Stratospheric Aerosol Extinction Profile Retrieval from SCIAMACHY Limb Measurements          下载免费PDF全文

YANG Jing-Mei  ZONG Xue-Mei 《大气和海洋科学快报》2014,(3):265-268

Stratospheric aerosol extinction profiles are retrieved from Scanning Imaging Absorption Spectrome- ter for Atmospheric Cartography （SCIAMACHY） limb scatter measurements. In the process of retrieval, the SCIATRAN radiative transfer model is used to simulate the limb scattering radiation received by the SCIAMACHY instrument, and an optimal estimation algorithm is used to calculate the aerosol extinction profiles. Sensitivity analy- ses are performed to investigate the impact of the surface albedo on the accuracy of the retrieved aerosol extinction profiles in the northern midlatitudes. It is found that the errors resulting from the bias of the assumed surface albedo in the retrieval are generally below 6%. The retrieved SCIAMACHY aerosol extinction profiles are compared with corresponding Stratospheric Aerosol and Gas Experi- ment （SAGE） II measurements, and the results indicate that for the zonal mean profiles, the SCIAMACHY retrievals show good agreement with SAGE II measurements, with the absolute differences being less than 2.3 × 10-5 km-1 from 14-25 km, and less than 5.9×10-6 km-1 from 25-35 km; and the relative differences being within 20% over the lati- tude range of 14-35 km.  相似文献   

Ka波段雷达弱降水雨量估计方法与试验     

史朝张勇  王丽娟 《成都信息工程学院学报》2014,(1):23-27

毫米波雷达适合降水云的水凝粒子的观测,设备轻便且空间分辨率和角度分辨率较高,可用于机载或星载等对有效载荷要求苛刻且关注云雨探测的应用,因而毫米波雷达在气象科学研究中备受关注。在成都地区进行了Ka波段雷达弱降水累积雨量的观测,采用了HTI(高度时间显示)观测模式,分析了雷达测量降水的方法,联合雨量计对比了Z-R关系与衰减法计算累计降水量的效果,并通过测量误差拟合调整经验参数,减小了估测误差。  相似文献   

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何志堂  韩宇飞  康胜军  王晓栋  贺小明  李辉  陈永生 《大地测量与地球动力学》2014,34(3):142-145

????A10/028??FG5?????????????α?????????????????????????????????????????????A10/028??FG5????????????????????±5×10^-8 ms^-2????????????????A10/028???????????????????????????????????????????±(2~3)×10^-8 ms^-2??  相似文献   

河北秋季层状云物理结构及适播性分析   总被引：1，自引：0，他引：1  

孙玉稳  李宝东  刘伟  韩洋  孙霞  董晓波  姜岩 《高原气象》2015,34(1)

利用2006-2010年河北省人工影响天气办公室对29块云体9架次飞机探测(或作业)资料,统计分析了河北地区秋季层状云气溶胶粒子、云凝结核CCN、小云粒子、大云粒子、降水粒子浓度和云粒子有效直径等物理特征。结果表明,河北地区适宜增雨作业的云系为中、低或高、中、低搭配的层状云,过冷层催化有利于云体发展,促使气流流入形成正反馈。适宜催化的作业层指标有:云层高度为4582 m,云内平均含水量≥0.1 g·m-3,所对应温度为-8.0℃,小云粒子浓度为236.5 cm-3。  相似文献   

Final report of project Mamex     

Paul E. Carlson 《大气与海洋》2013,51(2):67-69

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Measurements of CO,HCN, and C2H6 Total Columns in Smoke Plumes Transported from the 2010 Russian Boreal Forest Fires to the Canadian High Arctic     

C. Viatte  K. Strong  C. Paton-Walsh  J. Mendonca  N. T. O'Neill  J. R. Drummond 《大气与海洋》2013,51(5):522-531

In August 2010, simultaneous enhancements of aerosol optical depth and total columns of carbon monoxide (CO), hydrogen cyanide (HCN), and ethane (C₂H₆) were observed at the Polar Environment Atmospheric Research Laboratory (PEARL, 80.05°N, ?86.42°W, 0.61 km above sea level, Eureka, Nunavut, Canada). Moderate Resolution Imaging Spectroradiometer (MODIS) hot spots, Ozone Monitoring Instrument (OMI) aerosol index maps, and Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) back-trajectories were used to attribute these enhancements to an intense boreal fire event occurring in Russia. A ground-based Fourier Transform InfraRed (FTIR) spectrometer at PEARL provided vertically integrated measurements of trace gases transported in smoke plumes. We derived HCN and C₂H₆ equivalent emission ratios with respect to CO of 0.0054?±?0.0022 and 0.0108?±?0.0036, respectively, and converted them into equivalent emission factors of 0.66?±?0.27 g kg^?1 and 1.47?±?0.50 g kg^?1 (in grams of gas per kilogram of dry biomass burnt, with one-sigma uncertainties). These emission factors add new observations to the relatively sparse datasets available and can be used to improve the simulation of biomass burning fire emissions in chemical transport models. These emission factors for the boreal forest are in agreement with the mean values recently reported in a compilation study.  相似文献   

