2021 Vol. 41, No. 5

Display Method:
Spitzer在银河系人马臂发现断裂结构
2021, 41(5): 691-691.
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TESS发现振荡红巨星遍布整个天空
2021, 41(5): 691-691.
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ESA总结欧洲遥感卫星在轨30年科学成果
2021, 41(5): 692-692.
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NASA发现最可能揭示月球深层奥秘的月表区域
2021, 41(5): 692-692.
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Mars Express长期火星大气研究取得新发现
2021, 41(5): 692-692.
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NASA研究发现气候变化导致高层大气冷却和收缩
2021, 41(5): 693-693.
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中国空间站建设稳步推进
2021, 41(5): 694-695.
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NASA航天服研发滞缓或导致2024年载人登月目标落空
2021, 41(5): 695-695.
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俄罗斯发射国际空间站新舱段——科学号多功能实验舱
2021, 41(5): 696-696.
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Research Articles
Correlation Analysis between Magnetic Storms and Solar Extreme Ultraviolet Radiation during the 23rd Solar Cycle
SUN Xiaoying, DUAN Suping, LIU Weining
2021, 41(5): 697-703. doi: 10.11728/cjss2021.05.697
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The statistics of magnetic storms with moderate and higher intensity during the 23rd solar cycle are presented, and investigated the correlation by linear analysis between the intensity of the magnetic storm Dstmin and the solar Extreme Ultraviolet Radiation (EUV) intensity by using the observation of F10.7 index before the maximum of the storm main phase. Our statistical analysis results show that during the 23rd solar cycle:firstly, with an increase in solar EUV input, the number of moderate or higher intensity storms increases. There are 56 moderate or higher intensity storms under low solar extreme ultraviolet radiation activity, 85 storms under intermediate solar extreme ultraviolet radiation activity, and 80 events under high solar extreme ultraviolet radiation activity. Secondly, with increasing EUV input, the number and the probability of strong (-200nT ≤ Dstmin<-100nT) and big (Dstmin< -200nT) storms occurring also show an increasing trend, especially the number (1, 4, 12) and the probability (1.79%, 4.76%, 14.12%) of big storms. Thirdly, there is a moderate positive correlation of big storm (|Dstmin|) with F10.7, where the correlation coefficient is 0.532, and the correlation of big storm (|Dstmin|) with F10.7 is more significantly under high solar extreme ultraviolet radiation activity, where the coefficient is 0.582. Our results that there exists the moderate positive correlation of big storm with high solar extreme ultraviolet radiation activity can provide foundation information for space weather forecasting.
TIEGCM Numerical Study on the Thermospheric Density Response to Solar F10.7 Radio Flux Variations during the 23rd Solar Cycle
TANG Cheng, LI Jiawei, ZHANG Xiaoxin, WANG Wenbin, YU Chao
2021, 41(5): 704-714. doi: 10.11728/cjss2021.05.704
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Thermospheric densities at the altitude of 400km during the 23rd solar cycle (1996—2008) are calculated using the NCAR-TIEGCM. The modeled responses of thermospheric density to solar radiation index F10.7 variations are statistically analyzed. The results show that during the 23rd solar cycle, the variations of thermospheric density are basically consistent with those of F10.7. However, the responses of thermospheric density to changes in F10.7 are different in different years and months. The increase of solar radiation from solar minimum to maximum is more than a factor of 4 in the 23rd solar cycle, and the increase of thermospheric density from solar minimum to maximum is more than a factor of 10 during the same interval. The intra-annual density variations in the solar minimum years are less than a factor of 2 between density minimum and maximum, whereas those in the high solar activity years can be greater than a factor of 2 or even 3. The correlation coefficients between the thermospheric mass density and the F10.7 index in the middle and high latitudes of the Northern Hemisphere are larger than those in the middle and high latitudes of the Southern Hemisphere, exhibiting an evident norther-south asymmetry. In the low latitudes, the correlation coefficients between the thermospheric mass density and the F10.7 index in high solar activity years are larger than those in solar minimum years. At different latitudes, the correlation coefficient between the thermospheric density and the 27-day variation of F10.7 is greater than that between the 81-day variations of thermospheric density and F10.7.
