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arXiv 2025年

作者： Wang, Hao P. Yang, Li P. Poedts, S. Lani, A. Zhou, Yu H. Gao, Yu H. Linan, L. Lv, Jia K. Baratashvili, T. Guo, Jing H. Rong, L. Su, Z. Li, Cai X. Zhang, M. Wei, Wen W. Yang, Y. Li, Yu C. Ma, Xin Y. Husidic, E. Jeong, H.-J. Mahdi, Najafi Z. Wang, J. Schmieder, B. Centre for Mathematical Plasma-Astrophysics Department of Mathematics KU Leuven Celestijnenlaan 200B Leuven3001 Belgium State Key Laboratory of Space Weather Chinese Academy of Sciences Beijing100190 China Institute of Physics University of Maria Curie-Sklodowska ul. Radziszewskiego 10 Lublin20-031 Poland Von Karman Institute For Fluid Dynamics Waterloosesteenweg 72 Sint-Genesius-Rode Brussels1640 Belgium School of Earth and Space Sciences Peking University Beijing100871 China Beijing Institute of Applied Meteorology Beijing100029 China School of Astronomy and Space Science Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Nanjing210023 China SIGMA Weather Group State Key Laboratory for Space Weather National Space Science Center Chinese Academy of Sciences Beijing100190 China Shenzhen Key Laboratory of Ultraintense Laser and Advanced Material Technology Center for Intense Laser Application Technology College of Engineering Physics Shenzhen Technology University Shenzhen518118 China Space Sciences Laboratory University of California BerkeleyCA94720 United States School of Mathematical Sciences Nanjing Normal University Nanjing210023 China Ministry of Education Key Laboratory of NSLSCS China College of Earth and Planetary Sciences University of Chinese Academy of Sciences Beijing100049 China School of Systems Science Beijing Normal University Beijing100875 China Meudon Principal F-92195 Cedex France SUPA School of Physics & Astronomy University of Glasgow GlasgowG12 8QQ United Kingdom

Time-evolving magnetohydrodynamic (MHD) coronal modeling, driven by a series of time-dependent photospheric magnetograms, represents a new generation of coronal simulations. This approach offers greater realism compared to traditional coronal models constrained by a static magnetogram. However, its practical application is seriously limited by low computational efficiency and poor numerical stability. Therefore, we propose an extended magnetic field decomposition strategy and implement it in the implicit MHD model to develop a coronal model that is both efficient and numerically stable enough for simulating the long-term evolutions of the global corona. The traditional decomposition strategies split the magnetic field into a time-invariant potential field and a time-dependent component B1. It works well for quasi-steady-state coronal simulations where |B1| is typically small. However, as the inner-boundary magnetic field evolves, |B1| can grow significantly larger and its discretization errors often lead to nonphysical negative thermal pressure, ultimately causing the code to crash. In this paper, we mitigate such undesired situations by introducing a temporally piecewise-constant variable to accommodate part of the non-potential field and remain |B1| consistently small throughout the simulations. We incorporate this novel magnetic field decomposition strategy into our implicit MHD coronal model and apply it to simulate the evolution of coronal structures within 0.1 AU over two solar-maximum Carrington rotations. The results show that this coronal model effectively captures observations and performs more than 80 times faster than real time using only 192 CPU cores, making it well-suited for practical applications in simulating the time-evolving corona. © 2025, CC BY-NC-SA.

关键词： Electric corona

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Determination of the Backward Predictability Limit and Its Relationship with the Forward Predictability Limit

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Advances in Atmospheric sciences 2019年第6期36卷 669-677页

作者： Xuan LI Ruiqiang DING Jianping LI State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology College of Global Change and Earth System Sciences (GCESS) Beijing Normal University

In this work, two types of predictability are proposed—forward and backward predictability—and then applied in the nonlinear local Lyapunov exponent approach to the Lorenz63 and Lorenz96 models to quantitatively estimate the local forward and backward predictability limits of states in phase space. The forward predictability mainly focuses on the forward evolution of initial errors superposed on the initial state over time, while the backward predictability is mainly concerned with when the given state can be predicted before this state happens. From the results, there is a negative correlation between the local forward and backward predictability limits. That is, the forward predictability limits are higher when the backward predictability limits are lower, and vice versa. We also find that the sum of forward and backward predictability limits of each state tends to fluctuate around the average value of sums of the forward and backward predictability limits of sufficient ***, the average value is constant when the states are sufficient. For different chaotic systems, the average value is dependent on the chaotic systems and more complex chaotic systems get a lower average value. For a single chaotic system,the average value depends on the magnitude of initial perturbations. The average values decrease as the magnitudes of initial perturbations increase.

