基于地基微波辐射计的大气参数廓线遥感探测

介绍了实时连续遥感探测大气温度廓线、湿度廓线和液态水含量廓线的地基微波辐射计。通过无线电气球探空测量的温度、湿度廓线、太阳辐射计测量的晴天水汽总量与微波辐射计探测结果的对比,证明该微波辐射计可以可靠地探测大气温度、湿度和水汽总量。通过对两个典型天气事件微波辐射计的观测数据分析表明：微波辐射计还可以监测云和天气变化的过程信息。     

基于微波辐射计进行海雾监测

QFW-6000型微波辐射计可连续监测大气温度和湿度廓线,并实时输出大气水汽含量和液态水含量等信息。本文介绍了海雾的形成条件和观测手段,并详细阐述基于QFW-6000型微波辐射计进行海雾监测的方法,通过海雾生消过程下的观测结果分析,表明该设备具有优良的海雾观测能力。     

基于微波高光谱技术的数据仿真及参数反演研究

发展高光谱微波辐射计对于提升大气参数反演精度具有重要意义。利用微波辐射传输模型mpm93以及BP 神经网络方法分别构建正演上行辐射亮温和反演大气温度廓线的模型,并研究了晴空条件下高光谱微波辐射计反演大气温度廓线的精度。54～58 GHz、64～68 GHz 在氧气吸收波段选取80 个通道作为高光谱通道,基于2015 年5～12 月昆明的探空资料进行正、反演仿真实验。选取微波成像仪/ 探测仪(SSMIS)的9 个温度探测通道进行对比实验,评估分析反演效果。实验结果表明:在大气3～10 km 高度范围内,高光谱通道的反演精度较SSMIS 提高了0.3 ～0.6 K;在0～3 km 高度范围内,反演精度提高了1 K。     

QFW-6000型地基多通道微波辐射计及典型天气过程观测结果分析

QFW-6000型微波辐射计是中国电波传播研究所自主研发的地基多通道微波辐射计,可实时监测大气柱积分水汽量、大气柱积分云水含水量,实时输出0-10km高度的高分辨率大气温湿廓线。本文介绍了QFW-6000型微波辐射计的主要功能、工作原理、大气参数建模方法,通过与气象探空数据及参考文献中MP-3000输出结果的对比分析,以及典型天气过程下的观测结果的分析,表明该设备具有优良的工作性能。     

数字全极化微波辐射计系统设计与定标分析

海洋风场是海洋与大气作用的重要参数之一。全极化微波辐射计是一种新型的微波遥感器。数字全极化微波辐射计采用多路数字相关技术,对水平和垂直极化信号进行相关处理,产生反演海面风场模型所需海面亮温Stokes矢量。详细介绍了数字全极化微波辐射计的系统设计方法,包括射频前端、中频段和数字相关器的设计。同时给出了系统内定标以及外定标方法。对数字全极化微波辐射计做了细致的理论分析和硬件实现设计。     

地基多通道微波辐射计在大气遥感中的应用

地基多通道微波辐射计可实时探测大气微波辐射亮温并反演出大气温度、水汽密度、相对湿度和液态水廓线等。本文主要介绍了自主研制的地基多通道微波辐射计以及数据反演方法,同时将微波辐射计反演的大气参数与探空资料对比分析了反演精度,结果表明微波辐射计观测反演大气温度、湿度和液态水廓线具有很好的精度。同时辐射计可实时精确的探测反演大气边界层逆温,能够很好的探测到地表辐射逆温的强度和逆温厚度,这对研究大气边界层有着重要作用。     

高(主)波束效率毫米波天线

本文介绍一种用于机载微波遥感的8毫米波段的微波辐射计天线。它是一种高波束效率的低噪声天线。微波辐射计实际上是一台高灵敏度的低噪声接收机,它从接收的非相干(似噪声)的电磁辐射中得出有用的信息。无论什么辐射源,辐射信号的性质都是由物体的物理特性——特别是温度和吸收性质,及由此引起的宽带辐射能谱之间的关系决定的。微波辐射计需要通过天线接收微弱的电磁辐射来判别物体的物理特性。天线则是微波辐射计的     

