Earthshine and Asteroseismology Telescope (East) Network

Several automated optical telescopes have been setup at appropriate longitudes around the globe to study earthshine variations and asteroseismology. The first telescope has been setup at Teide Observatory, Tenerife, Spain in October 2004. The intensity of earthshine relates to the average of Earth’s albedo, and in turn relates to the global temperature of the Earth. A global network is necessary because each site can measure the earthshine reflected from only a part of the Earth. The network will also be used for asteroseismology study. It can measure photometric variations of pulsating stars. The long-term and continuous measurements allow the accurate determination of mode frequencies of stellar pulsations, which provides information on the properties of stellar interior.     

辐射发射参考源在EMC比对中的应用

辐射发射参考源是在对EMC测试系统进行比对测试和定期场地校验时必不可少的设备,介绍了辐射发射参考源的原理和特点、各种实现方式、国内外应用概况及其稳定性考核措施。     

气体采样计量误差的研究

研究与制订大气环境质量标准，即确定和评价大气中污染物浓度与暴露时间的影响、损害作用及彼此的相互关系乃是环境保护的重要研究课题。本文建议统一采用“标准状况下，标准组成干燥空气中所含污染物浓度”的严格概念。同时，还研究了大气采样中由于现场条件与大气成分不同所产生的气体流量（率）计量误差，得到了这种误差的一般数学表达式。     

BTT导弹协调式耦合变结构自动驾驶仪设计

本文应用多变量不确定性系统的模型参考变结构自适应控制理论设计了某型ＢＴＴ导弹协调中变结构自动驾驶仪，有铲地克服了通道间的交叉耦合效应，较好地保证了ＢＴＴ导弹偏航衮动通道之间的协调动作，获得了较高的指令跟踪性能。     

Advances in the Studies of the Middle and Upper Atmosphere in 2004 - 2006

This paper summarizes the research results obtained by Chinese scientists and/or through international collaborations during 2004 to 2006. Within the context of COSPAR, the progresses in the studies of the middle and upper atmosphere in China in the past two years are introduced with focusing the developments in facilities and instruments, and the advancements in scientific issues, e.g., dynamics related processes, atmospheric constituents, and the coupling with the lower atmosphere.     

汽车尾气分析仪中的大气压力补偿技术

控制汽车尾气量的增加,是减少汽车废气污染改善人类生活环境的重要措施。汽车尾气分析仪主要是通过检测汽车尾气中不同气体的含量,以达到合理控制的目的。在对气体浓度的检测中,大气压力的影响不能忽视。本文围绕这个问题,详细讨论了大气压力影响的补偿方法。     

A Possible Transfer Mechanism for the 11-Year Solar Cycle to the Lower Stratosphere

Observational evidence of the 11-year solar cycle (SC) modulation of stratosphere temperatures and winds from the ERA-40 dataset is reviewed, with emphasis on the Northern winter hemisphere. A frequency modulation of sudden warming events is noted, with warmings occurring earlier in solar minimum periods than in solar maximum periods. The observed interaction between the influence of the SC and the quasi biennial oscillation (QBO) on the frequency of sudden warmings is noted as a possible clue for understanding their mechanism of influence. A possible transfer route for the 11-year solar cycle from the equatorial stratopause region to the lowest part of the stratosphere is proposed, via an influence on sudden warming events and the associated induced meridional circulation. SC and QBO composites of zonal wind anomalies show anomalous wind distributions in the subtropical upper stratosphere in early winter. Mechanistic model experiments are reviewed that demonstrate a sensitivity of sudden warmings to small wind anomalies in this region. Various diagnostics from these experiments are shown, including EP fluxes and their divergence and also the synoptic evolution of the polar vortex, in order to understand the mechanism of the influence. Some recent GCM experiments to investigate the SC/QBO interaction are also described. They simulate reasonably well the observed SC/QBO interaction of sudden warming events and appear to support the hypothesis that tropical/subtropical upper stratospheric wind anomalies are an important influence on the timing of sudden warmings.     

火星大气来流模拟装置CFD仿真与试验

根据我国火星着陆巡视器工作过程,其着陆发动机需要在相对火星大气高速迎风运动中可靠点火。由于巡视器着陆时发动机喷管出口气流与火星稀薄气流方向相反,目前无法通过理论计算准确获得着陆过程的动态流场对发动机起动过程的影响量值。为验证火星着陆环境下发动机点火的适应性,需要建立发动机的火星大气来流试验环境模拟条件。为模拟发动机在火星大气条件下的相对运动,在真空舱内发动机保持固定,前端设置环形来流形成装置,该装置在发动机喷管周围形成一定速度的逆向来流包络。采用数值模拟技术结合试验验证方法,在火星着陆器巡视器主发动机性能考核试验中,针对来流的形成装置开展了设计研究工作。来流模拟试验测试数据表明:在确保贮箱供应压力稳定的条件下,来流模拟系统能够形成100~200 m/s速度的稳定来流,发动机在来流下能稳定启动工作,真空舱压力满足试验要求。     

Numerical modeling of inhomogeneous orographic wave influence on planetary waves in the middle atmosphere

Parameterization of dynamical and thermal effects of stationary orographic gravity waves (OGWs) generated by the Earth’s surface topography is incorporated into a numerical model of general circulation of the middle and upper atmosphere. Responses of atmospheric general circulation and characteristics of planetary waves at altitudes from the troposphere up to the thermosphere to the effects of OGWs propagating from the earth surface are studied. Changes in atmospheric circulation and amplitudes of planetary waves due to variations of OGW generation and propagation in different seasons are considered. It is shown that during solstices the main OGW dynamical and heat effects occur in the middle atmosphere of winter hemispheres, where changes in planetary wave amplitudes due to OGWs may reach up to 50%. During equinoxes OGW effects are distributed more homogeneously between northern and southern hemispheres.     

Comparison between observed ionospheric foF2 and IRI-2001 predictions over periods of severe geomagnetic activities at Grahamstown,South Africa

The observed ionospheric F2 critical frequency (foF2) values over a South Africa mid-latitude station, Grahamstown, (geographic coordinates: 33.3°S, 26.5°E), were analysed and compared with International Reference Ionosphere (IRI) model, using the CCIR (Comite´ Consultatif International des Radio communications) and URSI (Union Radio-Scientifique Internationale) coefficients, during four geomagnetically disturbed days in the year 2000. These days are April 5, May 23, August 10 and September 15. The data were analysed for five days around the storm day. Comparisons between the IRI-2001 predicted foF2 values, using both CCIR and URSI coefficients and the observed values are shown with their root-mean-square error (RMSE) and the relative deviation module mean (rdmm) for the various storm periods. The CCIR option performed more accurately than the URSI option.