植被冠层日光诱导叶绿素荧光塔基自动观测方法及系统介绍     

李朝晖  张永光  张乾  吴云飞  张小康  章钊颖 《遥感学报》2021,25(5):1152-1168

植物光合作用所提供的物质和能量是人类赖以生存的关键因素,而日光诱导叶绿素荧光SIF (SunInduced chlorophyll Fluorescence)是植物光合作用的副产品,与光合作用关系密切,深入研究SIF将对于更加深入理解光合作用机制有着重要的意义。目前,近地面植被冠层SIF遥感观测发展迅速,但不同SIF观测系统间差异较大。本文通过比较分析不同塔基SIF观测系统及其特征,归纳了塔基SIF观测方式和方法,提出了塔基SIF观测技术规范。塔基SIF观测主要有两台光谱仪和一台光谱仪结合光路切换开关的观测方法,可以采取双半球和半球—锥体两种观测方式。SIFprism系统是一种新的基于光学棱镜的SIF自动观测系统,本文介绍了SIFprism系统软硬件组成和光谱数据采集流程,并以SIFprism系统为例阐述了塔基观测系统光谱数据处理流程,分析了SIF反演过程可能存在的不确定性,最后对近地面SIF观测进行了展望。  相似文献   

Basaltic thermals and Subplinian plumes: Constraints from acoustic measurements at Shishaldin volcano, Alaska     

Sylvie Vergniolle  Jacqueline Caplan-Auerbach 《Bulletin of Volcanology》2006,68(7-8):611-630

The 1999 basaltic eruption of Shishaldin volcano (Alaska, USA) included both Strombolian and Subplinian activity, as well as a “pre-Subplinian” phase interpreted as the local coalescence within a long foam in the conduit. Although few visual observations were made of the eruption, a great deal of information regarding gas velocity, gas flux at the vent and plume height may be inferred by using acoustic recordings of the eruption. By relating acoustic power to gas velocity, a time series of gas velocity is calculated for the Subplinian and pre-Subplinian phases. These time series show trends in gas velocity that are interpreted as plumes or, for those signals lasting only a short time, thermals. The Subplinian phase is shown to be composed of a thermal followed by five plumes with a total expelled gas volume of .The initiation of the Subplinian activity is probably related to the arrival of a large overpressurised bubble close to the top of the magma column. A gradual increase in low-frequency (0.01–0.5 Hz) signal prior to this “trigger bubble” may be due to the rise of the bubble in the conduit. This delay corresponds to a reservoir located at ≈3.9 km below the surface, in good agreement with studies on other volcanoes.The presence of two thermal phases is also identified in the middle of the pre-Subplinian phase with a total gas release of and . Gas velocity at the vent is found to be and for the Subplinian plumes and the pre-Subplinian thermals respectively.The agreement is very good between estimates of the gas flux from modelling the plume height and those obtained from acoustic measurements, leading to a new method by which eruption physical parameters may be quantified. Furthermore, direct measurements of gas velocity can be used for better estimates of the flux released during the eruption.  相似文献   

Flow-induced vibration analysis of elastic propellers in a cyclic inflow: An experimental and numerical study     

《Applied Ocean Research》2017

In this paper, the flow-induced vibrations of marine propellers in cyclic inflows are investigated both experimentally and numerically. A Laser-Doppler velocimetry (LDV) system is used to measure the axial flow velocity distributions produced by the seven-cycle wake screen in the water tunnel. A customized underwater slip ring and a single axis accelerometer sealed by silicon sealant are employed to measure the acceleration responses of rotating propeller blade. Numerical simulations of pressure fluctuations on the blades are performed using large eddy simulation (LES), while the forced vibrations of the propeller blades are obtained by a combined finite element and boundary element method. Experimental and numerical results are presented for two model propellers with the same geometries and different flexible properties, which show that the propeller blade vibrates at a frequency which is seven times as large as the axial passing frequency (APF) in the seven-cycle inflow. Moreover, the propeller blades are observed to resonance when the 7 APF excitation frequency is equal to the fundamental frequency of the propellers. The results indicate that both the inflow feature and the modal characteristic of blades contribute to flow-induced vibrations of elastic propellers.  相似文献   

精密重磁测量勘查矿泉水的研究     

刘元龙  阎雅芬 《地球物理学进展》1999,14(2):81-87

本文给出精密重磁测量勘查矿泉水的原理,分析方法及实际应用,钻探及化学分析结果证实我们的推断,发现了矿泉水。  相似文献