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Automatic detection of Cyanobacterial blooms using multi-source optical satellite imagery: method development and application

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Ecological Indicators 2025年 176卷

作者： Hailong Zhang Chen Lu Deyong Sun Xiaomin Ye Shengqiang Wang Quan Qin State Key Laboratory of Climate System Prediction and Risk Management Nanjing University of Information Science and Technology Nanjing 210044 China Key Laboratory of Coastal Zone Exploitation and Protection Ministry of Natural Resources Nanjing 210017 China School of Marine Sciences Nanjing University of Information Science and Technology Nanjing 210044 China Key Laboratory of Space Ocean Remote Sensing and Application Ministry of Natural Resources Beijing 100081 China Shandong Provincial Climate Center Jinan 250031 China

Cyanobacterial blooms (CyanoBloom) are a widespread environmental concern in lakes, and optical satellite imagery has been widely used to monitor their spatiotemporal dynamics. Many spectral-based CyanoBloom detection methods rely on Rayleigh- or atmosphere-corrected surface reflectance. However, these methods require ancillary atmospheric data and preprocessing procedures, thereby limiting their operational efficiency and scalability. The potential of multi-source satellite imagery remains underexploited due to the lake of robust methods for automatic CyanoBloom detection across various satellite platforms. To address this challenge, we proposed a novel automatic CyanoBloom detection (ACD) method that directly utilizes satellite top-of-atmosphere reflectance ( R TOA ) data. Cross-index and cross-sensor analyses confirmed the high detection accuracy and robustness of the ACD method against atmospheric and observational variations. The method was successfully applied to various inland lakes, including Lake Taihu, Lake Chaohu, Lake Dianchi, and Lake Xingyun in China, Lake Okeechobee in the United States, and Lough Neagh in Northern Ireland. Requiring only for four spectral bands (blue, green, red, and near-infrared), the ACD method was compatible with various optical sensors, including HY1C/D-CZI, GF-WFV, GF4-PMS, HJ-CCD, Sentinel2-MSI, Landsat9-OLI, and Terra-MODIS. This study presents a novel automatic and rapid approach for detecting CyanoBloom in lakes, providing valuable technical support for water quality monitoring and bloom management.

关键词： Cyanobacterial bloom Automatic detecting Satellite R TOA Optical satellite imagery

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Better Modeling the Hierarchical Structure of Language for Sentence Semantic Matching

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Journal of Physics: Conference Series 2020年第1期1651卷

作者： Zhongmin Pei Changqun Li Wei Xiong Zhangkai Luo Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing 100014 China

Sentence semantic matching requires understanding the semantic relationship between two sentences, which is widely used in various natural language tasks such as paraphrase identification, natural language inference and question answering. Usually, the underlying structure of sentence is not strictly sequential, this structure is hierarchical. This paper studies how to better model the hierarchical structure of sentence for semantic matching. Recent research suggests that BERT implicitly captures classical, tree-like structures. Based on this, this paper proposes to further enhance the strength of modeling hierarchical structure of language with an advanced variant of LSTM – Ordered Neurons LSTM(ON-LSTM), which introduces a syntax-oriented inductive bias to perform the composition of classical tree structure. Experimental results demonstrate that the proposed approach, which enhances hierarchical structure of language, significantly improves the performance of sentence semantic matching.

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A location method for ground moving target with azimuth spectrum aliasing in Geosynchronous spaceborne-Airborne Bistatic multichannel SAR

A location method for ground moving target with azimuth spec...

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Signal, Information and Data Processing (ICSIDP), IEEE International Conference on

作者： Ying Zhang Wei Xiong Xichao Dong Cheng Hu Chengxiang Liu Yang Sun Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China Key Laboratory of Electronic and Information Technology in Satellite Navigation (Beijing Institute of Technology) Ministry of Education Beijing China

ISBN: (数字)9781728123455

ISBN: (纸本)9781728123462

Geosynchronous spaceborne-Airborne Bistatic multichannel SAR (GEO-SABM SAR) maintains the fine temporal sampling and wide coverage characteristics of monostatic GEO SAR. But due to the PRF of GEO platform is very low, azimuth spectrum aliasing (ASA) will occur in GEO-SABM SAR which will make a moving target divided into several sub-targets. In this paper, a location method for ground moving target with ASA has given. From the simulation results, the moving target can be discriminated and located.

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Research on vulnerability of space information network based on interdependent networks 3

Research on vulnerability of space information network based...

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3rd IEEE International Conference on Data science in Cyberspace, DSC 2018

作者： Zhao, Zhongwen Li, Zhangyuan Guo, Huanghuang Yang, Miaoben Space Engineering University Science and Technology On Complex Electronic System Simulation Laboratory Beijing China 63710 troops Taiyuan China

ISBN: (纸本)9781538642108

With the development and growing applications of information technology, the coupling and dependency of space information network are becoming more and more intense. In this paper, the vulnerability of space information network coupled with the communication network and function network is studied. Aiming at the shortage of traditional attack model, we put forward physical-attack and cyber-attack and set up different attack strategies such as random attack, targeted attack and gray attack. The concept of combat component is proposed and the cascading failure algorithm is given. The simulation shows that compared with traditional single network model, the interdependent network model based on the combat component can more accurately reflect the cascading failure mechanism of the space information network. This research results can provide guidance for space information network security research and invulnerability design. © 2018 IEEE.

