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Multi-Time-Scale Variational Mode Decomposition-Based Robust Fault Diagnosis of Railway Point Machines Under Multiple Noises

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Chinese Journal of Electronics 2024年第3期33卷 814-822页

作者： Junqi LIU Tao WEN Guo XIE Yuan CAO Clive Roberts Shaanxi Key Laboratory of Complex system Control and Intelligent information Processing Xi'an University of Technology The School of Electronic and information Engineering Beijing Jiaotong University Birmingham centre for Railway Research and Education University of Birmingham

The fault diagnosis of railway point machines(RPMs) has attracted the attention of engineers and *** have studies considered diverse noises along the *** fulfill this aspect,a multi-time-scale variational mode decomposition(MTSVMD) is proposed in this paper to realize the accurate and robust fault diagnosis of RPMs under multiple *** decomposes condition monitoring signals after coarse-grained processing in varying *** this manner,the information contained in the signal components at multiple time scales can construct a more abundant feature space than at a single *** the experimental validation,a random position,random type,random number,and random length(4R) noise-adding algorithm helps to verify the robustness of the *** adequate experimental results demoristrate the superiority of the proposed MTSVMD-based fault diagnosis.

关键词： Fault diagnosis Condition monitoring Noise Signal processing algorithms Aerospace electronics Rail transportation Robustness

Counteracting effects on ENSO induced by ocean chlorophyll interannual variability and tropical instability wave-scale perturbations in the tropical Pacific

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Science China Earth Sciences 2024年第2期67卷 387-404页

作者： Rong-Hua ZHANG Feng TIAN Qidong SHI Xiujun WANG Tongwen WU School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China Laoshan Laboratory Qingdao266237China Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao266071China University of Chinese Academy of Sciences Beijing101408China Faculty of geographical Sciences Beijing Normal UniversityBeijing100875China Earth system Modeling and Prediction centre China Meteorological AdministrationBeijing100081China

Large perturbations in chlorophyll(Chl)are observed to coexist at interannual and tropical instability wave(TIW)scales in the tropical Pacific;at present,their combined effects on El Ni?o-Southern Oscillation(ENSO)through ocean biologyinduced heating(OBH)feedbacks are not understood ***,a hybrid coupled model(HCM)for the atmosphere and ocean physics-biogeochemistry(AOPB)in the tropical Pacific is adopted to quantify how ENSO can be modulated by Chl perturbations at interannual and TIW scales,individually or collectively,*** HCM-based sensitivity experiments demonstrate a counteracting effect on ENSO:the bio-climate feedback due to large-scale Chl interannual variability acts to damp ENSO through its impact on upper-ocean stratification and vertical mixing,whereas that due to TIW-scale Chl perturbations tends to amplify *** ENSO simulations are sensitively dependent on the ways Chl effects are represented at these different scales,it is necessary to adequately take into account these related differential Chl effects in climate modeling.A bias source for ENSO simulations is illustrated that is related with the Chl effects in the tropical Pacific,adding in a new insight into interactions between the climate system and ocean ecosystem on different scales in the *** results reveal a level of complexity of ENSO modulations resulting from Chl effects at interannual and TIW scales,which are associated with ocean biogeochemical processes and their interactions with physical processes in the tropical Pacific.

关键词： Ocean chlorophyll Bio-climate feedbacks Interannual variability Tropical instability waves Counteracting effects A hybrid coupled model

Optimal Assimilation of Microwave Upper-Level Sounding Data in CMA-GFS

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Advances in Atmospheric Sciences 2024年第10期41卷 2043-2060页

作者： Changjiao DONG Hao HU Fuzhong WENG School of Atmospheric Physics Nanjing University of Information Science and Technology CMA Earth system Modeling and Prediction centre (CEMC) China Meteorological Administration State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences

Various approaches have been proposed to minimize the upper-level systematic biases in global numerical weather prediction（NWP） models by using satellite upper-air sounding channels as anchors. However, since the China Meteorological Administration Global Forecast system（CMA-GFS） has a model top near 0.1 hPa（60 km）, the upper-level temperature bias may exceed 4 K near 1 hPa and further extend to 5 h Pa. In this study, channels 12–14 of the Advanced Microwave Sounding Unit A（AMSU-A） onboard five satellites of NOAA and METOP, whose weighting function peaks range from 10 to 2 h Pa are all used as anchor observations in CMA-GFS. It is shown that the new “Anchor” approach can effectively reduce the biases near the model top and their downward propagation in three-month assimilation cycles. The bias growth rate of simulated upper-level channel observations is reduced to ±0.001 Kd–1, compared to –0.03 Kd–1derived from the current dynamic correction scheme. The relatively stable bias significantly improves the upper-level analysis field and leads to better global medium-range forecasts up to 10 days with significant reductions in the temperature and geopotential forecast error above 10 hPa.

