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Space advanced technology demonstration satellite

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Science China(Technological Sciences) 2024年第1期67卷 240-258页

作者： ZHANG XiaoFeng CHEN Wen ZHU XiaoCheng MENG Na HE JunWang BI XingZi ZHANG YongHe SHI Qi LI Fei LIU Rui FENG ZhengGong LIU Liu LI JinSong WU HaiChen XU DongXiao LI TaiJie HUANG JiangJiang LIU Shuo LI TianTong YU XianSheng GAO Yang ZHOU Heng BAN HanYu ZHANG YanLi ZHANG YueTing YANG YingQuan HE Tao DUAN XuLiang CHEN Xin WANG YaMin SUN AnTai ZHANG KuoXiang SUN Ying WANG YaoBin FAN ChengCheng XIONG ShaoLin LI XinQiao WEN XiangYang LING ZhiXing SUN XiaoJin ZHANG Chen BAI XianYong WANG ZhanShan DENG YuanYong TIAN Hui YANG JianFeng XUE HongBo SANG Peng LIU JinGuo ZHENG HuiLong ZHU Xiang HE JianWu LI Hui XU LuXiang XU ShuYan CHEN WenWu LIU ZhenDong WANG ZhaoLi MAO XiangLong GAO Rong LI ZongXuan DING GuoPeng WANG XinYu DOU RunJiang WENG LuBin LUO Hao WANG YaPing LIANG XianFeng FANG ZiRuo Innovation Academy for Microsatellites Chinese Academy of SciencesShanghai 201203China institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China National Astronomical Observatory of China Beijing 100101China Shanghai institute of Technical Physics Chinese Academy of SciencesShanghai 200083China institute of Precision Optical Engineering School of Physics Science and EngineeringTongji UniversityShanghai 200092China School of Earth and Space Sciences Peking UniversityBeijing 100871China Xi’an institute of Optics and Precision Mechanics Chinese Academy of SciencesXi’an 710119China National Space Science Center Chinese Academy of SciencesBeijing 100190China Shenyang institute of Automation Chinese Academy of SciencesShenyang 110016China institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China institute of Mechanics Chinese Academy of SciencesBeijing 100190China Shanghai institute of Organic Chemistry Chinese Academy of SciencesShanghai 200032China Hangzhou institute for Advanced Study University of Chinese Academy of SciencesHangzhou 310024China Nanyang Technological University Singapore 569830Singapore Dalian institute of Chemical Physics Chinese Academy of SciencesDalian 116023China Technical institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100049China Changchun institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China institute of Semiconductors Chinese Academy of SciencesBeijing 100083China institute of Automation Chinese Academy of SciencesBeijing 100190China School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310058China

The Space Advanced Technology demonstration satellite(SATech-01),a mission for low-cost space science and new technology experiments,organized by Chinese Academy of Sciences(CAS),was successfully launched into a Sun-synchronous orbit at an altitude of~500 km on July 27,2022,from the Jiuquan satellite Launch *** as an experimental platform for space science exploration and the demonstration of advanced common technologies in orbit,SATech-01 is equipped with 16 experimental payloads,including the solar upper transition region imager(SUTRI),the lobster eye imager for astronomy(LEIA),the high energy burst searcher(HEBS),and a High Precision Magnetic Field Measurement System based on a CPT Magnetometer(CPT).It also incorporates an imager with freeform optics,an integrated thermal imaging sensor,and a multi-functional integrated imager,*** paper provides an overview of SATech-01,including a technical description of the satellite and its scientific payloads,along with their on-orbit performance.

关键词： SATech-01 spacecraft design scientific instruments on-orbit performance

Variation in the surface heat flux on the north and south slopes of Mount Qomolangma

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Atmospheric and Oceanic Science Letters 2024年第5期17卷 28-33页

作者： Yonghao Jiang Maoshan Li Yuchen Liu Ting Wang Pei Xu Yaoming Ma Fanglin Sun School of Atmospheric Sciences/Plateau Atmosphere and Environment Key Laboratory of Sichuan Province/Chengdu Plain Urban meteorology and Environment Observation and Research Station of Sichuan Province Chengdu University of Information TechnologyChengduChina Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau ResearchChinese Academy of SciencesCAS Center for Excellence in Tibetan Plateau Earth SciencesBeijingChina Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions Chinese Academy of SciencesLanzhouChina

