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Advantages of the Multimodel Ensemble Approach for Subseasonal Precipitation Prediction in China and the Driving Factor of the MJO

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Advances in Atmospheric Sciences 2025年第3期42卷 551-563页

作者： Li GUO Jie WU Qingquan LI Xiaolong JIA China Meteorological Administration Key Laboratory for Climate Prediction studies National Climate CentreBeijing 100081China Collaborative Innovation centre On Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjing 210066China

Based on the hindcasts from five subseasonal-to-seasonal(S2S)models participating in the S2S Prediction Project,this study evaluates the performance of the multimodel ensemble(MME)approach in predicting the subseasonal precipitation anomalies during summer in China and reveals the contributions of possible driving *** results suggest that while single-model ensembles(SMEs)exhibit constrained predictive skills within a limited forecast lead time of three pentads,the MME illustrates an enhanced predictive skill at a lead time of up to four pentads,and even six pentads,in southern *** on both deterministic and probabilistic verification metrics,the MME consistently outperforms SMEs,with a more evident advantage observed in probabilistic *** superior performance of the MME is primarily attributable to the increase in ensemble size,and the enhanced model diversity is also a contributing *** reliability of probabilistic skill is largely improved due to the increase in ensemble members,while the resolution term does not exhibit consistent ***,the Madden–Julian Oscillation(MJO)is revealed as the primary driving factor for the successful prediction of summer precipitation in China using the *** improvement by the MME is not solely attributable to the enhancement in the inherent predictive capacity of the MJO itself,but derives from its capability in capturing the more realistic relationship between the MJO and subseasonal precipitation anomalies in *** study establishes a scientific foundation for acknowledging the advantageous predictive capability of the MME approach in subseasonal predictions of summer precipitation in China,and sheds light on further improving S2S predictions.

关键词： multimodel ensemble subseasonal predictions summer precipitation S2S model MJO

Deepening Collaboration China and Africa need to further align development strategies to realise the immense potential of economic cooperation

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ChinAfrica 2025年第1期17卷 24-26页

作者： EHIZUELEN MICHAEL MITCHELL OMORUYI centre for Nigerian studies Institute of African StudiesZhejiang Normal University

Humming factories,bustling ports,and shuttling merchants highlight the vibrancy of China-Africa economic and trade *** the years,this partnership has grown significantly,optimising trade structures and fostering mutual *** deepening collaboration is evident in China’s role as Africa’s largest bilateral trading partner for 15 consecutive *** the first seven months of 2024,trade between China and African countries reached$167 billion,reflecting a 5.5-percent increase compared to the same period in *** to the International Monetary Fund,approximately 20 percent of Africa’s exports now go to China,while 16 percent of its imports originate there.

关键词： trading deepening Africa

Trump Set to Reshape Africa Policy Trump’s return to the White House spells trouble for Africa

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ChinAfrica 2025年第3期17卷 14-15页

作者： ZHANG CHUN the Academic Committee Centre for African StudiesYunnan University

During his second White House term,Trump’s governing style remains characteristically assertive,launching a full-scale offensive from day ***,he’s pushing for sweeping government reforms.

关键词： return House Trump

Distribution and mapping of temperate savanna in the sandy lands of eastern China

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Science China Earth Sciences 2025年第1期68卷 128-141页

作者： Xiaoya LI Feng WANG Tao DUAN Kaijie YANG Bin YANG Chunmei WANG Xin TIAN Qi LU Institute of Ecological Conservation and Restoration Institute of Desertification StudiesChinese Academy of ForestryBeijing100091China Institute of Desertification Institute of Desertification StudiesChinese Academy of ForestryBeijing100091China Institute of Great Green Wall Bayan Nur015200China Satellite Application centre for Ecology and Environment MEEBeijing100094China Institute of Microelectronics Chinese Academy of SciencesBeijing100029China Aerospace Information Research Institute Chinese Academy of SciencesBeijing100094China Institute of Forest Resource Information Techniques Chinese Academy of ForestryBeijing100091China

