双线偏振雷达测雨效果的对比分析   总被引：8，自引：2，他引：8  

刘黎平  钱永甫  王致君  楚荣忠 《大气科学》1996,20(5):615-619

本文根据1993、1994年15次层状云和12次对流云降雨过程的地面降雨资料和C波段双线偏振雷达资料，对双线偏振雷达和普通雷达测量不同强度降雨的效果进行了评估和比较。结果表明，从相对误差来看，双线偏振雷达使普通雷达的小雨高估、大雨低估的测量误差趋势减弱，它对小到中雨的测量结果优于普通雷达。双线偏振雷达大雨高估的现象可能与强对流性降雨中冰相粒子的存在有关。  相似文献   

Elastic Wave Propagation In A Medium Containing Oriented Inclusions With A Changing Aspect Ratio: A Physical Model Study     

J. M. Ass'ad  J. A. Mcdonald  R. H. Tatham  T. M. Kusky 《Geophysical Journal International》1996,125(1):163-172

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Displacements and rays for splitting S-waves: perturbation theory and the failure of the ray method     

W. S. Guest  C. J. Thomson  M. Kendall 《Geophysical Journal International》1992,108(1):372-378

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偏光显微镜聚敛光系统光路分析   总被引：1，自引：0，他引：1  

包相臣 《矿物岩石》1995,15(2):73-77

通过实验和计算，文章证明了勃氏镜进入显微光路后，可使整个显微镜系统变成望远系统，望远系统接收平行光信号，形成干涉图或偏光图像，而显微系统接收非平行光信号形成矿物像，文章不仅对偏光图和干涉图在显微镜筒中的光路变化及成像机理进行了深入讨论，并且对如何保持干涉图和偏光图像清晰提出了调试意见。  相似文献   

双线偏振雷达的降水估测Ⅰ. 排序配对逼近法   总被引：6，自引：5，他引：1  

楚荣忠  贾伟 《高原气象》1999,18(1)

提出使用新的途径──排序配对逼近法得出的双线偏振雷达降水估测ＺＲ关系参数因子比线性拟合法具有更好的代表性,且能体现提高区域降水估测精度,也能根据实际情形采用其它的误差类型作为获取及衡量参数的标准。对指数函数形式的ＺＲ关系来说,其参数因子Ａ０,ＡＨ及ＡＤＲ分别为０．０１６８４,０．０９６和－０．４１６５。该方法可以推广应用到多个变元及参数因子的复杂函数中。  相似文献   

冕流与日冕物质抛射的关系     

堵锦生  童彝  杨静  伊塞列维奇 《紫金山天文台台刊》1999,18(2):135-138

本文研究了卡林顿自转周１５９１ － １５９２ 中冕流偏振亮度的变化。冕流带偏振亮度的分布是不均匀的,不均匀度为１０ ％ － ５０ ％ 。无日冕物质抛射影响存在时,沿冕流带冕流的分布可持续稳定存在近两个太阳自转周。当一个日冕物质抛射伴随冕流产生时,冕流的经向角大小若大于２７°,可导致冕流尖角区顶部上升速度大于２ｋｍ／ｓ。  相似文献   

VLBI观测双线极化条纹拟合方法     

黄逸丹  刘磊  舒逢春  郑为民 《测绘学报》2020,49(4):423-431

提出了一种可用于下一代VLBI观测系统(VGOS)的双线极化条纹拟合方法。现有的VLBI观测模式采用的是右圆极化(RCP),而VGOS系统采用的是双线极化。本文方法包括校正和组合条纹拟合两部分。校正部分选择一颗强源作为参考源,分别得到不同极化方式下的通道时延及相位校正数据,用于目标源的校正。组合条纹拟合部分将4种极化分量的可见度数据组合成伪Stokes分量,通过搜索差分星位角使伪Stokes分量的幅值达到最大,从而获得最终的时延观测量。与单极化条纹拟合相比,组合极化获得的条纹具有更高的信噪比(SNR)及更小的条纹相位弥散度。  相似文献   

Detection of optical circular polarization in the Herbig Ae star WW Vul     

D. N. Shakhovskoi  O. S. Shulov  E. N. Kopatskaya 《Astronomy Letters》2001,27(6):376-378

UBVRI observations of circular polarization in WW Vul are presented. A positive polarization of ～0.1% was detected with a signal-to-noise ratio from 3 to 5 in each of the bands and more than 5 when averaged over all five bands. This observed polarization roughly corresponds to a 1% circular polarization of the radiation scattered in a circumstellar disk, which is most likely attributable to the significant alignment of scattering nonspherical dust grains. Since grain alignment is possible only in a magnetic field, this result provides circumstantial evidence for the existence of a magnetic field in the circumstellar disk of WW Vul.  相似文献   

近场源激电法在桂西北两个金矿床的初步试验     

韦文珍 《南方国土资源》1993,(2)

本文通过对桂西北地区金牙、高龙两个微细粒浸染型金矿床进行的近场源激电法试验,在已知矿体上均获得较明显的极化率异常,其辅助参数(Js、Gs、Ps)亦有显示,其异常形态大体与矿体或矿化体产状一致。该法对寻找和评价该类型金矿床有一定的实用价值。  相似文献   

An evaluation of the role played by remote sensing technology following the World Trade Center attack     

Charles?K.?HuyckEmail author  Beverley?J.?Adams  David?I.?Kehrlein 《地震工程与工程振动(英文版)》2003,2(1):159-168

Remote sensing technology has been widely recognized for contributing to emergency response efforts after the World Trade Center attack on September 11th, 2001. The need to coordinate activities in the midst of a dense, yet relatively small area, made the combination of imagery and mapped data strategically useful. This paper reviews the role played by aerial photography, satellite imagery, and LIDAR data at Ground Zero. It examines how emergency managers utilized these datasets, and identifies significant problems that were encountered. It goes on to explore additional ways in which imagery could have been used, while presenting recommendations for more effective use in future disasters and Homeland Security applications. To plan adequately for future events, it was important to capture knowledge from individuals who responded to the World Trade Center attack. In recognition, interviews with key emergency management and geographic information system (GIS) personnel provide the basis of this paper. Successful techniques should not be forgotten, or serious problems dismissed. Although widely used after September 11th, it is important to recognize that with better planning, remote sensing and GIS could have played an even greater role. Together with a data acquisition timeline, an expanded discussion of these issues is available in the MCEER/NSF report “Emergency Response in the Wake of the World Trade Center Attack; The Remote Sensing Perspective” (Huyck and Adams, 2002)  相似文献