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Climatology of tropical cyclone tornadoes in China from 2006 to 2018

Science China Earth Sciences 2020年第1期63卷 37-51页

作者： Lanqiang BAI zhiyong meng Kenta SUEKI Guixing CHEN Ruilin ZHOU School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster StudiesSun Yat-sen UniversityGuangzhou 510275China Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking UniversityBeijing 100871China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519000China RIKEN Center for Computational Science Kobe 650-0047Japan

We surveyed the occurrence of tropical cyclone(TC) tornadoes in China from 2006 to 2018. There were 64 cataloged TC tornadoes, with an average of five per year. About one-third of the landfalling TCs in China were tornadic. Consistent with previous studies, TC tornadoes preferentially formed in the afternoon shortly before and within about 36 h after landfall of the TCs. These tornadoes mainly occurred in coastal areas with relatively flat terrains. The maximum number of TC tornadoes occurred in Jiangsu and Guangdong provinces. Most of the TC tornadoes were spawned within 500 km of the TC center. Two notable characteristics were found:(1) TC tornadoes in China mainly occurred in the northeast quadrant(Earth-relative coordinates) rather than the right-front quadrant(TC motion-relative coordinates) of the parent TC circulation;and(2) most tornadoes were produced by TCs with a relatively weak intensity(tropical depressions/storms), in contrast with the United States where most tornadoes are associated with stronger TCs. Further analyses showed that TC tornadoes in China tend to be spawned in an environment with large low-level storm relative helicity and large convective available potential energy taking entrainment effects into account. TC tornadoes were particularly active in 2018, with 24 reported tornadoes accounting for 37.5% of the total surveyed samples. The first recorded tornado outbreak in the modern history of China occurred in the envelope of TC Yagi(2018), in which 11 tornadoes were reported in association with significant midlevel intrusions of dry air and the interaction of Yagi with an approaching midlatitude midlevel trough.

关键词： Tornadoes Tropical cyclones Historical statistics China

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Impact of Coastal Radar Observability on the Forecast of the Track and Rainfall of Typhoon Morakot(2009)Using WRF-based Ensemble Kalman Filter Data Assimilation

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Advances in Atmospheric Sciences 2017年第1期34卷 66-78页

作者： Jian YUE zhiyong meng Cheng-Ku YU Lin-Wen CHENG Laboratory for Climate and Ocean–Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking University Department of Atmospheric Sciences NTU

This study explored the impact of coastal radar observability on the forecast of the track and rainfall of Typhoon Morakot （2009） using a WRF-based ensemble Kalman filter （EnKF） data assimilation （DA） system. The results showed that the performance of radar EnKF DA was quite sensitive to the number of radars being assimilated and the DA timing relative to the landfall of the tropical cyclone （TC）. It was found that assimilating radial velocity （Vr） data from all the four operational radars during the 6 h immediately before TC landfall was quite important for the track and rainfall forecasts after the TC made landfall. The TC track forecast error could be decreased by about 43% and the 24-h rainfall forecast skill could be almost tripled. Assimilating Vr data from a single radar outperformed the experiment without DA, though with less improvement compared to the multiple-radar DA experiment. Different forecast performances were obtained by assimilating different radars, which was closely related to the first-time wind analysis increment, the location of moisture transport, the quasi-stationary rainband, and the local convergence line. However, only assimilating Vr data when the TC was farther away from making landfall might worsen TC track and rainfall forecasts. Besides, this work also demonstrated that Vr data from multiple radars, instead of a single radar, should be used for verification to obtain a more reliable assessment of the EnKF performance.

