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IET International Radar Conference 2018, IRC 2018

作者： Wang, Ming-Liang Liu, Jia-Qi Xin, Liu Zhao, Xin-Ying Zhang, Sheng-Jun Lei, Mu Xia, Ai Guobin, Wan Wang, Wei-Dong Zhao, Ju-Yan National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematical Beijing100076 China Northwestern Polytechnical University Xi'an710072 China

To realise wide-band stealth of radar absorbing material, a special-shaped honeycomb radar absorbing structure within nested cone-shaped scattering configuration is designed. Based on the HS theory and the impedance matching design, the rule about the influence of the geometry parameter and electromagnetic parameter on the absorbing performance is analysed. In addition, the reflectivity performance is analysed on the condition of oblique incidence angles. By optimising the geometry parameters of the special-shaped honeycomb structure and designing the multilayer composite structure based on impedance matching theory, the results indicate that the two absorbing peaks can be formed for the special-shaped honeycomb radar absorbing structure, and the reflectivity is improved for both the vertical and oblique incidence angles. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Reflection

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The increase in hot–dry events with a high risk of mortality in China associated with the phase transition of the Atlantic Multidecadal Oscillation

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Atmospheric and Oceanic science Letters 2025年第4期18卷

作者： Ma, Yuting Shen, Xinyong Zhao, Liang Wang, Zijia Wang, Huibin Ding, Yihui Wang, Jingsong Liu, Yanju Huang, Cunrui State Key Laboratory of Climate System Prediction and Risk Management/Key Laboratory of Meteorological Disaster Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and Technology Nanjing China State Key Laboratory of Numerical Modeling for Atmosphere Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China College of Hydrology and Water Resources Hohai University Nanjing China The Second Affiliated Hospital Guangzhou Medical University Guangzhou China National Climate Center China Meteorological Administration Beijing China Key Laboratory of Space Weather National Satellite Meteorological Center (National Center for Space Weather) China Meteorological Administration Beijing China Innovation Center for FengYun Meteorological Satellite (FYSIC) Beijing China Vanke School of Public Health Tsinghua University Beijing China

Compound extreme climate events involving multiple meteorological elements usually have a more severe impact on the environment and human health than single-element extreme events. However, the current definition of multi-element compound extreme events is proposed from meteorological and statistical perspectives, without integrating health data, making the conclusions less practical for guiding health risk prevention. This study identified the threshold for hot–dry compound extreme events with high mortality risks (HMHDs) in China, using daily mortality data and temperature–humidity data from 278 districts or counties, and explored the interdecadal change and driving mechanisms of HMHD frequency in China from 1979 to 2021. The results show a significant increase in annual HMHD frequency in China after 2000, mainly occurring in summer (June, July, August). The northwestern to western regions of China (Xinjiang, Inner Mongolia, Gansu), and from the southwestern to the areas south of the Yangtze River (Sichuan, Hubei, Hunan, Jiangxi, Fujian, Guizhou, Yunnan), experience an increase of >10 days. The authors find that the interdecadal abrupt change in HMHD frequency can be attributed to the shift of the Atlantic Multidecadal Oscillation from a negative to a positive phase by affecting the Silk Road teleconnection. 摘要目前对复合极端事件的定义主要从气象和统计学角度出发, 未能结合健康数据, 使相关研究在指导健康风险预防方面的实用性较差. 本研究利用中国死亡数据和温湿度数据, 识别了中国高死亡风险的复合极端干热事件 (HMHDs) 的阈值, 并探讨了HMHD频率的年代际变化及其驱动机制. 结果显示, 中国西北地区, 西南地区和江南地区的HMHD频率平均每年都超过10 天. 2000年后, 中国HMHD频率显著增加, 主要发生在夏季. 驱动机制分析表明, HMHD频率的年代际变化可以归因于大西洋多年代际振荡由负相位转变为正相位. 本研究可为气候变化导致的健康风险防控提供参考依据. © 2025

