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以高层大气中的极光谱线为被探测源,提出了一种高层大气(80—300km)风场洛伦兹光谱线型的粒子辐射率被动探测的新原理.采用该原理不仅可获得高层大气风场的速度、温度和压强信息,更重要的是还能同时探测到高层大气中辐射粒子体辐射率,解决了目前高层大气风场研究中只能探测高层大气风场速度、温度和压强却不能获知粒子的体辐射率的问题.给出了基于洛伦兹光谱线型的辐射源粒子体辐射率、大气风场速度、温度和压强的理论计算公式.采用计算机模拟对探测误差进行了分析,给出了体辐射率、风场速度、温度、压强的误差分布规律,为进一步丰富和完善高层大气风场探测提供了理论依据和实验基础,对航空航天、空间探测、环境保护、国家安全和国民经济建设都具有重要的科学意义和广阔的应用前景. 相似文献
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从洛伦兹线型极光的干涉强度、调制度与光程差的理论公式出发,用λ/4的步进光程差即“四强度法”获得一个波长范围内的4个干涉强度值,以实现基于洛伦兹线型极光的上层大气的风速、温度、压强等物理量的探测。提出用改形萨尼亚克成像干涉仪替代迈克耳孙干涉仪实现上层大气风场,给出了基准光程差的公式,并用四面角锥棱镜镀膜技术获得4个干涉强度值来同时探测上层大气风场的模式。最后在实验室将Kr灯557.0nm调整光束到一定宽度,对称地从顶角为60°的两面镀膜角锥棱镜的顶点入射,用768pixel×576pixel的CCD照相机接收到两个光斑的成像,这两个光斑的再复制就得到镀膜四面角锥棱镜在一个周期内的4个干涉强度光斑,从而获得上层大气风场。 相似文献
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利用极光Lyman-Birge-Hopfield (LBH) 辐射图像数据可用来研究太阳风磁场与地球磁场耦合、亚暴与磁暴等过程,综合LBH辐射图像数据和O原子135.6nm辐射数据可反演电离层氧原子与氮气分子O/N2比值分布,进而研究高层大气组分信息及电离层分布变化,对科学研究和空间天气预报具有重要意义. 本文给出了LBH辐射传输机理和我国自主研制的搭载在风云三号D星(FY-3D)上的广角极光成像仪(Wide-field Auroral Imager, WAI)在轨获得的LBH 140-180nm波段极光辐射图像数据. 结合大气紫外辐射积分代码(Atmospheric Ultraviolet Radiance Integrated Code, AURIC)计算O135.6nm辐射数据、LBH辐射光谱以及MSISE00大气模型计算的O、N2数据,给出了利用WAI观测的LBH辐射图像数据反演大气O/N2比值理论计算方法,该方法将为利用我国自主观测LBH辐射数据和O135.6nm辐射数据开展空间信息反演研究打下基础. 相似文献
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O( Ⅰ ,Ⅱ) 禁戒线极光及其光化学反应 总被引:3,自引:0,他引:3
利用干涉成像光谱技术被动探测上层大气风场所使用的光源主要是氧禁戒线极光。讨论了禁戒跃迁出现较强谱线需要的两个条件,对满足上述条件的上层大气中的原子氧(OⅠ)和离子氧(OⅡ)的可见光波段禁戒线进行了详细的计算,并对应指出产生这些O(Ⅰ,Ⅱ)禁戒线的光化学反应。得出的结论是被动探测上层大气风场所用极光源可以使用所指认的10条O(Ⅰ,Ⅱ)禁戒线和允许线:557.7nm,630.0/636.4/639.3 nm,672.8nm,732.2/733.2nm,777.7/777.6/777.4nm,比加拿大的风成像光谱干涉仪(WINDII)使用的极光谱线增添了5条:639.3nm,672.8nm,777.7/777.6/777.4nm,扩展了成像光谱干涉仪的波段范围。 相似文献
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Russell C.T. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》2000,28(6):1818-1830
The size of the terrestrial magnetosphere is determined by the balance between the solar wind dynamic pressure and the pressure exerted by the magnetosphere, principally that of its magnetic field. The shape of the magnetosphere is additionally influenced by the drag of the solar wind, or tangential stress, on the magnetosphere. This drag is predominantly caused by the mechanism known as reconnection in which the magnetic field of the solar wind links with the magnetic field of the magnetosphere. The factors that control the rate of reconnection of the two fields are not understood completely, but a southward direction of the interplanetary field is critical to enabling reconnection with the dayside low-latitude magnetosphere, resulting in magnetic flux transfer to the magnetotail. Numerical simulations suggest that the conductivity of the ionosphere controls the rate of reconnection, but this has not been verified observationally. Although solar wind properties ultimately control the interaction, the properties of the plasma that make direct contact with the magnetosphere are different than those of the solar wind, having been altered by a standing bow shock wave. This standing shock is necessitated by the fact that the flow velocity of the solar wind far exceeds the velocity of the compressional wave that diverts the solar wind around the Earth. The upper atmosphere is the final recipient of all the energy and momentum that enters the magnetosphere. Coupling takes place along the magnetic field Lines principally in the polar and auroral region via current systems that close across the magnetic field both at low and high altitudes and flow parallel to the magnetic field between high and low altitudes 相似文献
