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Interannual Salinity Variability in the Tropical Pacific in CMIP5 Simulations

Advances in Atmospheric sciences 2019年第4期36卷 378-396页

作者： Hai ZHI Rong-Hua ZHANG Pengfei LIN Peng YU College of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Ocean and Climate Dynamics Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China University of Chinese Academy of Sciences Beijing 100029China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics (IAP)Chinese Academy of SciencesBeijing 100029China The Cooperative Institute for Climate and Satellites(CICS) University of MarylandCollege ParkMD 20740USA

Salinity variability and its causes in the tropical Pacific are analyzed using observations, reanalysis products and model simulations. The mixed-layer salinity(MLS) budget analyses from observations and reanalysis products indicate that its interannual evolution is closely related to ENSO and is predominantly governed by surface forcing and surface advection in the western-central equatorial Pacific. It is found that the observed MLS tendency leads Nin?o3.4 by about 12 months due to the effect of negative freshwater flux(evaporation minus precipitation). These observation-based analyses are used to evaluate the corresponding simulation using GFDL-ESM2 M. It is evident that the model can simulate the spatiotemporal variations of MLS with some discrepancies compared to observations. In the warm pool of the equatorial Pacific the MLS tendency in the model is sensitive to ocean dynamics, however model biases cause the tendency to be underestimated. In particular, the freshwater flux is overestimated while the ocean surface zonal current and vertical velocity at the base of the mixed layer are underestimated. Due to model biases in representing the related physics, the effects of surface forcing on the simulated MLS budget are overestimated and those of subsurface and surface advection are relatively weak. Due to weaker surface advection and subsurface forcing than observed, the simulated compensations for surface forcing are suppressed, and the simulated MLS tendency that leads Nin?o3.4 by 8–10 months, which is shorter than the observed lead time. These results are useful for the interpretation of observational analyses and other model simulations in the tropical Pacific.

关键词： mixed-layer salinity salt budget interannual variability tropical Pacific model simulation

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CONDITIONAL NONLINEAR OPTIMAL PERTURBATIONS: APPLICATION IN TROPICAL CYCLONE FORECASTS

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Journal of Tropical Meteorology 2019年第4期25卷 421-436页

作者： TIAN Hong-jun LI Ze-chun WANG Dong-liang WANG Bin Nanjing University of Information Science and Technology Nanjing 210044 China Shanghai Central Meteorological Observatory Shanghai 200030 China National Meteorological Centre Beijing 100081 China Shanghai Typhoon Institute CMAShanghai 200030 China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of ScienceBeijing 100029 China Ministry of Education Key Laboratory for Earth System Modeling Tsinghua UniversityBeijing 100084 China

Considering the feature of tropical cyclones(TCs) that strong positive vorticity exists in the lower layers of troposphere, this study proposed to use vorticity at 850 hPa as cost function to find the conditional nonlinear optimal perturbation(CNOP), which was largely different from previous studies using total energy of perturbed forecast variables. The CNOP was obtained by an ensemble-based approach. All of the sensitive areas determined by CNOP with vorticity at 850 hPa as cost function for the three cases were located over the TC core region and its vicinity. The impact of the CNOP-based adaptive observations on TC forecasts was evaluated with three cases via observational system simulation experiments(OSSEs). Results showed obvious improvements in TC intensity or track forecasts due to the CNOP-based adaptive observations, which were related to the main error source of the verification area, i.e.,intensity error or location error.

关键词： conditional nonlinear optimal perturbations tropical cyclone intensity track

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Spatial diffusion model and simulation analysis of the heterogeneous un-magnetized jet plasma 45

Spatial diffusion model and simulation analysis of the heter...

引用

45th EPS Conference on Plasma physics, EPS 2018

作者： Wu, Runhui Liu, Jiaqi Meng, Gang Chai, Song Liu, Xin Ren, Aimin Yan, Feng Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

ISBN: (纸本)9781510868441

In this paper, the spatial distribution characteristics of electron density are calculated based on the plasma jet diffusion model. The computed results are compared with the results of numerical calculation, validation test results. Researches of the paper are demonstrated that the plasma electron density is attenuated as the approximate exponential with increasing distance from the nozzle exit, the closer distance from the nozzle exit, the greater the attenuation slope, on the far away from the nozzle exit, the electron density attenuation with distance is the flat state. This method is simple and efficient, and it is a good tool to solve engineering calculation problems. © Copyright (2018) by European Physical Society (EPS) All rights reserved.

关键词： Plasma jets

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numerical and feasibility study of onboard MHD power extraction on supersonic vehicle 45

Numerical and feasibility study of onboard MHD power extract...

