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Assessment of ECMWF’s Precipitation Forecasting Performance for China from 2017 to 2022

Journal of Tropical Meteorology 2024年第3期30卷 257-274页

作者： PAN Liu-jie ZHANG Hong-fang LIANG Mian LIU Jia-huimin dai chang-ming Shaanxi Meteorological Observatory Xi’an 710014 China Key Laboratory of Eco-Environment and Meteorology for the Qinling Mountains and Loess Plateau Xi’an 710014 China Shaanxi Meteorological Service Centre Xi’an 710014 China

This study used the China Meteorological Administration(CMA)three-source fusion gridded precipitation analysis data as a reference to evaluate the precipitation forecast performance of the European Centre for Medium-Range Weather Forecasts(ECMWF)model for China from 2017 to *** main conclusions are as *** precipitation forecast capability of the ECMWF model for China has gradually improved from 2017 to *** scores such as bias,equitable threat score(ETS),and Fractions Skill Score(FSS)showed improvements for different categories of *** bias of light rain forecasts overall adjusted towards smaller values,and the increase in forecast scores was greater in the warm season than in the cold *** ETS for torrential rain more intense categories significantly increased,although there were large fluctuations in bias across different *** model exhibited higher precipitation bias in most areas of North China,indicating overprediction,while it showed lower bias in South China,indicating *** ETSs indicate that the model performed better in forecasting precipitation in the northeastern part of China without the influence of climatic background *** of the differences between the first period and the second period of the forecast shows that the precipitation amplitude in the ECMWF forecast shifted from slight underestimation to overestimation compared to that of CMPAS05,reducing the likelihood of missing extreme precipitation *** improvement in ETS is mainly due to the reduction in bias and false alarm rates and,more importantly,an increase in the hit *** 2017 to 2022,the area coverage error of model precipitation forecast relative to observations showed a decreasing trend at different scales,while the FSS showed an increasing trend,with the highest FSS observed in *** ETS followed a parabolic trend with increasing neighborhood radius,with the better ETS neighborhood radius generally

关键词： ECMWF forecasting verification neighborhood verification FSS

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一种小型化低相噪恒温晶体振荡器的设计

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时间频率学报 2024年第2期47卷 97-103页

作者：戴昌名占开忠蒋松涛吴海钧成都天奥电子股份有限公司成都610036

在恒温晶体振荡器的工作原理及主要指标分析的基础上,通过采用低相噪电路设计技术,选用具有高Q值、低老化的SC切晶体谐振器,以保证恒温晶体振荡器的低相噪和高稳定度;通过高精度的温度控制电路设计技术以及合理的热结构设计,以实现恒温... 详细信息

在恒温晶体振荡器的工作原理及主要指标分析的基础上,通过采用低相噪电路设计技术,选用具有高Q值、低老化的SC切晶体谐振器,以保证恒温晶体振荡器的低相噪和高稳定度;通过高精度的温度控制电路设计技术以及合理的热结构设计,以实现恒温晶体振荡器的高频率温度稳定度。结果表明恒温晶体振荡器在小体积尺寸下(20mm×20mm×12mm),其相位噪声达到-110dBc/Hz@1Hz,短期稳定度达到6.85×10^(-13)/1s。

关键词：恒温晶体振荡器小型化高稳定度低相位噪声

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陕西低槽强降水过程分析及客观订正方法

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陕西气象 2024年第1期 1-9页

作者：刘嘉慧敏戴昌明胡启元李培荣李文耀陕西省气象台西安710014 陕西省气象局秦岭和黄土高原生态环境气象重点实验室西安710016

为了提高中纬度低槽东移影响下陕西强降水天气的精准预报能力,采用欧洲中期天气预报中心全球模式(简称EC-thin)、中国气象局数值天气预报全球模式(简称CMA-GFS)、中央气象台格点指导预报产品(简称SCMOC)、陕西省气象局自主研发动态交叉... 详细信息

