舰载激光通信传输仰角误差分析与评估

阐述了对流层不同波长激光的大气折射率。基于几何光学的方法,用球面分层和平面分层两种大气分层模式对激光在对流层中传输路径以及产生的仰角误差进行分析。用MATLAB进行了仿真方法,得出了传输仰角误差角与传输高度、起始仰角和激光波长的关系,并给出了两种分层模式的应用条件。     

Diurnal variations of turbulence parameters over the tropical oceanic upper troposphere during SCSMEX

Using the method of Thorpe analysis,the TKE(turbulence kinematic energy)dissipation rate(ε)and turbulence diffusivity(K)were derived from the RS(radiosounding)measurements in the tropical oceanic upper troposphere.The measurements were performed four times per day during two intense observation periods(May 5–25,and June 5–25)on the Kexue#1 scientific observation ship of SCSMEX(South China Sea Monsoon EXperiment)in 1998.There are three new features obtained from our analysis.First,the responses ofεand K to the onset of monsoon are negligible over the ocean at least for the data used here.Second,the temporal variations ofεand K are in a similar manner and exhibit strong diurnal variations.The diurnal variations achieve their maxima in the morning(08 LT)and early afternoon(14 LT),and achieve their minima in the evening(20 LT)and early morning hours(02 LT).The diurnal variations of turbulence parameters(εand K)and their responses to the onset of monsoon are entirely different from those derived over land at similar latitudes.Finally,although the correlations between the variations ofεand MCSs(mesoscale convective systems),which were derived from TRMM(tropical rainfall measuring mission)satellite,are not very well in only few days,the diurnal variations ofεaveraged over May and June are strongly correlated with the diurnal variations of MCSs with correlation factors of 0.79 and 0.94,respectively.This indicates that the turbulence and its diurnal variations over the tropic oceanic upper stratosphere region are highly related to the MCSs.     

基于广州CORS的大气水汽含量遥感

首先介绍了GPS气象学原理以及计算对流层延迟量的方法,给出了对流层湿分量时延ZWD（Zenith Wet Delay）与可降水分PWV（Perceptible Water Vapor）的关系,最后利用广州CORS系统各个基准站的观测数据计算大气水汽含量,验证了广州CORS系统应用于大气水汽含量遥感的可行性。     

Photoinduced Heterogeneous Processes on Chemical Phase Components of Solid Tropospheric Aerosols

This work shows the results of photoinduced process investigations over some metal oxides of the semiconductor type (In₂O₃, Sc₂O₃, V₂O₅ and MoO₃) and insulator type (MgO). These metal oxides can be the chemical phase components of solid tropospheric aerosols. The quantum yields and spectral dependencies of the quantum yields of photoadsorption and photocatalytic oxidation in the spectral region including the spectral region of solar tropospheric irradiation are determined.     

A high sensitivity elemental analysis methodology for upper tropospheric aerosol

In this study, a sampling and analysis tool for aerosol particles has been developed. Its purpose is to characterize upper tropospheric aerosols, where concentrations are low. Since measurements will be made from an airplane, a time resolution of one hour is desirable. These conditions require efficient sampling and analysis with low detection limits. To accomplish this, our sampler uses impaction, concentrating the aerosol deposit on a small area. The impactor has 14 parallel sampling lines which are used sequentially to achieve the time resolution. The elemental analysis is done with Particle-Induced X-ray Emission (PIXE), profiting from its high absolute sensitivity. The aerosol is expected to contain primarily sulphur (S) and emphasis is placed on this element, however the multi-elemental nature of PIXE is of course used. Several substrates have been investigated regarding minimum detection limits. Scanning Transmission Ion Microscopy (STIM) analysis has been conducted on two outdoor aerosol samples, rendering three-dimensional images and mass distribution profiles. The setup was tested at ground level with high time resolution (5 min). Results show that the detection capabilities are excellent.     

