武汉上空平流层气溶胶的激光雷达探测结果的初步分析

采用武汉大学双波长激光雷达工作于589 nm波长的观测数据,对2001年3月到2002年1月期间武汉上空平流层气溶胶的消光系数和积分体后向散射系数等光学特性进行初步分析.结果表明,武汉上空平流层气溶胶在16—20 km间存在一气溶胶层,其厚度及散射峰值随季节有一定变化,并且气溶胶积分体后向散射系数在2.2×10~(-5)—7.0×10~(-4)sr~(-1)之间变化,呈现了夏季大冬季小的分布倾向.     

武汉上空对流层与平流层大气密度和温度探测的初步结果

利用武汉大学Rayleieh/钠荧光散射激光雷达和无线电探空仪进行联合探测的数据,反演出武汉地区上空(30.5°N,114.4°W)0—65km处的密度和温度分布曲线,并简单阐述了激光雷达的工作原理。将测量结果和MSISE-90参考大气模式比较,二者结果基本符合,温度廓线在中层顶附近和模式的差别约为3K。同时利用激光雷达探测到了中层大气中的重力波活动。     

基于GPS与磁强计组合的姿态确定

提出了一种基于信息融合的姿态确定方法用于姿态确定。利用星上的GPS接收机和磁强计两种敏感的测量,基于广义卡于尔曼滤波理论及信息融合理论,发展了基于此两种敏感器的全局最优融合估计算法。来确定卫星的姿态和姿态角速度。并对处法进行了设计和仿真,通过与单独使用GPS确定姿态的算法进行对比分析。结果验证了该算法进行对比分析,结果验证了该算法的优越性。     

平流层飞艇热力学验证温度测量方法研究

平流层飞艇的热力学分析是平流层飞艇关键技术之一。针对热力学分析的工程验证及模型完善,提出了适合于平流层飞艇的艇囊内气体及囊体表面的温度测量方法,包括采集点的分布,传感器的选型,数据传输和处理及数据准确性评价等。经过两次平流层飞艇的缩比飞行试验,对比同艇发放的探空仪采集的温度数据,验证了该方法测量到的数据的准确性。     

基于Unscented卡尔曼滤波器的近地卫星磁测自主导航

建立了近地卫星高精度轨道动力学模型和10×10阶地磁场模型,分别以地磁场矢量和强度幅值作为观测量,通过Unscented卡尔曼滤波实现自主导航。在采样周期10s,磁强计测量噪声100nT情况下仿真,仿真结果显示以地磁场矢量为观测量时卫星导航误差在卫星前进方向(切向)、轨道法向、卫星径向的分量分别为1km、0.9km、0.3km,而以地磁场强度幅值为观测量时误差分别为1.6km、1.3km、0.5km。     

Ozone mini-hole observation over the Balkan Peninsula in March 2005

Areas with dimensions of 1000–3000 km in which the total ozone content (TOC) decreases fast are called ozone mini-holes. They are generated mainly dynamically in two ways, either by poor-ozone air mass transport from the tropics to higher latitudes by planetary wave activity or, they are connected with strong adiabatic uplifting of the tropopause height. An ozone mini-hole, generated by the second mechanism, was observed over the Balkan Peninsula on 19/21 March 2005. In the middle of March, the polar vortex was strongly disturbed by Rossby waves, reaching up to the lower stratosphere. Warming episodes over a geographical area, covering the Barents Sea and the Polar Sea north from Central Siberia, displaced a polar vortex fragment extremely southwards. However, the vorticity was weak and the stratospheric temperatures did not reach low values, providing conditions for ozone chemical destruction via heterogenic reactions. At the same time, a Rossby wave ridge was located below the European polar fragment. In the period from 13 to 19 March, the thermal tropopause over Sofia was uplifted almost by 3 km. Ozone distributions observed by the SCIAMACHY instrument on 18–21 March show a fast TOC decrease westwards from Ireland, which was moving eastwards during the next days, increasing the area in which the ozone content decreased. On 20/21 March low ozone content was observed above the Stara Zagora (42°N, 25°E) ground-based station by means of the GASCOD instrument, using DOAS technique. The TOMS Earth probe instrument detected 237 DU over Sofia. This is a record low March value from the beginning of the TOMS instrument measurements in 1978. In March/April the ozone distribution was characterized by its mean annual maximum of 360 DU at 42°N.     

