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| 1 | A new global zenith tropospheric delay model IGGtrop for GNSS applications显示文摘Tropospheric delay is one of the main sources of measurement error in global navigation satellite systems.It is usually compensated by using an empirical correction model.In this paper,temporal and spatial variations of the global zenith tropospheric delay(ZTD) are further analyzed by ZTD time series from global International GNSS Service stations and annual ZTDs derived from global National Centers for Environmental Prediction reanalysis data,respectively.A new ZTD correction model,named IGGtrop,is developed based on the characteristics of ZTD.Experimental results show that this new 3D-grid-based model that accommodates longitudinal as well as latitudinal variations of ZTD performs better than latitude-only based models(such as UNB3,EGNOS,and UNB3m).The global average bias and RMS for IGGtrop are about-0.8 cm and 4.0 cm,respectively.Bias values for UNB3,EGNOS,and UNB3m are 2.0,2.0,and 0.7 cm,respectively,and respective RMS values 5.4,5.4,and 5.0 cm.IGGtrop shows much more consistent prediction errors for different areas than EGNOS and UNB3m,In China,the performance of IGGtrop(bias values from-2.0 to 0.4 cm and RMS from 2.1 to 6.4 cm) is clearly superior to those of EGNOS and UNB3m.It is also demonstrated that IGGtrop biases vary little with height,and its RMS values tend to decrease with increasing height.In addition,IGGtrop generally estimates ZTD with greater accuracy than EGNOS and UNB3m in the Southern Hemisphere. | LI Wei YUAN YunBin OU JiKun LI Hui LI ZiShen | 2012 | Chinese Science Bulletin2012，57，17： | 32 |
| 2 | Extraction of line-of-sight ionospheric observables from GPS data using precise point positioning显示文摘Here we propose a method for extracting line-of-sight ionospheric observables from GPS data using precise point positioning(PPP).The PPP-derived ionospheric observables(PIOs) have identical form with their counterparts obtained from leveling the geometry-free GPS carrier-phase to code(leveling ionospheric observables,LIOs),and are affected by the satellite and receiver inter-frequency biases(IFBs).Based on the co-location experiments,the effects of extracting error arising from the observational noise and multipath on the PIOs and the LIOs are comparatively assessed,and the considerably reduced effects ranging from 70% to 75% on the PIOs with respect to the LIOs can be verified in our case.In addition,based on 26 consecutive days' GPS observations from two international GNSS service(IGS) sites(COCO,DAEJ) during disturbed ionosphere period,the extracted PIOs and LIOs are respectively used as the input of single-layer ionospheric model to retrieve daily satellite IFBs station-by-station.The minor extracting errors underlying the PIOs in contrast to the LIOs can also be proven by reducing day-to-day scatter and improving between-receiver consistency in the retrieved satellite IFBs values. | ZHANG BaoCheng OU JiKun YUAN YunBin LI ZiShen | 2012 | Science China Earth Sciences2012，55，11： | 19 |
| 3 | Model analysis method (MAM) on the effect of the second-order ionospheric delay on GPS positioning solution显示文摘In this paper,we develop an approach to study the effect of second-order ionospheric delay on GPS positioning based on the ionosphere-free combination (abbreviated to Lc) of GPS dual-frequency carrier phase observables,in which the first-order ionospheric delay has been eliminated.GPS data from IGS WUHN tracking station during April 9 23,2003 is used to perform the above approach,and results show that the second-order ionospheric delay in GPS so-called ionosphere-free observables will result in the regular southward shift of GPS positioning solution.Additionally,the influence of the Earth's magnetic field on second-order ionospheric delay over the Wuhan area is discussed,and it indicates that the Earth's magnetic field is one of the main factors why second-order ionospheric delay results in the regular southward shift of GPS positioning solution over Wuhan area. | LIU XiFeng YUAN YunBin HUO XingLiang LI ZiShen LI Wei | 2010 | Chinese Science Bulletin2010，55，15： | 15 |
| 4 | 伶仃河口湾铜鼓水域水沙净输运分析显示文摘根据对珠江伶仃河口湾铜鼓水域丰水期9个测站大、中、小潮三次同步水文泥沙资料及57个底质样品的分析结果,本文讨论了此水域的水沙净输运趋势。结果表明,铜鼓水域表层余流向海,浅滩测站中底层余流指向河口方向,欧拉余流主要由径流构成。沟槽悬沙输运以净平流作用为主,浅滩区则以向上游的潮抽吸输运为主。 | Chen Zishen (Institute of Estuarine and Coastal Research,Zhongshan University, Guangzhou 510275) | 1999 | 海洋工程1999，17，1： | 10 |
| 5 | Analysis of the dynamic characteristics and stochastic simulation on variations of beach volumes显示文摘Analysisofthedynamiccharacteristicsandstochasticsimulationonvariationsofbeachvolumes￥ChenZishen(InstituteofEstuarineandCoasta... | Chen Zishen(Institute of Estuarine and Coastal Research of Zhongshan University, Guangzhou 510275, China) | 1995 | Acta Oceanologica Sinica1995，14，3： | 8 |