关键词： Network security

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Design and modeling of satellite network structure for business scenarios

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Journal of Physics: Conference Series 2020年第1期1684卷

作者： Lintao Ren Zhongmin Pei Wei Xiong Zhangkai Luo Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing 101416 China

In view of the actual decentralized development of the satellite service constellation and the trend of space-ground integrated information network, based on the idea of clustering, methodology of complex network community structure, a business scenario-oriented satellite network structure is designed. On the one hand, it reflects the different separation and integration of satellite constellations in business scenarios. On the other hand, the 'head node' mechanism is introduced to be responsible for the interaction between constellation in different business scenarios. The satellite network structure is modeled using the growth and priority connection mechanism, and through computational derivation and simulation validation, the scale-free characteristics of the satellite network are revealed. Finally, through the simulation experiments on different satellite network parameters, the effect of different parameters on the static geometry, network efficiency, etc., are obtained. The influence of the law of the network will provide theoretical and methodological reference for the design of satellite network structure.

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Early- And in-season crop type mapping without current-year ground truth: generating labels from historical information via a topology-based approach

arXiv

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arXiv 2021年

作者： Lin, Chenxi Zhong, Liheng Song, Xiao-Peng Dong, Jinwei Lobell, David B. Jin, Zhenong Department of Bioproducts and Biosystems Engineering University of Minnesota Twin Cities St PaulMN United States Ant Group Beijing China Department of Geosciences Texas Tech University LubbockTX United States Key Laboratory of Land Surface Pattern and Simulation Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Department of Earth System Science Center on Food Security and the Environment Stanford University StanfordCA United States

Land cover classification in remote sensing is often faced with the challenge of limited ground truth labels. Incorporating historical ground information has the potential to significantly lower the expensive cost associated with collecting ground truth and, more importantly, enable early- and in-season mapping that is helpful to many pre-harvest decisions. In this study, we propose a new approach that can effectively transfer knowledge about the topology (i.e. relative position) of different crop types in the spectral feature space (e.g. the histogram of SWIR1 vs RDEG1 bands) to generate labels, thereby support crop classification in a different year. Importantly, our approach does not attempt to transfer classification decision boundaries that are susceptible to inter-annual variations of weather and management, but relies on the more robust and shift-invariant topology information. We tested this approach for mapping corn/soybeans in the US Midwest and paddy rice/corn/soybeans in Northeast China using Landsat-8 and Sentinel-2 data. Results show that our approach automatically generates high-quality labels for crops in the target year immediately after each image becomes available. Based on these generated labels from our approach, the subsequent crop type mapping using a random forest classifier can reach the F1 score as high as 0.887 for corn as early as the silking stage and 0.851 for soybean as early as the flowering stage and the overall accuracy of 0.873 in the test state of Iowa. In Northeast China, F1 scores of paddy rice, corn and soybeans and the overall accuracy can exceed 0.85 two and half months ahead of harvest. Overall, these results highlight unique advantages of our approach in transferring historical knowledge and maximizing the timeliness of crop maps. Our approach supports a general paradigm shift towards learning transferrable and generalizable knowledge to facilitate land cover classification. © 2021, CC BY-NC-ND.

关键词： Remote sensing

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Fusion of panchromatic and multispectral images via morphological operator and improved PCNN in mixed multiscale domain 10

Fusion of panchromatic and multispectral images via morpholo...

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10th IAPR Workshop on Pattern Recognition in Remote Sensing, PRRS 2018

作者： Jiao, Jiao Lingda, Wu Department of Graduate Management Space Engineering University Beijing China Simulation Laboratory Space Engineering University Science and Technology on Complex Electronic System Beijing China

ISBN: (纸本)9781538684795

In order to effectively combine the spectral information of the multispectral (MS) image with the spatial details of the panchromatic (PAN) image and improve the fusion quality, a fusion method based on morphological operator and improved pulse coupled neural network (PCNN) in mixed multi-scale (MM) domain is proposed. Firstly, the MS and PAN images are decomposed by nonsubsampled shearlet transform (NSST) to low- and high-frequency coefficients, respectively;secondly, morphological filter-based intensity modulation (MFIM) technology and stationary wavelet transform (SWT) are applied to the fusion of the low-frequency coefficients;an improved PCNN model is employed to the fusion of the high-frequency coefficients;thirdly, the final coefficients are reconstructed with inverse NSST. The experimental results on QuickBird satellite demonstrate that the proposed method is superior to five other kinds of traditional and popular methods: HIS, PCA, SWT, NSCT-PCNN and NSST-PCNN. The proposed method can improve the spatial resolution effectively while maintaining the spectral information well. The experimental results show that the proposed method outperforms the other methods in visual effect and objective evaluations. © 2018 IEEE.

