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The largest CPIES array in the marginal sea:abundant dynamics in the northeast South China Sea

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Acta Oceanologica Sinica 2024年第1期43卷 135-137页

作者： Hua Zheng Xiao-Hua Zhu Min Wang Ruixiang Zhao Chuanzheng Zhang Feng Nan Fei Yu institute of Polar and Ocean Technology Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China State Key Laboratory of satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China National Marine Environmental Monitoring Center Dalian 116023China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China Laboratory for Ocean and Climate Dynamics Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

The South China Sea(SCS)is a marginal sea connecting the Pacific and Indian oceans and has gained much attention in recent *** dynamics in the northeast SCS are considerably influenced by topography,monsoons,tropical ... 详细信息

关键词： northeast marginal abundant

A Study on Height Reassignment for the AMV Products of the FY-2C satellite

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Acta meteorologica Sinica 2012年第5期26卷 614-628页

作者：杨成荫陆其峰张鹏 meteorology institute PLA University of Science and Technology Harbin Air Force Flight Academy National satellite Meteorological Center

A method for using height reassignment to improve the quality of satellite-derived atmospheric motion vectors （AMVs） is presented. The rationale underlying height reassignment is explored, and the technical details are studied by applying three height reassignment schemes that use NCEP reanalysis winds. The quality of the AMVs is generally improved following reassignment, although the magnitude of the improve- ment differs according to the scheme applied. Scheme 3 provides the best quality and stability, followed by Scheme 1 and Scheme 2. The negative biases in the zonal components of the AMVs decrease from [ 5, 4] m s^-1 to 〈- 1 m s 1 following reassignment. The meridional components also improve. The AMVs derived from the infrared and water vapor channels improve by 58.7% and 25%, respectively, The feasibility of using Scheme 3 in the operational derivation of AMVs is studied by incorporating the forecast wind field predicted by a T511 medium-range numerical weather prediction （NWP） system. Incorporating the 12-h forecast reduces the negative biases in zonal winds and positive biases in meridional winds retrieved from the water vapor channel, improving the overall quality of the AMVs by 26.7%. Extending the validity period of the forecast field linearly reduces the improvement in retrieved AMVs, but the magnitude of this reduction is small. Incorporating the 120-h forecast field still results in a 13% improvement, although it may eliminate a larger number of AMVs of good quality.

关键词： AMV height reassignment the wind field of NWP quality control

High-precision analytical solutions for Earth coverage of constellation equipped with reentry glide vehicles

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Chinese Journal of Aeronautics 2024年第9期37卷 385-398页

作者： Ping MA Weibo SUN Jie GAO Tao CHAO Control and Simulation Center Harbin Institute of TechnologyHarbin 150001China Beijing institute of Spacecraft System Engineering Beijing 100094China

To efficiently and accurately design satellite constellations equipped with Reentry Glide Vehicles(RGVs),new analytical solutions are developed for calculating their coverage ***,a new coverage model is established by approximating the Reentry Reachable Domain(RRD).However,the computation of real-time relative distances between satellites and targets,which is essential for coverage analysis based on this model,imposes a significant compu-tational *** address this challenge,a coverage analysis method based on two-dimensional map theory is *** method represents the coverage conditions of a target as a fixed area on a two-dimensional map and transforms the satellite trajectory into a series of parallel *** determining the intersection points between these lines and the area boundaries,the coverage ana-lytical solutions for a target point are *** this basis,coverage theorems are presented for rapid calculation of the constellation coverage performance for an *** results demon-strate the effectiveness and high precision of the proposed analytical solutions.

关键词： Constellation Analytical solutions Reentry glide vehicle Reentry reachable domain Two-dimensional map

中新世气候适宜期构造运动加速全球海洋碳循环

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Science Bulletin 2024年第6期69卷 823-832页

作者：刘丰豪杜金龙黄恩清马文涛马小林 Lucas J.Lourens 田军 State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China State Key Laboratory of satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China Department of Earth Sciences Faculty of GeosciencesUtrecht UniversityUtrecht CB 3584Netherlands

Global warming during the Miocene Climate Optimum(MCO,~17-14 million years ago)is associated with massive carbon emissions sourced from the flood basalt volcanism and ocean crustal ***,the perturbation of tectonic carbon degassing on the interaction between climate change and carbon cycle remains ***,through time-evolutive phase analysis of new and published high-resolution benthic foraminiferal oxygen(δ^(18)O)and carbon(δ^(13)C)isotope records from the global ocean,we find that variations in the marine carbon cycle lead the climate-cryosphere system(δ^(13)Clead-δ^(18)O)on 405,000-year eccentricity timescales during the *** is in contrast to the previously reported climate-lead-carbon(δ^(18)O-lead-δ^(13)C)scenario during most of the Oligo-Miocene(~34-6 million years ago).Further sensitivity analysis and model simulations suggest that the elevated atmospheric CO_(2) concentrations and the resulting greenhouse effect strengthened the low-latitude hydrological cycle during the MCO,accelerating the response of marine carbon cycle to eccentricity *** climate processes played a more important role in regulating carbon-cycle variations when Earth's climate was in a warm regime,as opposed to the dominant influence of polar ice-sheet dynamics during the PlioPleistocene(after~6 million years ago).