数字增益自动补偿微波辐射计的计算机仿真

数字增益和补偿微波辐射计是一种新型的微波辐射计,它能很好地实现增益补偿,有效地提高微波辐射计性能,更适合星载使用,本文对以全功率微波辐射计为基础的数字增益自动２微波辐射计进行仿真,分析了全功率微波辐射计的特点,并在此荐 ,提出了在频程跨度很大时实现系统频域仿真的有效方法,仿真结果不仅证明功率微波辐射计的特点,在此基础上,提出了在频程跨度很大时实现系统频域仿真的有效方法,仿真的结果不仅证明所采用的方     

利用温度权重函数反演大气温度廓线的相关理论研究

要利用温度权重函数反演大气温度廓线,首先要了解相关概念和理论。本文的主要研究内容是地基双通道微波 辐射计在大气温度廓线遥感和反演中的相关理论：5mm频段氧气吸收带的吸收特征;微波遥感大气温度辐射方程特性; 大气透过率和权重函数的计算。得出了上行和下行大气辐射方程温度权重函数的特性、不同观测高度和观测角度的大气 透过率、地基微波辐射计的权重函数。     

固定指向型微波辐射计辐射传输模型分析

固定指向型微波辐射计通常采用多支路法进行定标，传输路径上的各微波组件存在一定的插入损耗，且组件间还存在阻抗失配，因此需要首先建立信号源经馈源口面至接收机输入端口处的辐射传输模型，然后结合两点定标法确定固定指向型微波辐射计的定标模型。首先对同类型微波辐射计的辐射传输模型进行叙述，然后采用正交试验设计法定量地分析了辐射传输模型中各组件对接收机等效输入噪声温度误差影响的大小以及主次关系，为同类型微波辐射计的辐射传输模型建立和定标模型初始参数的选取提供参考。     

用微波辐射计测量大气湿延迟和频率选择

采用具有最佳频率组合的双通道微波辐射计测量大气湿延迟,由于是在测量路径上实时获得测量信息的,测 量结果可反映大气时变特性和水平不均匀性,同时可消除云中液态水对湿延迟的“过量”估计。因此,用于电波折射误 差修正和解算大气积分水汽(或可降水量PWV )可有很高的精度。由历史气象探空数据分析,得出权函数随高度变化小 的频率对在不同气候区或地区不同,工作在最佳频率对时,在5km 以下高度权函数相对变化可小于5%。     

地基微波辐射计和太阳光度计反演大气水汽总量的对比研究

水汽是地球大气的重要成分,对大气中传输的红外辐射造成严重的衰减,影响光电设备的探测性能。利用改进的Langley法对太阳光度计940nm探测通道进行定标,根据水汽吸收透过率与水汽总量的关系,应用太阳辐射计的观测资料反演出合肥和新疆两地的大气水汽总量,并与同时期地基微波辐射计在以上两地区的探测值相比较。结果表明：地基微波辐射计观测的水汽总量日变化趋势和太阳光度计具有较好的一致性,二者观测的日均水汽总量变化趋势非常吻合,相对偏差小于5.1%。     

A new simplified water vapor measurement using a multifrequencymicrowave radiometer with two-different-beamwidth antennas

A simplified method for the measurement of the atmospheric water vapor is presented. A multifrequency microwave radiometer having two different beamwidth antennas is used to measure solar extinction in terms of the difference temperature of the antennas and the relative intensity at each pair of different frequency points. The atmospheric emission component and the effect of solar fluctuation are removed automatically. Cloud absorption can be estimated by simultaneous measurement at two different frequency pairs and compensated for by the water vapor absorption. Using the specific nature of the composite weighting function defined in the opacity integral, the radiometric data can be related to the integrated water vapor and the water vapor profile     