关键词： radial velocity ensemble Kalman filter observability tropical cyclone track rainfall

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Mesoscale Modeling Study of Severe Convection over Complex Terrain

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Advances in Atmospheric Sciences 2016年第11期33卷 1259-1270页

作者： Ying ZHANG zhiyong meng Peijun ZHU Tao SU Guoqing ZHAI Department of Atmospheric Sciences School of Earth SciencesZhejiang University Department of Atmospheric and Oceanic Sciences School of PhysicsPeking University

Short squall lines that occurred over Lishui, southwestern Zhejiang Province, China, on 5 July 2012, were investigated using the WRF model based on 1°× 1° gridded NCEP Final Operational Global Analysis data. The results from the numerical simulations were particularly satisfactory in the simulated radar echo, which realistically reproduced the generation and development of the convective cells during the period of severe convection. The initiation of this severe convective case was mainly associated with the uplift effect of mesoscale mountains, topographic convergence, sufficient water vapor, and enhanced low-level southeasterly wind from the East China Sea. An obvious wind velocity gradient occurred between the Donggong Mountains and the southeast coastline, which easily enabled wind convergence on the windward slope of the Donggong Mountains; both strong mid–low-level southwesterly wind and low-level southeasterly wind enhanced vertical shear over the mountains to form instability; and a vertical coupling relation between the divergence on the upper-left side of the Donggong Mountains and the convergence on the lower-left side caused the convection to develop rapidly. The convergence centers of surface streams occurred over the mountain terrain and updrafts easily broke through the lifting condensation level（LCL） because of the strong wind convergence and topographic lift, which led to water vapor condensation above the LCL and the generation of the initial convective cloud. The centers of surface convergence continually created new convective cells that moved with the southwest wind and combined along the Donggong Mountains, eventually forming a short squall line that caused severe convective weather.

关键词： convective convection divergence mesoscale mountains instability southwestern terrain moved uplift

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Lithofacies distribution characteristics and its controlling factors of shale in Wufeng Formation-Member 1 of Longmaxi Formation in the Jiaoshiba area

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Petroleum Research 2018年第4期3卷 306-319页

作者： Chao Wang Baiqiao Zhang Yongchao Lu Zhiguo Shu Yaqiu Lu Hanyong Bao zhiyong meng Lei Chen Exploration and Development Research Institute Sinopec Jianghan Oilfield CompanyHubei430223China College of Marine Science and Technology China University of GeosciencesHubei430074China School of Geoscience and Technology Southwest Petroleum UniversitySichuan610500China

It is essential to investigate shale lithofacies distribution and controlling factor of the shale for geological evaluation of shale gas exploration and development.Through comprehensive analysis of cores,thin sections,cathode luminescence,whole-rock X-ray diffraction,element capture spectroscopy,major/trace element and other data,three major types and eight sub-type shale lithofacies in the shale of Wufeng Formation-Member 1 of Longmaxi Formation in Jiaoshiba area are identified by the three-end-member method and shale lithological classification nomenclature,and the spatiotemporal distribution law and main development controlling factors of shale lithofacies are well studied.In the Jiaoshiba area,vertically,the marine shale develops siliceous shale,mixed shale and argillaceous shale from bottom to top.Besides,lateral distribution of the shale is different from north to south;the shale lithofacies in the north area changes rapidly,the mixed shale in the north area is much thicker than that in the south area,while the siliceous shale in the south area is relatively thicker.Difference in the shale lithofacies is controlled by special sedimentary geologic events;development of the siliceous shale is controlled by the Ordovician-Silurian global volcanic event to some extent,while the mixed shale is significantly influenced by effect of bottom current,and the argillaceous shale is mainly affected by supply of terrestrial clastic material.

关键词： Shale lithofacies Paleoproductivity Redox condition Volcanic activity Bottom current Wufeng formation-member 1 of Longmaxi Formation Jiaoshiba area

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内蒙古区域数值预报对探空和地面观测资料的敏感性试验研究

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气象 2024年第2期50卷 144-158页

作者：姚乐宝沈丹孟雪峰孙鑫孟智勇黄晓璐叶飞刘林春孙永刚中山大学大气科学学院/广东省气候变化与自然灾害研究重点实验室珠海519082 南方海洋科学与工程广东省实验室(珠海) 珠海519082 内蒙古自治区气象台呼和浩特010051 北京大学物理学院大气与海洋科学系北京100871 中国气象局雷达气象中心长沙气象雷达标校中心长沙410207