为了提高中纬度低槽东移影响下陕西强降水天气的精准预报能力,采用欧洲中期天气预报中心全球模式(简称EC-thin)、中国气象局数值天气预报全球模式(简称CMA-GFS)、中央气象台格点指导预报产品(简称SCMOC)、陕西省气象局自主研发动态交叉取优产品(简称DCOEF)、多源实况融合资料及全省396个气象监测站资料,选取了陕西三次低槽东移背景下强降水过程(2019年6月4—5日关中、陕南暴雨过程,简称“0604”暴雨过程;2018年6月17—18日陕南暴雨过程,简称“0617”暴雨过程;2018年7月10—11日关中西部、陕北暴雨过程,简称“0710”暴雨过程),对比分析强降水的实况差异及影响系统演变特征,提炼预报着眼点。基于各模式前期预报质量,提出了一种简单的动态融合客观订正方法,检验了该方法在此类强降水过程中的预报效果。结果表明:(1)“0604”暴雨过程和“0617”暴雨过程强降水主要集中在陕西关中和陕南地区,“0710”暴雨过程强降水主要集中在陕西西部和北部地区;“0604”“0710”暴雨相较“0617”暴雨过程,强降水持续时间短,雨带移动速度快。(2)尽管这三次暴雨过程均发生在500 hPa中纬度低槽配合850 hPa低涡东移过程中,但低涡结构的发展演变及其强度变化的差异导致了三次暴雨落区、强度、主要降水性质的不同;三次暴雨过程中850 hPa低涡发展在白天和夜晚均存在加强阶段。(3)基于加权评分的多模式动态融合强降水订正方法在低槽强降水过程中大雨以上量级、暴雨以上量级TS评分相较单一模式产品均有小幅度提高,在长历时的系统性强降水过程中提高更多,表现出一定的正订正效果,可为陕西此类强降水天气预报提供客观参考。

关键词：强降水低涡发展多模式融合客观订正

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Mechanical Modeling and Analysis of Stability Deterioration of Production Well During Marine Hydrate Depressurization Production

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China Ocean Engineering 2024年第2期38卷 338-351页

作者： SUN Huan-zhao chang Yuan-jiang SUN Bao-jiang WANG Kang CHEN Guo-ming LI Hao dai Yong-guo Centre for Offshore Engineering and Safety Technology China University of Petroleum(East China)Qingdao 266580China School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China Jiangsu Shuguang Oil Tools Co. LtdTaizhou 225532China

Different from oil and gas production,hydrate reservoirs are shallow and unconsolidated,whose mechanical properties deteriorate with hydrate ***,the formations will undergo significant subsidence during depressurization,which will destroy the original force state of the production ***,existing research on the stability of oil and gas production wells assumes the formation to be stable,and lacks consideration of the force exerted on the hydrate production well by formation subsidence caused by hydrate decomposition during *** fill this gap,this paper proposes an analytical method for the dynamic evolution of the stability of hydrate production well considering the effects of hydrate *** on the mechanical model of the production well,the basis for stability analysis has been proposed.A multi-field coupling model of the force state of the production well considering the effect of hydrate decomposition and formation subsidence is established,and a solver is *** analytical approach is verified by its good agreement with the results from the numerical method.A case study found that the decomposition of hydrate will increase the pulling-down force and reduce the supporting force,which is the main reason for the stability *** higher the initial hydrate saturation,the larger the reservoir thickness,and the lower the production pressure,the worse the stability or even *** work can provide a theoretical reference for the stability maintaining of the production well.

关键词： natural gas hydrate production well depressurization production formation deformation stability deterioration

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Trotter–Kato Approximations of Impulsive Neutral SPDEs in Hilbert Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1229-1243页

作者： ming LIU Xia ZHANG Ling Fei dai School of Mathematical Sciences Tiangong UniversityTianjin 300387P.R.China

This paper studies a class of impulsive neutral stochastic partial differential equations in real Hilbert *** main goal here is to consider the Trotter-Kato approximations of mild solutions of such equations in the pth-mean(p≥2).As an application,a classical limit theorem on the dependence of such equations on a parameter is *** novelty of this paper is that the combination of this approximating system and such equations has not been considered before.