关键词： Image fusion

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Radio dimming associated with filament eruptions in the meter and decimeter wavebands

arXiv

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arXiv 2025年

作者： Hou, Zhenyong Tian, Hui Yan, Jingye Madjarska, Maria S. Zhang, Jiale Xu, Yu Chen, Hechao Wu, Zhao Wu, Lin Lv, Xuning Yang, Yang Liu, Yujie Deng, Li Feng, Li Qiu, Ye School of Earth and Space Sciences Peking University Beijing100871 China Key Laboratory of Space Weather Chinese Academy of Sciences Beijing100871 China National Space Science Center Chinese Academy of Sciences Beijing100871 China Chengdu610041 China Korea Astronomy and Space Science Institute Daejeon34055 Korea Republic of Max Planck Institute for Solar System Research Justus-von-Liebig-Weg 3 Göttingen37077 Germany Space Research and Technology Institute Bulgarian Academy of Sciences Acad. Georgy Bonchev Str. Bl. 1 Sofia1113 Bulgaria School of Physics and Astronomy Yunnan University Kunming650050 China School of Space Science and technology Shandong University Weihai264209 China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory CAS Nanjing210023 China School of Astronomy and Space Science Nanjing University Nanjing210023 China

Filament eruptions are considered to be a common phenomenon on the Sun and other stars, yet they are rarely directly imaged in the meter and decimeter wavebands. Using imaging data from the DAocheng solar Radio Telescope (DART) in the 150–450 MHz frequency range, we present two eruptive filaments that manifest as radio dimmings (i.e., emission depressions). Simultaneously, portions of these eruptive filaments are discernible as dark features in the chromospheric images. The sun-as-a-star flux curves of brightness temperature, derived from the DART images, exhibit obvious radio dimmings. The dimming depths range from 1.5% to 8% of the background level and show a negative correlation with radio frequencies and a positive correlation with filament areas. Our investigation suggests that radio dimming is caused by free-free absorption during filament eruptions obscuring the solar corona. This may provide a new method for detecting stellar filament eruptions. Copyright © 2025, The Authors. All rights reserved.

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Robustness and orthogonality: Time series forecasting via wavelets

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Information sciences 2025年 717卷

作者： Tian, Yingjie Zhao, Siyu Zhang, Xingyu School of Economics and Management University of Chinese Academy of Sciences Beijing100190 China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing100049 China School of Computer Science and Technology University of Chinese Academy of Sciences Beijing101408 China Research Center on Fictitious Economy and Data Science Chinese Academy of Sciences Beijing100190 China Key Laboratory of Big Data Mining and Knowledge Management Chinese Academy of Sciences Beijing100190 China National Key Laboratory of Space Integrated Information System Institute of Software Chinese Academy of Sciences Beijing100190 China

Time series forecasting (TSF) is an important issue that spans various fields in daily life. With advancements in deep learning, numerous TSF methods have been developed leveraging both time and frequency domain characteristics of time series data. However, existing TSF methods primarily concentrate on data characteristics, yet which key property truly enhances model performance has not been thoroughly explored. Especially, for frequency domain-based methods, the reliance on stringent assumptions like the Linear Time-Invariant (LTI) system limits their applicability to non-stationary time series data. To address these issues, this paper introduces a novel TSF method called Robust Orthogonal decomposition via Wavelets (ROW). ROW employs wavelet transform to remove reliance on LTI assumptions and can capture local characteristics. Furthermore, this paper provides robustness analysis of ROW, i.e., the impact of orthogonal wavelet basis functions on model robustness. Through two examples, we illustrate that the robustness constant of ROW has a tighter upper bound under orthogonal wavelet basis, which indicates that ROW is more robust under perturbations. Experimental results also validate the effectiveness and robustness of ROW compared to existing methods. © 2025 Elsevier Inc.

关键词： Wavelet decomposition

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Researchment of Mainlobe Anti-jamming Algorithms

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Journal of Physics: Conference Series 2020年第1期1673卷

作者： Zhangkai Luo Zhongmin Pei Yinan Li Xinmin Wang Bo Zou Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing 101400 China.

Main lobe interferences usually cause the distortion and peak offset of main lobe and the heighten of side lobe level in adaptive beamformers. The block matrix algorithm utilized the direction vector which was determined by both the antenna arrays and the direction of interference to eliminate the main lobe interference. But this algorithms is sensitive to the error occurred in the interference arrive angle and would consume the array of degrees of freedom. In this paper a new algorithm is proposed which projects the receive signal into a space which is orthogonal to the signal subspace to achieve the goal. The space can get by three steps. Frist we obtain eigenvalues by the decomposition of the covariance matrix of the snapshots to evaluate the noise power. Then we get a new matrix by removing the noise from the covariance matrix of the snapshots. At last we get the target space by conducting the singular value decomposition to the new matrix. Performance is mainly assessed in terms of the beamforming gain and the signal to interference and noise (SINR) ratio. The computer simulation shows the effective of this method.

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