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The determination of appropriate sound speed profiles in the modeling of near-ground propagation using a ray tracing method is investigated using a ray tracing model which is capable of performing axisymmetric calculations of the sound field around an isolated source. Eigenrays are traced using an iterative procedure which integrates the trajectory equations for each ray launched from the source at a specific direction. The calculation of sound energy losses is made by introducing appropriate coefficients to the equations representing the effect of ground and atmospheric absorption and the interaction with the atmospheric turbulence. The model is validated against analytical and numerical predictions of other methodologies for simple cases, as well as against measurements for nonrefractive atmospheric environments. A systematic investigation for near-ground propagation in downward and upward refractive atmosphere is made using experimental data. Guidelines for the suitable simulation of the wind velocity profile are derived by correlating predictions with measurements. 相似文献
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基于风场探测的需求,采用1 550 nm波长连续激光种子源搭建了一套全光纤结构多普勒相干测风雷达系统。从雷达方程出发,对连续激光相干雷达载噪比方程和不同雷达收发望远镜聚焦位置下风速合成权重进行了分析。针对测风雷达要求设计了5~200 m的变焦激光收发望远镜模块。扩束系统采用伽利略折射式结构,发射光束准直下扩束比为23,光学质量接近衍射极限。标定测试通过对旋转电机圆盘转速测量完成。转盘转速范围为-3 000 r/min到+3 000 r/min,转盘直径为26 cm。在视向速度多普勒频移分别为正向和负向时,雷达系统速度测量结果与通过圆盘转速计算值的相关系数为0.998与0.993,标准差为0.151 m/s和0.229 m/s。使用该测风激光雷达开展室外大气风速探测实验,取得了良好效果。 相似文献
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利用干涉成像光谱技术和电磁波的多普勒效应,通过测量高层大气(80—300km)中的气辉(极光)辐射线的四个干涉强度值而获知高层大气的速度和温度信息.采用四强度干涉测量法,分别对基于Michelson干涉仪的动镜扫描和基于无动镜四分区镀膜的干涉图获取模式所引起的测量误差进行了深入的理论分析与研究.给出了由于此测量误差所导致的相位误差所引起的高层大气风场速度、温度的误差数值;采用计算机模拟得出了在不同相位误差条件下,两种模式计算得到的风场速度和温度的误差分布图;给出了风速误差、温度误差与相位步进误差的关系曲线
关键词:
高层大气风场测量
四强度测量法
模拟计算 相似文献
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The static polarization wind imaging interferometer (SPWII) is a device used to measure wind velocity and temperature of the upper atmosphere. In this paper, the principle of SPWII is expounded. Using the four-side pyramid prism and polarizer array, four intensity interferograms of different phase differences form on the four subareas of the CCD which is located at the focal plane of the imaging lens. The wind velocity and temperature can be derived from the interferograms. Using the approximation and the antitheses, we analyze the influences of the wavelength bandwidth on the measured wind velocity and atmospheric temperature. According to the design requirements of the SPWII, the errors of the wind velocity and the atmospheric temperature are less than 5 m/s and 5 K when the incident wavelength bandwidth is in the range of [?3.08, 3.08] nm. The range is estimated and verified by simulations. These results are helpful for the realization and data processing of the SPWII. 相似文献
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V E Ostashev T M Georges S F Clifford G H Goedecke 《The Journal of the Acoustical Society of America》2001,109(6):2682-2692
The paper deals with analytical and numerical studies of the effects of atmospheric stratification on acoustic remote sensing of wind velocity profiles by sodars. Both bistatic and monostatic schemes are considered. Formulas for the Doppler shift of an acoustic echo signal scattered by atmospheric turbulence advected with the mean wind in a stratified moving atmosphere are derived. Numerical studies of these formulas show that errors in retrieving wind velocity can be of the order of 1 m/s if atmospheric stratification is ignored. Formulas for the height at which wind velocity is retrieved are also derived. Approaches are proposed which allow one to take into account the effects of atmospheric stratification when restoring the wind velocity profile from measured values of the Doppler shift and the time interval of acoustic impulse propagation from a sodar to the scattering volume and back to the ground. 相似文献