关键词： Impulsive neutral stochastic partial diferential equation Trotter-Kato approximations classical limit theorem

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Supramolecular polymer-based gel fracturing fluid with a double network applied in ultra-deep hydraulic fracturing

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Petroleum Science 2024年第3期21卷 1875-1888页

作者： Yong-Ping Huang Yong Hu chang-Long Liu Yi-Ning Wu Chen-Wei Zou Li-Yuan Zhang ming-Wei Zhao Cai-Li dai School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongPR China Shandong Key Laboratory of Oilfield Chemistry China University of Petroleum(East China)Qingdao 266580ShandongPR China SINOPEC Petroleum Exploration and Production Research Institute Beijing102206PR China CNOOC China Co Ltd Tianjin BranchTianjin300459PR China

A gel based on polyacrylamide,exhibiting delayed crosslinking characteristics,emerges as the preferred solution for mitigating degradation under conditions of high temperature and extended shear in ultralong *** viscosity/viscoelasticity of the fracturing fluid was required to maintain excellent proppant suspension properties before *** into account both the cost and the potential damage to reservoirs,polymers with lower concentrations and molecular weights are generally *** this work,the supramolecular action was integrated into the polymer,resulting in significant increases in the viscosity and viscoelasticity of the synthesized supramolecular polymer *** double network gel,which is formed by the combination of the supramolecular polymer system and a small quantity of Zr-crosslinker,effectively resists temperature while minimizing permeability damage to the *** results indicate that the supramolecular polymer system with a molecular weight of(268—380)×10^(4)g/mol can achieve the same viscosity and viscoelasticity at 0.4 wt%due to the supramolecular interaction between polymers,compared to the 0.6 wt%traditional polymer(hydrolyzed polyacrylamide,molecular weight of 1078×10^(4)g/mol).The supramolecular polymer system possessed excellent proppant suspension properties with a 0.55 cm/min sedimentation rate at 0.4 wt%,whereas the0.6 wt%traditional polymer had a rate of 0.57 cm/*** comparison to the traditional gel with a Zrcrosslinker concentration of 0.6 wt%and an elastic modulus of 7.77 Pa,the double network gel with a higher elastic modulus(9.00 Pa)could be formed only at 0.1 wt%Zr-crosslinker,which greatly reduced the amount of residue of the fluid after *** viscosity of the double network gel was66 m Pa s after 2 h shearing,whereas the traditional gel only reached 27 m Pa s.

关键词： Ultra-deep reservoir Gel fracturing fluid Double network Supramolecular polymer system Proppant suspension property

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Effect of liquid surface depression size on discharge characteristics and chemical distribution in the plasma-liquid anode system

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Plasma Science and Technology 2024年第9期26卷 17-31页

作者： Yun LING Dong dai Jiaxin chang Buang WANG School of Electric Power South China University of TechnologyGuangzhou 510641People’s Republic of China University of Richmond Richmond 23173United States of America

Atmospheric pressure plasma-liquid interactions exist in a variety of applications,including wastewater treatment,wound sterilization,and *** practice,the phenomenon of liquid surface depression will inevitably *** applied gas will cause a depression on the liquid surface,which will undoubtedly affect the plasma generation and further affect the application ***,the effect of liquid surface deformation on the plasma is still *** this work,numerical models are developed to reveal the mechanism of liquid surface depressions affecting plasma discharge characteristics and the consequential distribution of plasma species,and further study the influence of liquid surface depressions of different sizes generated by different helium flow rates on the *** show that the liquid surface deformation changes the initial spatial electric field,resulting in the rearrangement of electrons on the liquid *** charges deposited on the liquid surface further increase the degree of distortion of the electric ***,the electric field and electron distribution affected by the liquid surface depression significantly influence the generation and distribution of active species,which determines the practical effectiveness of the relevant *** work explores the phenomenon of liquid surface depression,which has been neglected in previous related work,and contributes to further understanding of plasma-liquid interactions,providing better theoretical guidance for related applications and technologies.