Savannas are distributed globally across various *** perform a significant socioeconomic role in regulating net primary productivity and the terrestrial carbon *** to the high spatial heterogeneity induced by the mixed distribution of trees and grasses,current global land-cover classification maps often classify savannas as forests or grasslands Temperate savannas in China cover a vast area,yet their spatial patterns and extent remain poorly *** study developed a novel remote sensing temperate savannas mapping method by integrating very high-resolution(VHR)unmanned aerial vehicle(UAV)and GF-6 satellite imagery based on the vegetation structure characteristics of temperate savannas using the FAO definition of *** and validation datasets were collected from VHR UAV imagery covering the main temperate savannah types with a ground area of 1818 *** fractional woody vegetation cover(FWVC)and fractional herbaceous vegetation cover(FHVC)in temperate savannas were estimated by integrating Classification and Regression Tree and Random Forest *** current distribution of temperate savannas in the Horqin and Otindag Sandy Lands of Eastern China was mapped to a unit area of 0.5 *** root-mean-square error(RMSE)values for the FWVC and FHVC models were 10.69%and 11.67%,and the R^(2)values were 0.66 and 0.63,*** assessment indicated that the new temperate savanna map had high identification accuracy,with a Kappa coefficient of 0.70,overall accuracy of 0.88,and average accuracy of *** savannas in the sandy lands of eastern China were primarily distributed in the northern Horqin Sandy Land the central and eastern regions of the Otindag Sandy Land,and the transition zone from the southern slopes of the Greater Khingan Mountains to the plains,covering a total area of 3.27×10^(6)*** main savannah types were elm,oak/maple,and shrub *** savannas were widely distributed in the Otindag Sandy Land a

关键词： Temperate savanna UAV imagery GF-6 Fractional woody vegetation cover Fractional herbaceous vegetation cover Machine learning

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Laser-assisted ablation and plasma formation of titanium explored by LIBS,QCM, optical microscopy and SEM analyses along with mechanical modifications under different pressures of Ar and Ne

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Plasma Science and Technology 2023年第3期25卷 181-192页

作者： Maryam RIAZ Shazia BASHIR Asma HAYAT Zarish NAZ centre for advanced studies in Physics GC University Lahore

This study deals with the investigation of Nd:YAG laser-assisted ablation and plasma formation of Ti at irradiance of 0.85 GW cm-2 under Ar and Ne environment at various pressures ranging from 10-120 ***-induced breakdown spectroscopy is used to evaluate plasma parameters,whereas quartz crystal microbalance is used for ablation yield *** crater depth is evaluated by optical *** surface features are explored by scanning electron microscope(SEM) analysis and the micro-hardness is measured by a Vickers hardness *** is observed that the plasma parameters are higher in Ar than in Ne,and are strongly correlated with the ablation yield,ablation depth,surface features and hardness of laser-ablated *** parameters increase with increasing the pressure of environmental gases,attain their maxima at 40 Torr for Ar and at 60 Torr for ***,they show a decreasing trend up till a maximum pressure of 120 *** maximum value of the electron temperature(Te) is5480 K,number density(ne) is 1.46 × 1018 cm-3,ablation depth is 184 μm,ablation yield is3.9 × 1015 atoms/pulse and hardness is 300 HV in the case of Ar *** analysis reveals the growth of surface features,such as cones,ridges and pores,whose appearance is more distinct in Ar than Ne and is attributed to temperature,pressure and density gradients along with recoil pressure of the Ti plasma.

关键词： ablation plasma electron temperature electron density laser-induced breakdown spectroscopy surface structures

Energy and flux measurements of laser-induced silver plasma ions by using Faraday cup

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Plasma Science and Technology 2021年第8期23卷 188-198页

作者： Muhammad Usman Aslam BHATTI Shazia BASHIR Asma HAYAT Khaliq MAHMOOD Rana AYUB Mubashir JAVED Muhammad Shahzad KHAN centre for advanced studies in Physics(CASP) GC UniversityLahore 54000Pakistan

Silver(Ag)plasma has been generated by employing Nd:YAG laser(532 nm,6 ns)laser *** energy and flux of ions have been evaluated by using Faraday cup(FC)using time of flight(TOF)*** dual peak signals of fast and slow Ag plasma ions have been *** energy and flux of fast and slow ions tend to increase with increasing irradiance from 7 GW cm-2 to 17.9 GW cm-2 at all distances of FC from the target *** a decreasing trend of energies and flux of ions has been observed with increasing distance of FC from the *** maximum value of flux of the fast component is21.2×10^(10) cm^(-2),whereas for slow ions the maximum energy and flux values are 8.8 keV,8.2×10^(10) cm^(-2) *** the analysis of plume expansion dynamics,the angular distribution of ion flux measurement has also been *** overall analysis of both spatial and angular distributions of Ag ions revealed that the maximum flux of Ag plasma ions has been observed at an optimal angle of~15°.In order to confirm the ion acceleration by ambipolar field,the self-generated electric field(SGEF)measurements have also been performed by electric probe;these SGEF measurements tend to increase by increasing laser *** maximum value of 232 V m^(-1) has been obtained at a maximum laser irradiance of 17.9 GW cm^(-2).

