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Effects of monsoon onset vortex on heat budget in the mixed layer of the Bay of Bengal

Journal of Oceanology and Limnology 2020年第6期38卷 1616-1631页

作者： Effects of monsoon onset vortex on heat budget in the mixed layer of the Bay of BengalXU Kang LIU Boqi LIU Yu WANG Weiqiang HE Zhuoqi State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Innovation Academy of South China Sea Ecology and Environmental Engineering Chinese Academy of SciencesGuangzhou 510301China State Key Laboratory of Severe Weather and Institute of Climate System Chinese Academy of Meteorological SciencesBeijing 100081China Institute of Deep-sea Science and Engineering Chinese Academy of SciencesSanya 572000China University of Chinese Academy of Sciences Beijing 100049China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

We investigated the effects of monsoon onset vortex(MOV)on the mixed layer heat budget in the Bay of Bengal(BOB)in spring 2003 using the reanalysis *** results suggest that the solar radiation flux penetrating the mixed layer and the existence of barrier layer are both able to modulate the effects of MOV on the evolution of sea surface temperature(SST)in the *** to the formation of BOB MOV,the local SST raised quickly due to mass of solar radiation reaching the sea surface under the clear-sky ***,since the mixed layer was shallow before the onset of the Asian summer monsoon(ASM),some solar radiation flux could penetrate to directly heat the deeper water,which partly offset the warming effect of shortwave *** the other hand,the in-situ SST started to cool due to the upwelling of cold water when the MOV generated over the BOB,along with the rapidly increased surface wind speed and its resultant deeper mixed *** the MOV developed and moved northward,the SST tended to decrease remarkably because of the strong upward surface latent heat flux over the BOB ascribed to the wind-evaporation ***,the MOV-related precipitation brought more fresh water into the upper ocean to produce a thicker barrier layer,whose thermal barrier effect damped the cooling effect of entrainment upwelling on the decrease tendency of the BOB *** other words,the thermal barrier effect could slow down the decreasing trend of the BOB SST even after the onset of ASM,which facilitated the further enhancement of the MOV.

关键词： monsoon onset vortex(MOV) Bay of Bengal air-sea interaction mixed layer depth barrier layer thickness heat budget analysis

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Tensor-networks-based learning of probabilistic cellular automata dynamics

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Physical Review Research 2024年第4期6卷 043202-043202页

作者： Heitor P. Casagrande Bo Xing William J. Munro Chu Guo Dario Poletti Science Mathematics and Technology Cluster Singapore University of Technology and Design 8 Somapah Road 487372 Singapore Okinawa Institute of Science and Technology Graduate University Onna-son Okinawa 904-0495 Japan Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China EPD Pillar Singapore University of Technology and Design 8 Somapah Road Singapore 487372 Centre for Quantum Technologies National University of Singapore Singapore 117543 MajuLab CNRS-UNS-NUS-NTU International Joint Research Unit UMI 3654 Singapore

Algorithms developed to solve many-body quantum problems, like tensor networks, can turn into powerful quantum-inspired tools to tackle issues in the classical domain. This work focuses on matrix product operators, a prominent numerical technique to study many-body quantum systems, especially in one dimension. It has been previously shown that such a tool can be used for classification, learning of deterministic sequence-to-sequence processes, and generic quantum processes. We further develop a matrix product operator algorithm to learn probabilistic sequence-to-sequence processes and apply this algorithm to probabilistic cellular automata. This new approach can accurately learn probabilistic cellular automata processes in different conditions, even when the process is a probabilistic mixture of different chaotic rules. In addition, we find that the ability to learn these dynamics is a function of the bitwise difference between the rules and whether one is much more likely than the other.

关键词： Cellular automata Machine learning Tensor network methods

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Design of W-band Sheet Beam EIK

Design of W-band Sheet Beam EIK

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Asia-Pacific Conference on Microwave

作者： Shuyuan Chen Jinliang Bai Ran Zhang Pei Zheng Jiaqi Liu Xin Liu Hongyan Liu Lu Gao National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (数字)9781728135175

ISBN: (纸本)9781728135182

Microwave tube is a vacuum electron device which can be used for amplification in the microwave frequency range. Sheet beam Extended Interaction Klystron (EIK) is an attractive Millimeter Waves amplifier because of its compact configuration, small voltage and high gain per unit length. In this paper, RF structure and the whole tube for W-band sheet beam EIK has been designed. A new and effective method of designing and studying W-band sheet beam EIK is presented in this paper. In order to get the same output power, several kinds of W-band sheet beam EIK are designed and compared. By optimizing the position of cavities, the output power can achieve 30 kW, which is calculated by threedimensional particle in cell (3D-PIC) software. It is a powerful basis for the subsequent study of sheet beam EIK.