| 6 | An Investigation of Optimal Machine Learning Methods for the Prediction of ROTI显示文摘The rate of the total electron content(TEC)change index(ROTI)can be regarded as an effective indicator of the level of ionospheric scintillation,in particular in low and high latitude regions.An accurate prediction of the ROTI is essential to reduce the impact of the ionospheric scintillation on earth observation systems,such as the global navigation satellite systems.However,it is difficult to predict the ROTI with high accuracy because of the complexity of the ionosphere.In this study,advanced machine learning methods have been investigated for ROTI prediction over a station at high-latitude in Canada.These methods are used to predict the ROTI in the next 5 minutes using the data derived from the past 15 minutes at the same location.Experimental results show that the method of the bidirectional gated recurrent unit network(BGRU)outperforms the other six approaches tested in the research.It is also confirmed that the RMSEs of the predicted ROTI using the BGRU method in all four seasons of 2017 are less than 0.05 TECU/min.It is demonstrated that the BGRU method exhibits a high level of robustness in dealing with abrupt solar activities. | Fulong XU Zishen LI Kefei ZHANG Ningbo WANG Suqin WU Andong HU Lucas Holden | 2020 | Journal of Geodesy and Geoinformation Science2020，3，2： | 7 |
| 7 | Monitoring the ionosphere based on the Crustal Movement Observation Network of China显示文摘The Global Navigation Satellite System(GNSS) is becoming important for monitoring the variations in the earth's ionosphere based on the total electron content(TEC) and ionospheric electron density(IED). The Crustal Movement Observation Network of China(CMONOC), which includes GNSS stations across China's Mainland, enables the continuous monitoring of the ionosphere over China as accurately as possible. A series of approaches for GNSS-based ionospheric remote sensing and software has been proposed and developed by the Institute of Geodesy and Geophysics(IGG) in Wuhan. Related achievements include the retrieval of ionospheric observables from raw GNSS data, differential code biases estimations in satellites and receivers, models of local and regional ionospheric TEC,and algorithms of ionospheric tomography. Based on these achievements, a software for processing GNSS data to determine the variations in ionospheric TEC and IED over China has been designed and developed by IGG. This software has also been installed at the CMONOC data centers belonging to the China Earthquake Administration and China Meteorological Administration. This paper briefly introduces the related research achievements and indicates potential directions of future work. | Yuan Yunbin Li Zishen Wang Ningbo Zhang Baocheng Li Hui Li Min Huo Xingliang Ou Jikun | 2015 | Geodesy and Geodynamics2015，6，2： | 5 |
| 8 | Real-time GNSS precise point positioning with smartphones for vehicle navigation显示文摘The availability of raw Global Navigation Satellite System(GNSS)measurements from Android smart devices gives new possibilities for precise positioning solutions,e.g.,Precise Point Positioning(PPP).However,the accuracy of the PPP with smart devices currently is a few meters due to the poor quality of the raw GNSS measurements in a kinematic scenario and in urban environments,particularly when the smart devices are placed inside vehicles.To promote the application of GNSS PPP for land vehicle navigation with smart devices,this contribution studies the real-time PPP with smartphones.For data quality analysis and positioning performance validation,two vehicle-based kinematic positioning tests were carried out using two Huawei Mate30 smartphones and two Huawei P40 smartphones with different installation modes:the vehicle-roof mode with smartphones mounted on the top roof outside the vehicle,and the dashboard mode with smartphones stabilized on the dashboard inside the vehicle.To realize high accuracy positioning,we proposed a real-time smartphone PPP method with the data processing strategies adapted for smart devices.Positioning results show that the real-time PPP can achieve the horizontal positioning accuracy of about 1–1.5 m in terms of root-mean-square and better than 2.5 m at the 95th percentile for the vehicle-based kinematic positioning with the experimental smartphones mounted on the dashboard inside the vehicle,which is the real scenario in vehicle navigation. | Zishen Li Liang Wang Ningbo Wang Ran Li Ang Liu | 2022 | Satellite Navigation2022，3，3： | 2 |
| 9 | Polybrominated diphenyl ethers (PBDEs) in aquatic biota from the lower reach of the Yangtze River, East China显示文摘 | Zishen Gao Jie Xu Qiming Xian Jianfang Feng Xiaohui Chen Hongxia Yu | 2009 | Chemosphere2009，，9： | 1 |