关键词： laser ablation laser-induced plasma ions Faraday cup time of flight measurements self-generated electric field angular distribution

Ternary Hybrid Nanofluid with First and Second Order Velocity Slips: Dual Solutions with Stability Analysis

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Computer Modeling in Engineering & Sciences 2025年第2期142卷 1865-1881页

作者： Nur Syahirah Wahid Nor Ain Azeany Mohd Nasir Norihan Md Arifin Ioan Pop Department of Mathematics and Statistics Faculty of ScienceUniversiti Putra Malaysia(UPM)Serdang43400Malaysia Department of Mathematics Centre for Defence Foundation StudiesUniversiti Pertahanan Nasional MalaysiaKuala Lumpur57000Malaysia Institute for Mathematical Research Universiti Putra Malaysia(UPM)Serdang43400Malaysia Department of Mathematics Babes-Bolyai UniversityCluj-Napoca400084Romania Academy of Romanian Scientists Bucharest050044Romania

Modeling the boundary layer flow of ternary hybrid nanofluids is important for understanding and optimizing their thermal performance,particularly in applications where enhanced heat transfer and fluid dynamics are *** study numerically investigates the boundary layer flow of alumina-copper-silver/water nanofluid over a permeable stretching/shrinking sheet,incorporating both first and second-order velocity *** mathematical model is solved in MATLAB facilitated by the bvp4c function that employs the finite difference scheme and Lobatto IIIa *** solver successfully generates dual solutions for the model,and further analysis is conducted to assess their *** findings reported that only one of the solutions is *** the shrinking sheet case,increasing the first-order velocity slip delays boundary layer separation and enhances heat transfer,while,when the sheet is stretched,the second-order velocity slip accelerates separation and improves heat *** layer separation is most likely to occur when the sheet is shrinking;however,this can be controlled by adjusting the velocity slip with the inclusion of boundary layer suction.

关键词： Boundary layer ternary hybrid nanofluid stretching/shrinking velocity slip

Antiproton-nucleus reactions at intermediate energies

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Nuclear Science and Techniques 2015年第2期26卷 104-110页

作者： Alexei Borisovich Larionov Frankfurt Institute for advanced studies National Research centre Kurchatov Institute

Antiproton-induced reactions on nuclei at the beam energies from hundreds Me V up to several Ge V provide an excellent opportunity to study interactions between the antiproton and secondary particles(mesons, baryons and antibaryons) with nucleons. The antiproton projectile is unique in the sense that most of the annihilation particles are relatively slow in the target nucleus frame. Hence, the prehadronic effects do not much influence their interactions with the nucleons of the nuclear residue. Moreover, the particles with momenta less than about 1 Ge V/c are sensitive to nuclear mean field potentials. This paper discusses the microscopic transport calculations of the antiproton-nucleus reactions and is focused on three related problems:(i) antiproton potential determination,(ii) possible formation of strongly bound antiproton-nucleus systems, and(iii) strangeness production.

关键词：原子核反应反质子能量相互作用次级粒子核平均场核系统 iii

Flow on oscillating rectangular duct for Maxwell fluid

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Applied Mathematics and Mechanics(English Edition) 2012年第6期33卷 717-730页

作者： M.NAZAR F.SHAHID M.SAEED AKRAM Q.SULTAN centre for advanced studies in Pure and Applied Mathematics Bahauddin Zakariya University

This paper presents an analysis for the unsteady flow of an incompress- ible Maxwell fluid in an oscillating rectangular cross section. By using the Fourier and Laplace transforms as mathematical tools, the solutions are presented as a sum of the steady-state and transient solutions. For large time, when the transients disappear, the solution is represented by the steady-state solution. The solutions for the Newtonian fluids appear as limiting cases of the solutions obtained here. In the absence of the fre- quency of oscillations, we obtain the problem for the flow of the Maxwell fluid in a duct of a rectangular cross-section moving parallel to its length. Final!y, the required time to reach the steady-state for sine oscillations of the rectangular duct is obtained by graphical illustrations for different parameters. Moreover, the graphs are sketched for the velocity.

关键词： Maxwell fluid oscillating rectangular duct velocity field