关键词： Atlantic Multidecadal Oscillation Hot–dry compound events Relative humidity Temperature mortality

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A review of progress in coupled ocean-atmosphere model developments for ENSO studies in China

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Journal of Oceanology and Limnology 2020年第4期38卷 930-961页

作者： ZHANG Rong-Hua YU Yongqiang SONG Zhenya REN Hong-Li TANG Youmin QIAO Fangli WU Tongwen GAO Chuan HU Junya TIAN Feng ZHU Yuchao CHEN Lin LIU Hailong LIN Pengfei WU Fanghua WANG Lin Key Laboratory of Ocean Circulation and Waves Institute of Oceanologyand Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China Laboratory for Ocean and Climate Dynamics Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China Center for Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China University of Chinese Academy of Sciences Beijing 100049China LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100049China First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China Laboratory for Regional Oceanography and Numerical Modeling Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China Key Laboratory of Marine Science and Numerical Modeling(MASNUM) Ministry of Natural ResourcesQingdao 266061China National Engineering Laboratory for Integrated Aero-Space-Ground-Ocean Big Data Application Technology Qingdao 266061China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Laboratory for Climate Studies and CMA-NJU Joint Laboratory for Climate Prediction Studies National Climate CenterChina Meteorological AdministrationBeijing 100081China Environmental Science and Engineering University of Northern British ColumbiaBritish Columbia V2N 4Z9Canada State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural ResourcesHangzhou 310012China Key Laboratory of Meteorological Disaster Ministry of Education(KLME)and Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science and TechnologyNanjing 210044China Beijing Climate Center China Meteorological AdministrationBeijing 100081China

El Nino-Southern Oscillation(ENSO) is the strongest interannual signal that is producedby basinscale processes in the tropical Pacific,with significant effects on weather and climate *** the past,extensive and intensive international efforts have been devoted to coupled model developments for ENSO studies.A hierarchy of coupled ocean-atmo sphere models has been formulated;in terms of their complexity,they can be categorized into intermediate coupled models(ICMs),hybrid coupled models(HCMs),and fully coupled general circulation models(CGCMs).ENSO modeling has made significant progress over the past decades,reaching a stage where coupled models can now be used to successfully predict ENSO events 6 months to one year in ***,ENSO exhibits great diversity and complexity as observed in nature,which still cannot be adequately captured by current state-of-the-art coupled models,presenting a challenge to ENSO *** primarily reviewed the long-term efforts in ENSO modeling continually and steadily made at different institutions in China;some selected representative examples are presented here to review the current status of ENSO model developments and applications,which have been actively pursued with noticeable progress being made *** ENSO simulations are very sensitive to model formulations and process representations etc.,dedicated efforts have been devoted to ENSO model developments and ***,different ocean-atmosphere coupled models have been available in China,which exhibit good model performances and have already had a variety of applications to climate modeling,including the Coupled Model Intercomparison Project Phase 6(CMIP6).Nevertheless,large biases and uncertainties still exist in ENSO simulations and predictions,and there are clear rooms for their improvements,which are still an active area of researches and ***,model performances of ENSO simulations are assessed in terms of advantages and disadvantage

关键词： El Niño-Southern Oscillation(ENSO) coupled ocean-atmosphere models simulations and predictions model biases and uncertainties

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Evaluation and Uncertainty Analysis of Himawari-8 Hourly Aerosol Product Version 3.1 and its Influence on Surface Solar Radiation Before and During the COVID-19 Outbreak

SSRN

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SSRN 2023年

作者： Tang, Chenqian Shia, Chong Husi, Letu Ma, Run Yoshida, Mayumi Kikuchi, Maki Xu, Jian Li, Nan Zhao, Mengjie Chen, Liangfu Shi, Guangyu State Key Laboratory of Remote Sensing Science Aerospace Information Research Institute Chinese Academy of Sciences Beijing100101 China Nanjing University of Information Science & Technology Nanjing210044 China Remote Sensing Technology Center of Japan Tsukuba305-8505 Japan Japan Aerospace Exploration Agency Tsukuba305-8505 Japan National Space Science Center Chinese Academy of Sciences Beijing100190 China Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science & Technology Nanjing210044 China Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing100101 China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing100029 China University of Chinese Academy of Sciences Beijing100049 China

