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Predictability of Ensemble Forecasting Estimated Using the Kullback–Leibler Divergence in the Lorenz Model

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Advances in Atmospheric Sciences 2019年第8期36卷 837-846页

作者： Ruiqiang DING Baojia liU Bin GU jianping li Xuan li State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth Sciences University of Chinese Academy of SciencesBeijing 100049China Institute of Space Weather School of Math and StatisticsNanjing University of Information Science and TechnologyNanjing 210044China College of Physics and Optoelectronic Engineering Nanjing University of Information Science and TechnologyNanjing 210044China College of Global Change and Earth System Sciences Beijing Normal UniversityBeijing 100875China

A new method to quantify the predictability limit of ensemble forecasting is presented using the Kullback–Leibler(KL)divergence(also called the relative entropy), which provides a measure of the difference between the probability distributions of ensemble forecasts and local reference(true) states. The KL divergence is applicable to a non-normal distribution of ensemble forecasts, which is a substantial improvement over the previous method using the ensemble spread. An example from the three-variable Lorenz model illustrates the effectiveness of the KL divergence, which can effectively quantify the predictability limit of ensemble forecasting. On this basis, the KL divergence is used to investigate the dependence of the predictability limit of ensemble forecasting on the initial states and the magnitude of initial errors. The local predictability limit of ensemble forecasting varies considerably with the initial states, as well as with the magnitude of initial errors. Further research is needed to examine the real-world applications of the KL divergence in measuring the predictability of ensemble weather forecasts.

关键词： predictability ensemble forecasting Kullback–Leibler divergence

Supply of terrigenous organic matter from tidal flat to the marine environment:An example of neritic source rocks in the Eocene Pinghu Formation,Xihu Depression,East China Sea Shelf Basin

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Acta Oceanologica Sinica 2023年第3期42卷 138-150页

作者： Shanshan Zhou Youchuan li jianping li Wenjing Ding Xin li Weilai Zhang China National Offshore Oil Corporation(CNOOC)Research Institute Co. Ltd.Beijing 100028China School of Chemical Engineering and Environment China University of Petroleum(Beijing)Beijing 102200China

The terrigenously-dominated marine shales which were deposited in the lower Eocene Pinghu Formation were thought to be a potential source rock in the Xihu Depression of the East China Sea Shelf ***,the exceptionally high total organic carbon content(TOC,>6%on average)of the tidal sand ridge samples was not compatible with their sedimentary environment,indicating coal-bearing sedimentary debris may have been transferred from the coast to the *** this study,new sights into the origins and supply of organic materials in the coastal environment were proposed in the neritic organic matter of the Eocene Pinghu Formation.A discriminant model was developed using plynofacies analysis data to pinpoint the source of organic materials in marine source *** discrimination results suggested that marine mudstones were associated with tidal flat mudstones rather than deltaic *** biomarker characteristics of mudstones deposited in various environments support this assertion,indicating that the supply of plant materials in tidal flats is the primary organic matter source for the marine *** organic matter abundance was elevated in tidal flats due to their superior preservation ***,the lithological assemblage of tidal flats suggests that tidal currents can scour marshes and then transport dispersed terrigenous organic materials to neritic *** findings indicate that coal-bearing sedimentary debris was likely transferred from the coast to the ocean,and tidal currents are thought to be the dominant mechanism driving organic matter from the tidal to the marine environment.

关键词： terrestrial organic matter neritic source rocks palynofacies analysis discriminant analysis

Numerical analysis of rainfall infiltration in the slope with a fracture

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Science China(Technological Sciences) 2005年第Z1期48卷 107-120页

作者： FAN Ping liU Qingquan li Jiachun SUN jianping Division of Engineering Science Institute of Mechanics Chinese Academy of Sciences Beijing 100080China Division of Engineering Science Institute of Mechanics Chinese Academy of Sciences Beijing 100080China Division of Engineering Science Institute of Mechanics Chinese Academy of Sciences Beijing 100080China Division of Engineering Science Institute of Mechanics Chinese Academy of Sciences Beijing 100080China

With the finite volume method, a 2D numerical model for seepage in unsaturated soil has been established to study the rainfall infiltration in the fractured slope. The result shows that more rain may infiltrate into the slope due to existing fracture and then the pore pressure rises correspondingly. Very probably, it is one of the crucial factors accounting for slope failure. Furthermore a preliminary study has been conducted to investigate the influence of various fracture and rainfall factors such as the depth, width and location of a crack, surface condition, rainfall intensity and duration. Pore pressure and water volumetric content during the transient seepage are carefully examined to reveal the intrinsic mechanism.

关键词： fracture slope, rainfall infiltration, numerical simulation.