基于内蒙古睿图预报系统的低分辨率版本和WRFDA-FSO诊断工具,评估2021年7月现有探空和地面观测对内蒙古睿图预报系统预报的影响。该方法计算代价相对低廉,并允许根据观测变量、观测类型、气压层次、地理区域等观测的子集对观测影响进行... 详细信息

基于内蒙古睿图预报系统的低分辨率版本和WRFDA-FSO诊断工具,评估2021年7月现有探空和地面观测对内蒙古睿图预报系统预报的影响。该方法计算代价相对低廉,并允许根据观测变量、观测类型、气压层次、地理区域等观测的子集对观测影响进行划分。代价函数为以干总能量为度量的背景场和分析场的预报误差之间的差异。结果表明:观测影响的总体总和为负,观测对预报起正贡献作用。对12 h预报误差减小贡献最大的观测来自探空观测的动力变量(U、V风分量)。而单时次单位数量平均观测影响,探空观测的贡献约为地面观测的1/2。探空观测对12 h预报误差减小从近地面层至模式层顶均保持正贡献作用,并在对流层中低层和对流层高空急流层存在两个极大值区域;地面观测在850 hPa以下低层正贡献占比明显。探空观测在被同化系统同化时均总体具有有利的影响,也反映出探空观测数据稳定、质量较高的特征;地面观测对12 h预报误差减小起正贡献作用次数最多的区域在河套地区尤为显著。同时,探讨了需进一步提高地面观测资料同化率的问题。

关键词：数值预报资料同化基于伴随的预报对观测敏感性(FSO) 观测影响

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接地共面波导与芯片级联结构设计与优化

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河北科技大学学报 2024年第4期45卷 373-380页

作者：孟志永吉星照张秀清倪永婧于国庆张明河北科技大学信息科学与工程学院河北石家庄050018

针对传输线与芯片级联时产生阻抗突变,导致传输效率下降的问题,基于接地共面波导与芯片级联结构,提出了一种适用于X~Ka波段的匹配带线解决方法。通过S参数提取芯片的输入阻抗,并对射频电路中的阻抗不连续点进行分析,设计阻抗匹配电路并... 详细信息

针对传输线与芯片级联时产生阻抗突变,导致传输效率下降的问题,基于接地共面波导与芯片级联结构,提出了一种适用于X~Ka波段的匹配带线解决方法。通过S参数提取芯片的输入阻抗,并对射频电路中的阻抗不连续点进行分析,设计阻抗匹配电路并建立三维仿真模型。通过有限元仿真分析,讨论了匹配电路和键合引线中心间距对射频传输性能的影响,对比分析了不同结构及不同匹配电路的传输性能差异。仿真结果显示:在X~Ka波段范围内,匹配电路可令接地共面波导与芯片级联结构的S11-0.19 dB。优化后的接地共面波导与芯片级联结构可在降低传输损耗的同时显著提高射频信号的隔离度,减少信道串扰,为厘米波频段下射频电路的设计提供理论参考。

关键词：微波技术共面波导阻抗匹配金丝键合射频性能

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Impact of assimilating Taiwan＇s coastal radar radial velocity on forecasting Typhoon Morakot (2009) in southeastern China using a WRF-based EnKF

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Science China Earth Sciences 2017年第2期60卷 315-327页

作者： YUE Jian meng zhiyong Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic Sciences School of Physics Peking University Beij'ing 100871 China

This study explores for the first time the impact of assimilating radial velocity(Vr)observations from a single or multiple Taiwan's coastal radars on tropical cyclone(TC)forecasting after landfall in the Chinese mainland by using a Weather Research and Forecasting model(WRF)-based ensemble Kalman filter(EnKF)data assimilation system.Typhoon Morakot(2009),which caused widespread damage in the southeastern coastal regions of the mainland after devastating Taiwan,was chosen as a case study.The results showed that assimilating Taiwan's radar Vr data improved environmental field and steering flow and produced a more realistic TC position and structure in the final EnKF cycling analysis.Thus,the subsequent TC track and rainfall forecasts in southeastern China were improved.In addition,better observations of the TC inner core by Taiwan's radar was a primary factor in improving TC rainfall forecast in the Chinese mainland.

