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Coupling Ensemble Kalman Filter with Four-dimensional Variational Data Assimilation

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Advances in Atmospheric Sciences 2009年第1期26卷 1-8页

作者： fuqing ZHAnG Meng ZHAnG James A. HAnSEn Department of Meteorology Pennsylvania State University University Park Pennsylvania USA navy Research Laboratory Monterrey California USA

This study examines the performance of coupling the deterministic four-dimensional variational assimilation system （4DVAR） with an ensemble Kalman filter （EnKF） to produce a superior hybrid approach for data assimilation. The coupled assimilation scheme （E4DVAR） benefits from using the state-dependent uncertainty provided by EnKF while taking advantage of 4DVAR in preventing filter divergence： the 4DVAR analysis produces posterior maximum likelihood solutions through minimization of a cost function about which the ensemble perturbations are transformed, and the resulting ensemble analysis can be propagated forward both for the next assimilation cycle and as a basis for ensemble forecasting. The feasibility and effectiveness of this coupled approach are demonstrated in an idealized model with simulated observations. It is found that the E4DVAR is capable of outperforming both 4DVAR and the EnKF under both perfect- and imperfect-model scenarios. The performance of the coupled scheme is also less sensitive to either the ensemble size or the assimilation window length than those for standard EnKF or 4DVAR implementations.

关键词： data assimilation four-dimensional variational data assimilation ensemble Kalman filter Lorenz model hybrid method

Scale-dependent Regional Climate Predictability over north America Inferred from CMIP3 and CMIP5 Ensemble Simulations

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Advances in Atmospheric Sciences 2016年第8期33卷 905-918页

作者： fuqing ZHAnG Wei LI Michael E.MAnn Department of Meteorology and Center for Advanced Data Assimilation and Predictability Techniques The Pennsylvania State UniversityUniversity ParkPA 16802USA IMSG at nOAA NWSNCEPEnvironmental Modeling CenterCollege ParkMD 20740USA

Through the analysis of ensembles of coupled model simulations and projections collected from CMIP3 and CMIP5, we demonstrate that a fundamental spatial scale limit might exist below which useful additional refinement of climate model predictions and projections may not be possible. That limit varies among climate variables and from region to region. We show that the uncertainty（noise） in surface temperature predictions（represented by the spread among an ensemble of global climate model simulations） generally exceeds the ensemble mean（signal） at horizontal scales below 1000 km throughout north America, implying poor predictability at those scales. More limited skill is shown for the predictability of regional precipitation. The ensemble spread in this case tends to exceed or equal the ensemble mean for scales below 2000 km. These findings highlight the challenges in predicting regionally specific future climate anomalies, especially for hydroclimatic impacts such as drought and wetness.

关键词： regional climate predictability CMIP5 ensemble north America climate ch.nge

Quantitatively distinguishing sediments from the Yangtze River and the Yellow River using δEu_n-ΣREEs plot

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Science ch.na Earth Sciences 2009年第2期52卷 232-241页

作者： JIAnG fuqing ZHOU XiaoJing LI Anch.n LI TieGang Key laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China Graduate University Chinese Academy of SciencesBeijing 100049China

Sediment samples were collected from the lower ch.nnel of the Yangtze River and the Yellow River and the contents of rare earth elements (REEs) were measured. In addition, some historical REEs data were collected from published literatures. Based on the δEun-ΣREEs plot, a clear boundary was found be-tween the sediments from the two rivers. The boundary can be described as an orthogonal polynomial equation by ordinary linear regression with sediments from the Yangtze River located above the curve and sediments from the Yellow River located below the curve. To validate this method, the REEs con-tents of sediments collected from the estuaries of the Yangtze River and the Yellow River were meas-ured. In addition, the REEs data of sediment Core 255 from the Yangtze River and Core YA01 from the Yellow River were collected. Results show that the samples from the Yangtze River estuary and Core 255 almost are above the curve and most samples from the Yellow River estuary and Core YA01 are below the curve in the δEun-ΣREEs plot. The plot and the regression equation can be used to distin-guish sediments from the Yangtze River and the Yellow River intuitively and quantitatively, and to trace the sediment provenance of the eastern seas of ch.na. The difference between the sediments from two rivers in the δEun-ΣREEs plot is caused by different mineral compositions and regional climate patterns of the source areas. The relationship between δEun and ΣREEs is ch.nged little during the transport from the source area to the river, and from river to the sea. Thus the original information on mineral compositions and climate of the source area was preserved.

