征分析模式;冷湖地区用比值方法进行油砂遥感信息增强效果较好,马海地区则差值方法较好。 相似文献
123.
Yuanzhi Zhang Hongtao Duan Hongyan Xi Zhaojun Huang JinYeu Tsou Tingchen Jiang 《大气与海洋》2018,56(4):277-288
AbstractAquatic plants and lake bottoms in optically shallow waters (OSWs) wield great influence on reflectance spectra, resulting in the inapplicability of most existing bio-optical models for water colour remote sensing in lakes. Based on radiative transfer theory and measured spectra from a campaign for Lake Taihu in October 2008, absorption and backscattering coefficients were used to simulate the remote-sensing reflectance, which are considered to be reliable if matched to their measured counterparts. Several cases of measured spectra at different depths, Secchi disk depth transparency, and aquatic plant height and coverage were analyzed thoroughly for spectral properties. The contribution of aquatic plants was evaluated and compared with the measured and simulated remote-sensing reflectance values. This is helpful for removing the influence of aquatic plants and lake bottoms from the spectra and for constructing an improved chlorophyll a retrieval model for OSWs, such as that for Lake Taihu, China. 相似文献
124.
针对目前国产卫星对气溶胶遥感监测应用较少的情况,本研究综合暗象元和SARA算法优势,基于FY-3D MERSI2数据构建了一套气溶胶光学厚度(Aerial Optical Depth, AOD)快速遥感反演方法。首先,引入了传统暗象元算法中的地表反射率经验关系,然后利用AERONET长时间序列的地基观测数据,构建了红波段和蓝波段气溶胶光学厚度、不对称因子和单次散射率之间的关系,最后利用MOD04和AERONET的AOD产品对研究反演结果进行了验证和评估分析。结果发现:① 本研究反演的AOD不仅保持了与MODIS的气溶胶产品空间分布的一致性,而且合理地呈现了AOD的高值分布,改进了MOD04气溶胶产品在云和亮目标方面反演缺失问题;② 利用AERONET地基观测结果对本研究获取的MERSI2的AOD反演结果进行了对比分析,发现二者具有较高的线性相关性,蓝波段AOD线性相关系数超过0.85;③ 利用MERSI2数据完整地捕捉到了2018年3月9—14日京津冀及周边区域的一次重污染过程中气溶胶时空分布变化情况,这也说明了FY3D卫星具备良好的气溶胶遥感监测能力,为我国灰霾监测和预警提供参考依据。本研究对大力发展国产卫星在大气环境遥感的应用有重要参考意义。 相似文献
125.
126.
D. Gournis A. E. Mantaka-Marketou M. A. Karakassides D. Petridis 《Physics and Chemistry of Minerals》2001,28(4):285-290
The interaction of γ-rays with smectites induces paramagnetic defects in the structure of these clay minerals. The EPR spectra
of three different smectites detect the creation of structural defects and trapping of organic free radicals in the clay structure
upon irradiation. The defects are assigned to positive holes or trapped electrons stabilised by existing local charge imbalances
in the mineral lattice. The organic radicals are derived from organic compounds present as impurities in the crystal lattice
of the clay minerals. In addition, γ-rays cause migration of small interlayer cations (such as Li+) into the layers, as clearly evidenced by EPR and FT-IR reflectance spectroscopies.
Received: 20 April 2000 / Accepted: 2 December 2000 相似文献
127.
lNTRODUCTIONIt is wel1 established that the vitrinite reflectance (R<, ) de-pends on the temperature history that a basin has undergone.In general, Ro is a function of maximum paleotemperature andeffective heating time. Thus, the paleotemperature of sedi-ments and the value of vitrinite ref1ectance are controlled by theflow of heat Q(t) into the basin and by the thermal parametersof the sediments. Therefore, in principle, it is possible to cal-culate the thermal vitrinite reflectance of … 相似文献
128.
Xu Ruisong 《《地质学报》英文版》1992,5(4):411-425
Abstract The vegetation has been poisoned by gold in the western Guangdong-Hainan region. The gold content of the leaves there is as high as 10-1961 times the abundance, the chlorophyll content is 10%-30% lower than that of the vegetation in metamorphic terrains and 10%-20% higher than that in granite terrains, and the carotenoid content is 10%-44% lower than the background value. The water content of leaves is 10% to 20% lower than the background value. The cells of leaves are deformed and broken. The leaf surface shows colour spots and becomes yellow or dark green. The spectral reflectance of the leaf surface is 5%-30% higher than the background value; the spectral shape has shifted 5-15 nm to the short wavelength. The gray scales of eanopy on images of Landsat TM and airborne imaging scanner (AIS) are 10%-100% higher than the background values. On Landsat TM and AIS false colour images, plants poisoned by gold display a yellow color, which disinguishes them from background plants. According to the spectral and image features of gold biogeochemical effects, the author has constructed a gold information system and expert prediction system, and thus two gold target areas and two gold prospect areas have been identified rapidly, economically and accurately in the western Guangdong-Hainan region which is extensively covered by vegetation. 相似文献
129.
The Saar basin contains bituminous coals (high volatile A and B). Five coals of Westphalian and Stephanian age with distinctly varying maceral compositions were analysed by Soxhlet extraction and supercritical extraction with different solvents and microscopically. From the data obtained it is concluded that the oldest coals have a potential for oil generation, whereas the younger coals do not. This conclusion is explained by varying liptinite contents and varying adsorption capacities of different vitrinite macerals for bitumen. 相似文献
130.
Rudolf Bertrand 《Organic Geochemistry》1990,15(6)
Paleozoic marine sequences sampled in outcrops and wells of northeastern Gaspe Peninsula (Quebec Appalachians) yield kerogen composed in part of vitrinite and zooclasts (chitinozoans, scolecodonts and graptolites) on which reflectance measurements were made.The comparison between means of random measurements show that reflectance of chitinozoans is similar to that of telinite (vitrinite with a cellular texture) and that the reflectance of scolecodonts is significantly lower than that of telinite in the lower range of studied values. At higher reflectivities differences decrease but, at the end of the condensate gas zone reflectancea are not yet identical. As shown by previous studies, reflectance of graptolites is slightly less than that of telinite.Pyrobitumen reflectance is related to the lithology of the host-rock and no generalized correlation can be established between the reflectance of pyrobitumen and that of vitrinite. 相似文献