关键词： nonlinear local Lyapunov exponent forward and backward predictability limit negative correlation average value

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Influence of the Preceding Austral Summer Southern Hemisphere Annular Mode on the Amplitude of ENSO Decay

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Advances in Atmospheric sciences 2017年第11期34卷 1358-1379页

作者： Fei ZHENG Jianping LI Ruiqiang DING State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technologyqingdao 266237China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technologychengdu 610103China

There is increasing evidence of the possible role of extratropical forcing in the evolution of ENSO. The Southern Hemi- sphere Annular Mode （SAM） is the dominant mode of atmospheric circulation in the Southern Hemisphere extratropics. This study shows that the austral summer （December-January-February; DJF） SAM may also influence the amplitude of ENSO decay during austral autumn （March-April-May; MAM）. The mechanisms associated with this SAM-ENSO relationship can be briefly summarized as follows： The SAM is positively （negatively） correlated with SST in the Southern Hemisphere middle （high） latitudes. This dipole-like SST anomaly pattern is referred to as the Southern Ocean Dipole （SOD）. The DJF SOD, caused by the DJF SAM, could persist until MAM and then influence atmospheric circulation, including trade winds, over the Nifio3.4 area. Anomalous trade winds and SST anomalies over the Nifio3.4 area related to the DJF SAM are further developed through the Bjerkness feedback, which eventually results in a cooling （warming） over the Nifio3.4 area followed by the positive （negative） DJF SAM.

关键词： Southern Hemisphere Annular Mode ENSO Southern Ocean Dipole

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A REMAPPING METHOD BASED ON MULTI-POINT FLUX CORNER TRANSPORT UPWIND ADVECTION ALGORITHM

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Journal of Computational mathematics 2013年第6期31卷 592-619页

作者： Zhijun Shen Guixia Lv National Key Laboratory of Science and Technology on Computational Physics Institute of Applied Physics and Computational Mathematics P.O.Box 8009-26 Beijing 100088 China Center for Applied Physics and Technology HEDPS Peking University Beijing 100871 China

A local remapping algorithm for scalar function on quadrilateral meshes is described. The remapper from a distorted grid to a rezoned grid is usually regarded as a conservative interpolation problem. The present paper introduces a pseudo time to transform the interpolation into an initial value problem on a moving grid, and construct a moving mesh method to solve it. The new feature of the algorithm is the introduction of multi- point information on each edge, which leads to the numerical flux consistent with grid node motion. During the procedure of deriving scheme, we illustrate a framework about how the algorithms on a rectangular mesh are easily generated to those on a moving mesh. The basic ideas include：（i） introducing coordinate transformation, which maps the irregular domain in physical space to a perfectly regular computational domain, and （ii） deriving finite volume methods in the physical domain, which can be viewed as a discretization of the transformed equation. The resulting scheme is second-order accurate, conservative and monotonicity preserving. numerical examples are carried out to show the good performance of ore＂ schemes.

关键词： Remapping Advection Multi-point flux Coordinate transformation Geometric conservation law.