安第斯山上空平流层山地波统计特征的AIRS观测研究

利用AIRS红外探测仪在2013—2018年的辐射测量数据,对安第斯山20km,27km,35km及41km高度的山地波进行个例研究和统计分析.观测结果表明安第斯山上空山地波主要发生在5—10月,月平均水平波长、垂直波长及动量通量均没有明显的年际变化.水平波长在5月和10月相比6—9月较小,垂直波长和动量通量5—7月逐渐升高,达到峰值后在8—10月逐渐下降.在20～41km范围内,水平波长从43.5～53.9km缓慢升高至89.3～176.8km,垂直波长从7.4～14.7km上升至7.4～29.7km,动量通量由376.0～801.3mPa显著下降至10.4～239.3mPa.总体而言,山地波在向上传播的过程中,水平波长缓慢增加,在逆风传播的情况下,受到背景风场影响垂直波长随高度升高而增大.动量通量随高度升高显著下降,说明安第斯山山地波向上传播的同时伴有强烈耗散,耗散的能量将储存在背景大气中,对高平流层甚至中间层产生重要影响.     

Evolution of scientific ballooning and its impact on astrophysics research

As we celebrate the centennial year of the discovery of cosmic rays on a manned balloon, it seems appropriate to reflect on the evolution of ballooning and its scientific impact. Balloons have been used for scientific research since they were invented in France more than 200 years ago. Ballooning was revolutionized in 1950 with the introduction of the so-called natural shape balloon with integral load tapes. This basic design has been used with more or less continuously improved materials for scientific balloon flights for more than a half century, including long-duration balloon (LDB) flights around Antarctica for the past two decades. The U.S. National Aeronautics and Space Administration (NASA) is currently developing the next generation super-pressure balloon that would enable extended duration missions above 99.5% of the Earth’s atmosphere at any latitude. The Astro2010 Decadal Survey report supports super-pressure balloon development and the giant step forward it offers with ultra-long-duration balloon (ULDB) flights at constant altitudes for about 100 days.     

空间探测磁强计安装部件的力学特性分析

对某深空探测器中的有效载荷-高精度磁强计的安装部件进行了有限元分析,分别获取了磁强计安装部件在升空过程中承受40g加速度冲击载荷以及-180～75℃的极限温度情况下,在x,y,z方向上的最大应力和最大位移,给出了由于磁强计安装部件的变形而导致的三个探头在x,y,z方向上的偏转角度,采用扫频实验法分析了磁强计安装部件的频谱特性,为空间探测磁强计的设计提供了依据.     

Temperature comparison between CHAMP radio occultation and TIMED/SABER measurements in the lower stratosphere

Global Positioning System (GPS) receiver on the CHAllenging Mini-satellite Payload (CHAMP) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, one of four on board the TIMED satellite, provide middle atmosphere temperature profiles by Radio Occultation (RO) and limb viewing infrared emission measurements, respectively. These temperature profiles retrieved by two different techniques in the stratosphere are compared with each other using more than 1300 correlative profiles in March, September and December 2005. The over-all mean differences averaged over 15 and 35 km are approximately −2 K and standard deviation is less than 3 K. Below 20 km of altitude, relatively small mean temperature differences ∼1 K are observed in wide latitudinal range except for June (during the SABER nighttime observation). In the middle to low latitudes, between 30°S and 30°N, the temperature difference increases with height from ∼0–1 K at 15 km, to ∼−4 K at 35 km of altitude. Large temperature differences about −4 to −6 K are observed between 60°S and 30°N and 31–35 km of altitude for all months and between 0° and 30°N below 16 km during June (nighttime).     

AIRS观测资料研究全球平流层重力波特性

利用2012—2014年1月和7月AIRS（Atmospheric Infrared Sounder）第79通道的观测数据,分析了平流层重力波活动强弱的全球分布以及重力波发生频率的全球分布;分析了重力波活动随纬度和经度的变化特征,给出了重力波活动在全球范围内的热点区域及其活动强度;对比了白天与夜间的重力波活动强度及发生频率.研究表明重力波活动强度呈现出随纬度变化的特征,在低纬度地区（0°—30°）,冬季半球重力波活动强度低,夏季半球重力波活动高;在中高纬度地区,冬季半球重力波活动强度高而夏季半球重力波活动强度低.在1月,全球重力波活动有4个突出的热点区域,分别为50°N附近欧洲大陆与大西洋交接地带、北美洲与大西洋交接地,20°S附近南美洲与大西洋交接地区、非洲与印度洋交接地区.在7月,重力波活动突出的地方为巴塔哥尼亚至南极半岛地区,以及50°S和75°E附近的印度洋区域.重力波活动强度在夜间大于白天,但是夜间的强重力波活动区域小于白天.     

