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高光谱分辨率激光雷达(HSRL)大气温度测量模拟 总被引:1,自引:0,他引:1
激光雷达探测大气温度通常采用探测大气分子瑞利散射的方法,这种方法由于低层气溶胶的存在,一般只能探测高空(约12km以上)的大气温度,而探空气球又存在不能获取连续数据和定位性差的问题.文章给出了利用高光谱分辨率激光雷达探测大气温度的方法,并对此方法作了理论模拟.结果表明此方法可用于低层大气温度垂直剖面探测. 相似文献
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海浪微波散射理论模式 总被引:4,自引:1,他引:3
在假设海面白帽为球形气泡层的基础上,利用白帽海面的矢量辐射传输方程各随机粗糙面散射模型建立了海面的微波散射模型。辐射传输方程利用迭代法求解,随机粗糙面散射模型采用双尺度散射模型,利用白帽覆盖率的经验公式计算海面的微波散射特性。数值计算结果表明,随着气泡厚度的增加球形气泡散射系数越来越接近球形粒子散射系数;白帽对散射同的贡献随风速增大而增大;侧风情况比逆风和顺风情况影响均大;水平极化比垂直极化影响大 相似文献
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黄东海海区总悬浮物散射特性研究 总被引:2,自引:0,他引:2
我国黄东海水体散射特性非常复杂,这是造成该海域水色区划特点显著的原因之一。文中利用2003年4月黄东海试验数据(HD200304)对总悬浮物(TSM,Total Suspended Matter)的后向散射概率~bbs和单位散射系数bs*进行研究。基于对现场数据的统计分析,我们开发了总悬浮物后向散射概率模型,通过相对偏差分析表明,有近90%的样品反演相对偏差控制在±30%之内。对总悬浮物单位散射系数研究时,选择555 nm为参考波段,开发了不同波段间总悬浮物单位散射系数关系模型,通过相对偏差分析表明,有近94%的样品反演相对偏差在±10%之内,反演效果非常好。 相似文献
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Sea-surface acoustic backscattering measurements at moderate to high frequencies were performed in the shallow water of the south Yellow Sea, using omnidirectional spherical sources and omnidirectional hydrophones. Sea-surface backscattering data for frequencies in the 6–25 k Hz range and wind speeds of(3.0±0.5)and(4.5±1.0) m/s were obtained from two adjacent experimental sites, respectively. Computation of sea-surface backscattering strength using bistatic transducer is described. Finally, we calculated sea-surface backscattering strengths at grazing angles in the range of 16°–85°. We find that the measured backscattering strengths agree reasonably well with those predicted by using second order small-roughness perturbation approximation method with "PM" roughness spectrum for all frequencies at grazing angles ranged from 40° to 80°. The backscattering strengths varied slightly at grazing angles of 16°–40°, and were much stronger than roughness scattering. It is speculated that scattering from bubbles dominates the backscattering strengths at high wind speeds and small grazing angles. At the same frequencies and moderate to high grazing angles, the results show that the backscattering strengths at a wind speed of(4.5±1.0) m/s were approximately 5 d B higher than those at a wind speed of(3.0±0.5) m/s. However, the discrepancies of backscattering strength at low grazing angles were more than 10 d B. Furthermore the backscattering strengths exhibited no significant frequency dependence at 3 m/s wind speed. At a wind speed of 4.5 m/s, the scattering strengths increased at low grazing angles but decreased at high grazing angles with increasing grazing angle. 相似文献
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目标特性研究对军事及海洋开发具有重要意义。作者用Ingenito的简正波方法对浅海波导中刚性球的散射进行了理论研究。在理论推导中直接利用波导中简正波解,同时去掉文F.Izngenito等研究中的远场假设,使理论结果更具一般性。文中对浅海波导中刚性球的散射进行了数值计算,并进行了分析。结果表明,浅海波导中目标散射场特性与自由场中明显不同,海底、海面的存在使散射场在深度方向产生干涉,从而影响散射场的空间分布,海底声速及衰减系数对散射场空间分布有重要影响。 相似文献