引用

45th EPS Conference on Plasma physics, EPS 2018

作者： Chai, Song Meng, Gang Wu, Runhui Liu, Jiaqi Liu, Xin Sun, Ruiqi Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing100076 China

ISBN: (纸本)9781510868441

Within this paper, a concept model containing main features of on-board magnetohydrodynamic (MHD) generators has been constructed and its feasibility of power extraction on supersonic vehicle for a typical flight condition has been studied numerically. The results revealed that the MHD generator is capable of providing substantial energy output up to tens of kilowatts per square meter or even several hundred kilowatts if the alkali-seeded boundary layer has been coated. © Copyright (2018) by European Physical Society (EPS) All rights reserved.

关键词： Magnetohydrodynamic converters

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Compound extreme events and health risks in China: A review

引用

Atmospheric and Oceanic science Letters 2025年

作者： Tang, Haosu Huang, Gang Hu, Kaiming Wang, Jun Huang, Cunrui Yang, Xianke School of Geography and Planning University of Sheffield Sheffield United Kingdom National Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China University of Chinese Academy of Sciences Beijing China The Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Vanke School of Public Health Tsinghua University Beijing China MARA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River College of Plant Science and Technology Huazhong Agricultural University Hubei China

Against the backdrop of global warming, China has been facing increasingly frequent and severe extreme weather and climate events, with a prominent risk of compound extreme events induced by interactions among multiple climate drivers and/or hazards. The present study first reviews the definition and classification of compound extreme events in China. Then, it summarizes research progress on the evolutionary characteristics, formation mechanisms, and future projections of different types of compound extreme events. The potential risks and possible impact pathways of three specific event types—namely, continuous day–night hot extremes, temperature–humidity compound events, and high-temperature–ozone compound events—on the health of the Chinese population are then explored. Finally, a framework for assessing the hazard risk of compound extreme events is constructed, accompanied by response strategies based on carbon neutrality targets. Building on existing research achievements, five future research directions are proposed: (1) identifying the risk chains of compound events;(2) addressing the constraints of observational records and coupled model performances;(3) attributing and understanding the drivers of compound extreme events;(4) finding optimal pathways for carbon reduction and air quality improvement;and (5) promoting inter-disciplinary, multi-regional, and cross-sectoral collaboration. Strengthening research in these directions will deepen our understanding of compound extreme events and provide technological support for climate change adaptation and health risk responses in China. 摘要在全球变暖的背景下, 中国面临着日益频繁和严峻的极端天气气候事件, 其中以多种气候驱动因子和/或灾害相互作用而形成的复合型极端事件风险尤为突出. 本文首先回顾了中国区域复合型极端事件的定义与分型;然后综述了不同类型复合型极端事件的演变特征, 形成机制以及未来预估等方面的研究进展;随后, 探讨了日夜持续型极端高温事件, 温湿复合事件以及高温–臭氧复合事件等三类事件对我国人群健康的潜在风险及可能的影响途径;最后, 阐述了复合型极端事件灾害风险评估框架, 并在此基础上提出了基于碳中和目标的应对策略. 在总结既有研究成果的基础上, 提出了五个未来亟需关注的研究方向: (1)复合事件灾害风险链的识别问题;(2)观测资料和耦合模式性能的制约问题;(3)复合型极端事件的归因与成因问题;(4)碳减排与空气质量改善的最优路径问题;(5)多学科, 多区域, 多部门的合作问题

关键词： Air pollution Carbon neutrality Compound extreme event Extreme weather Global warming Population health

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test of lepton flavour universality in W-boson decays into electrons and τ-leptons using pp collisions at = 13 TeV with the ATLAS detector