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Impacts of the MJO on Winter Rainfall and Circulation in China

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Advances in Atmospheric sciences 2011年第3期28卷 521-533页

作者：贾小龙陈丽娟任福民李崇银 National Climate Center China Meteorological Administration State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences Institute of Meteorology PLA University of Science and Technology

Impacts of the MJO on winter rainfall and circulation in China are investigated using a real-time multivariate MJO *** results using the daily rainfall anomalies and "rainy day" anomalies according to eight different MJO phases show that the MJO has considerable influence on winter rainfall in China. Rainfall anomalies show systematic and substantial changes(enhanced/suppressed) in the Yangtze River Basin and South China with the eastward propagation of the MJO convective center from the Indian Ocean to the western *** the MJO is in phase 2 and 3(MJO convective center is located over the Indian Ocean),rainfall probability is significantly *** in phase 6 and 7(MJO convective center is over the western Pacific),rainfall probability is significantly reduced. MJO in winter influences the rainfall in China mainly through modulating the circulation in the subtropics and mid-high *** the subtropics,MJO influences the northward moisture transport coming from the Bay of Bengal and the South China Sea by modulating the southern trough of the Bay of Bengal and the western Pacific subtropical *** the mid-high latitudes,the propagation of the low frequency perturbations associated with the eastward-propagating MJO convection modulate the circulation in the mid-high latitudes,*** East Asian winter monsoon and the low trough over central Asia.

关键词： MJO rainfall anomaly subtropics mid-high latitudes vertical motion

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Estimating the Predictability Limit of Tropical Cyclone Tracks over the Western North Pacific Using Observational Data

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Advances in Atmospheric sciences 2018年第12期35卷 1491-1504页

作者： Quanjia ZHONG Lifeng ZHANG Jianping LI Ruiqiang DING Jie FENG State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences College of Meteorology and Oceanography National University of Defense Technology College of Earth Science University of Chinese Academy of Sciences Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology College of Global Change and Earth System Sciences Beijing Normal University School of Meteorology University of Oklahoma

In this study,the nonlinear local Lyapunov exponent(NLLE)approach was used to quantitatively determine the predictability limit of tropical cyclone(TC)tracks based on observed TC track data obtained from the Joint Typhoon Warning *** results show that the predictability limit of all TC tracks over the whole western North Pacific(WNP)basin is about 102 h,and the average lifetime of all TC tracks is about 174 *** predictability limits of the TC tracks for short-,medium-,and long-lived TCs are approximately 72 h,120 h,and 132 h,*** predictability limit of the TC tracks depends on the TC genesis location,lifetime,and intensity,and further analysis indicated that these three metrics are closely *** more intense and longer-lived TCs tend to be generated on the eastern side of the WNP(EWNP),whereas the weaker and shorter-lived TCs tend to form in the west of the WNP(WWNP)and the South China Sea(SCS).The relatively stronger and longer-lived TCs,which are generated mainly in the EWNP,have a longer travel time before they curve northeastwards and hence tend to be more predictable than the relatively weaker and shorter-lived TCs that form in the WWNP region and ***,the results show that the predictability limit of the TC tracks obtained from the best-track data may be underestimated due to the relatively short observational records currently *** work is needed,employing a numerical model to assess the predictability of TC tracks.

关键词： predictability tropical cyclone tracks nonlinear local Lyapunov exponent

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Higher order shift operater FDTD scheme for scattering of cloaking structure

Higher order shift operater FDTD scheme for scattering of cl...

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IET International Radar Conference 2015

作者： Xia Ai Shengjun Zhang Mingliang Wang Weidong Wang Jiaqi Liu Chengguo Liu Xuemei Liu National Key Laboratory of Science and Technology on Test physics & Numerical Mathematical China

ISBN: (纸本)9781510822023

In this paper, a higher-order shift operater (SO) FDTD scheme with second-order accuracy in time and fourth-order in space has been proposed to accurately model scattering of perfect electronic conductor coated with cloaking structures. Several different electromagnetic parameters of the cloaks are taken into account using SO-FDTD method. numerical results indicate that the proposed method is more accuracy than the traditional method maintaining the same grid size. Scattering of different kinds of simplified cylindrical cloaks including thickness and loss are presented and could be served as further study on this subject.

关键词： Finite difference time domain method Higher-order algorithm Scattering of cloaks

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Multi-feature radar signal modulation recognition based on improved PSO algorithm

Multi-feature radar signal modulation recognition based on i...