Ascent trajectory optimization for stratospheric airship with thermal effects

Ascent trajectory optimization with thermal effects is addressed for a stratospheric airship. Basic thermal characteristics of the stratospheric airship are introduced. Besides, the airship’s equations of motion are constructed by including the factors about aerodynamic force, added mass and wind profiles which are developed based on horizontal-wind model. For both minimum-time and minimum-energy flights during ascent, the trajectory optimization problem is described with the path and terminal constraints in different scenarios and then, is converted into a parameter optimization problem by a direct collocation method. Sparse Nonlinear OPTimizer(SNOPT) is employed as a nonlinear programming solver and two scenarios are adopted. The solutions obtained illustrate that the trajectories are greatly affected by the thermal behaviors which prolong the daytime minimum-time flights of about 20.8% compared with that of nighttime in scenario 1 and of about 10.5% in scenario 2. And there is the same trend for minimum-energy flights. For the energy consumption of minimum-time flights, 6% decrease is abstained in scenario 1 and 5% decrease in scenario 2. However, a few energy consumption reduction is achieved for minimum-energy flights. Solar radiation is the principal component and the natural wind also affects the thermal behaviors of stratospheric airship during ascent. The relationship between take-off time and performance of airship during ascent is discussed. it is found that the take-off time at dusk is best choice for stratospheric airship. And in addition, for saving energy, airship prefers to fly downwind.     

Kalman filtering for GPS/magnetometer integrated navigation system

This paper investigated the data processing method for a GPS/IMU/magnetometer integrated system with Kalman filtering (KF). As a result of GPS/IMU/magnetometer land vehicle system, dead-reckoning of magnetometer and accelerometer integrated subsystem bridged very well the GPS signal outage due to the trees on the two sides of the road. Both differential GPS data processing method and the carrier-phase method with magnetometers’ outputs for predicting the car position, velocity, and acceleration (PVA) are presented. The results from DGPS with Kinematical Positioning (KINPOS) software shown that the averages of the north, east, and down direction standard deviation (short for “std”) are 0.014, 0.010, and 0.018 m, respectively. The std of velocities and accelerations derived by the position and velocity differentiation are 10, 7, 13 mm/s, 7, 5, 9 mm/s², respectively. This method for getting velocities and accelerations requires higher accurate position coordinates. But the position accuracy has frequently been degraded in this case when the car drove under the trees or other similar kinematical environments. That caused the larger velocity and acceleration errors. While the results from the carrier-phase method are std of the velocities = 2.1 mm/s, 1.3 mm/s, 3.7 mm/s in north, east, down, and std of the accelerations = 1.5 mm/s², 0.9 mm/s², 2.3 mm/s² for the static test period; as compared with KINPOS software results, std of the velocity difference between the carrier-phase method and the DGPS method = 7 mm/s, 6.9 mm/s, 9.7 mm/s in north, east, down direction, and std of acceleration difference = 5.0 mm/s², 4.5 mm/s², 7.5 mm/s² in north, east, down direction for the kinematical test period. Obviously, errors come from both the carrier-phase method and DGPS velocity and acceleration results derived directly by the position differentiation. In addition, better accuracy of positions than that before KF has been got by means of velocities and accelerations derived by the carrier-phase method after KF.     

An all-sky survey at 230 GHz by MLS on Aura

The Microwave Limb Sounder (MLS) instrument is a small satellite-borne radio telescope. Its purpose is to make limb-scanning measurements of atmospheric composition. One of the gases to which it is sensitive is carbon monoxide (CO), detected via the J = 2 → 1 rotational transition at 230 GHz. CO is present in molecular gas clouds in the Milky Way. Although it was not designed for the purpose, MLS can detect emissions from galactic CO, allowing a map of the 230 GHz radio sky to be constructed. We report the MLS measurements of galactic radio emission and discuss their effect on the atmospheric mission of MLS. The region of the Milky Way with emissions strong enough to significantly affect MLS observations of atmospheric CO is identified. Ground-based radio astronomers have been mapping the sky using CO emission for many years. However, the MLS data are the first such survey to be carried out from space. The MLS survey covers a larger area of the sky than any other 230 GHz survey, but no previously unknown gas clouds are observed.