Networking Observation and Applications of Chinese Ocean Satellites

This paper presents the networking observation capabilities of Chinese ocean satellites and their diverse applications in ocean disaster prevention,ecological monitoring,and resource development.Since the inaugural launch in 2002,China has achieved substantial advancements in ocean satellite technology,forming an observation system composed of the HY-1,HY-2,and HY-3 series satellites.These satellites are integral to global ocean environmental monitoring due to their high resolution,extensive coverage,and frequent observations.Looking forward,China aims to further enhance and expand its ocean satellite capabilities through ongoing projects to support global environmental protection and sustainable development.

Energetic electron detection packages on board Chinese navigation satellites in MEO

Energetic electron measurements and spacecraft charging are of great significance for theoretical research in space physics and space weather applications.In this paper,the energetic electron detection package(EEDP)deployed on three Chinese navigation satellites in medium Earth orbit(MEO)is reviewed.The instrument was developed by the space science payload team led by Peking University.The EEDP includes a pinhole medium-energy electron spectrometer(MES),a high-energy electron detector(HED)based onΔE-E telescope technology,and a deep dielectric charging monitor(DDCM).The MES measures the energy spectra of 50−600 keV electrons from nine directions with a 180°×30°field of view(FOV).The HED measures the energy spectrum of 0.5−3.0 MeV electrons from one direction with a 30°cone-angle FOV.The ground test and calibration results indicate that these three sensors exhibit excellent performance.Preliminary observations show that the electron spectra measured by the MES and HED are in good agreement with the results from the magnetic electron-ion spectrometer(MagEIS)of the Van Allen Probes spacecraft,with an average relative deviation of 27.3%for the energy spectra.The charging currents and voltages measured by the DDCM during storms are consistent with the highenergy electron observations of the HED,demonstrating the effectiveness of the DDCM.The observations of the EEDP on board the three MEO satellites can provide important support for theoretical research on the radiation belts and the applications related to space weather.

Chinese GF-1 and GF-3 satellites observed the giant iceberg calving off the Larsen C Ice Shelf

A massive iceberg, named A-68 by National Ice Center （NIC） officially, calved away from the Larsen C Ice Shelf in Antarctica on luly 12, 2017. The iceberg A-68 is about 5 800 km2, weighs more than a trillion tons and it is one of the biggest ever recorded icebergs. Chinese satellites Gaofen-1 （GF-1） and Gaofen-3 （GF-3） data was used to monitoring the propagation of the rift and the iceberg by National Satellite Ocean Application Service （NSOAS）.

Validation of Chinese HY-2 satellite radar altimeter significant wave height

Chinese Haiyang-2（HY-2） satellite is the first Chinese marine dynamic environment satellite. The dual-frequency （Ku and C band） radar altimeter onboard HY-2 has been working effective to provide operational significant wave height （SWH） for more than three years （October 1, 2011 to present）.We validated along-track Ku-band SWH data of HY-2 satellite against National Data Buoy Center （NDBC） in-situ measurements over a time period of three years from October 1, 2011 to September 30, 2014, the root mean square error （RMSE） and mean bias of HY-2 SWH is 0.38 m and （-0.13±0.35） m, respectively. We also did cross validation against Jason-2 altimeter SWH data, the RMSE and the mean bias is 0.36m and （-0.22±0.28） m, respectively. In order to compare the statistical results between HY-2 and Jason-2 satellite SWH data, we validated the Jason-2 satellite radar altimeter along-track Ku-band SWH data against NDBC measurements using the same method. The results demonstrate the validation method in this study is scientific and the RMSE and mean bias of Jason-2 SWH data is 0.26 m and （0.00±0.26） m, respectively. We also validated both HY-2 and Jason-2 SWH data every month, the mean bias of Jason-2 SWH data almost equaled to zero all the time, while the mean bias of HY-2 SWH data was no less than -0.31m before April 2013 and dropped to zero after that time. These results indicate that the statistical results for HY-2 altimeter SWH are reliable and HY-2 altimeter along-track SWH data were steady and of high quality in the last three years. The results also indicate that HY-2 SWH data have greatly been improved and have the same accuracy with Jason-2 SWH data after April, 2013. SWH data provided by HY-2 satellite radar altimeter are useful and acceptable for ocean operational applications.

