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Bidirectional Translations Between Observational and Topography-Based Hydrographic Data Sets: MERIT-Basins and the SWOT River Database (SWORD)

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Water Resources Research 2025年第5期61卷

作者： Jeffrey Wade Cédric H. David Elizabeth H. Altenau Elyssa L. Collins Hind Oubanas Stephen Coss Arnaud Cerbelaud Manu Tom Michael Durand Tamlin M. Pavelsky Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA Department of Earth Marine and Environmental Sciences University of North Carolina Chapel Hill NC USA Hydrological Sciences Laboratory NASA Goddard Space Flight Center Greenbelt MD USA Earth System Science Interdisciplinary Center University of Maryland College Park MD USA INRAE UMR G-eau Montpellier France School of Earth Sciences Ohio State University Columbus OH USA Byrd Polar and Climate Research Center Columbus OH USA

The recently launched Surface Water and Ocean Topography (SWOT) Mission is expected to provide transformative observations of water surface elevation, width, and slope and produce derived estimates of discharge for global rivers along rivers in the SWOT River Database (SWORD). However, the hydrographic representation of rivers in SWORD differs from hydrography data sets commonly used for modeling purposes, such as Multi-Error-Removed Improved Terrain (MERIT)-Basins. Here, we develop links between the river networks of SWORD and MERIT-Basins (MB) to enable interoperability between SWOT data products and hydrologic modeling frameworks. This data set, termed MERIT-SWORD, identifies a subset of ∼277,000 global MB river reaches that most closely represent the location and extent of the SWORD river network and establishes bidirectional, one-to-many translations between reaches in the two hydrographic data sets. The MERIT-SWORD data set serves to unite SWOT observations with river routing models, allowing for the seamless and standardized assimilation of SWOT vector products into global river simulations and the provision of improved a priori discharge estimates for SWOT discharge computation. Data transfer pathways between hydrographic networks enable interoperability between satellite observations and hydrologic models The Multi-Error-Removed Improved Terrain (MERIT)-SWOT River Database (SWORD) data set provides critical links between the SWORD and MERIT-Basins hydrographic networks MERIT-SWORD establishes global, bidirectional, one-to-many translations between ∼240,000 SWORD and ∼277,000 MB river reaches The Surface Water and Ocean Topography (SWOT) Mission observes the water surface elevation, width, and slope of river reaches described in the SWOT River Database (SWORD). The location and extent of rivers in SWORD differ considerably from other river network data sets that are commonly used for hydrological modeling such as Multi-Error-Removed Improved Terrain (MERIT)-

关键词： SWOT surface water hydrology satellite remote sensing hydrography MERIT-Basins SWORD

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A MAC Protocol Identification Approach Based on Convolutional Neural Network

A MAC Protocol Identification Approach Based on Convolutiona...

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International Conference on Wireless Communications and Signal Processing (WCSP)

作者： Xutong Zhang Weiguo Shen Jianliang Xu Zitong Liu Guoru Ding Colledge of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing China Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information Technology Science and Technology on Communication Information Security Control Laboratory No.36 Research Institute of CETC Jiaxing China College of Communication Engineering Army Engineering University Nanjing China

ISBN: (数字)9781728172361

ISBN: (纸本)9781728172378

The medium access control (MAC) protocol identification is of great application value in cognitive radio. In order to realize the MAC protocol identification with high accuracy and avoid manual feature extraction, we convert the sampled data into the form of spectrogram. Then, a graphical scheme which combines the convolutional neural network (CNN) and the spectrogram is proposed. The simulation includes CNN method and support vector machine (SVM) method. It is suggested that the CNN method has better identification performance.

关键词： Media Access Protocol Spectrogram Protocols Support vector machines Time division multiple access Feature extraction Cognitive radio

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How the area of solar coronal holes affects the properties of high-speed solar wind streams near Earth - I. An analytical model

arXiv

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arXiv 2022年

作者： Hofmeister, Stefan J. Asvestari, Eleanna Guo, Jingnan Heidrich-Meisner, Verena Heinemann, Stephan G. Magdalenic, Jasmina Poedts, Stefaan Samara, Evangelia Temmer, Manuela Vennerstrom, Susanne Veronig, Astrid Vršnak, Bojan Wimmer-Schweingruber, Robert Institute of Physics University of Graz Austria Columbia Astrophysics Laboratory Columbia University New York United States Leibniz Institut for Astrophysics Potsdam Germany Department of Physics University of Helsinki Finland Institute of Experimental and Applied Physics University of Kiel Germany CAS Key Laboratory of Geospace Environment University of Science and Technology of China Hefei China Max Planck Institute for Solar System Research Göttingen Germany Department of Mathematics KU Leuven Belgium Solar-Terrestrial Centre of Excellence - SIDC Royal Observatory of Belgium Brussels Belgium Institute of Physics University of Maria Curie-Sklodowska Lublin Poland DTU Space Copenhagen Denmark Kanzelhöhe Observatory for Solar and Environmental Research University of Graz Austria Hvar Observatory Faculty of Geodesy University of Zagreb Croatia