Study on the Position Diffusion Coefficients of Fokker Planck Equation of Magnetosphere Energetic Particle
CHU Wei, QIN Gang, XU Song, HUANG Jianping, ZEREN Zhima, SHEN Xuhui
2021, 41(5): 715-723. doi: 10.11728/cjss2021.05.715
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In this paper, the quasi-linear theory is used to calculate the diffusion coefficients of the Fokker Planck equation of energetic particles in the observable phase space, and the comparison with the adiabatic invariant radial diffusion coefficients is carried out. The main findings are as follows. The diffusion coefficients of the position items will increase rapidly with the radial distance. Under the same radial distance, the diffusion coefficient of the position items in the high latitude will be smaller than that in the low latitude. Compared with the radial diffusion coefficient, it is found that the two have the same magnitude, but the relative size of the two needs to be analyzed according to the specific disturbance form. This study will use the test particles to simulate the motion of energetic particles in the magnetosphere, especially the guidance center theory, and use the Monte Carlo method of stochastic partial differential to solve the Fokker Planck equation of the motion of energetic particles in the magnetosphere.
Response of the Temperature in the Mesosphere and Lower Thermosphere during the Recovery Phase of the Storm
LUO Qinshun, LI Jingyuan, LÜ Jianyong, SU Ye, WEI Guangchun, LI Zheng, WU Yewen, HE Fang, YU Yao
2021, 41(5): 724-736. doi: 10.11728/cjss2021.05.724
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Using Thermosphere Ionosphere Mesosphere Electrodynamics General Circulation Model (TIMEGCM), the nature and causes of MLT temperature variations at high latitudes during the 10 September 2005 storm were elucidated, which were caused by Coronal Mass Ejection (CME). At the beginning of the recovery phase of the geomagnetic storm, the temperature decreased in the dusk region but increased in the other regions. As the recovery phase evolved, the temperature decreases at high latitudes disappeared and the temperature increases were distributed throughout the whole high-latitude north hemisphere. The storm-time temperature changes at high latitudes were closely correlated with vertical wind changes. When the vertical wind was upward, the total heating was negative, corresponding to the decreased temperature variations, vice versa. In the thermosphere, radiative cooling, especially NO cooling, was "natural thermostat", which is the most important cooling mechanism. The radiative cooling contributes about 80% temperature reduction due to Joule heating enhancement during the storm. However, the NO radiative cooling has little effect on the temperature changes during the recovery phase of the storm, which was only a tenth of total heating. Therefore, the NO radiative cooling was a minor cause of MLT high-latitude temperature changes during the recovery phase of the storm.
Comparative Analysis of Optical Observation Characteristics between PMAFs and Throat Aurora
LIU Yingyu, XING Zanyang, FENG Huiting, CHEN Xiangcai, ZHANG Qinghe, HAN Desheng
2021, 41(5): 737-745. doi: 10.11728/cjss2021.05.737
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Both Poleward Moving Auroral Forms (PMAFs) and throat aurora are typical transient auroral structures occurred near the magnetic noon. Previous studies have shown that throat auroras contain PMAFs. However, their characteristics and the correlation between these two auroras are not clear yet. By using the observation data of the high-resolution All-Sky Imagers (ASI) at the Yellow River Station in Arctic, together with solar wind and Interplanetary Magnetic Field (IMF) observations, the evolution characteristics of polar ionospheric PMAFs and the throat aurora are detailedly analyzed. It was found that a series of PMAFs and throat auroras appeared in the field of view of the all-sky imagers of the Yellow River Station. Among them, PMAFs mainly occurred in polar side of the equatorial boundary of aurora oval dayside of cusp area, were distributed along the east-west direction, and extended to the high latitude after brightening. Throat auroras were distributed along the north-south direction, which extended to low latitude from equatorward of discrete auroral oval and moved to the west after brightening, usually exist in the side of PMAFs. The frequency of PMAFs during observed period is higher than that of the throat aurora. When PMAFs and the throat aurora appear simultaneously, PMAFs can appear almost simultaneously with throat aurora or slightly later than throat aurora, and have a shorter duration than throat aurora. Based on the above observations, we suggest that magnetopause reconnection corresponding to PMAFs and magnetopause reconnection mapping to throat aurora caused by magnetopause indentations are two relatively independent processes happening in adjacent magnetopause region. The formation processes of the two auroral events are relatively independent, and there may be no mutual triggering relationship.
