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An accurate and efficient radiative transfer model for simulating all-sky images from Fengyun satellite radiometers

Science China Earth Sciences 2020年第11期63卷 1701-1713页

作者： Bin YAO Chao LIU shiwen teng Lei BI Zhiqing ZHANG Peng ZHANG Byung-Ju SOHN Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjing 210044China Department of Atmospheric Sciences Zhejiang UniversityHangzhou 310027China Key Laboratory of Radiometric Calibration and Validation for Environment Satellite National Satellite Meteorological CenterChina Meteorological AdministrationBeijing 100081China School of Earth and Environmental Sciences Seoul National UniversitySeoul 151747South Korea

Forward radiative transfer models(RTM)are an indispensable tool for quantitative applications of satellite radiometers,e.g.,for data calibration,instrument development,retrieval,and so *** this study,we develop an accurate and efficient RTM for radiometers onboard Fengyun satellites,namely FYRTM(RTM for Fengyun Radiometers).Correlated k-distribution models are developed to improve the computational efficiency for gas absorption,and the effects of cloud and aerosol multiple scattering and emission are accelerated with pre-computed look-up *** is evaluated with a rigorous simulation based on discrete ordinate radiative transfer model(DISORT)as well as a popular fast forward model,i.e.,the Community Radiative Transfer Model(CRTM).Results indicate that FYRTM-based simulations are two to three orders of magnitudes faster than the DISORT-based *** to the rigorous model,FYRTM relative errors are within 2%at solar channels,and brightness temperatures(BT)differences are within 1 K at infrared *** with CRTM,FYRTM is computationally similar at solar channels,but three times faster at infrared ***,simulated reflectances/BTs using FYRTM are in a good agreement with the satellite ***,FYRTM is capable to simulate satellite observations under different atmospheric conditions,and can be extended to other radiometers onboard the Fengyun satellites(both geostationary and polarorbiting satellites).It is expected to play important roles in future applications with Fengyun observations.

关键词： Radiative transfer model Fengyun satellites Cloud and aerosol

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A cloud optical and microphysical property product for the advanced geosynchronous radiation imager onboard China's Fengyun-4 satellites: The first version

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Atmospheric and Oceanic Science Letters 2023年第3期16卷 52-57页

作者： Chao Liu Yuxing Song Ganning Zhou shiwen teng Bo Li Na Xu Feng Lu Peng Zhang Collaborative Innovation Center on Forecast and Evaluationof Meteorological Disasters/China Meteorological Administration Aerosol-Cloud-Precipitation Key Laboratory School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjingChina Innovation Center for FengYun Meteorological Satellite(FYSIC) National Satellite Meteorological Center(National Center for Space Weather)BejingChina Jiangsu Yangzhou Meteorological Bureau YangzhouChina College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdaoChina

风云四号作为中国新一代静止气象卫星,提供了高时空分辨率的监测产品。本文介绍风云四号搭载的先进地球同步轨道辐射成像仪AGRI的云光学和微物理特性产品.该产品包含了基于双光谱通道反演的云光学厚度和云粒子有效半径产品,以及基于机... 详细信息

风云四号作为中国新一代静止气象卫星,提供了高时空分辨率的监测产品。本文介绍风云四号搭载的先进地球同步轨道辐射成像仪AGRI的云光学和微物理特性产品.该产品包含了基于双光谱通道反演的云光学厚度和云粒子有效半径产品,以及基于机器学习的云识别和云相态产品。与时空匹配的主动卫星观测结果对比显示,该产品的云识别和云相态的准确率分别在95%和85%;该产品提供的云光学厚度和云有效粒径与经典的MODIS产品的相关系数达到0.76和0.63.团队将持续优化和更新该云光学和微物理特性定量产品,服务风云四号卫星定量应用。

关键词：风云四号先进地球同步轨道辐射成像仪云相态云光学厚度云有效粒子半径

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Analysis of the record-breaking August 2021 rainfall over the Greenland Ice Sheet

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Advances in Polar Science 2023年第3期34卷 165-176页