引用

Journal of High Energy physics 2025年第5期2025卷 1-49页

作者： Aad, G. Aakvaag, E. Abbott, B. Abdelhameed, S. Abeling, K. Abicht, N. J. Abidi, S. H. Aboelela, M. Aboulhorma, A. Abramowicz, H. Abulaiti, Y. Acharya, B. S. Ackermann, A. Adam Bourdarios, C. Adamczyk, L. Addepalli, S. V. Addison, M. J. Adelman, J. Adiguzel, A. Adye, T. Affolder, A. A. Afik, Y. Agaras, M. N. Aggarwal, A. Agheorghiesei, C. Ahmadov, F. Ahuja, S. Ai, X. Aielli, G. Aikot, A. Ait Tamlihat, M. Aitbenchikh, B. Akbiyik, M. Åkesson, T. P. A. Akimov, A. V. Akiyama, D. Akolkar, N. N. Aktas, S. Al Khoury, K. Alberghi, G. L. Albert, J. Albicocco, P. Albouy, G. L. Alderweireldt, S. Alegria, Z. L. Aleksa, M. Aleksandrov, I. N. Alexa, C. Alexopoulos, T. Alfonsi, F. Algren, M. Alhroob, M. Ali, B. Ali, H. M. J. Ali, S. Alibocus, S. W. Aliev, M. Alimonti, G. Alkakhi, W. Allaire, C. Allbrooke, B. M. M. Allen, J. S. Allen, J. F. Allendes Flores, C. A. Allport, P. P. Aloisio, A. Alonso, F. Alpigiani, C. Alsolami, Z. M. K. Alvarez Estevez, M. Alvarez Fernandez, A. Alves Cardoso, M. Alviggi, M. G. Aly, M. Amaral Coutinho, Y. Ambler, A. Amelung, C. Amerl, M. Ames, C. G. Amidei, D. Amini, B. Amirie, K. J. Amor Dos Santos, S. P. Amos, K. R. Amperiadou, D. An, S. Ananiev, V. Anastopoulos, C. Andeen, T. Anders, J. K. Anderson, A. C. Andreazza, A. Angelidakis, S. Angerami, A. Anisenkov, A. V. Annovi, A. Antel, C. Antipov, E. Antonelli, M. Anulli, F. Aoki, M. Aoki, T. Aparo, M. A. Aperio Bella, L. Appelt, C. Apyan, A. Arbiol Val, S. J. Arcangeletti, C. Arce, A. T. H. Arguin, J-F. Argyropoulos, S. Arling, J.-H. Arnaez, O. Arnold, H. Artoni, G. Asada, H. Asai, K. Asai, S. Asbah, N. A. Ashby Pickering, R. A. Assamagan, K. Astalos, R. Astrand, K. S. V. Atashi, S. Atkin, R. J. Atmani, H. Atmasiddha, P. A. Augsten, K. Auriol, A. D. Austrup, V. A. Avolio, G. Axiotis, K. Azuelos, G. Babal, D. Bachacou, H. Bachas, K. Bachiu, A. Bachmann, E. Badea, A. Baer, T. M. Bagnaia, P. Bahmani, M. Bahner, D. Bai, K. Baines, J. T. Baines, L. Baker, O. K. Bakos, E. Bakshi Gupta, D. Balabram Filho, L. E. Balakrishnan, V. Balasubramanian, R. Baldin, E. CPPM Aix-Marseille Université CNRS/IN2P3 Marseille France Department for Physics and Technology University of Bergen Bergen Norway Homer L. Dodge Department of Physics and Astronomy University of Oklahoma Norman United States of America New York University Abu Dhabi Abu Dhabi United Arab Emirates II. Physikalisches Institut Georg-August-Universität Göttingen Göttingen Germany Fakultät Physik Technische Universität Dortmund Dortmund Germany Physics Department Brookhaven National Laboratory Upton United States of America Physics Department Southern Methodist University Dallas United States of America Faculté des sciences Université Mohammed V Rabat Morocco Raymond and Beverly Sackler School of Physics and Astronomy Tel Aviv University Tel Aviv Israel Department of Physics New York University New York United States of America INFN Gruppo Collegato di Udine Sezione di Trieste Udine Italy ICTP Trieste Italy Department of Physics King’s College London London United Kingdom Kirchhoff-Institut für Physik Ruprecht-Karls-Universität Heidelberg Heidelberg Germany LAPP Université Savoie Mont Blanc CNRS/IN2P3 Annecy France AGH University of Krakow Faculty of Physics and Applied Computer Science Krakow Krakow Poland SLAC National Accelerator Laboratory Stanford United States of America School of Physics and Astronomy University of Manchester Manchester United Kingdom Department of Physics Northern Illinois University DeKalb United States of America Department of Physics Istanbul University Istanbul Türkiye Particle Physics Department Rutherford Appleton Laboratory Didcot United Kingdom Santa Cruz Institute for Particle Physics University of California Santa Cruz Santa Cruz United States of America Enrico Fermi Institute University of Chicago Chicago United States of America Institut de Física d’Altes Energies (IFAE) Barcelona Institute of Science and Technology Barcelona Spain Institut für Physik Universität Mainz Mainz Germany Department of Physics

A measurement of the ratio of the branching fractions, Rτ/e = B(W → τν)/B(W → eν), is performed using a sample of W bosons originating from top-quark decays to final states containing τ-leptons or electrons. This measurement uses pp collisions at $$ \sqrt{s} $$ = 13 TeV, collected by the ATLAS experiment at the Large Hadron Collider during Run 2, corresponding to an integrated luminosity of 140 fb−1. The W → τντ (with τ → eνeντ) and W → eνe decays are distinguished using the differences in the impact parameter distributions and transverse momentum spectra of the electrons. The measured ratio of branching fractions Rτ/e = 0.975 ± 0.012 (stat.) ± 0.020 (syst.), is consistent with the Standard Model assumption of lepton flavour universality in W-boson decays.

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Dual-Polarized Filtering Antenna for Base Station Application

Dual-Polarized Filtering Antenna for Base Station Applicatio...