基于VRS技术的误差分析与建模

在对网络RTK以及虚拟参考站技术（VRS）进行介绍的基础上，对包括电离层误差、对流层误差、轨道误差等误差在内的各种主要系统误差源进行了分析，并主要针对对流层误差的减弱以及消除提出了采用带有测站高差因子的内插法计算双差对流层延迟的参数化模型。从系统误差建模和分离的角度对VRS技术的精度和可靠性进行了讨论。     

典型区域气候下的D-InSAR大气形变误差分析

利用单站全球导航卫星系统(Global Navigation Satellite System, GNSS)精密单点定位原理(Precise Point Positioning, PPP)解算天顶方向的对流层大气天顶延迟, 并对其一天内的变化进行统计平均, 结合经典的Kolmogorov-Obukhov“2/3”扰动理论和随机场理论, 基于对流层天顶延迟与大气折射率的时变相关性获得大气结构常数的平方C_n2, 通过计算我国北京、上海、昆明、乌鲁木齐四个典型区域在不同时间的C_n2, 评估各区域大气环境的湍流特性对不同基线长度的合成孔径雷达差分干涉(Differential Interferometry Synthetic Aperture Radar, D-InSAR)系统形变误差的影响.计算结果表明:对于基线距离较长的合成孔径雷达(Synthetic Aperture Radar, SAR)系统来说, 大气湍流的影响不容忽略, 尤其是当大气结构常数的数量级在10-14 m-2/3以上时, 形变误差基本会达到厘米级.准确获取雷达成像时间内的大气结构常数, 对进一步降低D-InSAR系统的形变误差起到举足轻重的作用.     

一次江淮暴雨过程的数值模拟和诊断分析

利用WRF模式对2003年7月4-5日江淮地区的梅雨锋暴雨过程进行了数值模拟和诊断分析.结果表明:暴雨区处于高温高湿环境,高、低空急流的耦合和低层辐合以及高层辐散的配置有利于暴雨的产生发展.通过计算湿位涡还发现,ζ_MPV1高低层正负值区叠加的配置、ζ_MPV1<0及ζ_MPV2>0的演变,表明此次过程中不仅有对流不稳定能量存在,还有倾斜涡度的发展.ζ_MPV1和ζ_MPV2综合反映了暴雨区对流不稳定和斜压不稳定的增强.     

Validation of Ozone Product by Satellite OMPS with Sounding Measurements over Beijing

Ozone Mapping and Profiler Suites (OMPS) provide vertical distributions of ozone with high vertical resolutions. They can also provide data for studying the temporal and spatial distribution of ozone in atmosphere. To verify the accuracy of OMPS ozone products, the ozone sounding data from 2016 to 2018 in Beijing were selected, comparing the OMPS v2.5 ozone profile with the total amount of v2.1 ozone profile. The results show that the vertical distributions of ozone in OMPS over Beijing are in good agreement with the ozone sounding data in the upper stratosphere, the relative deviation is less than 10%. The relative deviation in the upper stratosphere is in the range of 15%~40% and 80% in some cases; the relative deviation between the total ozone in OMPS stratosphere and the total ozone in the stratosphere integrated by the ozone sounding profile is little and the average deviation is less than 5%, the root mean square error is 18.3 DU, and the correlation coefficient is 0.89. The average deviation of total tropospheric ozone is more than 30%, and the correlation coefficient of total tropospheric column is 0.62.     

数字引导中大气折射修正技术研究

无线电波在大气中传输时受大气中不均匀介质的影响,会产生电波折射效应,使得地面定向天线在利用GPS数据进行数字引导跟踪目标时产生折射误差,导致链路质量下降或中断。针对此问题,通过对流层大气折射修正技术研究,结合航空测控实际情况,提出了利用基于地面参数预测的线性分层法对大气折射效果进行修正的解决方法,给出了补偿算法,据此进行仿真并在工程中进行试验验证,取得了预期效果。