关键词： sediment provenance Yangtze River Yellow River δEun-ΣREEs plot

Equivalent Kelvin Impact Model for Seismic Pounding Analysis of Bridges

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Transactions of Tianjin University 2006年第B09期12卷 83-87页

作者： DInG Yang YUE fuqing LI Zhongxian School of Civil Engineering Tianjin University Tianjin 300072 China

Based on Hertz contact theory, a method to determine the parameters of Kelvin impact model for seismic pounding analysis of bridges is proposed. The impact stiffness of Kelvin model is determined by the ratio of maximum impact force to maximum contact deformation, which is calculated based on Hertz contact theory with considering the vibration effect. The restitution coefficient which has great influence on the damping coefficient of Kelvin impact model is investigated by numerical analysis. numerical results indicate that the impact stiffness of Kelvin impact model increases with the increment of the Hertz contact stiffness, approach.ng velocity or the length ratio of short to long girders. Vibration effect has remarkable influence on the impact stiffness and cannot be neglected. The restitution coefficient decreases when approach.ng velocity increases or the length ratio of short girder to long girder decreasing. The practical ranges of impact stiffness and restitution coefficient are obtained as 3 × 10^8--6 × 10^8 n/m and 0.6-3.95 respectively.

关键词： bridge seismic pounding impact model contact stiffness restitution coefficient

Observations of equatorial plasma bubbles during the geomagnetic storm of October 2016

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Earth and Planetary Physics 2021年第5期5卷 416-426页

作者： fuqing Huang JiuHou Lei chao Xiong JiaHao Zhong GuoZhu Li ch.nese Academy of Sciences Key Laboratory of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Mengch.ng national Geophysical Observatory University of Science and Technology of ChinaHefei 230026China ch.nese Academy of Sciences Center for Excellence in Comparative Planetology University of Science and Technology of ChinaHefei 230026China Electronic Information School Wuhan UniversityWuhan 430072China Planetary Environmental and Astrobiological Research Laboratory School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519082China ch.nese Academy of Sciences Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Beijing national Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

We investigated the variations of equatorial plasma bubbles(EPBs)in the East-Asian sector during a strong geomagnetic storm in October 2016,based on observations from the Beidou geostationary(GEO)satellites,Swarm satellite and ground-based *** nighttime depletions of F region in situ electron density from Swarm and obvious nighttime EPBs in the Beidou GEO observations were observed on 13 October 2016 during the main ***,one interesting feature is that the rare and unique sunrise EPBs were triggered on 14 October 2016 in the main phase rather than during the recovery phase as reported by previous *** addition,the nighttime EPBs were suppressed during the whole recovery phase,and absent from 14 to 19 October ***,the minimum virtual height of F trace(h’F)at Sanya(18.3°n,109.6°E,MLAT 11.1°n)displayed obvious ch.nges during these *** h’F was enhanced in the main phase and declined during the recovery phase,compared with the values at pre-and *** results indicate that the enhanced nighttime EPBs and sunrise EPBs during the main phase and the absence nighttime EPBs for many days during the recovery phase could be associated with storm-time electric field ch.nges.

关键词： EPBs ionospheric irregularities Beidou GEO TEC geomagnetic storm electron density electric field

Deviation Inequality for the number of k-Cycles in a Random Graph

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Wuhan University Journal of natural Sciences 2009年第1期14卷 11-13页

作者： WAnG Yanqing GAO fuqing School of Mathematics and Statistics Wuhan UniversityWuhan 430072 Hubei China

We study the number of k-cycles in a random graph G（n, p）. We estimate the probability that a random graph contains more k-cycles than expected. In this case, the usual martingale inequality with bounded difference is not effective. By construct- ing a variable that approximates to the number of k-cycles in a random graph and using a new and extensive martingale inequality, we get the results in this paper.

关键词： random graph deviation inequality k-cycles

Dynamics of local extreme rainfall of super Typhoon Soudelor (2015) in East ch.na

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Science ch.na Earth Sciences 2018年第5期61卷 572-594页

作者： Jinsong PAn Daigao TEnG fuqing ZHAnG Lingli ZHOU Ling LUO Yonghui WEnG Yunji ZHAnG Zhejiang Meteorological Observatory Hangzhou 310021 China Department of Meteorology and Atmospheric Sciences and Center for Advanced Data Assimilation and Prediction Techniques Pennsylvania State University University Park Pennsylvania 16802 USA