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Microwave remote sensing has become the primary means for sea-ice research, and has been supported by a great deal of field experiments and theoretical studies regarding sea-ice microwave scattering. However, these studies have been barely carried in the Bohai Sea. The sea-ice microwave scattering mechanism was first developed for the thin sea ice with slight roughness in the Bohai Sea in the winter of 2012, and included the backscattering coefficients which were measured on the different conditions of three bands(L, C and X), two polarizations(HH and VV), and incident angles of 20° to 60°, using a ground-based scatterometer and the synchronous physical parameters of the sea-ice temperature, density, thickness, salinity, and so on. The theoretical model of the sea-ice electromagnetic scattering is obtained based on these physical parameters. The research regarding the sea-ice microwave scattering mechanism is carried out through two means, which includes the comparison between the field microwave scattering data and the simulation results of the theoretical model, as well as the feature analysis of the four components of the sea-ice electromagnetic scattering. It is revealed that the sea-ice microwave scattering data and the theoretical simulation results vary in the same trend with the incident angles. Also, there is a visible variant in the sensitivity of every component to the different bands.For example, the C and X bands are sensitive to the top surface, the X band is sensitive to the scatterers, and the L and C bands are sensitive to the bottom surface, and so on. It is suggested that the features of the sea-ice surfaces and scatterers can be retrieved by the further research in the future. This experiment can provide an experimental and theoretical foundation for research regarding the sea-ice microwave scattering characteristics in the Bohai Sea. 相似文献
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微囊藻和栅列藻吸收与散射特性的实验研究 总被引:1,自引:0,他引:1
利用分光光度计,分别检测不同浓度梯度的微囊藻和栅列藻的光束衰减系数、吸收系数等。根据线性加和关系计算出2种藻的散射系数。结果表明,400~650 nm光束衰减系数大致呈下降趋势,之后又逐渐上升.在675 nm附近出现由于浮游植物吸收而形成的峰值,微囊藻、栅列藻的c*(675)分别为(0.075±0.007)m~(-1)、(0.079±0.007)m~(-1)。微囊藻、栅列藻吸收系数、比吸收系数在440、675 nm存在明显的吸收峰值,PAR波段积分平均比吸收系数分别为0.0172、0.0178 m~2/(mgCh1a)。散射系数在440、675 nm一般出现谷值,而在550、700 nm一般为峰值。微囊藻、栅列藻PAR波段积分平均比散射系数分别为0.0686、0.0737 m~2/ (mgCh1a),比散射系数明显大于比吸收系数。另外,栅列藻比散射系数均要大于微囊藻.而其比吸收系数则差异不明显。微囊藻、栅列藻吸收系数与叶绿素a浓度存在非常好的线性关系,显示其不存在色素包裹效应。微囊藻、栅列藻平均Q*.值分别为1.13、1.19.均大于1.包襄因子的分析也证明不存在色素包裹效应。实验条件下得到比吸收系数、比散射系数可以用于计算浮游植物的吸收和散射系数。 相似文献
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为了解各向异性随机粗糙海面的微波双站散射机制及其特性,本文利用解析近似的积分方程模型以及一种改进的半经验海浪谱模型实现了对各向异性随机粗糙海面的全极化微波散射仿真模拟,并与卫星观测数据、经验的地球物理模式函数及已有的解析近似散射模型仿真结果进行了对比,验证了仿真结果的可行性和准确性。利用该模型分析了入射波频率、入射角、极化方式、海面风速及风向等参数对各向异性海面双站散射的影响。模拟结果表明,在不同的入射角、散射角及方位角等观测几何条件下,海面不同波段的双站散射表现出不同的空间散射特性,且对风速、风向等海面动力学参数表现出不同的敏感性,以L波段为例,海面向后半球双站散射在各个极化方式下都对风速较为敏感,而在同极化方式下,其对风向的响应在中低风速和高风速条件下相反,整体而言,低风速下海面双站散射对风向更为敏感。这表明对于海面动力参数的反演,双站散射可以提供比传统单站雷达后向散射更丰富的物理信息。本文探讨了各向异性海面微波双站散射特性,为基于主动式及分布式微波传感器的海洋动力参数遥感反演提供了理论分析基础。 相似文献
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光学散射方法被广泛用于获取海洋微生物的形态和浓度信息.通过测量散射光的空间分布可以测量海洋微生物的形态和浓度;而最近发现,散射光的偏振特征却对细胞内部亚微米级散射颗粒更加敏感.把海洋微生物等效为粒径远大于入射波长的“米氏”粒子和远小于入射波长的“瑞利”粒子的混合体,以两种不同粒径的实心球作为微生物偏振光散射模型.利用蒙... 相似文献