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Collaborative Assessment of Reflectivity Consistency between FY-3G Precipitation Measurement Radar and Ground-Based Radars 认领 引用
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作者 Chunyan ZHANG Heng HU +4 位作者 Jiashan ZHU Qinqiang ZHOU Lei WU Jianyong LI Xuan ZHU 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2026年第5期1065-1078,共14页
FY-3G is the first polar-orbiting satellite equipped with a precipitation measurement radar(PMR)operating at Ku-andKa-band frequencies in China.In this study,we compare the reflectivity data from the FY-3G PMR Ku prod... FY-3G is the first polar-orbiting satellite equipped with a precipitation measurement radar(PMR)operating at Ku-andKa-band frequencies in China.In this study,we compare the reflectivity data from the FY-3G PMR Ku product and groundbasedradars(GRs)during 2024.Also,the FY-3G PMR is used as a third-party reference to evaluate the reflectivityconsistency among different GRs.The FY-3G PMR and GRs share similarities in their general distribution,characteristics,and intensity of reflectivity in strong precipitation cloud systems,though the former presents less detailed system structure.Systematic deviations between the FY-3G PMR and GRs and between GRs are comparable,albeit the reflectivity of the FY-3G PMR is generally slightly stronger than that of GRs(especially X-band GRs),with a mean bias ranging from 0.7 to 1.7dB.S-band GRs exhibit the smallest systematic deviation(STD=3.09 dB)from the FY-3G PMR,whereas the X-band GRsshow the largest(STD=3.61 dB),indirectly indicating the highest internal consistency among S-band GRs and the lowestamong X-band GRs.Besides,both S-and C-band GRs display similar deviations when paired with the FY-3G PMR as wellas when paired with their adjacent S/C-band GRs,suggesting good consistency between these two bands.In contrast,XbandGRs exhibit relatively poor consistency with S-band GRs and the FY-3G PMR,showing a deviation ranging from 3.0to 4.6 dB. 展开更多
关键词 reflectivity deviation consistency FY-3G PMR ground-based radars
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Effects of ground-based camera deployment parameters on SfM-Based 3D reconstruction of deformation features on stepped slopes 认领 引用
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作者 SHU Yunlong NIE Wen +4 位作者 ZHU Tianqiang MEHMOOD Mudassir YU Wen LIU Aixing KONG Qiuping 《Journal of Mountain Science》 SCIE CSCD 2026年第5期1941-1955,共15页
Stepped slopes are common in mountainous regions and are characterized by pronounced benches and risers,which generate strong occlusions during ground-based image acquisition and limit the accuracy of Structure-from-M... Stepped slopes are common in mountainous regions and are characterized by pronounced benches and risers,which generate strong occlusions during ground-based image acquisition and limit the accuracy of Structure-from-Motion(SfM)-based 3D reconstruction of surface deformation features.Despite the increasing application of SfM in slope monitoring,practical guidelines for optimizing ground-based camera deployment on stepped terrains remain limited.To address this gap,this study investigates the effects of ground-based camera deployment parameters on SfM reconstruction accuracy through geometrically scaled physical modeling and field validation.A 1:10 physical model of a rainfall-induced stepped slope was constructed to reproduce representative surface cracking patterns,with rainfall applied solely to induce deformation rather than treated as an experimental variable.Camera height,layout type,inter-camera angular interval,and camera number were systematically varied under controlled single-elevation configurations.Reconstruction accuracy was evaluated using the mean relative error between manually measured and SfM-derived crack widths.The results show that deployment geometry strongly governs reconstruction performance.A camera height of approximately one-third of slope height provides a favorable balance between spatial resolution and coverage.Compared with conventional horizontal layouts,fan-shaped configurations significantly reduce occlusion effects and improve crack-width measurement accuracy.Increasing the number of cameras generally reduces reconstruction error,but the improvement becomes marginal beyond four to five cameras under single-elevation deployment conditions.Under the optimal configuration,the physical model achieved a minimum mean relative error of 4.3%,while the field application at a prototype stepped slope yielded a mean relative error of 12.2%,which is acceptable for routine engineering monitoring.These findings provide practical and cost-effective guidance for ground-based SfM monitoring of deformation on stepped slopes in mountainous terrain. 展开更多
关键词 SfM Ground-based photogrammetry Stepped slopes Camera deployment parameters Crack-width measurement