Since the 1970s, it is empirically known that the area of solar coronal holes affects the properties of high-speed solar wind streams (HSSs) at Earth. We derive a simple analytical model for the propagation of HSSs from the Sun to Earth, and thereby show how the area of coronal holes and the size of their boundary regions affect the HSS velocity, temperature, and density near Earth. We presume that velocity, temperature, and density profiles form across the HSS cross-section close to the Sun, and that these spatial profiles translate into corresponding temporal profiles in a given radial direction due to the solar rotation. These temporal distributions drive the stream interface to the preceding slow solar wind plasma, and disperse with distance from the Sun. The HSS properties at 1 AU are then given by all HSS plasma parcels launched from the Sun that did not impinge into the stream interface at Earth distance. We show that the velocity plateau region of HSSs as seen at 1 AU, if apparent, originates from the center region of the HSS close to the Sun, whereas the velocity tail at 1 AU originates from the trailing boundary region. The peak velocity of HSSs at Earth depends on the longitudinal width of the HSS close to the Sun. The shorter the longitudinal width of a HSS close to the Sun, the more of its'fastest' HSS plasma parcels from the HSS core and trailing boundary region have impinged into the stream interface to the preceding slow solar wind, and the smaller is the peak velocity of the HSS at Earth. As the longitudinal width is statistically correlated to the area of coronal holes, this explains also the well-known empirical relationship between coronal hole areas and HSS peak velocities. Further, the temperature and density of HSS plasma parcels at Earth depend on their radial expansion from the Sun to Earth. The radial expansion is determined by the velocity gradient across the HSS boundary region close to the Sun, and gives the velocity-temperature and dens

关键词： Velocity

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Global context aware RCNN for object detection

arXiv

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arXiv 2020年

作者： Zhang, Wenchao Fu, Chong Xie, Haoyu Zhu, Mai Tie, Ming Chen, Junxin School of Computer Science and Engineering Northeastern University Shenyang110819 China Engineering Research Center of Security Technology of Complex Network System Ministry of Education China Key Laboratory of Intelligent Computing in Medical Image Ministry of Education Northeastern University Shenyang110819 China Science and Technology on Space Physics Laboratory Beijing100076 China College of Medicine and Biological Information Engineering Northeastern University Shenyang110819 China

RoIPool/RoIAlign is an indispensable process for the typical two-stage object detection algorithm, it is used to rescale the object proposal cropped from the feature pyramid to generate a fixed size feature map. However, these cropped feature maps of local receptive fields will heavily lose global context information. To tackle this problem, we propose a novel end-to-end trainable framework, called Global Context Aware (GCA) RCNN, aiming at assisting the neural network in strengthening the spatial correlation between the background and the foreground by fusing global context information. The core component of our GCA framework is a context aware mechanism, in which both global feature pyramid and attention strategies are used for feature extraction and feature refinement, respectively. Specifically, we leverage the dense connection to improve the information flow of the global context at different stages in the top-down process of FPN, and further use the attention mechanism to refine the global context at each level in the feature pyramid. In the end, we also present a lightweight version of our method, which only slightly increases model complexity and computational burden. Experimental results on COCO benchmark dataset demonstrate the significant advantages of our approach. Copyright © 2020, The Authors. All rights reserved.

关键词： Object recognition

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Approaching the Fundamental Limit of Orbital Angular Momentum Multiplexing Through a Hologram Metasurface

arXiv

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arXiv 2021年

作者： Yuan, Shuai S.A. Wu, Jie Chen, Menglin L.N. Lan, Zhihao Zhang, Liang Sun, Sheng Huang, Zhixiang Chen, Xiaoming Zheng, Shilie Jiang, Li Jun Zhang, Xianmin Sha, Wei E.I. College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China Ministry of Education The Key Laboratory of Electromagnetic Environmental Sensing Department of Education of Anhui Province Anhui University Hefei230039 China Department of Electrical and Electronic Engineering The University of Hong Kong Hong Kong Department of Electronic and Electrical Engineering University College London Torrington Place LondonWC1E 7JE United Kingdom Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Hefei Normal University Hefei230601 China School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu611731 China School of Information and Communications Engineering Xi’an Jiaotong University Xi’an710049 China