作者： DOU Tingfeng XIE Zuowei Jason E.BOX YANG Qing YANG Yifan teng shiwen XU Gaojie LIU Chao LI Xichen Derek HOUTZ GONG Xun DU Zhiheng DING Minghu YU Yongqiang XIAO Cunde College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Geological Survey of Denmark and Greenland(GEUS) Copenhagen 1350Denmark Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjing 210044China Swiss Federal Institute for Forest Snow and Landscape Research(WSL)Birmensdorf CH-8903Switzerland Hubei Key Laboratory of Marine Geological Resources China University of GeosciencesWuhan 430074China State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Institute of Global Change and Polar Meteorology Chinese Academy of Meteorological SciencesBeijing 100081China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China

Rainfall was witnessed for the first time at the highest area of the Greenland Ice Sheet on 14 August,*** thermodynamic mechanisms supporting the rainfall are revealed by ERA5 reanalysis,in-situ and satellite *** find that a strong southward intrusion of the polar vortex favored the maintenance of a deep cyclone over Baffin Island and an amplification of anticyclonic circulation over the southeastern ice sheet,which pumped warm and moist air toward Greenland from anomalously warm waters south of *** a wide swath of the ice sheet,atmospheric uplift maintained above-melting and rainfall conditions via condensation and enhanced downward infrared *** the low-level liquid clouds,the spatial extent and duration of the rainfall would have been *** the ice sheet topographic summit,the air temperature from the ground to 250 hPa level was~2℃higher than the previous record set on 12 July,*** events may occur more frequently with the decreased temperature contrast between the Arctic and the mid-latitude regions that drives highly amplified jet ***,this extreme event serves as a harbinger of a more likely wet surface condition across all elevations of the ice sheet.

关键词： Greenland Ice Sheet rainfall polar vortex liquid cloud

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Heterogeneous expression of Osa-MIR156bc increases abiotic stress resistance and forage quality of alfalfa

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The Crop Journal 2021年第5期9卷 1135-1144页

作者： Kexin Wang Yanrong Liu Fengkui teng Huifang Cen Jianpin Yan shiwen Lin Dayong Li Wanjun Zhang College of Grassland Science and Technology China Agricultural UniversityBeijing 100193China Key Lab of Grassland Science in Beijing China Agricultural UniversityBeijing 100193China College of Biological Science China Agricultural UniversityBeijing 100193China College of Life Sciences Shandong Normal UniversityJinan 250014ShandongChina

Alfalfa (Medicago sativa L.) is the most widely cultivated perennial leguminous forage crop *** RNA156 (miR156) precursor genes from dicotyledonous species are reportedly useful for improving alfalfa plant architecture and abiotic stress ***,there has been no report on whether a miR156 precursor gene from a monocotyledonous species functions in *** introduced two tandem precursor genes of miR156,rice Osa-MIR156b and Osa-MIR156c (Osa-MIR156bc),into *** expression of miR156 in the transgenic (TG) alfalfa was significantly *** to wild-type plants,the TG plants overexpressing miR156 had more branches and leaves and showed improved salt and drought *** of miR156 slightly reduced plant height,but the biomass yield of TG plants grown in flowerpots was still *** quality of TG plants was markedly improved by reduction of acid detergent lignin (ADL) content and increase in crude protein *** expression of the putative miR156 target genes Ms SPL6,Ms SPL12,and Ms SPL13 in TG plants was repressed by miR156overexpression,and that of all tested Ms SPLs would be sharply increased under drought or salt *** sequencing revealed that overexpression of miR156 affected the expression of genes associated with abiotic stress resistance and plant development in multiple *** first report of overexpression of monocot miR156 precursors in alfalfa sheds light on the function of mi RNA156 precursors from the monocot species rice that could be used for genetic improvement of the dicot forage crop alfalfa.

关键词： Alfalfa miR156 Biomass yield Forage quality Abiotic stress

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Fractal Characteristics and Microstructure Evolution of Magnetron Sputtering Cu Thin Films

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Chinese Journal of Mechanical Engineering 2013年第1期26卷 137-143页

作者： DU shiwen LI Yongtang School of Materials Science and Engineering Taiyuan University of Science and Technology