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Closed-loop dynamics and disturbance propagation mechanisms of a drag-free control ground-based validation system 认领 引用
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作者 Qixian Zhou Ke An +4 位作者 Pengcheng Wang Wei Lu Yonghe Zhang Huawang Li Tao Yu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2026年第5期488-503,共16页
In space-based gravitational wave detection missions and other space experiments utilizing the ultra-static and ultra-stable space-craft,the drag-free control system(DFCS)plays a key role in maintaining the free-falli... In space-based gravitational wave detection missions and other space experiments utilizing the ultra-static and ultra-stable space-craft,the drag-free control system(DFCS)plays a key role in maintaining the free-falling motion of the test masses(TMs).However,high-precision ground-based verification of DFCS faces a great challenge in suppressing and evaluating multiple dis-turbances and noises accurately.To this end,this article first proposes an active disturbance rejection controller for TM with a two-stage torsion pendulum.The dual-loop scheme with robust control approach is introduced for this underactuated pendulum system,which significantly reduces the impact of seismic noise on TM.Subsequently,on the basis of suspended TM and the controlled Stewart platform,the closed-loop dynamics of a ground-based DFCS validation system is conducted.The emulat-ing capability of this system for in-orbit flight dynamics is analyzed.Furthermore,complex propagation mechanism models of multiple disturbances and noises are built,and residual acceleration and tracking performance are precisely evaluated.?Finally,numerical simulations are performed to validate the theoretical work.The presented work provides a design and analysis method-ology for ground-based verification of DFCS. 展开更多
关键词 Drag-free control system Ultra-static and ultra-stable spacecraft Ground-based validation Active disturbance rejection control Dynamic similarity
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Comparison of Reflectivity Consistency between Spaceborne Precipitation Radar and Ground-based Weather Radar in China and the United States 认领 引用 被引量：2
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作者 Peng CHEN Lin CHEN +3 位作者 Gang WANG Qiong WU Huiying WANG Peng ZHANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2025年第7期1376-1394,共19页
The Global Precipitation Measurement(GPM)dual-frequency precipitation radar(DPR)products(Version 07A)are employed for a rigorous comparative analysis with ground-based operational weather radar(GR)networks.The reflect... The Global Precipitation Measurement(GPM)dual-frequency precipitation radar(DPR)products(Version 07A)are employed for a rigorous comparative analysis with ground-based operational weather radar(GR)networks.The reflectivity observed by GPM Ku PR is compared quantitatively against GR networks from CINRAD of China and NEXRAD of the United States,and the volume matching method is used for spatial matching.Additionally,a novel frequency correction method for all phases as well as precipitation types is used to correct the GPM Ku PR radar frequency to the GR frequency.A total of 20 GRs(including 10 from CINRAD and 10 from NEXRAD)are included in this comparative analysis.The results indicate that,compared with CINRAD matched data,NEXRAD exhibits larger biases in reflectivity when compared with the frequency-corrected Ku PR.The root-mean-square difference for CINRAD is calculated at 2.38 d B,whereas for NEXRAD it is 3.23 d B.The mean bias of CINRAD matched data is-0.16 d B,while the mean bias of NEXRAD is-2.10 d B.The mean standard deviation of bias for CINRAD is 2.15 d B,while for NEXRAD it is 2.29 d B.This study effectively assesses weather radar data in both the United States and China,which is crucial for improving the overall consistency of global precipitation estimates. 展开更多
关键词 GPM DPR volume matching reflectivity ground-based radar
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CloudViT:A Lightweight Ground-Based Cloud Image Classification Model with the Ability to Capture Global Features 认领 引用
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作者 Daoming Wei Fangyan Ge +5 位作者 Bopeng Zhang Zhiqiang Zhao Dequan Li Lizong Xi Jinrong Hu Xin Wang 《Computers, Materials & Continua》 SCIE EI 2025年第6期5729-5746,共18页