Establishing and approaching the fundamental limit of orbital angular momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate the fundamental limit in terms of independent scattering channels (or the degrees of freedom of scattered fields) through angular-spectral analysis, in conjunction with a rigorous Green’s function method. The scattering-channel limit is universal for arbitrary spatial-mode multiplexing, which is launched by a planar electromagnetic device, such as antenna, metasurface, etc., with a predefined physical size. As a proof of concept, we demonstrate both theoretically and experimentally the limit by a phase-only metasurface hologram that transforms orthogonal OAM modes to plane-wave modes scattered at critically separated angular-spectral regions. Particularly, a minimax optimization algorithm is applied to suppress angular-spectrum aliasing, achieving good performances in both full-wave simulation and experimental measurement at microwave frequencies. This work offers a theoretical upper bound and corresponding approach route for engineering designs of OAM multiplexing. Copyright © 2021, The Authors. All rights reserved.

关键词： Spectrum analysis

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An evaluation method for network communication system efficiency based on multi-source information fusion 37

An evaluation method for network communication system effici...

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37th Chinese Control Conference, CCC 2018

作者： Yuan, Cao Yue-Ping, Wang Xue-Mei, Tang Xiao-Fang, Zhao Science and Technology on Complex Land Systems Simulation Laboratory Beijing100012 China Beijing Institute of Spacecraft System Engineering 100094 China

ISBN: (纸本)9789881563941

The number of experimental data obtained under different conditions is large, and there are some differences in the distribution characteristics of samples. If a large number of different types of data are mixed and the network communication Effectiveness evaluation is carried out, the characteristics of some samples may be drowned out, on the other hand, the information of many experimental samples is not fully utilized. In order to solve this problem, this paper proposes a method of network communication effectiveness evaluation based on multi-source information fusion. This method firstly analyzes the communication success rate of the cell communication node by longitudinal fusion of experimental information. Based on this, the confidence degree is used to construct the weighting coefficient, and the whole communication success rate of the network information system is evaluated by the experiment information of multiple nodes. Thus, the comprehensive evaluation of the communication efficiency of the unit node and the network Information system is realized. © 2018 Technical Committee on Control Theory, Chinese Association of Automation.

关键词： Efficiency

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Performance comparison of different approximation schemes in matrix MOC

Performance comparison of different approximation schemes in...

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2018 International Conference on Physics of Reactors: Reactor Physics Paving the Way Towards More Efficient systems, PHYSOR 2018

作者： Yong, Zheng Peng, Minjun Zhou, Yueshan Qiang, Shenglong Ping, An Wei, Lu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin Engineering University Harbin150001 China

ISBN: (纸本)9781713808510

The method of characteristics (MOC) with matrix form has theoretically more favorable features than its standard application, since the time-consuming track sweeping operations are replaced with explicit solution of matrix equation. In traditional MOC, there are three optional discretization strategies: the step characteristic method, diamond difference scheme and linear source approximation. However, their performances in matrix MOC have not be reported so far. The current paper develops their matrix forms and solves the resulted linear systems using preconditioned generalized minimal residual (PGM-RES) method. Additionally, their performances with respect of computation accuracy and efficiency are compared with each other, by simulating a homogeneous hexagonal cell problem and the 2D C5G7 benchmark. The results show that their performances in matrix form are different from that of traditional form. With the same angular quadrature and region partition scheme, the step characteristic method is more efficient significantly than the diamond difference scheme and linear source approximation. Whether the diamond difference scheme and linear source approximation can improve the calculation accuracy or not depends on whether the the spatial mesh is fine enough for every scheme. For the coarser spatial partition strategy, diamond difference scheme and linear source approximation can significantly improve the accuracy of local pin power. © 2018 International Conference on Physics of Reactors, PHYSOR 2018: Reactor Physics Paving the Way Towards More Efficient systems. All rights reserved.

关键词： Diamonds

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Ages of Main-Sequence Turn-Off Stars from the GALAH Survey

arXiv

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arXiv 2022年

作者： Chen, Xunzhou Ge, Zhishuai Chen, Yuqin Bi, Shaolan Yu, Jie Yang, Wuming Ferguson, Jason W. Wu, Yaqian Li, Yaguang Department of Astronomy Beijing Normal University Beijing100875 China Beijing Planetarium Beijing Academy of Science and Technology Beijing100044 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences A20 Datun Rd Chaoyang District Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Max Planck Institute for Solar System Research Justus-von-Liebig-Weg 3 GottingenD-37077 Germany Department of Physics Wichita State University WichitaKS67260-0032 United States School of Physics University of Sydney NSW2006 Australia Stellar Astrophysics Centre Department of Physics and Astronomy Aarhus University Ny Munkegade 120 Aarhus C8000 Denmark