关键词： Global warming Eccentricity cycle Carbon cycle Low-latitude hydrological cycle

Repeat-pass space-surface bistatic SAR tomography:accurate imaging and first experiment

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Science China(Information Sciences) 2024年第9期67卷 245-262页

作者： Zhiyang CHEN Yuanhao LI Cheng HU Shenglei WANG Xinpeng CHEN Mihai DATCU Andrea Virgilio MONTI-GUARNIERI Radar Technology Research institute School of Information and Electronics Beijing Institute of Technology Beijing Key Laboratory of Embedded Real-Time Information Processing Technology Beijing Institute of Technology Advanced Technology Research institute Beijing Institute of Technology CEOSpace Tech University Politehnica of Bucharest Dipartimento di Elettronica Informazione e Bioingegneria Politecnico di Milano

Space-surface bistatic synthetic aperture radar(SS-BiSAR) offers an additional observation angle for monostatic spaceborne SAR, making it a promising technology for high-accuracy deformation retrieval technology in local regions. Repeat-pass SS-BiSAR tomography can accurately estimate the surfaces of buildings and steep areas, effectively removing terrain phases during deformation retrieving. However, inaccuracies in the orbital ephemeris can lead to image geometry distortion, reducing image pair coherence,introducing interferometric phase errors, and consequently deteriorating tomographic precision. This paper precisely models the image geometry distortion and interferometric phase error caused by repeat-pass ephemeris error. We propose an ephemeris correction method based on the chirp-Z transform to address these issues. Furthermore, we introduce an accurate tomography model to improve 3D reconstruction *** first SS-BiSAR tomography experiment, conducted using the Chinese Lutan-1 satellite, demonstrates that the correlation coefficient is improved by 0.16 after ephemeris error correction. Moreover, the density and precision of the tomographic point cloud are improved by 13.7% and 12.1%, respectively.

关键词： space-surface SAR tomography orbit error image distortion Lutan-1

Absolute pose estimation of UAV based on large-scale satellite image

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Chinese Journal of Aeronautics 2024年第6期37卷 219-231页

作者： Hanyu WANG Qiang SHEN Zilong DENG Xinyi CAO Xiaokang Wang School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China Beijing institute of Technology Chongqing Innovation Center Chongqing 401120China

Obtaining absolute pose based on pre-loaded satellite images is one of the important means of autonomous navigation for small Unmanned Aerial Vehicles(UAVs)in Global Navigation satellite System(GNSS)denied *** of the previous works have tended to build Convolutional Neural Networks(CNNs)to extract features and then directly regress the pose,which will fail when solving the challenges caused by the huge viewpoint and size differences between“UAV-satellite”image pairs in real-world ***,this paper proposes a probability distribution/regression integrated deep model with the attention-guided triple fusion mechanism,which estimates discrete distributions in pose space and three-dimensional vectors in translation *** order to overcome the shortage of the relevant dataset,this paper simulates image datasets captured by UAVs with forward-facing cameras during target searching and autonomous *** effectiveness,superiority,and robustness of the proposed method are verified by simulated datasets and flight tests.

关键词： satellite imagery Unmanned Aerial Vehicle(UAV) Deep neural networks Vision navigation von Mises-Fisher distribution

Change in observed long-term greening across Switzerlandevidence from a three decades NDVI time-series and its relationship with climate and land cover factors

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Big Earth Data 2024年第1期8卷 1-32页

作者： Claire Obuchowicz Charlotte Poussin Gregory Giuliani institute for Environmental Sciences EnviroSPACE labUniversity of GenevaGenevaSwitzerland institute for Environmental Sciences University of GenevaGenevaSwitzerland