The distinctive conditions present on the north and south slopes of Mount Qomolangma,along with the intricate variations in the underlying surfaces,result in notable variations in the surface energy flux patterns of the two *** this paper,data from TESEBS(Topographical Enhanced Surface Energy Balance System),remote sensing data from eight cloud-free scenarios,and observational data from nine stations are utilized to examine the fluctuations in the surface heat flux on both *** inclusion of MCD43A3 satellite data enhances the surface albedo,contributing to more accurate simulation *** model results are validated using observational *** RMSEs of the net radiation,ground heat,sensible heat,and latent heat flux are 40.73,17.09,33.26,and 30.91 W m^(−2),*** net radiation flux is greater on the south slope and exhibits a rapid decline from summer to *** to the influence of the monsoon,on the north slope,the maximum sensible heat flux occurs in the pre-monsoon period in summer and the maximum latent heat flux occurs during the *** south slope experiences the highest latent heat flux in *** dominant flux on the north slope is sensible heat,while it is latent heat on the south *** seasonal variations in the ground heat flux are more pronounced on the south slope than on the north *** in summer,the ground heat flux on the north slope surpasses that on the south slope.

关键词： Mount Qomolangma TESEBS model Remote sensing retrieval Surface heat fluxes

A Strategy for Merging Objective Estimates of Global Daily Precipitation from Gauge Observations, satellite Estimates, and Numerical Predictions

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Advances in Atmospheric Sciences 2016年第7期33卷 889-904页

作者： Suping NIE Tongwen WU Yong LUO Xueliang DENG Xueli SHI Zaizhi WANG Xiangwen LIU Jianbin HUANG National Climate Center China Meteorological Administration Center for Earth System Science Tsinghua University Key Laboratory of Atmospheric Science and satellite Remote Sensing Anhui Institute of Meteorology

This paper describes a strategy for merging daily precipitation information from gauge observations, satellite estimates （SEs）, and numerical predictions at the global scale. The strategy is designed to remove systemic bias and random error from each individual daily precipitation source to produce a better gridded global daily precipitation product through three steps. First, a cumulative distribution function matching procedure is performed to remove systemic bias over gauge-located land areas. Then, the overall biases in SEs and model predictions （MPs） over ocean areas are corrected using a rescaled strategy based on monthly precipitation. Third, an optimal interpolation （OI）-based merging scheme （referred as the HL-OI scheme） is used to combine unbiased gahge observations, SEs, and MPs to reduce random error from each source and to produce a gauge--satellite-model merged daily precipitation analysis, called BMEP-d （Beijing Climate Center Merged Estimation of Precipitation with daily resolution）, with complete global coverage. The BMEP-d data from a four-year period （2011- 14） demonstrate the ability of the merging strategy to provide global daily precipitation of substantially improved quality. Benefiting from the advantages of the HL-OI scheme for quantitative error estimates, the better source data can obtain more weights during the merging processes. The BMEP-d data exhibit higher consistency with satellite and gauge source data at middle and low latitudes, and with model source data at high latitudes. Overall, independent validations against GPCP-1DD （GPCP one-degree daily） show that the consistencies between B MEP-d and GPCP-1DD are higher than those of each source dataset in terms of spatial pattern, temporal variability, probability distribution, and statistical precipitation events.

关键词： global daily precipitation multi-source merging strategy bias correction quantitative error estimation

A step to the decentralized real-time timekeeping network

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Chinese Physics B 2024年第1期33卷 183-191页

作者：王芳敏陈雨锋周建华蔺玉亭杨军王波王力军 State Key Laboratory of Precision Space-time Information Sensing Technology Department of Precision InstrumentTsinghua UniversityBeijing 100084China Key Laboratory of Photonic Control Technology Tsinghua UniversityBeijing 100084China Beijing satellite Navigation Center Beijing 100094China Beijing institute of Radio Metrology and Measurement Beijing 100854China

The composite time scale(CTS) provides an accurate and stable time-frequency reference for modern science and technology. Conventional CTS always features a centralized network topology, which means that the CTS is accompanied by a local master clock. This largely restricts the stability and reliability of the CTS. We simulate the restriction and analyze the influence of the master clock on the CTS. It proves that the CTS's long-term stability is also positively related to that of the master clock, until the region dominated by the frequency drift of the H-maser(averaging time longer than ~10~5s).Aiming at this restriction, a real-time clock network is utilized. Based on the network, a real-time CTS referenced by a stable remote master clock is achieved. The experiment comparing two real-time CTSs referenced by a local and a remote master clock respectively reveals that under open-loop steering, the stability of the CTS is improved by referencing to a remote and more stable master clock instead of a local and less stable master clock. In this way, with the help of the proposed scheme, the CTS can be referenced to the most stable master clock within the network in real time, no matter whether it is local or remote, making democratic polycentric timekeeping possible.