引用

International Conference on Microwave and Millimeter Wave technology Proceedings

作者： Chao Feng Ding Xiu Yin Zhang Zhi Jie Zhang Yun Fei Cao Lu Gao Jun Yang School of Electronic and Information Engineering South China University of Technology Guangzhou China The State Key Laboratory of Millimeter Waves Nanjing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

In this paper, a broadband dual-polarized filtering dipole is proposed for base station application. Filtering response is obtained by adding simple slits on each arm of the traditional dual polarized dipole antenna. Both lower and upper stopband radiation nulls are generated. The operating bandwidth of the proposed antenna is 1.7-2.9 GHz (52%). The out-of-band suppression level is about 10 dB within 0.69-1.5 GHz and 3.3-3.8 GHz. The simulated port isolation is more than 26 dB. The proposed antenna element is suitable for potential base station applications.

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The Most Probable Transition Paths of Stochastic Dynamical Systems: A Sufficient and Necessary Characterization

arXiv

引用

arXiv 2021年

作者： Huang, Yuanfei Huang, Qiao Duan, Jinqiao School of Mathematics and Statistics Center for Mathematical Sciences Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and Technology Wuhan430074 China Department of Statistics and Data Science National University of Singapore 6 Science Drive 2 Singapore117546 Singapore School of Data Science City University of Hong Kong Kowloon Hong Kong Department of Mathematics Faculty of Sciences University of Lisbon Campo Grande Edifício C6 LisboaPT-1749-016 Portugal Division of Mathematical Sciences School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link Singapore637371 Singapore The Dongguan Key Laboratory for Data Science and Intelligent Medicine Department of Mathematics Department of Physics Great Bay University Guangdong Dongguan523000 China

The most probable transition paths of a stochastic dynamical system are the global minimizers of the Onsager–Machlup action functional and can be described by a necessary but not sufficient condition, the Euler–Lagrange equation (a second-order differential equation with initial-terminal conditions) from a variational principle. This work is devoted to showing a sufficient and necessary characterization for the most probable transition paths of stochastic dynamical systems with Brownian noise. We prove that, under appropriate conditions, the most probable transition paths are completely determined by a first-order ordinary differential equation. The equivalence is established by showing that the Onsager–Machlup action functional of the original system can be derived from the corresponding Markovian bridge process. For linear stochastic systems and the nonlinear Hongler’s model, the first-order differential equations determining the most probable transition paths are shown analytically to imply the Euler–Lagrange equations of the Onsager–Machlup functional. For general nonlinear systems, the determining first-order differential equations can be approximated, in a short time or for the small noise case. Some numerical experiments are presented to illustrate our results. Copyright © 2021, The Authors. All rights reserved.

关键词： Dynamical systems

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PolSAR Image Edge Detection via Structure Tensor Analysis

PolSAR Image Edge Detection via Structure Tensor Analysis

引用

IEEE International Geoscience and Remote Sensing Symposium

作者： Xiangrong Liu Wei Mao Shunsheng Zhang Lei Wu Wen-Qin Wang National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China Sch. of Info. Comm. Engin. University of Electronic Science and Technology of China Chengdu China

The weighted structure tensor (ST) can be usually used on edge detection of multi-channel images, including polarimetric synthetic aperture radar (polSAR) images. The traditional weighting method is average weighting, each channel considered to provide the same edge information. But in fact different channels tend to contain different amount of edge information, so the traditional weighting method cannot be adopted to extract full edge information of the multi-channel images. This letter proposes a novel weighting method for ST, in which the weight of each channel is obtained by the eigenvalue-measured way. Experimental results show that the proposed method outperforms the traditional method on edge detection.

关键词： Image edge detection Eigenvalues and eigenfunctions Estimation Optical imaging Hyperspectral imaging Corner detection

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Two-Dimensional Imaging With Stationary Nonuniform Frequency Diverse Array Transmitter

Two-Dimensional Imaging With Stationary Nonuniform Frequency...

引用

IEEE International Geoscience and Remote Sensing Symposium

作者： Xiangrong Liu Wei Mao Lei Wu National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China Sch. of Info. Comm. Engin. University of Electronic Science and Technology of China Chengdu China

This paper proposes a simple two-dimensional imaging via stationary nonuniform frequency diverse array (FDA) transmitter by exploiting FDA both range and angle dependent transmit beampattern. The nonuniform FDA transmitter only generates range-dependent beampattern, so that two-dimensional (range-angle dimension) imaging of targets can be achieved without the employment of moving radar platform, by jointly utilizing the only range-dependent transmitter beampattern and general single-antenna or phased-array antenna. The effectiveness of the proposed method is verified by simulation results.

关键词： Radar imaging Imaging Frequency diversity Radar antennas Transmitters Radar remote sensing

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