Ionosphere Responses to Geomagnetic Storms at Middle to Low Latitude Region in Different Seasons
LI Weixin, CHEN Yanhong, YUAN Tianjiao
2021, 41(5): 746-759. doi: 10.11728/cjss2021.05.746
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Knowledge of ionospheric responses to geomagnetic storms is important for knowing about the physical process of ionosphere, and useful for ionospheric application research as well. This paper analyzed and compared the ionospheric responses to four geomagnetic storms in four seasons in 2015, based on the ionospheric observations from Mohe (53.5°N, 122.3°E), Beijing (40.3°N, 116.2°E), Wuhan (30.5°N, 114.2°E), Sanya (18.3°N, 109.6°E) in China. The responses of ionosphere to four geomagnetic storms are different and have significant seasonal dependence. There are prominent negative responses during storms in spring, summer or autumn, and significant positive responses in winter. It is shown that neutral composition (O/N2) is related to the negative phase storm, while westward Disturbance Dynamo Electric Field (DDEF) is responsible for the negative storm in Sanya. The reason of ionospheric positive response is different in different events. The Penetration of Electric Field (PEF) may cause a short-time positive response during the geomagnetic storm in spring, whereas neutral wind and PEFs are jointly responsible for the long-duration positive response during the storm in winter.
Characteristics Analysis of the Spatial and Temporal Distributions of Stratopause Temperature Based on SABER Measurements
WANG Miao, LI Zheng, LÜ Jianyong
2021, 41(5): 760-768. doi: 10.11728/cjss2021.05.760
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A climatology of the stratopause temperature (Tsp) between 50°S—50°N is studied using the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) measurement from 2002 to 2017. The results show that Tsp is higher in the equator and the summer of the northern or southern hemispheres and the lowest temperature is near 40° latitude in the winter of northern or southern hemispheres. The characteristics are interpreted in the ozone volume mixing ratio (O3-VMR) on stratopause, the Earth-Sun distance, and solar activity using the Empirical Orthogonal Function (EOF) method. The first mode represents 91% of the total Tsp variability and its coefficient has the highest correlation of -0.75 with stratopause height, while the correlations with the stratopause O3-VMR, the Earth-Sun distance, and solar activity are 0.49, 0.44, and 0.33, respectively. According to these relations, further researches find that Tsp has the opposite latitudinal variation with stratopause O3-VMR and the opposite seasonal variation with the Earth-Sun distance. Moreover, the annual averaged Tspvaries in a range of 2K from 2002 to 2017 and has a good correlation with F10.7. The best correlation coefficient is 0.74 near 20°S and 20°N.