Main sequence turn-off (MSTO) stars are good tracers of Galactic populations since their ages can be reliably estimated from atmospheric parameters. Based on the GALAH survey, we use the Yale Rotation Evolution Code to determine ages of 2926 MSTO stars with mean age uncertainty ∼10% considering the variation of C and O abundances. Ages of CO-poor stars are systematically affected by ∼10% due to the C and O abundances, globally shifting to ∼0.5 Gyr older compared to the results using solar metal-mixture. Of the stars with [Fe/H] ∼0.3-0.5 or [O/Fe] ≤ -0.25, many have fractional age differences ≥ 20%, and even reach up to 36%. The age-metallicity relation appears to possibly exist two distinct sequences: a young sequence of stars with age mostly 7 Gyr, overlapping at 5 Gyr ≤ age ≤ 7 Gyr. Moreover, the trends of abundances to age ratios show two corresponding sequences, especially in [O/Fe]-age plane. We also find that [Y/Mg] is a good chemical clock in disk populations. The young sequence and the old sequence can not be separated based on chemistry or kinematics, therefore stellar age is an important parameter to distinguish these two sequences in our sample. Copyright © 2022, The Authors. All rights reserved.

关键词： Stars

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A Corrective Control Approach For Combined Heat And Power system integrated with Multiple Energy Storage system

A Corrective Control Approach For Combined Heat And Power Sy...

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2019 IEEE PES Innovative Smart Grid Technologies Asia, ISGT 2019

作者： Lin, Qunli Shen, Xinwei Sun, Yong Li, Zhenyuan Guo, Qinglai Sun, Hongbin Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen Insitute Tsinghua University Shenzhen China State Grid Corp. of China Jilin Power Grid Company Jilin China State Key Lab. of Control and Simulation of Power System and Generation Equipments Tsinghua University Beijing China

ISBN: (纸本)9781728135205

The integrated Energy system (IES) becomes very important nowadays, however, the coupling between multiple energy systems will bring new challenges to the security control of the IES, such as combined heat and power (CHP) system. The corrective control means that the operations can be adjusted after contingency happens to eliminate the constraints violation in the contingency state such as the transmission outage or generator outage. This paper proposes a corrective control approach for CHP system integrated with the energy storage system based on security constrained economic dispatch (SCED) model. Case studies based on the IEEE 9-bus CHP system are presented to verify the method. The case result shows that the energy storage device can solve the ramping of the unit's output adjustment well. The corrective control method is more scientific and economical. © 2019 IEEE.

关键词： Outages

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Daniel Mögling’s sunspot observations in 1626 – 1629: A manuscript reference for the solar activity before the Maunder Minimum

arXiv

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arXiv 2021年

作者： Hayakawa, Hisashi Iju, Tomoya Murata, Koji Besser, Bruno P. Institute for Space-Earth Environmental Research Nagoya University Nagoya4648601 Japan Institute for Advanced Research Nagoya University Nagoya4648601 Japan UK Solar System Data Centre Space Physics and Operations Division RAL Space Science and Technology Facilities Council Rutherford Appleton Laboratory Harwell Oxford Oxfordshire DidcotOX11 0QX United Kingdom Nishina Centre Riken Wako3510198 Japan National Astronomical Observatory of Japan Mitaka1818588 Japan Graduate School for Humanities Nagoya University Nagoya4648601 Japan Space Research Institute Austrian Academy of Sciences Graz8042 Austria Institute of Physics University of Graz Universitätsplatz 5/II Graz8010 Austria

The sunspot groups have been observed since 1610 and their numbers have been used for evaluating the amplitude of solar activity. Daniel Mögling recorded his sunspot observations for more than 100 days in 1626 – 1629 and formed a significant dataset of sunspot records before the Maunder Minimum. Here, we have analysed his original manuscripts in the Universitäts- und Landesbibliothek Darmstadt (ULBD) to review Mögling’s personal profile and observational instruments and derive number and positions of the sunspot groups. In his manuscript, we have identified 134 days with an exact sunspot group number and 3 days of additional descriptions. Our analyses have completely revised their observational dates and group number, added 19 days of hitherto overlooked observations, and removed 8 days of misinterpreted observations. We have also revisited sunspot observations of Schickard and Hortensius and revised their data. These results have been compared with the contemporary observations. Moreover, we have derived the sunspot positions from his sunspot drawings and located them at 2°–23° in the heliographic latitude in both solar hemispheres. Contextualised with contemporary observations, these results indicate their temporal migration to lower heliographic latitudes and emphasise its location in the declining phase of Solar Cycle −12 in the 1620s. His observations were probably conducted using a pinhole and camera obscura, which made Mögling likely underestimate the sunspot group number by ≥ 33% – 52 %. This underestimation should be noted upon their comparison with the modern datasets. Copyright © 2021, The Authors. All rights reserved.

关键词： Solar energy

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