| 10 | Status of CAS global ionospheric maps after the maximum of solar cycle 24显示文摘As a new Ionosphere Associate Analysis Center(IAAC)of the International GNSS Service(IGS),Chinese Academy of Sciences(CAS)started the routine computation of the real-time,rapid,and final Global Ionospheric Maps(GIMs)in 2015.The method for the generation of CAS rapid and final GIMs and recent updates are presented in the paper.The quality of CAS post-processed GIMs is assessed during 2015-2018 after the maximum of solar cycle 24.To perform an independent and fair assessment,Jason-2/3 Vertical Total Electron Contents(VTEC)are first used as the references over the ocean.GPS differential Slant TECs(dSTEC)generated from 55 Multi-GNSS Experimental(MGEX)stations of the IGS are also employed,which provides a complementing way to evaluate the ability of electron content models to reproduce the spatial and temporal gradients in the ionosphere.During the test period,Jet Propulsion Laboratory(JPL)GIMs present significantly positive deviations compared to the Jason VTEC and GPS dSTEC.Technical University of Catalonia(UPC)rapid GIM UQRG exhibits the best performance in both Jason VTEC and GPS dSTEC analysis.The CAS GIMs show comparable performance with the results of the first four IAACs of the IGS.As expected,the poor performance of all GIMs is in equatorial regions and the high latitudes of the southern hemisphere.The consideration of generating multi-layer or three-dimensional ionospheric maps is emphasized to mitigate the inadequacy of ionospheric single-layer assumption in the presence of pronounced latitudinal gradients.The use of ionospheric observations from the new GNSS constellations and other space-or ground-based observation techniques is also suggested in the generation of future GIMs,given the sparse GPS/GLONASS stations in the southern hemisphere. | Zishen Li Ningbo Wang Ang Liu Yunbin Yuan Liang Wang Manuel Hernández-Pajares Andrzej Krankowski Hong Yuan | 2021 | Satellite Navigation2021，2，1： | 1 |
| 11 | Wave-dominated,mesotidal headland-bay beach morphodynamic classsfications of the Shuidong Bay in South China显示文摘Beach morphodynamic classifications have achieved extensive acceptance in foreign coastal geomorphological studies.Three beaches located in different zones of a headland-bay coast are classified according to a dimensionless fall parameter,a relative tide range parameter and a dimensionless embayment scaling parameter.Synchronous data,including wave,tide,sediment and beach morphology,are respectively collected from the tangential beach,the transitional beach and the shadow beach of the Shuidong Bay during each spring tide for 16 successive months.The research results indicate that(1) the beach in the tangential zone falls between two major categories which are low tide terrace beaches with rips and barred beaches;the beach in the transitional zone exhibits two main types which are low tide bar/rip beaches and barred dissipative beaches;and the beach in the shadow zone mainly mirrors dissipative states with presence or absence of bars;and(2) the sequential changes and differences of beach states in different coastal zones reflect spatial and temporal variabilities of the headlandbay coast,totally meeting the actual measured beach morphology changes,showing that studies on wavedominated,meso-macrotidal beaches need to consider the influences of the tides.Meanwhile,the research mainly provides a framework about beach state studies,due to different beach states with different erosion patterns,which requires the need to strengthen the researches in this respect,in order to further enrich theoretical basis for a beach topography evolution,beach morphodynamic processes and beach erosion prevention in China. | YU Jitao DING Yuanting CHENG Huangxin CAI Lailiang CHEN Zishen | 2016 | Acta Oceanologica Sinica2016，35，7： | 1 |
| 12 | Safety Performance of a Precast Concrete Barrier: Numerical Study显示文摘The numerical simulation for a new type of precast concrete barrier for viaducts is carried out systematically.To obtain an accurate representation of the damage state of the concrete barrier under the impact of a vehicle,a stochastic damage-plasticity model of the concrete is adopted in the finite element model.Meanwhile,a simplified mathematical model of the impact between vehicles and the concrete barrier was established and the input energy was converted to the impact load to facilitate the investigation of the safety performance of the concrete barriers.On this basis,a refined finite element(FE)model of a precast concrete barrier was developed.The impact locations,impact load,boundary constraints,and reinforcement types were used as variables and the dynamic response of the precast concrete barrier was systematically analyzed under 36 working conditions.The simulated results indicated that the damage state of the concrete barrier and the stress of the reinforcing bars were accurately and quantitatively reflected.According to the computed results,some suggestions were put forward for selecting the appropriate reinforcement type of the precast concrete barrier and the connection between the superstructure and foundation. | Zishen Li Xiangling Gao Zicheng Tang | 2020 | Computer Modeling in Engineering & Sciences2020，，6： | 1 |