Bayesian and Least Square Method for Temperature Inversion of Adjacent Space Atmosphere Based on Oxygen A-band
YANG Xiaojun, LI Yefei, WANG Houmao, WANG Yongmei, FU Jianguo
2021, 41(5): 769-777. doi: 10.11728/cjss2021.05.769
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This paper shows that the atmospheric temperature profile in near space is inverted based on the simulated data of adjacent radiation in oxygen A-band. Based on the inversion results, the characteristics of two different inversion algorithms, Bayes and least square, are analyzed and compared. Below 80km, the mean inversion errors of the three spectral lines based on Bayes inversion at 761.59, 762.2 and 764.05nm were 5.52, 3.94 and 4.73K, respectively, after adding the noise with a signal-to-noise ratio of 103. The mean inversion errors of the least square inversion were 10.57, 7.04 and 8.80K, respectively. The mean inversion errors of the three spectral lines based on Bayes were 18.27, 12.18 and 18.27K, respectively, after adding the noise with a signal-to-noise ratio of 102. The mean errors of the least square inversion were 103.18, 68.79 and 85.98K, respectively. Research results show that the inversion method is based on Bayes theory, the inversion results to make use of a priori information constraints and correction, in the case of noisy a more reasonable solution is obtained, which improves the inversion precision and anti-interference ability. It lays a solid foundation for the research and development of the algorithm for detecting the adjacent space atmosphere temperature on board and provides theoretical guidance for increasing the signal-to-noise ratio of spectral instruments to improve the inversion accuracy of temperature.
Martian Atmosphere Study Using THz Limb Sounder
WANG Zhenzhan, WANG Wenyu, DONG Xiaolong, LIU Jingyi, ZHANG Dehai
2021, 41(5): 778-786. doi: 10.11728/cjss2021.05.778
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Mars is one of the main targets of deep space exploration. Continuous and high spatial resolution global monitoring of Martian atmosphere is an important way to understand the aeronomy and meteorology of Mars. The atmospheric wind and chemical species in the photochemical cycle such as CO, O3, H2O, H2O2 can be measured in large scale by Terahertz limb sounding technique to improve our understanding of Martian atmospheric chemistry and dynamics. The spectrum in the frequency region of 300~1000GHz is analyzed according to the request of Mars exploration. Considering the requirements of the satellite on the parameters of load weight and power, a Martian atmosphere THz limb sounder working in the frequency of 547~579GHz is proposed. The planetary toolbox of ARTS is used to simulate the performance of the instrument. Results show that by using CO lines to retrieve the temperature profile, the total precision can be < 4K. The precision is < 2K at an altitude below 45km. The retrieval precision of H2O is < 50% at an altitude below 50km, and the best precision is 2%. The retrieval precision of H2O2 is < 50% below 40km. The retrieval precision of O3 is < 60% below 50km. The retrieval precision of the atmospheric line of sight wind is < 5m·s-1 above 65km, and the best precision is 2m·s-1. In conclusion, the middle and upper atmospheric wind and the abundance of the chemical species can be well measured by using THz limb sounding technique.
Release Behavior Research of In-situ Helium-3 Resources Extraction in Moon under Heating
SONG Hongqing, DU Hengchang, ZHANG Jie, MA Dongyu, ZHANG Xianguo, KOU Jue
2021, 41(5): 787-792. doi: 10.11728/cjss2021.05.787
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The In-situ Resource Utilization (ISRU) of Helium-3 in Moon can not only solve the energy problem, but also greatly reduce the cost of deep space exploration. In this paper, ilmenite is selected as the representative mineral of lunar soil. The molecular dynamics model of Helium-3 atoms trapped in ilmenite crystal in the ways of vacancies and interstitial sites was established. The diffusion and release of Helium-3 atoms at different temperatures were presented. Simulation results show that Helium-3 atoms would gather into bubbles when they diffused. Meanwhile, two obvious zones were identified according to the release amounts of Helium-3 in ilmenite with temperature, which are the first release zone and the second release zone. The optimal heating temperature for in-situ Helium-3 resources extraction in Moon should be above 1000K. A large number of Helium-3 atoms trapped in different forms can be released at the temperature. The research can provide theoretical basis for energy supply in Moon base.