Environmental changes are significantly modifying terrestrial vegetation dynamics,with serious consequences on Earth system functioning and provision of ecosystem *** conditions are an essential element underpinning global sustainability frameworks,such as the Sustainable Development Goals(SDGs),requiring effective solutions to assess the impacts of changing land conditions induced by various driving *** the global scale,long-term increase of vegetation greening has been widely reported notably in seasonally snow-covered ecosystems as a response to warming ***,greening trends at the national scale have received less attention,although countries like Switzerland are prone to important changing climate ***,we used a 35-year satellite-derived annual and seasonal time-series of Normalized Difference Vegetation Index(NDVI)to assess vegetation greenness evolution at different spatial and temporal scales across Switzerland and related them to temperature,precipitation,and land cover to investigate possible responses of changing climatic *** indicate that there is a statistically significant greening trend at the national scale with an NDVI mean increasing slope of 0.6%/year for the 61%significant pixels across *** particular,the seasonal mean NDVI shows an important break for winter,autumn and spring seasons starting from 2010,potentially indicating a critical point of changing land *** biogeographical scale,we observed an apparent clustering(Jura-Plateau;Northern-Southern Alps;Eastern-Western Alps)related to landscape characteristics,while forested land cover classes are more responsive to NDVI ***,the NDVI values are mostly a function of temperature at elevations below the tree line rather than *** findings suggest that multi-annual and seasonal NDVI can be a valuable indicator to monitor vegetation conditions at different scales and can provide complementary observati

关键词： Landsat climate land cover NDVI anomaly

Filtering and regret network for spacecraft component segmentation based on gray images and depth maps

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Chinese Journal of Aeronautics 2024年第7期37卷 439-449页

作者： Xiang LIU Hongyuan WANG Zijian WANG Xinlong CHEN Weichun CHEN Zhengyou XIE institute of Aeronautics Harbin Institute of TechnologyHarbin 150001China Qian Xuesen Laboratory of Space Technology China Academy of Space TechnologyBeijing 100080China

Identifying and segmenting spacecraft components is vital in many on-orbit space missions,such as on-orbit maintenance and component *** depth maps with visual images has been proven effective in improving segmentation ***,existing methods ignore the noise and fallacy in collected depth maps,which interfere with the network to extract representative features,decreasing the final segmentation *** this end,this paper proposes a Filtering and Regret Network(FRNet)for spacecraft component *** FRNet incorporates filtering and regret mechanisms to suppress the abnormal depth response in shallow layers and selectively reuses the filtered cues in deep layers,avoiding the detrimental effects of low-quality depth information while preserving the semantic context inherent in depth ***,a two-stage feature fusion module is proposed,which involves information interaction and *** module effectively explores the feature correlation and unifies the multimodal features into a comprehensive ***,a large-scale spacecraft component recognition dataset is constructed for training and evaluating spacecraft component segmentation *** results demonstrate that the FRNet achieves a state-of-the-art performance with a mean Intersection Over Union(mIOU)of 84.13%and an average inference time of 133.2 ms when tested on an NVIDIA RTX 2080 SUPER GPU.

关键词： Spacecraft component recognition Multi-modal feature fusion satellite dataset Intelligent systems Deep learning

Spatiotemporal characteristics of water exchange between the Andaman Sea and the Bay of Bengal

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Acta Oceanologica Sinica 2024年第5期43卷 1-15页

作者： Yihao Wang Feng Zhou Xueming Zhu Ruijie Ye Yingyu Peng Zhentao Hu Haoran Tian Na Li Ocean College Zhejiang UniversityZhoushan 316021China State Key Laboratory of satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Observation and Research Station of Yangtze River Delta Marine Ecosystems Ministry of Natural ResourcesZhoushan 316022China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200240China School of Marine Sciences Sun Yat-sen UniversityZhuhai 519080China

A high-resolution customized numerical model is used to analyze the water transport in the three major water passages between the Andaman Sea(AS)and the Bay of Bengal,i.e.,the Preparis Channel(PC),the Ten Degree Channel(TDC),and the Great Channel(GC),based on the daily averaged simulation results ranging from 2010 to *** analysis and Empirical Orthogonal Function(EOF)methods are employed to investigate the spatiotemporal variability of the water exchange and controlling *** results of model simulation indicate that the net average transports of the PC and GC,as well as their linear trend,are opposite to that of the *** indicates that the PC and the GC are the main inflow channels of the AS,while the TDC is the main outflow channel of the *** transport variability is most pronounced at surface levels and between 100 m and 200 m depth,likely affected by monsoons and circulation.A 182.4-d semiannual variability is consistently seen in all three channels,which is also evident in their second principal *** on sea level anomalies and EOF analysis results,this is primarily due to equatorial winds during the monsoon transition period,causing eastward movement of Kelvin waves along the AS coast,thereby affecting the spatiotemporal characteristics of the flow in the *** first EOF of the PC flow field section shows a split at 100 m deep,likely due to *** first EOF of the TDC flow field section is steady but has potent seasonal oscillations in its time ***,the first EOF of the GC flow field section indicates a stable surface inflow,probably influenced by the equatorial Indian Ocean’s eastward current.

关键词： Andaman Sea water exchange Regional Ocean Modeling Systems(ROMS) Kelvin waves spatiotemporal characteristics