风云二号静止气象卫星图像杂散信号分析   总被引：3，自引：0，他引：3       下载免费PDF全文

魏彩英张晓虎  邱康睦 《应用气象学报》2004,15(5):564-571

该文利用GMS 5原始数据、GMS 5展宽数据、FY-2A展宽数据和FY-2B展宽数据, 采用伪彩色增强和灰度直方图分析方法, 分别对这4种数据的红外、水汽、可见光通道图像进行了针对杂散光的对比分析以及对杂散信号来源分析。分析表明这三颗静止气象卫星的图像中都存在一定的杂散信号。该文提出了解决杂散光问题主要依靠优化辐射计光路设计; 地面系统在实时处理、展宽图像时采取简单剔除处理, 可以减小或消除图像冷空间区域的杂散信号, 但是去掉地球圆盘图像内部的杂散信号将非常困难。  相似文献   

微波焙烧炉在分析测试中的应用研究     

荣耀 《铀矿地质》2004,20(6):376-379,384

本文详细论述了微波焙烧炉代替马弗炉应用于样品焙烧、熔融、活性炭灰化工作中的实际效果。结果表明：其应用不但可行，而且与马弗炉相比，微波焙烧炉具有更加优越的经济性与环保效果。  相似文献   

无机盐超细粉体制备技术的回顾与展望   总被引：3，自引：0，他引：3       下载免费PDF全文

吴健松  李海民 《盐湖研究》2004,12(3):50-54

评述了制备无机盐超细粉体的传统方法以及一些传统方法的改进 ,对当前几种新技术做了介绍与展望  相似文献   

Direct Current Plasma Emission Spectrometric Determination of Major, Minor and Trace Elements in Microwave Oven Acid Leachates of Powdered Whole Coal Samples     

Sandro Fadda 《Geostandards and Geoanalytical Research》2005,29(1):143-156

Major concentrations of Al₂O₃, Fe₂O₃, MgO, CaO, Na₂O and K₂O, minor levels of TiO₂, P₂O₅ and thirty petrologically, geochemically and environmentally significant trace elements have been determined in microwave oven acid leachates of whole powdered coal samples by direct current plasma‐atomic emission spectrometry (DCP‐AES). A single sample preparation procedure was suitable for all the determinations with no additional dilution step for major elements solution. Dried samples (0.5 g) were treated in low‐pressure PFA digestion vessels with HF/HCl/HNO₃/HClO₄ acids to quantitatively extract the analytes from the bulk material, while leaving the major part of organic matrix as a residue. The major constituents of geological samples, in particular the easily ionised elements (EIEs) such as alkali and alkaline earths, may complicate the instrumental determinations in DCP‐AES because of differential enhancements of elemental emission intensities and stray light interferences. Taking account of these factors, the coal matrix is considered to have very low major oxide totals as compared to many other common geo‐environmental and related materials (rocks, sediments, soil, ashes etc.). The sample size employed here, while yielding a relatively concentrated solution to cover a wide range of elemental determinations, provided a sample matrix that significantly diminished interferences for DCP measurements. The need for closely matching the unknowns and calibrators was eliminated except for overall acidity and an excess quantity of caesium for EIE buffering. Calibration of the spectrometer was accomplished by simple aqueous single element solutions as high concentration calibrators in addition to a reagent blank as a low concentration calibrator. Two point working curves were established to allow for the maximum concentrations of each element expected in the unknowns. The precision of determinations under routine conditions as well as the reproducibility of the leaching and precision of instrumental measurements have been evaluated. Relative standard deviations (RSD) were of 1–2% for those elements whose concentrations in solid samples were well above the limits of quantification. Method detection limits in the buffered solutions were also evaluated. To evaluate the accuracy of the microwave oven‐DCP method a suite of eight certified coal reference materials of differing rank, were analysed with good agreement with the certified and/or available published data. Results are presented for the uncertified major oxides in the AR series reference materials.  相似文献   

Development of a rain‐on‐snow detection algorithm using passive microwave radiometry          下载免费PDF全文

Caroline Dolant  Alexandre Langlois  Benoit Montpetit  Ludovic Brucker  Alexandre Roy  Alain Royer 《水文研究》2016,30(18):3184-3196

