High vertical resolution water vapour profiles in the upper troposphere and lower stratosphere retrieved from MAESTRO solar occultation spectra

An algorithm has been developed that retrieves water vapour profiles in the upper troposphere and lower stratosphere from optical depth spectra obtained by the Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation (MAESTRO) instrument onboard the SCISAT satellite as part of the Atmospheric Chemistry Experiment (ACE) mission. The retrieval relies on ro-vibrational absorption of solar radiation by water vapour in the 926–970 nm range. During the iterative inversion process, the optical depth spectra are simulated at the spectral resolution and sampling frequency of MAESTRO using the correlated-k approximation. The Chahine inversion updates the water vapour volume mixing ratio (VMR), adjusting all retrieval layers simultaneously, to match the observed differential optical depth due to absorption by water vapour and ozone at each tangent height. This approach accounts for significant line saturation effects. Profiles are typically obtained from ∼22 km down to the cloud tops or to 5 km, with relative precision as small as 3% in the troposphere. In the lower stratosphere, the precision on water vapour VMR is ∼1.3 μmol/mol in an individual retrieval layer (∼1 km thick). The spectral capability of MAESTRO allows for the clear separation of extinction due to water vapour and aerosol, and for the fitting quality to be quantified and used to determine an altitude-dependent convergence criterion for the retrieval. In the middle troposphere, interhemispheric differences in water vapour VMR are driven by oceanic evaporation whereas in the upper troposphere, deep convection dominates and a strong seasonal cycle is observed at high latitudes.     

The dynamic heliosphere,solar activity,and cosmic rays

This brief review addresses the relation between solar activity, cosmic ray variations and the dynamics of the heliosphere. The global features of the heliosphere influence what happens inside its boundaries on a variety of time-scales. Galactic and anomalous cosmic rays are the messengers that convey vital information on global heliospheric changes in the manner that they respond to these changes. By observing cosmic rays over a large range of energies at Earth, and with various space detectors, a better understanding is gained about space weather and climate. The causes of the cosmic ray variability are reviewed, with emphasis on the 11-year and 22-year cycles, step modulation, charge-sign dependent modulation and particle drifts. Advances in this field are selectively discussed in the context of what still are some of the important uncertainties and outstanding issues.     

激光陀螺稳频测试技术研究

本文研究了机抖激光陀螺稳频系统性能测试的两种新方法：压电扫频和光强扫频。通过两种方法实现对稳频抓卡系统进行动、静态测试,描绘出稳频系统在工作频率段（5KHz~18KHz）范围内的谐振峰特性曲线。试验结果表明,两种方法,尤其是光强扫频,更具有实际操作性,有助于稳频电路调试参数的选择,从而有效的避开谐振峰,提高激光陀螺工作的稳定性及环境适应性,也为稳频系统电路设计提供了改进方向和依据。     

弱太阳闪烁中深空探测信道的自适应控制

为提高探测器发射机功率利用率,在探测器和地球间建立可靠的传输链路,弱太阳闪烁中的深空信道的自适应控制十分重要。根据CCSDS规范,提出了一种基于连续功率控制和离散速率控制策略的深空信道自适应控制方法。数学分析和计算机仿真表明,(1) 太阳闪烁越强,自适应功率控制效果越明显;(2) 当太阳闪烁引起的信号衰减不大,小于9.4dB时,MPSK自适应控制信道容量高于非自适应控制信道容量。
     

空间目标在天基光学探测中的特性分析与仿真

分析了空间目标的分布及几何特性,研究了空间目标光学特性与天基探测系统、太阳以及目标自身参数的关系,提出了空间目标光学特性仿真的思路,建立的天基空间目标光学特性分析系统可以计算并绘制相对距离、太阳相位角及目标星等变化曲线.由于很难获取准确的空间目标实际光度数据,文中提出了对仿真结果的验证方法.通过对仿真结果的分析,得出了天基空间目标光学探测的特点,为天基光学探测和识别的研究提供了参考.      

Determination of K,Ar, Cl,S, Si and Al flare abundances from RESIK soft X-ray spectra

The RESIK is a high sensitivity, uncollimated bent crystal spectrometer which successfully operated aboard Russian CORONAS-F solar mission between 2001 and 2003. It measured for the first time in a systematic way solar soft X-ray spectra in the four wavelength channels from 3.3 Å to 6.1 Å. This range includes characteristic strong lines of H- and He-like ions of K, Ar, Cl, Si, S and Al in the respective spectral channels. A distinguishing feature of RESIK is its possibility of making reliable measurements of the continuum radiation in flares. Interpretation of line and the continuum intensities observed in vicinity of respective strong lines provides diagnostics of plasma temperature and absolute abundances of K, Ar, Cl, S, Si and Al in several flares. We analyzed the observed intensities of spectral lines and the nearby continuum using the CHIANTI v5.2 atomic data package. A specific, so-called “locally isothermal” approach has been used in this respect allowing us to make not only flare-averaged abundance estimates, but also to look into a possible variability of plasma composition during the course of flares.     

Element and Isotopic Fractionation in Closed Magnetic Structures

Recent papers have suggested that the slow solar wind is a super-position of material which is released by reconnection from large coronal loops. This reconnection process is driven by large-scale motions of solar magnetic flux driven by the non-radial expansion of the solar wind from the differentially rotating photosphere into more rigidly rotating coronal holes. The elemental composition of the slow solar wind material is observed to be fractionated and more variable than the fast solar wind from coronal holes. Recently, it has also been reported that fractionation also occurs in 3He/4He. This may be interpreted in the frame-work of an existing model for fractionation on large coronal loops in which wave-particle interactions preferentially heat ions thereby modifying their scale-heights. This revised version was published online in June 2006 with corrections to the Cover Date.     

飞机应急照明电源原理及校验方法

通过对BPS7－3飞机应急照明电源的原理分析,提出了内场校验方法,为该设备的维护和修理以及应急照明电源的设计提供参考。     

用蒙特卡罗法数值模拟CCD相机的杂光

采用蒙特卡罗（Ｍｏｎｔｅ－Ｃａｒｌｏ）法对卫星ＣＣＤ相机的地气杂光进行了计算。主体段杂光系数的计算值与用积分球实验测量值属同一数量级,表明该方法和计算软件具有一定的可靠性;分析计算值与测量值产生偏差的因素发现,热物性参数的不确定性对数值模拟影响很大。分析了遮光罩长度、反光镜扫描角度等变化对杂光系数的影响,结果表明,遮光罩长度不变,而反光镜的扫描角度为４５℃时,光线的进入比例最大,而杂光系数最小。