How to describe surface morphology characteristic and microstructure evolution are the hottest researches of current thin film researches. But in traditional characterization of surface morphology, the roughness parameters are scale related. And the microstructure evolution of thin film during post-treatment is usually not considered in detail, To give a better understanding of the roughness of thin films topography, fractal method is carried out. In addition, microstrueture evolution of thin films is analyzed based on the crystallography and energy theory. Cu thin films are deposited on Si （100） substrates by magnetron sputtering, and then annealed at different temperatures. Surface topography is characterized by atomic force microscope （AFM）. Triangular prism surface area （TPSA） algorithm is used to calculate the fractal dimension of the AFM images. Apparent scale effect exists between the surface morphology roughness and film thickness. Relationship between the fractal dimension and roughness is analyzed by linear regression method and linear relationship exists between fractal dimension and surface roughness root mean square （RMS）. Fractal dimension can be characterized as a scale independence parameter to represent the complex degree and roughness level of surface. With the increase of annealing temperature, surface roughness and fractal dimension decrease. But when the annealing temperature exceeds the recrystallization temperature, due to the agglomeration and coalescence of Cu grain, surface roughness and fractal dimension increase. Scale effect and changing regularity of grain growth and shape evolution for different film thickness under different annealing temperatures are analyzed. Based on minimum total free energy, regularity of grain growth and changing is proposed. The proposed research has some theory significance and applicative value of Cu interconnect process and development of MEMS.

关键词： fractal dimension metal thin film surface morphology microstructure evolution

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RFID-based 3D human pose tracking: A subject generalization approach

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Digital Communications and Networks 2022年第3期8卷 278-288页

作者： Chao Yang Xuyu Wang shiwen Mao Dept.of Electrical and Computer Engineering Auburn UniversityAuburnAL36849-5201USA Dept.of Computer Science California State UniversitySacramentoCA95819-6021USA

Three-dimensional (3D) human pose tracking has recently attracted more and more attention in the computer vision field. Real-time pose tracking is highly useful in various domains such as video surveillance, somatosensory games, and human-computer interaction. However, vision-based pose tracking techniques usually raise privacy concerns, making human pose tracking without vision data usage an important problem. Thus, we propose using Radio Frequency Identification (RFID) as a pose tracking technique via a low-cost wearable sensing device. Although our prior work illustrated how deep learning could transfer RFID data into real-time human poses, generalization for different subjects remains challenging. This paper proposes a subject-adaptive technique to address this generalization problem. In the proposed system, termed Cycle-Pose, we leverage a cross-skeleton learning structure to improve the adaptability of the deep learning model to different human skeletons. Moreover, our novel cycle kinematic network is proposed for unpaired RFID and labeled pose data from different subjects. The Cycle-Pose system is implemented and evaluated by comparing its prototype with a traditional RFID pose tracking system. The experimental results demonstrate that Cycle-Pose can achieve lower estimation error and better subject generalization than the traditional system.

关键词： Radio-frequency identification(RFID) Three-dimensional(3D)human pose tracking Cycle-consistent adversarial network Generalization

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扬子板块西南缘早前寒武纪地质演化:来自撮科元古宙变沉积岩碎屑锆石U-Pb年龄、Hf-O同位素的制约

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岩石学报 2025年第1期41卷 304-320页

作者：高嘉敏谢士稳刘倩王舫陶鹏龙涛中国地质大学(北京)地球科学与资源学院北京100083 中国地质科学院地质研究所北京离子探针中心北京100037 山东省第四地质矿产勘查院潍坊261021

扬子板块的太古宙-古元古代基底出露十分有限,制约了对扬子早前寒武纪地质演化的认识。本次研究对扬子板块西南缘撮科地区的大红山群和昆阳群变沉积岩开展了碎屑锆石原位U-Pb年龄、Hf-O同位素及微量元素研究。测年结果显示,大红山群谐... 详细信息

扬子板块的太古宙-古元古代基底出露十分有限,制约了对扬子早前寒武纪地质演化的认识。本次研究对扬子板块西南缘撮科地区的大红山群和昆阳群变沉积岩开展了碎屑锆石原位U-Pb年龄、Hf-O同位素及微量元素研究。测年结果显示,大红山群谐和锆石年龄分布于3092~1786Ma之间,最年轻碎屑锆石年龄为1786Ma,限定大红山群最大沉积时代为古元古代晚期。昆阳群谐和锆石年龄分布于2874~1031Ma之间,最年轻碎屑锆石年龄为1031Ma,表明昆阳群最大沉积时代为中元古代晚期。除少量较年轻锆石(<1.75Ga)外,昆阳群和大红山群具有相似的年龄分布特征,两个主要的年龄峰为2.0~1.85Ga和2.4~2.2Ga。尽管古元古代碎屑锆石的年龄峰与撮科地区已报道的古元古代岩浆活动期次一致,但仅有少部分碎屑锆石的Hf-O同位素特征与撮科古元古代岩浆岩相似,大多数碎屑锆石Hf-O同位素组成与加拿大Rae克拉通古元古代变沉积岩中碎屑锆石相似,暗示古元古代碎屑物质可能仅少部分来自撮科地区已识别的古元古代岩浆岩,而大部分可能来自与Rae克拉通发育的古元古岩浆岩相似的源区。大红山群和昆阳群中1.9~1.03Ga的碎屑锆石可能来自扬子西南缘发育的古元古代晚期-中元古代晚期岩浆岩。结合前人的资料,我们认为我国撮科和越南北部的Phan Si Pan带经历了与加拿大Rae克拉通相似的古元古代演化过程,支持2.4~2.3Ga扬子西南缘卷入Arrowsmith造山事件,并与Rae克拉通一起参与哥伦比亚超大陆聚合过程的认识。