Design Spaceborne of Radiation Dosimeter in Depth
SUN Ying, ZHANG Binquan, ZHANG Xiaoxin, ZHANG Xin, ZHANG Shenyi, SHEN Guohong, CHANG Zheng, WANG Chunqin, SUN Yueqiang, ZONG Weiguo, GUO Jianguang, XUE Bingsen, ZHANG Liguo, CHEN Qiang, ZHANG Ruyi
2021, 41(5): 793-799. doi: 10.11728/cjss2021.05.793
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In view of the radiation dose effect of space charged particles on spacecraft in orbit, which leads to performance degradation and life decline of onboard equipment and aerospace materials, a multi-point and multi-directional total radiation dose detection technology in satellite is proposed. The scheme of dose monitoring in depth is adopted for the first time in China. Each probe is equipped with five dose monitoring points, corresponding to the aluminum structure with shielding thickness of 0 (open window), 1mm, 2.5mm, 3.5mm and 6mm. The total detection dose range is 2×106rad (Si), and the highest sensitivity is 1rad (Si). The on-board radiation dosimeter in depth will carry out real-time monitoring and early warning of the radiation dose suffered by the satellite in orbit. The detection results will be used to carry out the research on the depth distribution of the dose in the satellite, which is conducive to the analysis and evaluation of the working state of the satellite load in orbit, and provide a reliable basis for the follow-up anti-radiation hardening design of the satellite.
A Missing Values Imputation Method for Radiation Data from Beidou MEO Satellite Sensors
GUO Xingliang, CUI Ruifei, ZHU Yaguang, TIAN Chao, JIANG Jianmin, YUE Fulu
2021, 41(5): 800-807. doi: 10.11728/cjss2021.05.800
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Radiation dose refers to the sum of ionization energy deposited by various incident high-energy particles in unit mass material. The radiation dose data detected by Beidou MEO satellites suffers from the problem of missing values that tend to occur continuously and there is little difference in the radiation dose detection values in the three directions in the satellite cabin. Firstly, the detector 3 data with strong regularity is selected as the research object. In order to fill the missing values, a sine-adjusted linear spline regression method is proposed, in which each continuous data-missing time period is individually processed in a spline and the missing values are filled with the sine-adjusted linear equation. The experiment shows that with our approach the filling curve is highly consistent with the true curve in terms of growth trend and periodic fluctuation. And our method performs significantly better with respect to errors and correlation coefficient between true and filled values, than alternative methods such as forward interpolation and linear interpolation. This paper selects the data of different time periods to analyze the filling effect, and draws the above conclusions. The proposed method properly solves the problem of continuous data-missing, leading to a data set with good completeness and high accuracy, which lays a foundation for the subsequent tasks like data release, modeling and visualization.
Impact of the Correlation of Visibility Noise in Redundant Baselines on Radiometric Sensitivity of Aperture Synthesis Radio Telescope
ZHANG Rongyu, YAN Jingye, WU Lin, WU Ji
2021, 41(5): 808-818. doi: 10.11728/cjss2021.05.808
Abstract:
In Earth remote sensing using aperture synthesis microwave radiometers, the brightness temperature distribution of observed scene is smooth, and the correlation between visibility noise is small. Therefore, the visibility noise is assumed to be uncorrelated when calculating the radiometric resolution. However, in the case of observing quiet Sun or solar bursts with the aperture synthesis radio telescope, it should not be assumed that the visibility noise is uncorrelated. The correlation between visibility noise of an aperture synthesis radio telescope plays a vital role in the computation of the radiometric resolution and modifying the improvement introduced by redundant baselines. Firstly, the study focuses on two factors:scene brightness temperature distribution and equivalent receiver noise temperature, both play a decisive role in the correlation. And simulations are used to verify the conclusion. Finally, additional radiometric sensitivity simulations are applied to demonstrate that the improvement of sensitivity can be achieved by optimizing the placement of redundant antenna elements. Moreover, the degree of improvement depends on the correlation level between the visibility noise of redundant samples.