Accurate cloud classification plays a crucial role in aviation safety,climate monitoring,and localized weather forecasting.Current research has been focusing on machine learning techniques,particularly deep learning b... Accurate cloud classification plays a crucial role in aviation safety,climate monitoring,and localized weather forecasting.Current research has been focusing on machine learning techniques,particularly deep learning based model,for the types identification.However,traditional approaches such as convolutional neural networks(CNNs)encounter difficulties in capturing global contextual information.In addition,they are computationally expensive,which restricts their usability in resource-limited environments.To tackle these issues,we present the Cloud Vision Transformer(CloudViT),a lightweight model that integrates CNNs with Transformers.The integration enables an effective balance between local and global feature extraction.To be specific,CloudViT comprises two innovative modules:Feature Extraction(E_Module)and Downsampling(D_Module).These modules are able to significantly reduce the number of model parameters and computational complexity while maintaining translation invariance and enhancing contextual comprehension.Overall,the CloudViT includes 0.93×106parameters,which decreases more than ten times compared to the SOTA(State-of-the-Art)model CloudNet.Comprehensive evaluations conducted on the HBMCD and SWIMCAT datasets showcase the outstanding performance of CloudViT.It achieves classification accuracies of 98.45%and 100%,respectively.Moreover,the efficiency and scalability of CloudViT make it an ideal candidate for deployment inmobile cloud observation systems,enabling real-time cloud image classification.The proposed hybrid architecture of CloudViT offers a promising approach for advancing ground-based cloud image classification.It holds significant potential for both optimizing performance and facilitating practical deployment scenarios. 展开更多
关键词 Image classification ground-based cloud images lightweight neural networks attention mechanism deep learning vision transformer
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A target imaging simulation method for ground-based system based on signal-to-noise ratio 认领 引用
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作者 Chunxu Ren Yun Li +3 位作者 Yanzhao Li Weihua Gao Wenlong Niu Xiaodong Peng 《Astronomical Techniques and Instruments》 CSCD 2025年第5期288-298,共11页
Space target imaging simulation technology is an important tool for space target detection and identification,with advantages that include high flexibility and low cost.However,existing space target imaging simulation... Space target imaging simulation technology is an important tool for space target detection and identification,with advantages that include high flexibility and low cost.However,existing space target imaging simulation technologies are mostly based on target magnitudes for simulations,making it difficult to meet image simulation requirements for different signal-to-noise ratio(SNR)needs.Therefore,design of a simulation method that generates target image sequences with various SNRs based on the optical detection system parameters will be important for faint space target detection research.Addressing the SNR calculation issue in optical observation systems,this paper proposes a ground-based detection image SNR calculation method using the optical system parameters.This method calculates the SNR of an observed image precisely using radiative transfer theory,the optical system parameters,and the observation environment parameters.An SNR-based target sequence image simulation method for ground-based detection scenarios is proposed.This method calculates the imaging SNR using the optical system parameters and establishes a model for conversion between the target’s apparent magnitude and image grayscale values,thereby enabling generation of target sequence simulation images with corresponding SNRs for different system parameters.Experiments show that the SNR obtained using this calculation method has an average calculation error of<1 dB when compared with the theoretical SNR of the actual optical system.Additionally,the simulation images generated by the imaging simulation method show high consistency with real images,which meets the requirements of faint space target detection algorithm research and provides reliable data support for development of related technologies. 展开更多
关键词 Image SNR calculation Imaging simulation Ground-based optical detection system Space target image sequence
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Influence of assimilating ground-based microwave radiometer data into the WRF model on precipitation 认领 引用 被引量：6
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作者 HE Wenying CHEN Hongbin LI Jun 《Atmospheric and Oceanic Science Letters》 CSCD 2020年第2期107-112,共6页