关键词： frequency synchronization network composite time scale frequency stability democratic timekeeping

Salinity fronts shape spatial patterns in zooplankton distribution in Hangzhou Bay

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Acta Oceanologica Sinica 2024年第6期43卷 96-106页

作者： Yepeng Xu Yiqi Wang Lin Zhan Yijun Ou Kangning Jia Ming Mao Xuyu Zhu Zhibing Jiang Yuanli Zhu Wei Huang Ping Du Jiangning Zeng Lu Shou Feng Zhou Key Laboratory of Marine Ecosystem Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Key Laboratory of Nearshore Engineering Environment and Ecological Security of Zhejiang Province Hangzhou 310012China State Key Laboratory of satellite Ocean Environment Dynamics Ministry of Natural ResourcesHangzhou 310012China Nantong Marine Environmental Monitoring Center Ministry of Natural ResourcesNantong 226002China Key Laboratory of Ocean Space Resource Management Technology Ministry of Natural ResourcesHangzhou 310012China Observation and Research Station of Marine Ecosystem in the Yangtze River Delta Ministry of Natural ResourcesZhoushan 316021China

Ocean fronts play important roles in nutrient transport and in the shaping ecological *** zones in small bays are typically small in scale,have a complex structure,and they are spatially and temporally variable,but there are limited data on how biological communities respond to this *** Bay,a mediumsized estuary in China,is an ideal place in which to study the response of plankton to small-scale ocean fronts,because three water masses(Qiantang River Diluted Water,Changjiang River Diluted Water,and the East China Sea current) converge here and form dynamic salinity fronts throughout the *** investigate zooplankton communities,and temperature,salinity and chlorophyll a(Chl a) in Hangzhou Bay in June(wet perio d) and December(dry period) of 2022 and examine the dominant environmental factors that affect zooplankton community spatial *** then match the spatial distributions of zooplankton communities with those of salinity fronts.S alinity is the most important explanatory variable to affect zooplankton community spatial variability during both wet and dry periods,in that it contributes>60% of the variability in community ***,the spatial distributions of zooplankton match well with salinity *** December,with weaker Qiantang River Diluted Water and a stronger secondary Changjiang River Plume,zooplankton communities occur in moderate salinity(MS,salinity range 15.6±2.2) and high salinity(HS,22.4±1.7) regions,and their ecological boundaries closely match the Qiantang River Diluted Water *** June,different zooplankton communities occur in low salinity(LS,3.9±1.0),MS(11.7±3.6) and HS(21.3±1.9) *** the LS region occurs abnormally in the central bay rather than its apex because of the anomalous influence of rising and falling tides during the sampling perio d,the ecological boundaries still match salinity ***-salinity or brackish-water zooplankter taxa are relatively more abunda

关键词： zooplankton spatial distribution salinity fronts Hangzhou Bay

The four dimensional variational data assimilation with multiple regularization parameters as a weak constraint(Tikh-4D-Var) and its preliminary application on typhoon initialization

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Science China Earth Sciences 2014年第7期57卷 2690-2701页

作者： ZHONG Jian FEI JianFang CHENG XiaoPing HUANG XiaoGang China satellite Maritime Tracking and Control Department institute of meteorology and Oceanography PLA University of Science and Technology

Traditional variational data assimilation （VDA） with only one regularization parameter constraint cannot produce optimal error tuning for all observations. In this paper, a new data assimilation method of ＂four dimensional variational data assimilation （4D-Var） with multiple regularization parameters as a weak constraint （Tikh-4D-Var）＂ is proposed by imposing different reg- ularization parameters for different observations. Meanwhile, a new multiple regularization parameters selection method, which is suitable for actual high-dimensional data assimilation system, is proposed based on the posterior information of 4D-Var system. Compared with the traditional single regularization parameter selection method, computation of the proposed multiple regularization parameters selection method is smaller. Based on WRF3.3.1 4D-Vat data assimilation system, initiali- zation and simulation of typhoon Chaba （2010） with the new Tikh-4D-Var method are compared with its counterpart 4D-Var to demonstrate the effectiveness of the new method. Results show that the new Tikh-4D-Var method can accelerate the con vergence with less iterations. Moreover, compared with 4D-Var method, the typhoon track, intensity （including center surface pressure and maximum wind speed） and structure prediction are obviously improved with Tikh-4D-Var method for 72-h pre- diction. In addition, the accuracy of the observation error variances can be reflected by the multiple regularization parameters.