Output Feedback Finite-dimensional Repetitive Learning Control on Virtual Force for Flexible-base Flexible-link and Flexible-joint Space Robot
FU Xiaodong, CHEN Li
2021, 41(5): 819-827. doi: 10.11728/cjss2021.05.819
Abstract:
Motion control and flexible vibration synchronous suppression of base, links and joints for flexible space robot are studied. By combining linear spring, torsion spring, simply supported beam and hypothetical modal method, and using Lagrange equation, the dynamic model of flexible-base, flexible-link and flexible-joint space robot is established. Then, by using singular perturbation method, the model is decomposed into a joint motion slow subsystem and joint flexible vibration fast subsystem. In order to control the rigid motion of the base and joints in the slow subsystem and suppress flexible vibration of links, according to the concept of virtual control force, an output feedback repetitive learning algorithm based on the finite-dimensional Fourier series analytical periodic signal is proposed. The algorithm uses virtual force to suppress the flexible vibration of the robotic links. The output feedback method is designed so that the controller can be implemented based on position measurement only. It is proposed that the repetitive learning algorithm can effectively compensate for repeated errors in periodic tasks and improve the control quality of the system. The Lyapunov direct method confirms the stability of the above controller. In addition, in order to suppress the flexible vibration of the base and joint in the fast subsystem, the linear quadratic optimal control method and the joint flexible compensator are used to indirectly increase the joint equivalent stiffness, so that the control algorithm cannot be limited to solving the weak nonlinear problem. Simulation results show that the proposed controller can effectively suppress the vibration of multiple flexible components of the system, and achieve high-quality tracking of the desired signal.
Near Space Scientific Exploratory Data Sharing Research and Practice
ZHU Jiajia, MI Lin, LI Xiaohui, ZHANG Jing, DOU Shuai, LI Ziyang, YUAN Xinfang, LI Chuanrong
2021, 41(5): 828-835. doi: 10.11728/cjss2021.05.828
Abstract:
In order to promote the application effect of near space scientific exploratory data resources which produced by Honghu Project, and add new data members to the national science data resources, the research on data sharing. Technology of scientific exploratory data resources is developed. According to the relevant national standards of metadata and the experience of the construction methods of scientific data metadata in many related fields, by analyzing the data characteristics of near space scientific exploratory data, a core metadata model is designed to meet the needs of data sharing. The data characteristics and the information which users concern is described from different perspectives. Based on the core metadata model, the resource directory service and data sharing service platform of near space scientific exploratory data is designed and implemented. The archive management and the data shared distribution function of near space scientific exploratory is accomplished which provides an effective support for the scientific research and application with the exploratory data of Honghu project.
A Novel Ship Wake Detection Algorithm Based on WTHT and Radon Transform
ZHAO Moxin, ZHANG Yunhua, DONG Xiao, LI Dong, YANG Jiefang
2021, 41(5): 836-844. doi: 10.11728/cjss2021.05.836
Abstract:
This paper proposes a novel ship wake detection algorithm based on the White Top-hat Transform (WTHT) and the Radon transform, which aims to improve the contrast between the ship wake and the background so as to improve the detection performance on Synthetic Aperture Radar (SAR) images. The proposed algorithm includes two major processes, and one is to improve the contrast and another one is to locate the ship wake. In high sea state conditions, the contrast of ship wake and background can be very low, which makes it difficult to detect. In the first step, the proposed contrast improvement algorithm is applied to improving the contrast which helps for improving the detection performance. An attribute filter based on edge detection result is adopted here. In the second step the contrast improved image is transformed into the Radon domain followed by peak extraction process to find the wake, the WTHT is used once more in this step. Finally, in the last step, the wake is overlapped on the original image. Experimental results on Tiangong-2 Interferometric Imaging Radar Altimeter (InIRA) images are presented and compared with that obtained by using the classical algorithm, and in this way, the better performance of our algorithm is demonstrated.