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IET International Radar Conference 2018, IRC 2018

作者： Gao, Jing-Peng Shen, Liang-Xi Ye, Fang Wang, Shang-Yue Zhang, Ran College of Information and Communication Engineering Harbin Engineering University Harbin China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

In order to solve the problem that radar emitter signal modulation recognition under low signal-to-noise ratio (SNR) has difficulty in selecting the parameters of the classifier and the problem of low recognition rate caused by the improper selection of features, a multi-feature fusion modulation recognition algorithm based on improved particle swarm optimisation (PSO) algorithm is proposed. Firstly, the algorithm uses Choi-Williams distribution time-frequency analysis to transform the radar signals into time-frequency images, and combines transfer learning and principal component analysis (PCA) to extract the transfer features. Then it extracts the Renyi entropy and AR model coefficients of the signals and combines with the image features to realise multi-feature fusion. Finally, the improved PSO algorithm optimises support vector machine parameters so that population converge quickly. The simulation results show that the recognition rate of this algorithm is 95.3% when the SNR is 0 dB. The number of iterations of this algorithm is small, the signal recognition rate of the system is improved, and the effectiveness of the system is improved by applying PCA. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Principal component analysis

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A Radar Signal Modulation Recognition Algorithm Based on Multi-branch Fusion Difference 6

A Radar Signal Modulation Recognition Algorithm Based on Mul...

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6th IEEE International Conference on Electronic Information and Communication technology, ICEICT 2023

作者： Jiang, Sisi Gao, Jingpeng Jiang, Zhiye Ye, Fang College of Information and Communication Engineering Harbin Engineering University Harbin China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China College of Information and Communication Engineering Harbin Engineering University National Key Laboratory of Underwater Acoustic Technology Harbin China

ISBN: (纸本)9798350399059

The time-frequency images of radar modulation signals are similar at low signal-to-noise ratios, which will lead to lower recognition accuracy. This paper proposes an algorithm based on multi-branch fusion differences to identify radar modulation signals. The algorithm designs a multi-branch fusion differential module based on the attention mechanism and differential thinking, to extract time-frequency image fine-grained features and improve the Convolution Neural Network characterization ability. After that, a dual-branch differential network is proposed by combining vanilla convolution and multi-branch fusion difference module. The network can fuse global and detailed features of time-frequency images, which can achieve radar signal modulation recognition. The simulation results show that the recognition accuracy of the algorithm can reach 93.17% at 0dB. Therefore, the algorithm can obtain high recognition accuracy and has high recognition performance. © 2023 IEEE.

关键词： Convolution

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Supertetragonal BaZrS_(3):A promising perovskite sulphide with giant ferroelectricity and low band gap

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science China(physics,Mechanics & Astronomy) 2024年第8期67卷 126-133页

作者： Menglu Li Sa Zhang Chenhan Liu Xiaotao Zu Liang Qiao Haiyan Xiao School of Physics University of Electronic Science and Technology of ChinaChengdu 611731China College of Mathematics and Physics Chengdu University of TechnologyChengdu 610059China Micro-and Nano-scale Thermal Measurement and Thermal Management Laboratory Ministry of Education Key Laboratory of Numerical Simulation of Large-Scale Complex SystemsSchool of Energy and Mechanical EngineeringNanjing Normal UniversityNanjing 210023China

Over the past century,ferroelectricity has offered exciting opportunities for fundamental research and device ***,most of the discovered excellent ferroelectrics are oxide materials with large band gaps,limiting their potential for optoelectronics *** using first-principles calculations we identify a new narrow-gap ferroelectric beyond oxides,i.e.,ferroelectric perovskite sulphide BaZrS_(3).Under large compressive strains,BaZrS_(3)can be stabilized into a unique supertetragonal phase with an extraordinary polarization of 67.16μC/cm^(2),which is even stronger than that of conventional oxide ***,the supertetragonal BaZrS_(3)exhibits a direct narrow band gap of 1.2 eV and excellent electronic *** on the chemical bonding analysis,we attribute the formation of supertetragonal phase to charge re-ordering in which theπbond overlap along the long〈Zr-S〉bond completely vanishes and the antibonding states of theσbond appear below the Fermi *** work provides a conceptual strategy for designing new ferroelectrics for electronic and photovoltaic applications.

关键词： supertetragonal phase perovskite sulphide ferroelectricity

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