The first quantitative remote sensing of ocean internal waves by Chinese GF-3 SAR satellite

Quantitative analysis and retrieval is given by the State Key Laboratory of Satellite Ocean Environment Dynamics（SOED）,Second Institute of Oceanography（SIO）,State Oceanic Administration（SOA）,China,from the first batch of GF-3 synthetic aperture radar（SAR）data with ocean internal wave features in the Yellow Sea.

Level study on fractal characteristics of tidal creeks and information of seashell habitats in the Gaizhou Beach based on high-resolution satellite images

The fractal characteristics of tidal creeks in the Gaizhou Beach are analyzed based on high-resolution images fusionof Landsat TM and ERS2, and then the graphic models and characteristics of converse information tree of tidalcreeks in the Gaizhou Beach are established. A calculation model is established based on the above results, and at thesame time, quantitative calculation of the evolution characteristics and the diversity between the northern and thesouthern parts of the Gaizhou Beach is carried out. By the supervised classification of these images, distribution andareas of high tidal flats, middle tidal flats and low tidal flats in the Gaizhou Beach are studied quantitatively, and imagecharactistics of seashell habitats in the Gaizhou Beach and the correlation between mudflat distribution and seashellhabitats are studied. At last, the engineering problems in the Gaizhou Beach are discussed.

An Integrated Framework for Road Detection in Dense Urban Area from High-Resolution Satellite Imagery and Lidar Data

Automatic road detection, in dense urban areas, is a challenging application in the remote sensing community. This is mainly because of physical and geometrical variations of road pixels, their spectral similarity to other features such as buildings, parking lots and sidewalks, and the obstruction by vehicles and trees. These problems are real obstacles in precise detection and identification of urban roads from high-resolution satellite imagery. One of the promising strategies to deal with this problem is using multi-sensors data to reduce the uncertainties of detection. In this paper, an integrated object-based analysis framework was developed for detecting and extracting various types of urban roads from high-resolution optical images and Lidar data. The proposed method is designed and implemented using a rule-oriented approach based on a masking strategy. The overall accuracy (OA) of the final road map was 89.2%, and the kappa coefficient of agreement was 0.83, which show the efficiency and performance of the method in different conditions and interclass noises. The results also demonstrate the high capability of this object-based method in simultaneous identification of a wide variety of road elements in complex urban areas using both high-resolution satellite images and Lidar data.

THE CAS AND CHINA'S FIRST MAN-MADE EARTH SATELLITE Lu Shouguan(Chinese Academy of Sciences)

In the festivedays whencelebrating the50th anniversa-ry of the found-ing of the Peo-ple’s Republic,and the 50th an-niversary of thefounding of theChinese Acad-emy of Scienc-es (CAS), it isnatural for thepeople to thinkwith pride ofChina’s

Autumn migration routes of fledgling Chinese Egrets(Egretta eulophotes)in Northeast China and their implications for conservation