The hourly Himawari-8 version 3.1 (V31) aerosol product has been released and incorporates an updated Level 2 algorithm that uses forecast data as an a priori estimate. However, there has not been a thorough evaluation of V31 data across a full-disk scan, and V31 has yet to be applied in the analysis of its influence on surface solar radiation (SSR). This study firstly investigates the accuracy of V31 aerosol products, which includes three categories of aerosol optical depth (AOD) (AODMean, AODPure, and AODMerged) as well as the corresponding Ångström exponent (AE), using ground-based measurements from the AERONET and SKYNET. Results indicate that V31 AOD products are more consistent with ground-based measurements compared to previous products (V30). The highest correlation and lowest error were seen in the AODMerged, with a correlation coefficient of 0.8335 and minimal root mean square error of 0.1919. In contrast, the AEMerged shows a larger discrepancy with measurements unlike the AEMean and AEPure. Error analysis reveals that V31 AODMerged has generally stable accuracy across various ground types and geometrical observation angles, however, there are higher uncertainties in areas with high aerosol loading, particularly for fine aerosols. The temporal analysis shows that V31 AODMerged performs better compared to V30, particularly in the afternoon. Finally, the impacts of aerosols on SSR based on the V31 AODMerged are investigated through the development of a sophisticated SSR estimation algorithm in the clear sky. Results demonstrate that the estimated SSR is significant consistency with those of well-known CERES products, with preservation of 20 times higher spatial resolution. The spatial analysis reveals a significant reduction of AOD in the North China Plain before and during the COVID-19 outbreak, resulting in an average 24.57 W m–2 variation of the surface shortwave radiative forcing in clear sky daytime. © 2023, The Authors. All rights reserved.

关键词： COVID-19

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Deep representation method for radar emitter signal using wavelet packets decomposition

Deep representation method for radar emitter signal using wa...

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IET International Radar Conference 2018, IRC 2018

作者： Cao, Yang Bai, Jin Liang Li, Hongbo Zhao, Jian Liu, Shuo Gao, Zhiyong National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China School of Electronics and Information Engineering Harbin Institute of Technology Harbin China

Signal representation is to transform the intercepted original signal into feature parameters, which is the basis for the electronic reconnaissance system to analyse and identify a radar. The traditional method is to manually design a limited number of features with prior knowledge, which can only achieve the desired results in specific applications. Therefore, it is necessary to study signal representation methods that are more adaptable, reasonable, and effective. This study proposes a feature-level design scheme that extracts multi-level signal feature parameters to obtain deep essential feature representations, which is consistent with deep-learning frameworks. Through the decomposition through wavelet packet transform (WPT), the best sub-band tree structure of the signal can be obtained, and the depth representation of the signal can be well achieved, which can meet requirements of time-frequency analysis automatically. Here, Symlets wavelet packet decomposition (WPD) is used as an example to implement multi-layer signal feature representation. The combination of characteristic parameters at different levels can reflect the different information contained in different radar signals. The simulation results show that the method can effectively identify the modulation mode of radar signals and enhance the information mining ability from radar signals. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Radar

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Self-powered solar-blind photodiodes based on EFG-grown(100)-dominant β-Ga_(2)O_(3) substrate

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Chinese physics B 2021年第1期30卷 483-486页