关键词： plasma-liquid interaction deformation of the liquid surface liquid anode species fluxes

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In-situ measurement via the flow-through method and numerical simulations for radon exhalation during measurements of the radon exhalation rate

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Nuclear Science and Techniques 2024年第7期35卷 192-207页

作者： ming Xia Yong-Jun Ye Shan-Wei Shang Ting Yu dai-Jia Chen School of Resources Environment and Safety Engineering University of South ChinaHengyang421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang421001China

Small-scale measurements of the radon exhalation rate using the flow-through and closed-loop methods were conducted on the surface of a uranium tailing pond to better understand the differences between the two *** abnormal radon exhalation behavior was observed,leading to computational fluid dynamics(CFD)-based simulations in which dynamic radon migration in a porous medium and accumulation chamber was *** on the in-situ experimental and numerical simulation results,variations in the radon exhalation rate subject to permeability,flow rate,and insertion depth were quantified and *** in-situ radon exhalation rates measured using the flow-through method were higher than those measured using the closed-loop method,which could be explained by the negative pressure difference between the inside and outside of the chamber during the *** consistency of the variations in the radon exhalation rate between the experiments and simulations suggests the reliability of CFD-based techniques in obtaining the dynamic evolution of transient radon exhalation rates for diffusion and convection at the porous medium-air *** synergistic effects of the three factors(insertion depth,flow rate,and permeability)on the negative pressure difference and measured exhalation rate were quantified,and multivariate regression models were established,with positive correlations in most cases;the exhalation rate decreased with increasing insertion depth at a permeability of 1×10^(−11) m^(2).CFD-based simulations can provide theoretical guidance for improving the flow-through method and thus achieve accurate measurements.

关键词： Radon exhalation Flow-through Numerical simulation Accumulation chamber Multivariate regression

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Global Spherically Symmetric Solutions for a Coupled Compressible Navier–Stokes/Allen–Cahn System

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Acta Mathematica Sinica,English Series 2024年第8期40卷 2037-2064页

作者： chang ming SONG Jian Lin ZHANG Yuan Yuan WANG Department of Applied Mathematics School of Mathematics and Information ScienceZhongyuan University of TechnologyZhengzhou 450007P.R.China

In this paper,we consider the global spherically symmetric solutions for the initial boundary value problem of a coupled compressible Navier–Stokes/Allen–Cahn system which describes the motion of two-phase viscous compressible *** prove the existence and uniqueness of global classical solution,weak solution and strong solution under the assumption of spherically symmetry condition for initial dataρ0 without vacuum state.

关键词： Diffuse interface model global solutions Navier-Stokes equations Allen-Cahn equation spherically symmetry

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Rational design of superior catalysts from topological semimetals with nontrivial energy window

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Rare Metals 2024年第5期43卷 1956-1964页

作者： Min Zhao Li-Rong Wang Wei Liu ming-Hang Li Ying Liu Xue-Fang dai Guo-Dong Liu Xiao-ming Zhang Key Laboratory of Reliability and Intelligence of Electrical Equipment School of Materials Science and Engineering ManufacturingHebei University of TechnologyTianjin 300130China

Materials featuring topological energy bands and nontrivial surface states hold significant promise in unlocking unprecedented opportunities for innovating electrocatalytic ***,it remains a challenge to realize superior topological catalysts which can carry both high catalytic activity and excellent catalytic ***,we propose that a family of Ni-based binary materials hosting fantasying topological conjunct-nodalpoint state and a large nontrivial energy window(NEWD)represents an ideal choice for such superior topological catalysts in hydrogen evolution *** presence of conjunct-nodal-points ensures long Fermi arcs on the surface,thereby enabling an extremely high catalytic *** NEWD plays a crucial role in stabilizing the high catalytic activity against external perturbations,such as strain and electron/hole *** roles for conjunctnodal-points and NEWD are substantiated by the observable weakening of catalytic performance during topological phase transitions,which result in the removal of the conjunct-nodal-points,NEWD and their corresponding long Fermi *** work unveils a hidden mechanism and opens a feasible route for developing superior quantum catalysts from novel topology point of view.

关键词： First-principles modeling Topological semimetal Nontrivial surface states Hydrogen evolution reaction

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