Ground-based microwave radiometers profilers(MWRPs)have been used in numerical weather prediction(NWP)systems and show different impacts on forecasts.Currently,there are around hundreds of ground-based MWPRs used in w... Ground-based microwave radiometers profilers(MWRPs)have been used in numerical weather prediction(NWP)systems and show different impacts on forecasts.Currently,there are around hundreds of ground-based MWPRs used in weather stations over China;however,the application of MWPRs in NWP systems is rather limited.In this work,two MWRP retrieved profiles were assimilated into the Weather Research and Forecasting(WRF)model for a rainstorm event that occurred in Beijing,China.The quality of temperature and humidity profiles retrieved from the MWRP was evaluated against radiosonde observations and showed the reliability of the two MWRP products.Then,comparisons between the measurements of ground-based rain gauges and the corresponding forecasted precipitation in different periods of the rainstorm were investigated.The results showed that assimilating the two MWRPs affected the distribution and intensity of rainfall,especially in the early stage of the rainstorm.With the development of the rainstorm,adding MWRP data showed only a slight influence on the precipitation during the stable and mature period of the rainstorm,since the two MWRP observations were too limited to affect the large area of heavy rainfall. 展开更多
关键词 Microwave radiometer ground-based observation assimilation precipitation
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Improving Satellite-Retrieved Cloud Base Height with Ground-Based Cloud Radar Measurements 认领 引用 被引量：3
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作者 Zhonghui TAN Ju WANG +3 位作者 Jianping GUO Chao LIU Miao ZHANG Shuo MA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第11期2131-2140,共10页
Cloud base height(CBH) is a crucial parameter for cloud radiative effect estimates, climate change simulations, and aviation guidance. However, due to the limited information on cloud vertical structures included in p... Cloud base height(CBH) is a crucial parameter for cloud radiative effect estimates, climate change simulations, and aviation guidance. However, due to the limited information on cloud vertical structures included in passive satellite radiometer observations, few operational satellite CBH products are currently available. This study presents a new method for retrieving CBH from satellite radiometers. The method first uses the combined measurements of satellite radiometers and ground-based cloud radars to develop a lookup table(LUT) of effective cloud water content(ECWC), representing the vertically varying cloud water content. This LUT allows for the conversion of cloud water path to cloud geometric thickness(CGT), enabling the estimation of CBH as the difference between cloud top height and CGT. Detailed comparative analysis of CBH estimates from the state-of-the-art ECWC LUT are conducted against four ground-based millimeter-wave cloud radar(MMCR) measurements, and results show that the mean bias(correlation coefficient) is0.18±1.79 km(0.73), which is lower(higher) than 0.23±2.11 km(0.67) as derived from the combined measurements of satellite radiometers and satellite radar-lidar(i.e., Cloud Sat and CALIPSO). Furthermore, the percentages of the CBH biases within 250 m increase by 5% to 10%, which varies by location. This indicates that the CBH estimates from our algorithm are more consistent with ground-based MMCR measurements. Therefore, this algorithm shows great potential for further improvement of the CBH retrievals as ground-based MMCR are being increasingly included in global surface meteorological observing networks, and the improved CBH retrievals will contribute to better cloud radiative effect estimates. 展开更多
关键词 cloud base height passive radiometer ground-based cloud radar remote sensing
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Ground-based GPS Used in the Snow Depth Survey of Greenland 认领 引用 被引量：4
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作者 Shuangcheng ZHANG Meiling ZHOU +3 位作者 Yajie WANG Ning LIU Qi LIU Jilun PENG 《Journal of Geodesy and Geoinformation Science》 CSCD 2021年第2期47-55,共9页
Snow cover is one of the important components of land cover,and it is necessary to accurately monitor the depth and coverage of snow cover.Using the GPS signal receiver data and the basic principle of snow depth detec... Snow cover is one of the important components of land cover,and it is necessary to accurately monitor the depth and coverage of snow cover.Using the GPS signal receiver data and the basic principle of snow depth detection based on GPS-MR technology,the snow depth of the three sites on the Greenland PBO network GLS1,GLS2,and GLS3 from 2012 to 2018 was obtained.The inversion snow depth is affected by site drift,which is a quite difference from the measured snow depth.Combined with the stable reference point,the velocity field distribution of Greenland Island and the U-direction component change value of the station can be obtained through GAMIT calculation.By analyzing the glacial flow and U-direction component,the influence of the site drift on the snow depth was deducted,and finally compared the corrected inversion snow depth and measured snow depth found that the two were better than before the correction,the results were significantly improved,and the consistency was good.The analysis of the experimental results showed that in extremely cold areas such as Greenland Island,affected by glaciers,the continuous,real-time,high-time resolution snow depth around the measured station obtained by ground-based GPS tracking stations has a large gap with the measured snow depth value,and the gap will gradually increase with time.By deducting the impact of glacier drift,the trend of the two is the same and the consistency is good.The correctness and feasibility of the application of ground-based GPS snow cover theory in the polar area further expand the application scope and practical value of ground-based GPS in snow monitoring. 展开更多