Radiometry in the Submillimeter Region Using the Interferometric Modulator

Radiometry in the submillimeter and far infrared regions involves problems of a type not encountered in the centimeter region which require solutions using techniques different from those used in centimeter-wavelength radiometry. The nonlinear variation of the magnitude of the black-body radiation spectral density with temperature and wavelength, the limitation of antenna beamwidth by factors connected with the size of the noncoherent detector and the antenna focal length (rather than by diffraction effects and the antenna aperture) and the heavy absorption of submillimeter radiation by atmospheric water vapor are typical of the problems normally not encountered in centimeter radiometry. The unavailability of microwave techniques (i.e., waveguides, coherent receivers, etc.) makes necessary the use of quasi-optical techniques in this wavelength region. The interferometric modulator, which has already been used in far infrared spectrometers, is proposed in this paper as the major component of a practical submillimeter radiometer. Its use as the wave-number-selection device in a radiometer is analyzed and estimates are obtained for the sensitivity of this submillimeter radiometer. It is estimated that a 0.2/spl deg/ minimum detectable temperature differential is achievable with this radiometer. Also discussed are the effects of atmospheric water vapor absorption and the sensitivity of a number of different types of radiation detectors suitable for use in the submillimeter-wavelength region.     

Analysis and improvement of tipping calibration for ground-basedmicrowave radiometers

The tipping-curve calibration method has been an important calibration technique for ground-based microwave radiometers that measure atmospheric emission at low optical depth. The method calibrates a radiometer system using data taken by the radiometer at two or more viewing angles in the atmosphere. In this method, the relationship between atmospheric opacity and viewing angle is used as a constraint for deriving the system calibration response. Because this method couples the system with radiative transfer theory and atmospheric conditions, evaluations of its performance have been difficult. In this paper, first a data-simulation approach is taken to isolate and analyze those influential factors in the calibration process and effective techniques are developed to reduce calibration uncertainties. Then, these techniques are applied to experimental data. The influential factors include radiometer antenna beam width, radiometer pointing error, mean radiating temperature error, and horizontal inhomogeneity in the atmosphere, as well as some other factors of minor importance. It is demonstrated that calibration uncertainties from these error sources can be large and unacceptable. Fortunately, it was found that by using the techniques reported, the calibration uncertainties can be largely reduced or avoided. With the suggested corrections, the tipping calibration method can provide absolute accuracy of about or better than 0.5 K     

基于FPGA的多通道高速数字谱仪的关键算法的设计与实现

为实现微波辐射计大带宽数字化探测的需求,解决现场可编程门阵列（Feild Programmable Gate Array,FPGA）内部处理速度限制输入数据速率的问题,提出了一种基于多相滤波器组和高级快速傅里叶变换（Fast Fourier Transform,FFT）结构的高速数字谱仪设计方案,介绍了多相滤波器组和高级FFT理论基础并给出了具体的硬件设计和硬件实现,完成了硬件的功能仿真,将MATLAB仿真和硬件功能仿真的结果进行对比,验证了该设计方案的可行性.在低时间成本和低经济成本条件下,该方案可实现微波辐射计后端的灵活配置和共享多个微波辐射计前端的功能.     

Measurements of Atmospheric Water Vapor Above Mauna Kea Using an Infrared Radiometer

This paper presents the first results from a prototype infrared radiometer which has been developed to measure variations in atmospheric water vapor column abundance from high altitude sites. The performance of the infrared radiometer is compared and contrasted with that of a water vapor monitor operating at radio frequencies. Analysis shows that the infrared radiometer can measure variations at the level of ～ 1 μm precipitable water vapor (pwv) in an integration time of 1 s when the total column abundance is ～0.5 mm pwv. Since variations in atmospheric water vapor are the dominant source of phase noise in (sub)millimeter astronomical interferometry, an instrument capable of rapid and high sensitivity water vapor measurements has the potential to provide the necessary phase correction information for interferometric arrays.