关键词： anchoring bias correction CMA-GFS satellite microwave data assimilation upper-level model bias

Data error propagation in stacked bioclimatic envelope models

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Integrative Zoology 2024年第2期19卷 262-276页

作者： Xueyan LI Babak NAIMI Peng GONG Miguel B.ARAÚJO Guangdong Provincial Key Laboratory of Remote Sensing and geographical information system Guangdong Open Laboratory of Geospatial Information Technology and ApplicationGuangzhou Institute of GeographyGuangdong Academy of ScienceGuangzhouChina ‘Rui Nabeiro’Biodiversity Chair CHANGE-MED InstituteUniversity ofÉvoraÉvoraPortugal Department of Geography and Department of Earth Sciences University of Hong KongHong KongChina Department of Biogeography and Global Change National Museum of Natural SciencesCSICMadridSpain

Stacking is the process of overlaying inferred species potential distributions for multiple species based on outputs of bioclimatic envelope models(BEMs).The approach can be used to investigate patterns and processes of species *** data limitations on individual species distributions are inevitable,but how do they affect inferences of patterns and processes of species richness?We investigate the influence of different data sources on estimated species richness gradients in *** fitted BEMs using species distributions data for 334 bird species obtained from(1)global range maps,(2)regional checklists,(3)museum records and surveys,and(4)citizen science data using presence-only(Mahalanobis distance),presence-background(MAXENT),and presence–absence(GAM and BRT)*** species predictions were stacked to generate species richness ***,we show that different data sources and BEMs can generate spatially varying gradients of species *** environmental predictors that best explained species distributions also differed between data *** using citizen-based data had the highest accuracy,whereas those using range data had the lowest *** richness patterns estimated by GAM and BRT models were robust to data *** multiple data sets exist for the same region and taxa,we advise that explicit treatments of uncertainty,such as sensitivity analyses of the input data,should be conducted during the process of modeling.

关键词： richness patterns species distribution stacked bioclimatic envelope models uncertainty

Changes of China’s Status in the Global system and Its Influencing Factors:A Multiple Contact Networks Perspective

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Chinese geographical Science 2024年第2期34卷 265-279页

作者： LIU Jian LIU Jibin YANG Qingshan CAI Sikai LIU Jie School of geographical Sciences Northeast Normal UniversityChangchun 130024China Key Laboratory of geographical Processes and Ecological Security of Changbai Mountains Ministry of EducationChangchun 130024China School of Architecture and Planning Jilin Jianzhu UniversityChangchun 130118China School of geographical Sciences Liaoning Normal UniversityDalian 116029China

Clarifying China’s position in the global system is an important logical basis for developing national *** much research has been done on China’s development status,most studies have been based on country comparisons or institutional *** today’s networked era in which the global economy,trade,personnel,and information are closely connected,studies on China’s global position and its status changes and influencing factors in multiple contact networks are still *** this study,from the perspective of diverse global contact networks,we constructed economic,cultural,and political influence indices to explore the changes and influencing factors on China’s status in the global system from 2005 to *** results show that during the study period,China’s global influence in the fields of economic ties,cultural exchanges,and political contacts increased significantly,but its influ-ence in the fields of cultural exchanges and political contacts lagged far economic *** pattern of China’s economic influence on various economies around the world has shown a transformation from an‘upright pyramid’to an‘inverted pyramid’*** proportion of these economies in low-influence zones has decreased from more than 60%in 2005 to less than 20%in ***’s cultural and political influence on various economies around the world has increased significantly;however,for the former,the percentage of high-influence areas is still less than 20%,whereas for the latter the percentage of these economies in medium-and high-influence areas is still less than 50%.Analyses such as a scatter plot matrix show that geographical proximity,economic globalization,close cooperation with developing countries,and a proactive and peaceful foreign policy are important factors in improving China’s status in the diverse global network system.