Currently observed climate warming in the Arctic has numerous consequences. Of particular relevance, the precipitation regime is modified where mixed and liquid precipitation can occur during the winter season leading to rain‐on‐snow (ROS) events. This phenomenon is responsible for ice crust formation, which has a significant impact on ecosystems (such as biological, hydrological, ecological and physical processes). The spatially and temporally sporadic nature of ROS events makes the phenomenon difficult to monitor using meteorological observations. This paper focuses on the detection of ROS events using passive microwave (PMW) data from a modified brightness temperature (T_B) gradient approach at 19 and 37 GHz. The approach presented here was developed empirically for observed ROS events with coincident ground‐based PMW measurements in Sherbrooke, Quebec, Canada. It was then tested in Nunavik, Quebec, with the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR‐E). We obtained a detection accuracy of 57, 71 and 89% for ROS detection for three AMSR‐E grid cells with a maximum error of 7% when considering all omissions and commissions with regard to the total number of AMSR‐E passes throughout the winter period. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

电感耦合等离子体质谱法测定铅合金中的微量杂质元素镉和锡   总被引：1，自引：1，他引：0  

郝原芳  刘新  宋丽华  李丽君  徐英奎 《岩矿测试》2016,35(4):378-383

铅合金中的镉和锡由于含量较低,国家标准方法均为单一元素分析,步骤繁琐,检出限高,难以达到理想的检出要求。本文建立了应用电感耦合等离子体质谱法(ICP-MS)测定铅合金中微量级(μg/g级)杂质元素镉和锡的分析方法。采用单一的低浓度硝酸溶解铅合金,用低温慢溶的方式使样品溶解更加完全,减少了多离子对仪器的干扰;通过铅基体匹配和加入酒石酸保证了标准与样品介质的一致性,同时避免了锡的水解;以~(103)Rh作为内标元素,~(111)Cd和~(118)Sn作为测量同位素克服了质谱干扰。方法检出限为镉0.05 ng/g、锡0.04 ng/g,比国家标准方法的检出限(1~6μg/g)低,精密度小于4%。该方法试剂用量少,减少了处理样品的复杂性,实现了合金中微量级元素的准确测定。  相似文献   

利用微波等离子体炬四极杆质谱在线测定稀土矿样中的多种稀土元素     

初晨  张瑛  王尚贤  周润芝  蒋涛  朱志强  卢爱民 《岩矿测试》2016,35(5):468-474

随着稀土的应用越来越广泛,开发稀土元素的快速在线检测技术已日趋成为行业发展的需求。本文以微波等离子体炬(MPT)为离子源,以四极杆质谱仪(QMS)作为质量分析器建立了一种快速、直接检测水样中稀土元素的质谱检测方法,并将其应用于分析稀土矿样中的多种稀土元素。研究表明,应用MPT-QMS测定水样中的钇、镧、铈、钕、铕五种稀土元素,检出限(LOD)可达11.0~60.5μg/L,测定范围为50~1000μg/L。当分析固体稀土矿样时,样品经酸溶处理后通过气动雾化形成气溶胶,再进行冷却干燥,气溶胶由MPT的中心管道进入等离子体中,产生稀土元素复合离子,再引入QMS中进行分析,即可以定量地测定矿样中稀土元素的含量。同一样品用电感耦合等离子体质谱(ICP-MS)进行对比实验,两者的检测结果在数量级上接近,证明了MPTQMS方法在半定量的意义下是准确、可靠的,因而这种快速的检测方法可发展成为水体中金属元素的现场分析方法,应用于环境水、生活水质量在线监测等领域。  相似文献   