关键词 ground-based GPS Greenland GPS-MR snow depth time series
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Ground-based and additional science support for SMILE 认领 引用 被引量：2
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作者 J.A.Carter M.Dunlop +46 位作者 C.Forsyth K.Oksavik E.Donovon A.Kavanagh S.E.Milan T.Sergienko R.C.Fear D.G.Sibeck M.Connors T.Yeoman X.Tan M.G.G.T.Taylor K.McWilliams J.Gjerloev R.Barnes D.D.Billet G.Chisham A.Dimmock M.P.Freeman D.-S.Han M.D.Hartinger S.-Y.W.Hsieh Z.-J.Hu M.K.James L.Juusola K.Kauristie E.A.Kronberg M.Lester J.Manuel J.Matzka I.McCrea Y.Miyoshi J.Rae L.Ren F.Sigernes E.Spanswick K.Sterne A.Steuwer T.Sun M.-T.Walach B.Walsh C.Wang J.Weygand J.Wild J.Yan J.Zhang Q.-H.Zhang 《Earth and Planetary Physics》 EI CAS CSCD 2024年第1期275-298,共24页
The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplane... The joint European Space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere ionosphere.Combining these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE mission.Here,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working Group,is facilitating these efforts.Preparations include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft conjunctions.We anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community. 展开更多
关键词 magnetosphere ionosphere magnetosphere-ionosphere coupling ground-based experimentation SMILE conjunctions missions
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Pose Estimation of Space Targets Based on Model Matching for Large-Aperture Ground-Based Telescopes 认领 引用 被引量：2
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作者 Zhengwei Li Jianli Wang +2 位作者 Tao Chen Bin Wang Yuanhao Wu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2018年第11期271-286,共16页
With the development of adaptive optics and post restore processing techniques,large aperture ground-based telescopes can obtain high-resolution images(HRIs)of targets.The pose of the space target can be estimated fro... With the development of adaptive optics and post restore processing techniques,large aperture ground-based telescopes can obtain high-resolution images(HRIs)of targets.The pose of the space target can be estimated from HRIs by several methods.As the target features obtained from the image are unstable,it is difficult to use existing methods for pose estimation.In this paper a method based on real-time target model matching to estimate the pose of space targets is proposed.First,the physicallyconstrained iterative deconvolution algorithm is used to obtain HRIs of the space target.Second,according to the 3D model,the ephemeris data,the observation time of the target,and the optical parameters of the telescope,the simulated observation image of the target in orbit is rendered by a scene simulation program.Finally,the target model searches through yaw,pitch,and roll until the correlation between the simulated observation image and the actual observation image shows an optimal match.The simulation results show that the proposed pose estimation method can converge to the local optimal value with an estimation error of about 1.6349°. 展开更多
关键词 Ground-based telescope pose estimation correlation matching space target image restoration
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Long-term gravity changes in Chinese mainland from GRACE and ground-based gravity measurements 认领 引用 被引量：3
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作者 Xing Lelin Li Hui +2 位作者 Xuan Songbai Kang Kaixuan Liu Xiaoling 《Geodesy and Geodynamics》 EI 2011年第3期61-70,共10页
A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-sca... A long-term （9 years） gravity change in Chinese mainland is obtained on the basis of observation of the ground-based national gravity network. The result shows several features that may be related to sore, large-scale groundwater pumping in North China, glacier-water flow and storage in Tianshan region, and pre seismic gravity changes of the 2008 MsS. 0 Wenchuan earthquake, which are spatially similar to co-seismi, changes but reversed in sign. These features are also shown in the result of the satellite-based GRACE obser vation, after a height effect is corrected with GPS data. 展开更多