作者： Xu-Long Chu Zeng Liu Yu-Song Zhi Yuan-Yuan Liu Shao-Hui Zhang Chao Wu Ang Gao Pei-Gang Li Dao-You Guo Zhen-Ping Wu Wei-Hua Tang Laboratory of Information Functional Materials and Devices School of Science&State Key Laboratory of Information Photonics and Optical CommunicationsBeijing University of Posts and TelecommunicationsBeijing 100876China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China The Engineering Research Center for Semiconductor Integrated Technology Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China China Aerospace System Simulation Technology Co. Ltd.(Beijing)Beijing 100195China Division of Interdisciplinary and Comprehensive Research&Platform for Characterization and Test Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Center for Optoelectronics Materials and Devices&Key Laboratory of Optical Field Manipulation of Zhejiang Province Department of PhysicsZhejiang Sci-Tech UniversityHangzhou 310018China School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China College of Electronic and Optical Engineering&College of Microelectronics Nanjing University of Posts and TelecommunicationsNanjing 210046China National and Local Joint Engineering Laboratory for RF Integration and Micro-Packing Technologies Nanjing University of Posts and TelecommunicationsNanjing 210046China

We report the edge-defined-film-fed(EFG)-grown β-Ga_(2)O_(3)-based Schottky *** device has a reverse leakage current of ~nA and a rectified ratio of ~10^(4) at ±5 *** addition,the photodiode detector shows a dark current of 0.3 pA,a photo-responsivity(R) of 2.875 mA/W,a special detectivity(D*) of 10^(10) Jones,and an external quantum efficiency(EQE) of 1.4% at zero bias,illustrating a self-powered *** work may advance the development of the Ga_(2)O_(3)-based Schottky diode solar-blind photodetectors.

关键词： β-Ga_(2)O_(3)substrate Schottky photodiode solar-blind detection

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Station Layout Optimization Genetic Algorithm for Four Stations TDOA Location

Station Layout Optimization Genetic Algorithm for Four Stati...

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第二届人工智能、网络与信息技术国际研讨会

作者： Ruiqi Sun Zhonghang He Lu Gao Jinliang Bai National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics

Station layout has a direct impact on localization precision for four-station TDOA(time difference of arrival) location system. In order to optimize the overall location precision of targets in certain area, genetic algorithm for station layout optimization is presented. GDOP is regarded as the measurement rule of location precision. Then the multi-object programming mathematical model of station layout optimization is built. The optimal solution is searched by genetic algorithm. Consequently, the optimal layout of station is obtained. The simulation provides the GDOP distribution of two station layouts. One is the initial station layout, and the other is the optimal station layout. The simulation results show that for the optimal station layout, the effect of improving the location precision is obvious, and also indicate the validity of genetic algorithm.

关键词： Station Layout Optimization Genetic Algorithm for Four Stations TDOA Location

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Data block processing structure for airship-borne passive bistatic radar

Data block processing structure for airship-borne passive bi...

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IET International Radar Conference 2018, IRC 2018

作者： Xu, Feng Liu, Xin Liu, Li Wang, Chao Wang, YiFei National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China DFH Satellite Co. Ltd Beijing100094 China

Serious ground clutter is of significant influence for target detection in an airship-borne passive bistatic radar (ABPBR) using frequency modulated broadcasting signals. The authors propose a data segment processing scheme to recover the direct signal from multi-path clutter and suppress the multi-path in the surveillance channel in an ABPBR. Super exponential (SE) equaliser and sample matrix inversion algorithm are exploited to recover the transmitted signal and suppress the serious multi-path interference, respectively. It is shown that the proposed algorithms can accomplish the target detection task effectively by computer simulations. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Airships

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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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Information Oriented Architecture of M&S Ecosystem

Information Oriented Architecture of M&S Ecosystem

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第三十八届中国控制会议

作者： Zheng ZHAO Chao ZHANG Jiaqi LIU LIUXin National Key Laboratory of Science&Technology on Test physics and Numerical mathematics

The paper conceives a new perspective of Architecture to build a ULS-liked M&S system. Under this perspective, Architecture of M&S ecosystems is developed under the "bottom-up" design pattern. To build the M&S ecosystem, we suggest a new concept of simulation resource name space such that all the simulation resource can be managed for the aim of sharing the resource by all simulation customer in the ecosystem. Also, the workflow of process of M&S ecosystems creating is provided.

关键词： Data Driven M&S simulation ecosystem

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