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Toshitaka TSUDA 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2014,90(1):12-27
The wind velocity and temperature profiles observed in the middle atmosphere (altitude: 10–100 km) show perturbations resulting from superposition of various atmospheric waves, including atmospheric gravity waves. Atmospheric gravity waves are known to play an important role in determining the general circulation in the middle atmosphere by dynamical stresses caused by gravity wave breaking. In this paper, we summarize the characteristics of atmospheric gravity waves observed using the middle and upper atmosphere (MU) radar in Japan, as well as novel satellite data obtained from global positioning system radio occultation (GPS RO) measurements. In particular, we focus on the behavior of gravity waves in the mesosphere (50–90 km), where considerable gravity wave attenuation occurs. We also report on the global distribution of gravity wave activity in the stratosphere (10–50 km), highlighting various excitation mechanisms such as orographic effects, convection in the tropics, meteorological disturbances, the subtropical jet and the polar night jet. 相似文献
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简要论述了大视场、消色差、温度补偿型风成像干涉仪用于高层探测的基本原理.对自行设计的风成像干涉仪的调制度进行了理论分析与计算,推导了调制度的理论表达式.采用计算机模拟,分析了仪器调制度随入射角的变化关系.当调制度大于075时,风成像干涉仪视场角可达129°,充分显示了大视场、高调制度的显著特点.分析了玻璃折射率对调制度的影响,得到了调制度取得最大值时玻璃的优化组合;分析了温度对调制度的影响,得到了调制度随着温度变化的曲线.此研究为高层大气探测理论的发展、大气探测以及大视场、消色差、温度补偿型风成像干涉仪的研制提供了重要的理论依据及实践指导.
关键词:
干涉成像技术
迈克尔逊干涉仪
调制度
双光束干涉 相似文献
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差分吸收光谱技术(differential optical absorption spectroscopy, DOAS)是利用气体分子在紫外-可见光谱范围的特征吸收来测量其浓度含量。被动DOAS以天顶太阳散射光为光源通过对污染源排放烟羽进行扫描测量能获取污染气体(如SO2,NO2)柱浓度的连续分部,再结合风场信息后可以估算出污染源污染气体的排放总量。在实际测量中由于无法准确获取烟羽速度这一重要参数使得排放总量的计算变得比较困难,并且这也成为估算总量中的主要误差来源。文章研究了被动DOAS测量污染源排放烟羽速度的原理和方法,两套系统以固定夹角在烟羽下方获取烟羽通过一定距离的时间差从而得到烟羽运动速度。通过两套被动DOAS系统对某电厂排放烟羽进行测量得到了两个时刻的烟羽速度3.6和5.4 m·s-1,并与单经纬仪测风法获取当时烟羽高度上的风速结果进行对比表明,这种基于被动DOAS光学遥测方法能够满足烟羽速度的测量。 相似文献
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阐述了“镀膜四面角锥棱镜(coating pyramid prism, CPP)”技术探测上层大气风场的原理,提出可以在四面角锥棱镜的4个面上分别按λ/4(λ波长)的步进光程差递增镀增透膜,同时获得一个干涉条纹中的4个强度值,实现上层大气风场的探测模式.对该模式下的相关参数进行了理论计算并得出结论:四面角锥棱镜的顶角必须大于24°、宽度为8mm的对称光束入射到CPP顶点能满足LF7玻璃上镀MgF2增透膜以实现大气风场探测的要 求.按9°×9°干涉仪视场和CCD4.5°×4.5°视场设计了干涉仪前后的光路,用CCD照相机并调 节定标光源Kr灯557.0nm到所需光束宽度进行了模拟实验,分别得到顶角为60°和90°的 两面镀膜棱镜在CCD上的两个干涉光斑,这两个光斑再复制即可获得CPP的4个干涉光斑,从 而证实了CPP技术探测上层大气风场的可行性.该模式发展了被动探测上层大气风场的光学遥 感探测技术.
关键词:
四面角锥棱镜
镀膜
上层大气风场
探测 相似文献
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Z.N. Begum 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,86(3):235-240
Radiative forcings due to aerosols and the pollutant gases accumulated as haze which are transported from nearby continent to the tropical ocean are essentially important elements of the world climate system. Vertical transport of aerosols and gaseous species takes place within the deep convective cloud clusters of the inter-tropical convergence zone and subsequently these are distributed by the upper atmospheric zonal wind flow, thereby have impact on the global atmospheric environment. The comprehensive global atmospheric models have shown capability of simulating the climate of the atmosphere with proper forcing. We have deduced the radiative forcing, optical depth and the global energy balance components by a global atmospheric model. The results are validated well with INDOEX and other available observational findings. 相似文献