关键词 GRACE ground-based gravity measurement mass distribution earthquake
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Ground-Based Atmospheric CO2,CH4,and CO Column Measurements at Golmud in the Qinghai-Tibetan Plateau and Comparisons with TROPOMI/S5P Satellite Observations 认领 引用 被引量：2
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作者 Minqiang ZHOU Qichen NI +7 位作者 Zhaonan CAI Bavo LANGEROCK Jingyi JIANG Ke CHE Jiaxin WANG Weidong NAN Yi LIU Pucai WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2023年第2期223-234,共12页
Measurements of carbon dioxide(CO2),methane(CH4),and carbon monoxide(CO)are of great importance in the Qinghai-Tibetan region,as it is the highest and largest plateau in the world affecting global weather and cl... Measurements of carbon dioxide(CO2),methane(CH4),and carbon monoxide(CO)are of great importance in the Qinghai-Tibetan region,as it is the highest and largest plateau in the world affecting global weather and climate systems.In this study,for the first time,we present CO2,CH4,and CO column measurements carried out by a Bruker EM27/SUN Fourier-transform infrared spectrometer(FTIR)at Golmud(36.42°E,94.91°N,2808 m)in August 2021.The mean and standard deviation of the column-average dry-air mixing ratio of CO2,CH4,and CO(XCO2,XCH4,and XCO)are 409.3±0.4 ppm,1905.5±19.4 ppb,and 103.1±7.7 ppb,respectively.The differences between the FTIR co-located TROPOMI/S5P satellite measurements at Golmud are 0.68±0.64%(13.1±12.2 ppb)for XCH4and 9.81±3.48%(–10.7±3.8 ppb)for XCO,which are within their retrieval uncertainties.High correlations for both XCH4and XCO are observed between the FTIR and S5P satellite measurements.Using the FLEXPART model and satellite measurements,we find that enhanced CH4and CO columns in Golmud are affected by anthropogenic emissions transported from North India.This study provides an insight into the variations of the CO2,CH4,and CO columns in the Qinghai-Tibetan Plateau. 展开更多
关键词 Ground-based FTIR greenhouse gas remote sensing TROPOMI/S5P Qinghai-Tibetan Plateau
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Seismic Noise Suppression for Ground-Based Investigation of an Inertial Sensor by Suspending the Electrode Cage 认领 引用 被引量：8
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作者 谭定银 尹航 周泽兵 《Chinese Physics Letters》 SCIE EI CAS CSCD 2015年第9期9-12,共4页
Performance test of a high precise accelerometer or an inertial sensor on the ground is inevitably limited by the seismic noise. A torsion pendulum has been used to investigate the performances of an electrostatic acc... Performance test of a high precise accelerometer or an inertial sensor on the ground is inevitably limited by the seismic noise. A torsion pendulum has been used to investigate the performances of an electrostatic accelerometer, where the test mass is suspended by a fiber to compensate for its weight, and this scheme demonstrates an advantage, compared with the high-voltage levitation scheme, in which the effect of the seismic noise can be suppressed for a few orders of magnitude in low frequencies. In this work, the capacitive electrode cage is proposed to be suspended by another pendulum, and theoretical analysis shows that the effects of the seismic noise can be further suppressed for more than one order by suspending the electrode cage. 展开更多
关键词 length Seismic Noise Suppression for Ground-Based Investigation of an Inertial Sensor by Suspending the Electrode Cage
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An approach to wide-field imaging of linear rail ground-based SAR in high squint multi-angle mode 认领 引用 被引量：3
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作者 ZHANG Yuan ZHANG Qiming +4 位作者 WANG Yanping LIN Yun LI Yang BAI Zechao LI Fang 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2020年第4期722-733,共12页
Ground-based synthetic aperture radar(GB-SAR) has been successfully applied to the ground deformation monitoring.However, due to the short length of the GB-SAR platform, the scope of observation is largely limited. Th... Ground-based synthetic aperture radar(GB-SAR) has been successfully applied to the ground deformation monitoring.However, due to the short length of the GB-SAR platform, the scope of observation is largely limited. The practical applications drive us to make improvements on the conventional linear rail GB-SAR system in order to achieve larger field imaging. First, a turntable is utilized to support the rotational movement of the radar.Next, a series of high-squint scanning is performed with multiple squint angles. Further, the high squint modulation phase of the echo data is eliminated. Then, a new multi-angle imaging method is performed in the wave number domain to expand the field of view. Simulation and real experiments verify the effectiveness of this method. 展开更多
关键词 ground-based synthetic aperture radar(GB-SAR) high squint multi-angle