关键词： global system economic ties cultural exchanges political contacts multiple contact networks China’s status

Large-scale land-sea interactions extend ozone pollution duration in coastal cities along northern China

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Environmental Science and Ecotechnology 2024年第2期18卷 150-160页

作者： Yanhua Zheng Fei Jiang Shuzhuang Feng Yang Shen Huan Liu Hai Guo Xiaopu Lyu Mengwei Jia Chenxi Lou Jiangsu Provincial Key Laboratory of Geographic information Science and Technology International Institute for Earth System ScienceNanjing UniversityNanjing210023China Jiangsu Center for Collaborative Innovation in geographical information Resource Development and Application Nanjing210023China Frontiers Science Center for Critical Earth Material Cycling Nanjing UniversityNanjing210023China School of Environment Tsinghua UniversityBeijing100084China Air Quality Studies Department of Civil and Environmental EngineeringHong Kong Polytechnic UniversityHong KongChina

Land-sea atmosphere interaction(LSAI)is one of the important processes affecting ozone(O_(3))pollution in coastal *** effects of small-scale LSAIs like sea-land breezes have been widely ***,it is not fully clear how and to what extent the large-scale LSAIs affect O_(3) *** we explored an O_(3) episode to illuminate the role of large-scale LSAIs in O_(3) pollution over the BohaieYellow Seas and adjacent areas through observations and model *** results show that the northern Bohai Sea's coastal region,influenced by the Mongolian High,initially experienced a typical unimodal diurnal O_(3) variation for three days,when O_(3) precursors from BeijingeTianjineHebei,Shandong,and Northeast China were transported to the BohaieYellow *** reactions generated O_(3) within marine air masses,causing higher O_(3) levels over the seas than coastal *** the Mongolian High shifted eastward and expanded,southerly winds on its western edge transported O_(3)-rich marine air masses toward the coast,prolonging pollution for an additional three days and weakening diurnal ***,emissions from the Korean Peninsula and marine shipping significantly affected O_(3) levels in the northern Bohai Sea(10.7%and 13.7%,respectively).Notably,Shandong's emissions played a substantial role in both phases(27.5%and 26.1%,respectively).These findings underscore the substantial impact of large-scale LSAIs driven by the Mongolian High on O_(3) formation and pollution duration in coastal *** insight helps understand and manage O_(3) pollution in northern Bohai Sea cities and broadly applies to temperate coastal cities worldwide.

关键词： Mongolian high Source apportionment WRF-CMAQ Sea-crossing transport

Geomorphology-oriented theoretical framework and construction method for value-added DEM

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Journal of geographical Sciences 2024年第1期34卷 165-184页

作者： ZHANG Haiping TANG Guoan XIONG Liyang YANG Xin LI Fayuan Key Laboratory of Virtual Geographic Environment Ministry of EducationNanjing Normal UniversityNanjing 210023China School of Geography Nanjing Normal UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in geographical information Resource Development and Application Nanjing 210023China

Digital elevation model(DEM)plays a fundamental role in the study of the earth system by expressing surface configuration,understanding surface process,and revealing surface *** is widely used in analysis and modeling in the field of ***,traditional DEM has the defect of single attribute,which is difficult to support the research in earth system science oriented to geoscience process and mechanism ***,realizing the value-added data model on the basis of traditional DEM is necessary to serve digital elevation modeling and terrain analysis under the background of a new geomorphology research paradigm and earth observation technology.A theoretical framework for value-added DEM that mainly includes concept,connotation,content,and categories,is constructed in this *** relationship between different types of value-added DEMs as well as the research significance and application category of this theoretical framework are also *** following are different methods of value-added DEMs:(1)value-added methods of DEM space and time dimensions that emphasize the integration of the ground and underground as well as coupling of time and space,(2)attribute-based value-added methods composed of material(including underground,surface,and ground)and morphological properties,and(3)value-added methods of features and physical elements that consider geographical objects and landform features formed by natural processes and artificial *** digital terrace,slope,and watershed models are used as examples to illustrate application scenarios of the three kinds of value-added *** study aims to improve expression methods of DEMs under the background of new surveying and mapping technologies by adding value to the DEM at three levels of dimensions,attributes,and elements as well as support knowledge-driven digital geomorphological analysis in the era of big data.