关键词： Power generation Klystrons Power amplifiers physics mathematics Urban areas

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Modulation recognition of emitter signals based on SDAE-ODCNN

Modulation recognition of emitter signals based on SDAE-ODCN...

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IET International Radar Conference (IET IRC 2020)

作者： X. Wang J. Gao L. Gao F. Wang Harbin Engineering University College of Information and Communication Engineering Harbin China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

In order to improve the recognition rate of emitter signals modulation under low signal noise ratio (SNR), an end-to-end method based on the stacked denoising autoencoder (SDAE) - one dimensional convolutional neural network (ODCNN) is proposed in this paper. The SADE-ODCNN is designed in this method and trained through a two-step training. In the SDAE-ODCNN model, the encoder of the SDAE can extract the denoised and compressed features of the received emitter signals. Then the ODCNN can further extract features to realize the recognition. The simulation results show that the average recognition rate of the method can reach 0.94 under 0dB. Thus the proposed method has a good application in the field of emitter signals modulation recognition.

关键词： radar computing modulation feature extraction neural nets image denoising learning (artificial intelligence) image classification

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Research on influence of special-shaped honeycomb radar absorbing structure for wide-band absorbing design

Research on influence of special-shaped honeycomb radar abso...

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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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Complex forward scattering coefficient for signal characterisation

Complex forward scattering coefficient for signal characteri...

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IET International Radar Conference 2018, IRC 2018

作者： Chen, Jing Liu, Xiangrong Liu, Changjiang Dong, Xichao School of Information and Electronics Beijing Institute of Technology Beijing China Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics 100076 China

In this study, modelling and characteristics analysis of forward scattering coefficients and echoes are investigated. Traditional ground-target forward scattering signal model has not considered the impact of scattering phase;thus it is not accurate enough for describing air-target echoes. To solve this problem, a novel echo model was proposed based on the analytical deduction of complex forward scattering coefficient. The novel model separately expresses the target scattering characteristics and Doppler, greatly facilitating the theoretical analyses of echo characteristics. Then, theoretical and simulation investigations on the amplitude and phase characteristics of forward scattering echoes were made based on the complex forward scattering coefficient model. Theoretical explanations for the periodical fluctuation of far-field echo amplitude, periodical saltation of far-field echo phase, shadow blocking of near-field echo amplitude, and slow variation of near-field echo phase were given, respectively. Meanwhile, the boundary between near-field forward scattering and far-field forward scattering was quantitatively defined, which laid the theoretical foundation for the corresponding signal processing algorithms. Finally, with CST simulation results the accuracy of the echo model is verified and impacts of objects' real shapes are analysed. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Forward scattering

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Simulated response of the active layer thickness of permafrost to climate change

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Atmospheric and Oceanic science Letters 2021年第1期14卷 40-45页

作者： Ruichao Li Jinbo Xie Zhenghui Xie Junqiang Gao Binghao Jia Peihua Qin Longhuan Wang Yan Wang Bin Liu Si Chen State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina School of Mathematics and Statistics Nanjing University of information Science and TechnologyNanjingChina College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijingChina

The active layer thickness(ALT)in permafrost regions,which affects water and energy exchange,is a key variable for assessing hydrological processes,cold-region engineering,and climate *** this study,the authors analyzed the variation trends and relative changes of simulated ALTs using the Chinese Academy of sciences Land Surface Model(CAS-LSM)and the Chinese Academy of sciences Flexible Global Ocean-Atmosphere-Land System Model,gridpoint version 3(CAS-FGOALS-g3).Firstly,the simulated ALTs produced by CAS-LSM were shown to be reasonable by comparing them with Circumpolar Active Layer Monitoring ***,the authors simulated the ALTs from 1979 to 2014,and their relative changes across the entire Northern Hemisphere from 2015 to *** is shown that the ALTs have an increasing *** 1979 to 2014,the average ALTs and their variation trends over all permafrost regions were 1.08 m and 0.33 cm yr-1,*** relative changes of the ALTs ranged from 1%to 58%,and the average relative change was 10.9%.The variation trends of the ALTs were basically consistent with the variation trends of the 2-m air *** 2100,the relative changes of ALTs are predicted to be 10.3%,14.6%,30.1%,and 51%,respectively,under the four considered hypothetical climate scenarios(SSP-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5).This study indicates that climate change has a substantial impact on ALTs,and our results can help in understanding the responses of the ALTs of permafrost due to climate change.

关键词： Active layer thickness CAS-LSM Variation trends Relative changes Climate change

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