The Chinese Egret(Egretta eulophotes)is a globally threatened bird species living on the coast and islands of Liaoning,northeastern China,mainly in summer.To further protect the breeding population of Chinese Egrets,it is important to understand the current protection status of their distribution sites at pre-migration period and migration routes.Thirty-three individuals were tagged with satellite transmitters at Fantuo Island in Changhai and Xingren Island in Zhuanghe,Liaoning Province,northeastern China,in July of 2016,2017,and 2018,to identify important distribution sites during the pre-migration period,as well as detailed migration routes.The results showed that coastal mudflats in Liaoning and the west coast of North Korea were important feeding and roosting sites for fledgling Chinese Egrets from August to September.The home range sizes in August were significantly larger than in September.The eastern coast from Shandong to Guangdong,as well as Taiwan,China,and Manila Bay and Galileo Islands in the Philippines,were important stopover sites during fall migration.Specifically,we found that the egrets’autumn migration could be divided into four routes,i.e.,sea-crossing migration(SCM),coastal migration(CM),inland migration(IM),and mixed migration(MM).The migration distance,timing,speed,and straightness of the four routes also differed.The SCM routes were the straightest,and had the fastest migration speed and shortest travel time,while the IM routes had the lowest straightness and speed,and the longest duration.Manila Bay and Bohol Island in the Philippines,the west coast of Tanintharyi in Myanmar,and the Zengwun River Estuary in Taiwan,China,were wintering sites.Our findings on the key distribution sites along pre-migration and fall migration routes,including some stopover sites,have important implications for the conservation of and global action plan development for the vulnerable Chinese Egret.

基于三维曲面Spline模型研究中国不同地区的磁场分布

利用地面台站以及子午工程测点,CHAMP卫星实测数据,建立了中国地区主磁场的三维曲面Spline(3DSS)模型。基于该模型进行了我国的高原地区(青藏高原28°N-38°N,78°E-102°E)、平原地区(长江中下游平原27°N-34°N,111°E-122°E)以及海洋地区(东海和南海部分区域16°N-30°N,123°E-136°E)的磁场模拟。分别基于高原及平原的实测数据建立了各自的3DSS模型。另外分别建立了对应的二维Taylor(2DTY)、三维Taylor多项式(3DTY)模型以比较验证。建模时考虑了所有测点的场源移除、地面及卫星数据间的数据真空、边界效应等问题。为了考察模型相对于实测值的模拟精度,对三个地区分别选取若干个测点不参与建模,将所建模型分别模拟这些测点,并计算残差、变化率及均方根偏差(RMSE)。结果显示无论是全国3DSS模型还是小区域3DSS模型,其变化率除了Y分量略大,其余分量都在1%以内,模拟精度均要好于2DTY和3DTY模型。小区域(高原及平原)3DSS模型能较好反映区域磁场分布。模型对高原的拟合最好,平原次之,海洋地区最差,说明3DSS模型不需要太多的测点即可完成建模,但建模精度依赖于测点的数量及分布。

中国共产党人的精神谱系融入卫星导航定位课程思政教学设计

中国共产党人的精神谱系是中华民族在百年非凡奋斗历程中凝练形成的系列伟大精神,真实反映中国人民的思想特性和精神特质,蕴含着丰富的育人资源,为高校课程思政建设提供强大精神力量。深刻把握党的精神谱系深刻内涵和时代价值,将其融入卫星导航定位课程,有助于构建有高度、有深度、有温度的课程思政教学体系。因此,该文以党的精神谱系为主线,重点设计适应本课程的精神谱系思政案例,引导学生在学思践悟中坚定理想信念,培养德才兼备的导航定位人才,从而实现立德树人的根本任务。

China’s high-resolution optical remote sensing satellites and their mapping applications

Since the beginning of the twenty-first century,several countries have made great efforts to develop space remote sensing for building a high-resolution earth observation system.Under the great attention of the government and the guidance of the major scientific and technological project of the high-resolution earth observation system,China has made continuous breakthroughs and progress in high-resolution remote sensing imaging technology.The development of domestic high-resolution remote sensing satellites shows a vigorous trend,and consequently,a relatively stable and perfect high-resolution earth observation system has been formed.The development of high-resolution remote sensing satellites has greatly promoted and enriched modern mapping technologies and methods.In this paper,the development status,along with mapping modes and applications of China’s high-resolution remote sensing satellites are reviewed,and the development trend in high-resolution earth observation system for global and ground control-free mapping is discussed,providing a reference for the subsequent development of high-resolution remote sensing satellites in China.