关键词： spatial data model value-added DEM digital terrain analysis geomorphological ontology geomorphology

Added Benefit of the Early-Morning-Orbit Satellite Fengyun-3E on the Global Microwave Sounding of the Three-Orbit Constellation

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Advances in Atmospheric Sciences 2024年第1期41卷 39-52页

作者： Juan LI Zhengkun QIN Guiqing LIU Jing HUANG CMA Earth system Modeling and Prediction centre Beijing 100081China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Joint Center for Data Assimilation Research and Applications School of Atmospheric SciencesNanjing University of Information Science&TechnologyNanjing 210044China

The three-orbit constellation can comprehensively increase the spatial coverage of polar-orbiting satellites,but the polar-orbiting satellites currently in operation are only mid-morning-orbit and afternoon-orbit ***-3E(FY-3E)was launched successfully on 5 July 2021 in *** an early-morning-orbit satellite,FY-3E can help form a complete three-orbit observation system together with the mid-morning and afternoon satellites in the current mainstream operational *** this study,we investigate the added benefit of FY-3E microwave sounding observations to the midmorning-orbit Meteorological Operational satellite-B(Met Op-B)and afternoon-orbit Fengyun-3D(FY-3D)microwave observations in the Chinese Meteorological Administration global forecast system(CMA-GFS).The results show that the additional FY-3E microwave temperature sounder-3(MWTS-3)and microwave humidity sounder-2(MWHS-2)data can increase the global coverage of microwave temperature and humidity sounding data by 14.8% and 10.6%,*** enables the CMA-GFS to achieve nearly 100% global coverage of microwave-sounding observations at each analysis ***,after effective quality control and bias correction,the global biases and standard deviations of the differences between observations and model simulations are also *** on the Advanced Microwave Sounding Unit A and the Microwave Humidity Sounder onboard Met Op-B,and the MWTS-2 and MWHS-2 onboard FY-3D,adding the microwave sounding data of FY-3E can further reduce the errors of analysis results and improve the global prediction skills of CMA-GFS,especially for the southern-hemisphere forecasts within 96 hours,all of which are significant at the 95% confidence level.

关键词： data assimilation microwave temperature sounder MWTS-3

Improved Diurnal Cycle of Precipitation on Land in a Global Non-Hydrostatic Model Using a Revised NSAS Deep Convective Scheme

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Advances in Atmospheric Sciences 2024年第6期41卷 1217-1234页

作者： Yifan ZHAO Xindong PENG Xiaohan LI Siyuan CHEN State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China CMA Earth system modeling and Prediction centre Beijing 100081China 2035 Future Laboratory PIESAT Information Technology Co Ltd.Beijing 100195China

In relatively coarse-resolution atmospheric models,cumulus parameterization helps account for the effect of subgridscale convection,which produces supplemental rainfall to the grid-scale precipitation and impacts the diurnal cycle of *** this study,the diurnal cycle of precipitation was studied using the new simplified Arakawa-Schubert scheme in a global non-hydrostatic atmospheric model,i.e.,the Yin-Yang-grid Unified Model for the *** new diagnostic closures and a convective trigger function were suggested to emphasize the job of the cloud work function corresponding to the free tropospheric large-scale *** results of the 0.25-degree model in 3-month batched real-case simulations revealed an improvement in the diurnal precipitation variation by using a revised trigger function with an enhanced dynamical constraint on the convective initiation and a suitable threshold of the *** reducing the occurrence of convection during peak solar radiation hours,the revised scheme was shown to be effective in delaying the appearance of early-afternoon rainfall peaks over most land areas and accentuating the nocturnal peaks that were wrongly concealed by the more substantial afternoon *** addition,the revised scheme enhanced the simulation capability of the precipitation probability density function,such as increasing the extremely low-and high-intensity precipitation events and decreasing small and moderate rainfall events,which contributed to the reduction of precipitation bias over mid-latitude and tropical land areas.

关键词： cumulus parameterization diurnal cycle of precipitation large-scale dynamic forcing global non-hydrostatic atmospheric model performance verification