气象卫星可见光红外光学成像仪发展沿革          下载免费PDF全文

杨忠东  刘健 《应用气象学报》2016,27(5):592-603

该文回顾了环境气象卫星可见光红外光学成像遥感仪器50多年的发展历程,从不同时期在轨运行的近百台 (套) 仪器中选择了12种作为代表,结合仪器功能性能技术指标和应用需求梳理分析了其历史发展脉络和主流业务发展趋势,并初步探讨了创新发展方向。50多年的发展可以分为3个阶段:早期探索20年, 美国第1代探索性仪器,开创了气象卫星对地观测的先河;初步应用20年, 基本形成初步应用格局,欧洲、中国等开始发展自己的环境气象卫星光学成像遥感仪器;稳定应用和进步发展10多年。新一代极轨卫星可见光红外光学成像遥感仪器,其典型特征是光谱波段20个以上,谱段带宽窄,光谱范围全面覆盖0.4~15 μm,辐射测量精度高,空间分辨率为200~1000 m,其改进型仪器代表了未来极轨气象卫星主流业务发展趋势。静止气象卫星可见光红外光学成像遥感仪器未来主流业务发展方向的典型特点是光谱波段15个以上,谱段带宽较窄,光谱范围全面覆盖0.4 ~15 μm,辐射测量精度高,空间分辨率为500~2000 m,圆盘图成像速度可达到分钟级,区域扫描速度更快。  相似文献   

冰雹云降水过程中微波亮温的变化特征     

何文英  陈洪滨 《气象与环境科学》2016,39(1):3-11

通过冰雹云模式模拟的一次冰雹云降水过程中降水粒子廓线和微波辐射传输模式结合,分析了冰雹云发展的不同阶段的微物理含量垂直结构变化及其对微波亮温的影响,得到以下几点结论:1)如果微波通道受到降水粒子散射和辐射的共同作用,如降水云早期的85 GHz亮温,成熟期的19 GHz亮温及消散期的37 GHz亮温,由于辐射和散射信息互相抵消,致使亮温随雨强的变化较复杂,这些通道亮温和雨强的相关性明显降低,不宜被用来反演地面雨强。2)根据19 GHz亮温随地面雨强或冰相粒子柱含量的改变,可以大致确定降雨云的不同阶段:在发展阶段,主要是降雨层以上的冰相粒子,尤其霰粒影响19 GHz亮温,致使其亮温与冰相粒子柱含量具有较好的负相关,而与地面雨强相关性较差;在成熟阶段,主要受雨水上层逐渐增加的辐射和冰相粒子散射共同作用,使得19GHz亮温与地面雨强和冰相粒子柱含量的相关性都不太好;在消散阶段,19 GHz亮温主要受较强的雨水辐射影响,与地面雨强和冰相粒子柱含量均有着较高的正相关。3)37 GHz是相对比较稳定的通道,其亮温与地面雨强有较好的线性关系,尤其与冰相粒子柱含量相关性更好,因此是反演地面雨强和冰相粒子柱含量的最佳通道。85 GHz亮温对降雨云体的中高层结构较为敏感,使得其亮温随地面雨强增加而降低的变化比较离散,不如37 GHz的集中。  相似文献   

Impact of sub-pixel heterogeneity on modelled brightness temperature for an agricultural region     

《International Journal of Applied Earth Observation and Geoinformation》2016

Knowledge of sub-pixel heterogeneity, particularly at the passive microwave scale, can improve the brightness temperature (and ultimately the soil moisture) estimation. However, the impact of surface heterogeneity (in terms of soil moisture, soil temperature and vegetation water content) on brightness temperature in an agricultural setting is relatively unknown. The Soil Moisture Active Passive Validation Experiment 2012 (SMAPVEX12) provided an opportunity to evaluate sub-pixel heterogeneity at the scale of a Soil Moisture Ocean Salinity (SMOS) or the Soil Moisture Active Passive (SMAP) radiometer footprint using field measured data. The first objective of this study was to determine if accounting for surface heterogeneity reduced the error between estimated brightness temperature (T_b) and T_b measured by SMOS. It was found that when accounting for variation in surface soil moisture, temperature and vegetation water content within the pixel footprint, the error between the modelled T_b and the measured T_b was less than if a homogeneous pixel were modelled. The correlation between the surface parameters and the error associated with not accounting for surface heterogeneity were investigated. It was found that there was low to moderate correlation between the error and the coefficient of variance associated with the measured soil moisture, soil temperature and vegetation volumetric water content during the field campaign. However, it was found that the correlations changed depending on the stage of vegetation growth and the amount of time following a precipitation event. At the start of the field campaign (following a precipitation event), there was strong correlation between the error and all three surface parameters (r ≥ 0.75). Following a precipitation event close to the middle of the field campaign (during which there was rapid growth in vegetation), there was strong correlation between the error and the variability in vegetation water content (r = 0.89), moderate correlation with soil moisture (r = 0.61) and low correlation with soil temperature (r = 0.26).  相似文献