Numerical study of coarse coal particle breakage in pneumatic conveying

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Particuology 2018年第3期16卷 204-214页

作者： Jiawei Zhou Yu liu Changlong Du Songyong liu jianping li School of Mechatronic Engineering China University of Mining and Technology Xuzhou 221116 Jiangsu China School of Mechanical and Power Engineering Henan Polytechnic University Jiaozuo 454000 Henan China

Pneumatic conveying of coarse coal particles with various pipeline configurations and swirling intensities was investigated using a coupled computational fluid dynamics and discrete element method. A particle cluster agglomerated by the parallel-bond method was modeled to analyze the breakage of coarse coal particles. The numerical parameters, simulation conditions, and simulation results were experimentally validated. On analyzing total energy variation in the agglomerate during the breakage process, the results showed that downward fluctuation of the total particle energy was correlated with particle and wall col- lisions, and particle breakage showed a positive correlation with the energy difference. The correlation between the total energy variation of a particle cluster and particle breakage was also analyzed. Parti- cle integrity presented a fluctuating upward trend with pipe bend radius and increased with swirling number for most bend radii. The degree of particle breakage differed with pipeline bending direction and swirling intensity： in a horizontal bend, the bend radius and swirling intensity dominated the total energy variations： these effects were not observed in a vertical bend. The total energy of the particle cluster exiting a bend was generally positively correlated with the bend radius for all conditions and was independent of bending direction.

关键词： Computational fluid dynamics-discreteelement method Pneumatic conveying Pipeline configuration Swirling intensity Coarse coal particle Breakage

The Chemical Kinetics in Migration of Organophosphorus in Clay with Different pH

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Acta Geologica Sinica(English Edition) 2013年第4期87卷 1162-1167页

作者： li Hongyan ZHANG Guangxin SONG Dingfeng WANG Yanliang li jianping li Xuqian Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Jilin Institute of Geo-Environment Monitoring SIPPR Engineering Group Co. Ltd limited Company of Metallurgy Engineering of China College of Environment and Resources Jilin University

In order to study the characters of chemical kinetics for organophosphorus migration in clay with different pH, waste of organophosphorus was put under pressure to leakage permeating the cohesive soil, and simulate the process of organophosphorus leakage permeating the Aquitard, searching the characters of chemical kinetics for organophosphorus migration in clay with different pH. It is shown that the ability of migration of organophosphorus leakage permeating the cohesive soil fall with increase of pH; the penetration rate of organophosphorus is about 1.25% when pH is 7.5, organophosphorus has not penetrated the cohesive soil when pH is equal or greater than 8.5. The effect of retardarce is obvious. Concentration of PO43？ that comes from the mineralization of organophosphorus is lowered slightly with increases of pH of clay, and rise with extension of time. The Chemical Kinetics equation is log c=-0.1pH＋0.2172k1t＋S.

关键词： Organophosphorus pH dynamics of migration

Experimental study of high to intermediate temperature alteration in porphyry copper systems and geological implications

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Science China Earth Sciences 2019年第3期62卷 550-570页

作者： jianping li Huayong CHEN Long SU Bing XIAO Yunfeng WANG Key Laboratory of Mineralogy and Metallogeny/Guangdong Provincial Key Laboratory of Mineral Physics and Materials Guangzhou Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Petroleum Resources Gansu Province/Key Laboratory of Petroleum Resources ResearchInstitute of Geology and Geophysics Chinese Academy of Sciences

Porphyry copper systems, which provide most of the world's copper resource, are commonly associated with characteristic concentric zonation of alteration and mineralization. In-depth knowledge of the distribution and transport mechanism of elements in the alteration zones is essential for understanding the ore-forming processes. We employed flow-reaction apparatus to simulate the fluid-rock interactions during porphyry ore formation so as to investigate the mechanisms that govern the transport of elements and the development of zonation. The results indicate more heterogeneous distribution of elements in the experimental products at 450°C compared to those at lower temperatures, which implies a crucial role of temperature in controlling elements redistribution in hydrothermal systems. Heating advances potassic alteration and Ca leaching of wall *** achieve the same degree of sodic alteration, it requires a higher concentration of Na+in the fluid toward higher *** also facilitates the incorporation of Ti, Sr and Pb into silicate minerals through cation substitution. We infer from experimental results that from the center of intermediate to mafic volcanic wall rocks toward periphery, the contents of K and Ti should decrease and the contents of Ca, Zn and Mn should increase, whereas the trend for Si and Na could be *** study provides experimental and theoretical insights into a variety of vital geological observations, including anhydrite formation and the widespread development of potassic rather than sodic alteration in porphyry copper deposits.