关键词：东南沿海地区中国东南部预测模型径向速度 WRF 台湾雷达吸收

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Review of Chinese atmospheric science research over the past 70 years: Synoptic meteorology

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Science China Earth Sciences 2019年第12期62卷 1946-1991页

作者： zhiyong meng Fuqing ZHANG Dehai LUO Zhemin TAN Juan FANG Jianhua SUN Xueshun SHEN Yunji ZHANG Shuguang WANG Wei HAN Kun ZHAO Lei ZHU Yongyun HU Huiwen XUE Yaping MA Lijuan ZHANG Ji NIE Ruilin ZHOU Sa LI Hongjun LIU Yuning ZHU Department of Atmospheric and Oceanic Sciences Peking UniversityBeijing 100871China Department of Meteorology and Atmospheric Science The Pennsylvania State UniversityUniversity ParkPA 16802USA Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China School of Atmospheric Science Nanjing UniversityNanjing 210093China National Meteorological Center Beijing 100081China School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China

Synoptic meteorology is a branch of meteorology that uses synoptic weather observations and charts for the diagnosis,study,and forecasting of weather.Weather refers to the specific state of the atmosphere near the Earth’s surface during a short period of time.The spatial distribution of meteorological elements in the atmosphere can be represented by a variety of transient weather phenomena,which are caused by weather systems of different spatial and temporal scales.Weather is closely related to people’s life,and its development and evolution have always been the focus of atmospheric scientific research and operation.The development of synoptic meteorology is closely related to the development of observation systems,dynamical theories and numerical models.In China,observation networks have been built since the early 1950 s.Up to now,a comprehensive meteorological observation systembased on ground,air and space has been established.In particular,the development of a new generation of dense radar networks,the development of the Fengyun satellite series and the implementation of a series of large field experiments have brought our understanding of weather from large-scale environment to thermal dynamics,cloud microphysical structure and evolution characteristics of meso and micro-scale weather systems.The development of observation has also promoted the development of theory,numerical model and simulation.In the early days,China mainly used foreign numerical models.Lately,China has developed numerical model systems with independent intellectual property rights.Based on the results of high-resolution numerical simulations,in-depth understanding of the initiation and evolution mechanism and predictability of weather at different scales has been obtained.Synoptic meteorology has gradually changed from an initially independent development to a multidisciplinary approach,and the interaction between weather and the change of climate and environment has become a hot and frontier topic in atmospheric science.This paper revie

关键词： Atmospheric sciences Synoptic meteorology Weather 70-year progresses

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SPARSE RECOVERY BASED ON THE GENERALIZED ERROR FUNCTION

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Journal of Computational Mathematics 2024年第3期42卷 679-704页

作者： zhiyong Zhou Department of Statistics and Data Science and Institute of Digital FinanceHangzhou City UniversityHangzhou 310015China

In this paper,we offer a new sparse recovery strategy based on the generalized error function.The introduced penalty function involves both the shape and the scale parameters,making it extremely flexible.For both constrained and unconstrained models,the theoretical analysis results in terms of the null space property,the spherical section property and the restricted invertibility factor are established.The practical algorithms via both the iteratively reweighted■_(1)and the difference of convex functions algorithms are presented.Numerical experiments are carried out to demonstrate the benefits of the suggested approach in a variety of circumstances.Its practical application in magnetic resonance imaging(MRI)reconstruction is also investigated.

关键词： Sparse recovery Generalized error function Nonconvex regularization Itera-tive reweighted Li Difference of convex functions algorithms

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Road map for, and technical challenges of, carbon-nanotube integrated circuit technology

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National Science Review 2024年第3期11卷 14-16页

作者： Jia Si Panpan Zhang zhiyong Zhang Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics School of Electronics Peking University State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

The past decade has witnessed an explosion of research on carbon-nanotube(CNT) electronics due to their outstanding properties, including an ultrathin body, a high carrier mobility and a high saturation velocity.

关键词： TRANSISTORS

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