关键词： multiple regularization parameters 4D-Var typhoon initialization

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Using deep learning to detect small targets in infrared oversampling images

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Journal of Systems Engineering and Electronics 2018年第5期29卷 947-952页

作者： LIN Liangkui WANG Shaoyou TANG Zhongxing Shanghai institute of satellite Engineering Shanghai 201109China

According to the oversampling imaging characteristics, an infrared small target detection method based on deep learning is proposed. A 7-layer deep convolutional neural network(CNN) is designed to automatically extract small target features and suppress clutters in an end-to-end manner. The input of CNN is an original oversampling image while the output is a cluttersuppressed feature map. The CNN contains only convolution and non-linear operations, and the resolution of the output feature map is the same as that of the input image. The L1-norm loss function is used, and a mass of training data is generated to train the network effectively. Results show that compared with several baseline methods, the proposed method improves the signal clutter ratio gain and background suppression factor by 3–4 orders of magnitude, and has more powerful target detection performance.

关键词： infrared small target detection oversampling deep learning convolutional neural network(CNN)

Response regimes of narrow-band stochastic excited linear oscillator coupled to nonlinear energy sink

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Chinese Journal of Aeronautics 2015年第2期28卷 457-468页

作者： Xiong Huai Kong Xianren Yang Zhenguo Liu Yuan Research Center of satellite Technology Harbin Institute of Technology

This paper draws attention to the issue of the vibration absorption of nonlinear mechani- cal system coupled to nonlinear energy sink （NES） under the impact of the narrow band stochastic excitation. Firstly, based on the complex-averaging method and frequency detuning methodology, response regimes of oscillators have been researched under the linear impact of coupling a nonlinear attachment with less relativistic mass and an external sinusoidal forcing, of which results turn out that the quasi-periodicity response regime of system which occurs when the external excitation amplitude exceeds the critical values will be the precondition of the targeted energy transfer. Secondly, basing on the path integration method, vibration suppression of NES has been researched when it is affected by a main oscillator with a narrow band stochastic force in the form of trigono- metric functions, of which results show that response regimes are affected by the amplitude of stochastic excitation and the disturbance strength. Finally, all these conclusions have been approved by the numerical verification and coincided with the theoretical analysis; meanwhile, after the com- paring analysis with the optimal linear absorber, it turns out that the NES which is affected by the narrow band stochastic force could also suppress the vibration of system with a better effect.

关键词： Nonlinear energy sink Path integration method Stochastic excitation Targeted energy transfer Vibration absorption

Deep tectonics and seismogenic mechanisms of the seismic source zone of the Jishishan M_(s)6.2 earthquake on December 18,2023,at the northeast margin of the Tibetan Plateau

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Earth and Planetary Physics 2024年第3期8卷 514-521页

作者： Qiong Wang ShuYu Li XinYi Li Yue Wu PanPan Zhao Yuan Gao Key Laboratory of Earthquake Prediction Institute of Earthquake ForecastingChina Earthquake AdministrationBeijing 100036China institute of Geophysics China Earthquake AdministrationBeijing 100081China

On December 18,2023,an M_(s)6.2 earthquake occurred in Jishishan,Gansu Province,*** earthquake happened in the eastern region of the Qilian Orogenic Belt,which is situated at the forefront of the NE margin of the Tibetan Plateau(i.e.,Qinghai-Tibet Plateau),encompassing a rhombic-shaped area that intersects the Qilian-Qaidam Basin,Alxa Block,Ordos Block,and South China *** this study,we analyzed the deep tectonic pattern of the Jishishan earthquake by incorporating data on the crustal thickness,velocity structure,global navigation satellite system(GNSS)strain field,and *** discovered that the location of the earthquake was related to changes in the crustal *** results showed that the Jishishan M_(s)6.2 earthquake occurred in a unique position,with rapid changes in the crustal thickness,Vp/Vs,phase velocity,and S-wave *** epicenter of the earthquake was situated at the transition zone between high and low velocities and was in proximity to a low-velocity ***,the source area is flanked by two high-velocity anomalies from the east and *** principal compressive strain orientation near the Lajishan Fault is primarily in the NNE and NE directions,which align with the principal compressive stress direction in this *** some areas of the Lajishan Fault,the principal compressive strain orientations show the NNW direction,consistent with the direction of the upper crustal fast-wave polarization from local earthquakes and the phase velocity azimuthal *** features underscore the relationship between the occurrence of the Jishishan M_(s)6.2 earthquake and the deep inhomogeneous structure and deep tectonic *** NE margin of the Tibetan Plateau was thickened by crustal extension in the process of northeastward expansion,and the middle and lower crustal materials underwent structural deformation and may have been filled with salt-containing fluids during the extension *** presence

关键词： Jishishan M_(s)6.2 earthquake crustal structure anisotropy stress and strain seismogenic mechanism northeast margin of the Tibetan Plateau