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0-10 KM TEMPERATURE AND HUMIDITY PROFILES RETRIEVAL FROM GROUND-BASED MICROWAVE RADIOMETER 认领 引用 被引量：3
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作者 BAO Yan-song CAI Xi +3 位作者 QIAN Cheng MIN Jin-zhong LU Qi-feng ZUO Quan 《Journal of Tropical Meteorology》 SCIE 2018年第2期243-252,共10页
Deviation exists between measured and simulated microwave radiometer sounding data. The bias results in low-accuracy atmospheric temperature and humidity profiles simulated by Back Propagation artificial neural networ... Deviation exists between measured and simulated microwave radiometer sounding data. The bias results in low-accuracy atmospheric temperature and humidity profiles simulated by Back Propagation artificial neural network models. This paper evaluated a retrieving atmospheric temperature and humidity profiles method by adopting an input data adjustment-based Back Propagation artificial neural networks model. First, the sounding data acquired at a Nanjing meteorological site in June 2014 were inputted into the Mono RTM Radiative transfer model to simulate atmospheric downwelling radiance at the 22 spectral channels from 22.234 GHz to 58.8 GHz, and we performed a comparison and analysis of the real observed data; an adjustment model for the measured microwave radiometer sounding data was built. Second, we simulated the sounding data of the 22 channels using the sounding data acquired at the site from 2011 to 2013. Based on the simulated rightness temperature data and the sounding data, BP neural network-based models were trained for the retrieval of atmospheric temperature, water vapor density and relative humidity profiles. Finally, we applied the adjustment model to the microwave radiometer sounding data collected in July 2014, generating the corrected data. After that, we inputted the corrected data into the BP neural network regression model to predict the atmospheric temperature, vapor density and relative humidity profile at 58 high levels from 0 to 10 km. We evaluated our model's effect by comparing its output with the real measured data and the microwave radiometer's own second-level product. The experiments showed that the inversion model improves atmospheric temperature and humidity profile retrieval accuracy; the atmospheric temperature RMS error is between 1 K and 2.0 K; the water vapor density's RMS error is between 0.2 g/m^3 and 1.93 g/m3; and the relative humidity's RMS error is between 2.5% and 18.6%. 展开更多
关键词 ground-based microwave radiometer BP neural network atmospheric profiles regression accuracy
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Trends in gravity changes from 2009 to 2013 derived from ground-based gravimetry and GRACE data in North China 认领 引用 被引量：4
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作者 Shen Chongyang Xuan Songbai +1 位作者 Zou Zhengbo Wu Guiju 《Geodesy and Geodynamics》 2015年第6期423-428,共6页
North China is a key region for studying geophysical progress. In this study, ground-based and Gravity Recovery and Climate Experiment（GRACE） gravity data from 2009 to 2013 are used to calculate the gravity change r... North China is a key region for studying geophysical progress. In this study, ground-based and Gravity Recovery and Climate Experiment（GRACE） gravity data from 2009 to 2013 are used to calculate the gravity change rate（GCR） using the polynomial fitting method. In general, the study area was divided into the Shanxi rift, Jing-Jin-Ji（Beijing-Tianjin-Hebei Province）, and Bohai Bay Basin（BBB） regions. Results of the distribution of the GCR determined from ground-based gravimetry show that the GCR appears to be ＂negativepositive-negative＂ from west to east, which indicates that different geophysical mechanisms are involved in the tectonic activities of these regions. However, GRACE solutions are conducted over a larger spatial scale and are able to show a difference between southern and northern areas and a mass redistribution of land water storage. 展开更多
关键词 North China Ground-based gravimetry Gravity Recovery and Climate Experiment（GRACE） Polynomial fitting method Gravity changes rate Tectonic activities Geophysical mechanisms Mass redistribution
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Ground-based remote sensing of atmospheric total column CO_2 and CH_4 by direct sunlight in Hefei 认领 引用 被引量：1
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作者 程巳阳 徐亮 +6 位作者 高闽光 李胜 金岭 童晶晶 魏秀丽 刘建国 刘文清 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第12期563-569,共7页