关键词： Porphyry copper deposit Fluid-rock interactions Flowing systems Elements transport mechanism

Direct-impact of sieving coal and gangue

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Mining Science and Technology 2010年第4期20卷 611-614页

作者： li jianping DU Changlong BAO Jianwei School of Mechanical and Electrical Engineering China University of Mining&TechnologyXuzhou 221116China

Gangue from underground separation of coal can directly be used for filling mined out areas, saving transport capacity and reducing the amount of waste polluting the environment above the ground. We introduced a structure and operating principle of an underground direct-impact sieving device by which a separation experiment was carried out. By means of high speed conveyer belts, coal and gangue impacted the breaking board at high speeds ranging from 6 to 14 m/s. Given the differences of hardness between coal and gangue, after selective crushing, the gangue with the higher hardness was crushed less and coal with lower hardness crushed more, which could be separated by a 50 mm sieving plate. The material above the sieving plate was disposed of as gangue and the material below as coal. The results indicate that the crush ratio below the 50 mm sieving plate increases linearly with an increase in impact velocity and decays exponentially with an increase in hardness. Employing this equipment to separate coal and gangue, the hardness of coal f should be <2. This separation device provides relatively good effect in separating coal and gangue with a relatively wide difference of hardness.

关键词： separation of coal and gangue direct-impact sieving difference of hardness selective crushing

Connection between earthquakes and deep fluids revealed by magnetotelluric imaging in Songyuan,China

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Science China Earth Sciences 2021年第1期64卷 161-176页

作者： Yu TANG Aihua WENG Yue YANG Shiwen li Jianjun NIU Yanhui ZHANG Yabin li jianping li College of Geo-exploration Sciences&Technology Jilin UniversityChangchun 130026China First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China China Aero Geophysical Survey and Remote Sensing Center for Natural Resources Beijing 100083China Construction Engineering College of Jilin University Changchun 130026China Guangzhou Marine Geological Survey China Geological SurveyGuangzhou 510760China

Songyuan is the most earthquake prone area in northeast *** 2006,earthquakes have occurred in the area in the form of swarms,with a maximum magnitude of M_*** is much controversy about the cause of the Songyuan *** attempted to determine the cause using a three-dimensional electrical conductivity structure inverted from a regional network of magnetotelluric data in the Songyuan *** L-BFGS inversion method was applied,with a fullimpedance tensor data set used as the inversion *** with an evaluation of the earthquake locations,the resistivity model revealed a northeast-oriented hidden fault running through the Songyuan earthquake area(SEA),which was speculated to be the preexisting Fuyu-Zhaodong Fault(FZF).Our resistivity model also found an apparent lithospheric low-resistivity anomaly beneath the earthquake area,which breached the high-resistivity lithospheric mantle and stalled at the base of the crust.A petrophysical analysis showed that this lower crustal low-resistivity anomaly was most likely attributed to hydrated partial melting,which could release water into the lower crust during later magma *** weakening the strength of the FZF,these ascending fluids also increased the pore pressure in the fault,further reducing the shear strength of the *** stress action(a fault strike component of the east-west regional compress),together with possible near-surface disturbances,may drive the fault to slip and trigger the earthquakes in *** is possible that the continuous replenishment of fluids from the deeper mantle forces the Songyuan earthquakes into the form of *** infer that the Songyuan earthquakes could be attributed to a combination of preexisting faults,regional stress,and deep fluids associated with plate subduction,and near surface disturbances might induce the earthquakes in *** Songyuan earthquakes are inherently induced earthquakes,fed by deep fluids.

关键词： Magnetotelluric Electrical resistivity Deep fluids Induced earthquakes Northeast China

Role of Ferrel cell in daily variability of Northern Hemisphere Annular Mode

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Chinese Science Bulletin 2014年第27期59卷 3457-3464页

作者： Xiao-Feng li jianping li Xiangdong Zhang Cheng Sun State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences International Arctic Research Center University of Alaska Fairbanks Fairbanks Alaska 99775 USA

The Northern Hemisphere Annular Mode(NAM) represents the zonally symmetric planetary-scale atmospheric mass fluctuations between middle and high latitudes, whose variations have shown a large impact on other components of the climate system. Previous studies have indicated that the NAM is correlated with the Ferrel cell in their monthly or longer timescale ***, there have been few studies investigating their connections at daily timescale, though daily variability of NAM has been suggested to be an important component and has significant implication for weather forecast. The results from this study demonstrate that variability of the Ferrel cell leads that of the NAM by about 1–2 days. This statistically identified temporal phase difference between NAM and Ferrel cell variability can be elucidated by meridional mass redistribution. Intensified(weakened)Ferrel cell causes anomalously smaller(larger) poleward mass transport from the middle to the high latitudes,resulting in an increase(a decrease) in mass in the middle latitudes and a decrease(an increase) in the high *** a consequence, anomalously higher(lower) poleward pressure gradient forms and the NAM subsequently shifts to a positive(negative) phase at a time lag of 1–2 days. The findings here would augment the existing knowledge for better understanding the connection between the Ferrel Cell and the NAM, and may provide skillful information for improving NAM as well as daily scale weather prediction.

关键词：环流变化北半球异性日变环状高纬度地区大气质量时间尺度