Assimilation of Feng-Yun-3B Satellite Microwave Humidity Sounder Data over Land

The ECMWF has been assimilating Feng-Yun-3B （FY-3B） satellite microwave humidity sounder （MWHS） data over ocean in an operational forecasting system since 24 September 2014, It is more difficult, however, to assimilate microwave observations over land and sea ice than over the open ocean due to higher uncertainties in land surface temperature, surface emissivity and less effective cloud screening. We compare approaches in which the emissivity is retrieved dynamically from MWHS channel l [150 GHz （vertical polarization）] with the use of an evolving emissivity atlas from 89 GHz observations from the MWHS onboard NOAA and EUMETSAT satellites. The assimilation of the additional data over land improves the fit of short-range forecasts to other observations, notably ATMS （Advanced Technology Microwave Sounder） humidity channels, and the forecast impacts are mainly neutral to slightly positive over the first five days. The forecast impacts are better in boreal summer and the Southern Hemisphere. These results suggest that the techniques tested allow for effective assimilation of MWHS/FY-3B data over land.

Development,application,and prospects for Chinese land observation satellites

The launching of CBERS-01(China Brazil Earth Resource Satellite)in 1999,China’s first land observation satellite,signifies an unprecedented milestone in Chinese satellite remote sensing history.Since then,a large number of applications have been developed that drew upon solely CBERS-01 and other Chinese land observation satellites.The application development evolves from one satellite to multiple satellites,from one series of satellites to multiple series,from scientific research to industrial applications.Six aspects of the Chinese land observation satellite program are discussed in this paper:development status,data sharing and distribution,satellite calibration,industrial data applications,future prospects,and conclusion.

Update on Fengyun Meteorological Satellite Program and Development

China began to develop its meteorological satellite program since 1969.With 50-years’growing,there are 17 Fengyun(FY)meteorological satellites launched successfully.At present,seven of them are in orbit to provide the operational service,including three polar orbiting meteorological satellites and four geostationary meteorological satellites.Since last COSPAR report,no new Fengyun satellite has been launched.The information of the on-orbit FY-2 series,FY-3 series,and FY-4 series has been updated.FY-3D and FY-2H satellites accomplished the commission test and transitioned into operation in 2018.FY-2E satellite completed its service to decommission in 2019.The web-based users and Direct Broadcasting(DB)users keep growing worldwide to require the Fengyun satellite data and products.A new Mobile Application Service has been launched to Fengyun users based on the cloud technology in 2018.In this report,the international and regional co-operations to facilitate the Fengyun user community have been addressed especially.To strengthen the data service in the Belt and Road countries,the Emergency Support Mechanism of Fengyun satellite(FY_ESM)has been established since 2018.Meanwhile,a Recalibrating 30-years’archived Fengyun satellite data project has been founded since 2018.This project targets to generate the Fundamental Climate Data Record(FCDR)as a space agency response to the Global Climate Observation System(GCOS).At last,the future Fengyun program up to 2025 has been introduced as well.

Advanced Digital Techniques and Tendencies in the Development of Modem Digital Satellite Broadcasting

The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendencies in the development of digital television broadcasting are: (1) Stereophonic or two-language sound transmission with television in existing analog TV system, (2) Digital direct satellite broadcasting (D-DBS); (3)Digital high definition television (HDTV) Broadcasting.