Fourier transform spectrometry has played an important role in the three-dimensional greenhouse gas monitoring as the focus of attention on global warming in the past few years. In this paper, a ground-based low-resol... Fourier transform spectrometry has played an important role in the three-dimensional greenhouse gas monitoring as the focus of attention on global warming in the past few years. In this paper, a ground-based low-resolution remote sensing system measuring the total columns of CO2 and CH4 is developed, which tracks the sun automatically and records the spectra in real-time and has the advantages of portability and low cost. A spectral inversion algorithm based on nonlinear least squares spectral fitting procedure for determining the column concentrations of these species is described. Atmospheric transmittance spectra are computed line-by-line in the forward model and observed on-line by direct solar radiation. Also, the wavelength shifts are introduced and the influence of spectral resolution is discussed. Based on this system and algorithm, the vertical columns of O2, CO2, and CH4 are calculated from total atmospheric observation transmittance spectra in Hefei, and the results show that the column averaged dry-air mole fractions of CO2 and CH4 are measured with accuracies of 3.7% and 5%, respectively. Finally, the H2O columns are compared with the results observed by solar radiometer at the same site and the calculated correlation coefficient is 0.92, which proves that this system is suitable for field campaigns and used to monitor the local greenhouse gas sources under the condition of higher accuracy, indirectly. 展开更多
关键词 carbon dioxide methane ground-based remote sensing solar absorption spectroscopy
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Time-varying baseline error correction method for ground-based micro-deformation monitoring radar 认领 引用
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作者 LEI Tianjie WANG Jiabao +4 位作者 HUANG Pingping TAN Weixian QI Yaolong XU Wei ZHAO Chun 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2022年第4期938-950,共13页
In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, gr... In recent years, ground-based micro-deformation monitoring radar has attracted much attention due to its excellent monitoring capability. By controlling the repeated campaigns of the radar antenna on a fixed track, ground-based micro-deformation monitoring radar can accomplish repeat-pass interferometry without a space baseline and thus obtain highprecision deformation data of a large scene at one time. However, it is difficult to guarantee absolute stable installation position in every campaign. If the installation position is unstable, the stability of the radar track will be affected randomly, resulting in time-varying baseline error. In this study, a correction method for this error is developed by analyzing the error distribution law while the spatial baseline is unknown. In practice, the error data are first identified by frequency components, then the data of each one-dimensional array(in azimuth direction or range direction) are grouped based on numerical distribution period, and finally the error is corrected by the nonlinear model established with each group.This method is verified with measured data from a slope in southern China, and the results show that the method can effectively correct the time-varying baseline error caused by rail instability and effectively improve the monitoring data accuracy of groundbased micro-deformation radar in short term and long term. 展开更多
关键词 ground-based micro-deformation monitoring radar deformation monitoring time-varying baseline error compensation
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Constrained geometry analysis to resolve 3-D deformations from three ground-based radars 认领 引用
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作者 DENG Yunkai ZHU Jiaxin +2 位作者 TIAN Weiming HU Cheng YANG Wenyu 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2021年第6期1263-1269,共7页
When multiple ground-based radars(GB-rads)are utilized together to resolve three-dimensional(3-D)deformations,the resolving accuracy is related with the measurement geometry constructed by these radars.This paper focu... When multiple ground-based radars(GB-rads)are utilized together to resolve three-dimensional(3-D)deformations,the resolving accuracy is related with the measurement geometry constructed by these radars.This paper focuses on constrained geometry analysis to resolve 3-D deformations from three GB-rads.The geometric dilution of precision(GDOP)is utilized to evaluate 3-D deformation accuracy of a single target,and its theoretical equation is derived by building a simplified 3-D coordinate system.Then for a 3-D scene,its optimal accuracy problem is converted into determining the minimum value of an objective function with a boundary constraint.The genetic algorithm is utilized to solve this constrained optimization problem.Numerical simulations are made to validate the correctness of the theoretical analysis results. 展开更多
关键词 three-dimensional(3-D)deformation ground-based radar(GB-rad) constrained geometry geometric dilution of precision(GDOP) accuracy evaluation
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