| 13 | Mesozoic Thrust-Nappe and Extensional Structure Frameworks in the East Segment of Southeast Yangtze Block, Southeast China显示文摘Multi-stage Mesozoic thrust-nappe and extensional structures are distributed in the east segment of the Southeast Yangtze Block situated in the junction region of Zhejiang-Jiangxi-Anhui provinces. The features and genetic mechanism of the deformations were analyzed after a detailed field observation of their distribution, geometry, and kinematics. In addition, the time sequences of the thrust and extensional structures were determined by combining the results of the comparative analysis with the chronological evidence of strata and magmatic rocks cut by a fault or formed after a fault according to field facts. This study identified three stages of the nappe structures and at least two stages of the extensional structures during the Mesozoic. The geotectonic setting of the nappe and extensional structures was considered to be related to the different geodynamics in the study area including the Early Mesozoic geological event, i.e., N-S compression, forming Lantian fault, etc.;the Late Mesozoic flat-slab subduction, forming Xiaoxi thrust fault and tectonic window;and the roll-back of the paleoPacific Plate, forming extensional structures like basin marginal fault;the last compression, forming Wucheng-Shenxian fault. These findings provide additional evidence for remodeling the tectonic and geodynamic evolution of Southeast China. | Xinqi Yu Ziwei Chen Jun Hu Yan Zeng Xiu Liu Yu He Zishen Wang Linghui Meng | 2020 | Journal of Earth Science2020，31，4： | 1 |
| 14 | Determination of the Differential Code Bias for Current BDS Satellites显示文摘 | ZISHEN LI YUNBIN YUAN LEI FAN | 2014 | IEEE Transactions on Geoscience and Remote Sensing2014，52，7： | 1 |
| 15 | Polybrominated diphenyl ethers (PBDEs) in aquatic biota from the lower reach of the Yangtze River, East China显示文摘 | Zishen Gao Jie Xu Qiming Xian Jianfang Feng Xiaohui Chen Hongxia Yu | 2009 | Chemosphere2009，，9： | 1 |
| 16 | A Multi-scale Perspective on Drought Monitoring and Assessment for the Pearl River Basin显示文摘It is accepted that climate change has a great impact on water cycle and regional water balance,and thus it would change the formation and evolution conditions of drought in some degree. By using data at 42 meteorological stations of the Pearl River Basin,the Standardized Precipitation Evapotranspiration Index( SPEI) at different time scales was calculated. Based on the SPEIs of 1- 12 months,a newly proposed index for drought——Joint Drought Index( JDI) was established under the multi-scale perspective through the copula function. Since short-term SPEIs are essential for the identification of emerging droughts and long-term SPEIs are useful for prolonged droughts,the JDI,which integrates all the usefull informations of drought and can thus form an overall judgement,is superior than the single SPEI in drought monitoring. By the forcast evaluation system and comparison to the actual drought,the accuracy and effectiveness of JDI in drought monitoring were verified. In general,JDI can be used as a new ideal index for future drought monitoring and assessment. Additionly,we analyzed the spatio-temperal characteristics of drought across the Pearl River Basin using the JDI. The results indicate that mild drought was the most frequent drought occurred in the Pearl River Basin over the past half century,and moderate drought followed. Severe drought and extreme drought would appear occasionally while exceptional drought could hardly be found. A dry-wet-dry interdecadal variation pattern had been found from the 1960 s to the 2000 s. Since the 21 stcentury,an obvious trend toward drought can be observed in the whole basin,especially in the Xijiang subbasin,which,consequently,poses an increasing challenge for the water resource planning and management. | Huang Qiang Chen Zishen Chen Qixin Wu Lei | 2014 | Meteorological and Environmental Research2014，5，10： | 1 |
| 17 | Hydrogen Gas Improves Survival Rate and Organ Damage in Zymosan-Induced Generalized Inflammation Model显示文摘 | Keliang Xie Yonghao Yu Zishen Zhang Wenbo Liu Yuping Pei Lize Xiong Lichao Hou Guolin Wang | 2010 | Shock2010，，5： | 1 |
| 18 | Levels and distribution of polybrominated diphenyl ethers ( PBDEs ) in the freshwater environment surrounding a PBDE manufacturing plant in China 显示文摘 | XU Jie GAO Zishen XIAN Qiming | 2009 | Environ Pollut2009，157，6： | 1 |
| 19 | Two-step Method for the Determination of the Differential Code Biases of COMPASS Satellites显示文摘 | Li Zishen Yuan Yunbin Li Hui | 2012 | Journal of Geodesy2012，86，11： | 1 |
| 20 | Synthesis,characterization and antifungal activity of copper,zinc,cobalt and nickelcomplexes derived from 2-chlorobenzaldehyde and glycine显示文摘 | Wang Zhong Wu Zishen Yen Zhenhuan etal | 1994 | Synth React Inorg Met-OrgChem1994，24，9： | 1 |
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