Modeling of CHAMP satellite data according to the 3D surface spline model of geomagnetic fi elds

Surface observations and CHAMP measurement data are employed to develop a three-dimensional surface spline(3DSS)model of China's Mainland.The magnetic field distribution at the satellite level is then demonstrated using the model obtained.The results of this model are compared and verifi ed by deriving the corresponding two(2DTY)and threedimensional(3DTY)Taylor polynomial models.Issues such as the removal of disruptive geomagnetic fi elds,the data gap between the surface and satellite levels,and boundary eff ects are carefully considered during modeling.We then focus on evaluating the modeling eff ect of the satellite data.Ten satellite points not involved in the modeling procedure are selected,and the residuals,absolute change rates,and RMSEs of these points are calculated.Results show that the distribution of the magnetic fi eld determined by the 3DSS model is highly consistent with that obtained from the IGRF12 model.Expect for component Y,the absolute change rates of other components are less than 0.5%.Specifi cally,the RMSE of Y of 3DSS is nearly 60%lower than those of 3DTY and 2DTY;the RMSE of other components of the former are also over 90%lower than those of the latter.This fi nding implies that the 3DSS model has good performance for modeling satellite data and its results are reliable.Moreover,the modeling eff ect of 3DTY is better than that of 2DTY.

中华民族共同体视域下“两弹一星”精神传承与践行的时代指向

作为红色基因的生动演绎和中国共产党精神谱系的闪亮标识,“两弹一星”精神是党领导人民在社会主义建设探索进程中对民族精神之一脉相承和时代精神之现实淬炼。在中国特色社会主义时代场景中,“两弹一星”精神的传承与践行对推动铸牢中华民族共同体意识具有重要意义。基于实践论域整体揆褚,“两弹一星”精神的传承与践行:首先,要立足于中华民族共同体建设的时代需求,基于民族精神的历时承继和时代精神的现实拓展,厘清其精神蕴涵的价值指向;其次,要立足于民族国家价值诉求的现实投射,为增强中华民族共同体意识的主体自觉,明晰其价值意涵的时代指向;最后,要立足于铸牢中华民族共同体意识的时代指向,基于民族地域生活场景中的价值诉求,强化其价值意涵的弘扬传播与自觉展演。

HUST-Grace2020模型反演中国内地区域水储量变化特征分析

中国水资源呈现人均水量少且水资源分布不平衡等特点,研究中国内地区域水储量及其变化特征,对水资源管理与调控意义重大。本文主要利用华中科技大学最新发布的HUST-Grace2020模型计算2003年1月—2016年7月中国内地区域水储量的变化,并将计算结果与瑞士伯尔尼大学最新发布的COST-G联合解算模型结果、CSR发布的CSR RL06模型结果、ITSG发布的ITSG-Grace2018模型结果和同济大学发布的Tongji-Grace2018模型结果进行对比。结果表明:(1)利用HUST-Grace2020模型得到的中国内地15个子流域的水储量变化与COST-G、ITSG-Grace2018、Tongji-Grace2018模型计算结果的一致性均很好。(2)西南地区边界处的雅鲁藏布江、澜沧江流域水储量变化最大,周年振幅分别为13.75、9.37 cm。长江流域、珠江流域和东南沿海水储量呈明显增长趋势,增加速率分别为0.54、0.78和0.70 cm/a;淮河、海河和雅鲁藏布江水储量呈现减少趋势,减小速率分别为-0.47、-0.88和-1.30 cm/a。(3)中国内地水储量变化具有明显的季节性,整体表现为夏秋水储量富足、冬春水储量匮乏。(4)基于典型流域的水储量变化特征可知,长江流域在2006年与2011年发生极端干旱事件,2010年与2016年发生洪水事件;黄河流域在2003年出现极端干旱事件,2013年出现洪水事件。

Overview of the key technologies for high-resolution satellite mapping

As the important infrastructures for land mapping and resource monitoring,highresolution remote sensing satellites(HRSS)are urgently demanded for the development of China.In this article,the key technologies of the main HRSS are summarized,and these technologies include sensor design,attitude and orbit determination,geometric calibration,imaging model construction,and block adjustment,etc.,which involve the mapping accuracy of HRSS.Finally,the system design of the ZY-3 Satellite(China’s first civil stereoscopic surveying and mapping satellite,to be launched in 2012)is introduced,which mainly include satellite technical specifications and strategies design based on these key technologies research.