关键词：扬子西南缘撮科地区哥伦比亚超大陆大红山群和昆阳群碎屑锆石

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Enhancing the performance of future wireless networks with software-defined networking

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Frontiers of Information Technology & Electronic Engineering 2016年第7期17卷 606-619页

作者： Mingjie FENG shiwen MAO Tao JIANG Department of Electrical & Computer Engineering Auburn University School of Electronics & Information Engineering Huazhong University of Science & Technology

To provide ubiquitous Internet access under the explosive increase of applications and data traffic,the current network architecture has become highly heterogeneous and complex,making network management a challenging *** this end,software-defined networking(SDN) has been proposed as a promising *** the SDN architecture,the control plane and the data plane are decoupled,and the network infrastructures are abstracted and managed by a centralized *** SDN,efficient and flexible network control can be achieved,which potentially enhances network *** harvest the benefits of SDN in wireless networks,the software-defined wireless network(SDWN) architecture has been recently *** this paper,we first analyze the applications of SDN to different types of wireless *** then discuss several important technical aspects of performance enhancement in SDN-based wireless ***,we present possible future research directions of SDWN.

关键词： Software-defined networking(SDN) Software-defined wireless networks(SDWN) Open Flow Performance enhancement

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Diffusion bound and reducibility for discrete Schrodinger equations with tangent potential

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Frontiers of Mathematics in China 2012年第6期7卷 1213-1235页

作者： shiwen ZHANG Zhiyan ZHAO Department of Mathematics Nanjing University Nanjing 210093 China

In this paper, we consider the lattice SchrSdinger equations iqn（t） = tan π（na＋x）qn（t）＋ε（qn＋1（t）＋ qn-1（t））＋δVn（t）｜qn（t）｜2τ-2qn（t）,with a satisfying a certain Diophantine condition, x∈ R/Z, and t- = 1 or 2, where vn（t） is a spatial localized real bounded potential satisfying ｜vn（t）｜ Ce-plnl. We prove that the growth of H1 norm of the solution {qn（t）}n∈Z is at most logarithmic if the initial data {qn（0）}n∈Z ∈ H1 for e sufficiently small and a.e. x fixed. Furthermore, suppose that the linear equation has a time quasi-periodic potential, i.e.,

关键词： Tangent potential reducibility Sobolev norm Birkhoff normal form

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Output Tracking Control of a Hydrogen-air PEM Fuel Cell

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IEEE/CAA Journal of Automatica Sinica 2017年第2期4卷 273-279页

作者： shiwen Tong Jianjun Fang Yinong Zhang College of Automation Beijing Union UniversityBeijing 100101China

Hydrogen-air proton exchange membrane U+0028 PEM U+0029 fuel cell is a promising clean energy. However, the stack output tracking control is still a challenging problem due to the soft characteristic of the stack. Both over- and less-control will cause the stack flooding or oxygen lacking which dramatically decreases the life of stacks. Traditional control methods rely on the accurate model of the fuel cell system, which is a high-order nonlinear system, and involve a complex controller design process. This paper combines the data-based fuzzy cluster modeling technology with the sliding mode control and the integral actions. The sliding mode controller tracks the dynamic changes of the fuel cell system and the integral controller eliminates the steady-state errors. Simulation results demonstrate good performance of the proposed control method. © 2017 Chinese Association of Automation.

关键词： Controllers Fuel cells Fuel systems Fuzzy clustering Navigation Sliding mode control

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