The characteristics and dynamics associated with the distribution, intensity, and triggering factors of local severe precipitation in Zhejiang Province induced by Super Typhoon Soudelor(2015) were investigated using mesoscale surface observations, radar reflectivity, satellite nephograms, and the final(FnL) analyses of the Global Forecasting System(GFS) of the national Center for Environmental Prediction(nCEP). The rainfall processes during Soudelor's landfall and translation over East ch.na could be separated into four stages based on rainfall characteristics such as distribution, intensity, and corresponding dynamics. The relatively less precipitation in the first stage resulted from interaction between the easterly wind to the north flank of this tropical cyclone(TC) and the coastal topography along the southeast of Zhejiang Province, ch.na. With landfall of the TC in East ch.na during the second stage, precipitation maxima occurred because of interaction between the TC's principal rainbands and the local topography from northeastern Fujian Province to southwestern Zhejiang Province. The distribution of precipitation presented significant asymmetric features in the third stage with maximal rainfall bands in the northeast quadrant of the TC when Soudelor's track turned from westward to northward as the TC decayed rapidly. Finally, during the northward to northeastward translation of the TC in the fourth stage, the interaction between a mid-latitude weather system and the northern part of the TC resulted in transfer of the maximum rainfall from the north of Zhejiang Province to the north of Jiangsu Province,which represented the end of rainfall in Zhejiang Province. Further quantitative calculations of the rainfall rate induced by the interaction between local topography and TC circulation(defined as "orographic effects") in the context of a one-dimensional simplified model showed that orographic effects were the primary factor determining the intensity of precipit

关键词： TC outer circulation TC principal rainband Orographic effect Expanding of TC's spiral bands

Fluorescent Organohydrogel with Thermal-Induced Color ch.nge for Anti-counterfeiting

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ch.nese Journal of chemistry 2022年第3期40卷 337-342页

作者： Xiaoxia Le Hui Shang Shirong Gu Guangqiang Yin fuqing Shan Danyang Li Tao ch.n 无 Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Material Technology and EngineeringChinese Academy of SciencesNingboZhejiang 315201China School of chemical Sciences University of Chinese Academy of SciencesBeijing 100049China Department of Orthopedics Lihuili Hospital of Ningbo Medical CenterNingboZhejiang 315048China

Smart fluorescent patterns enable dynamic color variation under external stimuli,showing a much higher security level in the field of ***,there is still lacking of a simple and convenient way to achieve dynamic fluorescence ***,a fluorescent organohydrogel made up of a poly(n,/n-dimethylacrylamide-co-isopropylacrylamide)(p(DMA-nIPAM))hydrogel network and a polyflauryl methacrylate)(PLMA)organogel network was fabricated via a two-step interpenetrating *** former network bears naphthalimide moieties(DEAn,green fluorescent monomer)and the later contains 6-acrylamidopicolinic acid(6APA,fluorescent ligand),leading to emitting green *** Eu^(3+) was introduced and coordinated with 6APA,the organohydrogel displays red fluorescence,which can further emit yellow after applying thermal ***,by adjusting the proportion of comonomers,various organohydrogels can be obtained,which can be programmed and act as an effective platform for the encryption and decryption of secret information.

关键词： Dyes/pigments Fluorescence Gels Information encryption Stimuli responsiveness

Excitation-wavelength-dependent fluorescent organohydrogel for dynamic information anti-counterfeiting

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ch.nese chemical Letters 2023年第11期34卷 180-183页

作者： Dong Guo Xiaoxia Le Hui Shang fuqing Shan Danyang Li ch.nfa Ouyang Tao ch.n School of Materials Science and Engineering Shanghai Institute of TechnologyShanghai 201499China Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Material Technology and EngineeringChinese Academy of SciencesNingbo 315201China School of chemical Sciences University of Chinese Academy of SciencesBeijing 100049China

Anti-counterfeiting labels with various fluorescent colors are of great importance in information encryption-decryption,but are still limited to static information ***,it is urgent to develop new materials and encryption-decryption logic for improving the security level of secret *** this study,an organohydrogel made up of poly(n,n-dimethylacrylamide)(pDMA)hydrogel network and polyoctadecyl methacrylate(pSMA)organogel network that copolymerized with two fluorophores,6-acrylamidopicolinic acid moieties(6APA,fluorescent ligand)and spiropyran units(SPMA,photochromic monomer),was prepared by a two-step interpenetrating *** UV light of 365nm and 254nm can both cleave C_(spiro)-O bonds of SPMA,and the green fluorescence of 6APA-Tb^(3+) can only be excited by 254nm light,the organohydrogel displays yellow and red under the irradiation of 254nm and 365 nm,*** addition to wavelength selectivity,these two fluorophores are thermal-responsive,leading to the fluorescence variation of the organohydrogel during heating *** a result,secret information loaded on the organohydrogel can be decrypted by the irradiation of UV light,and the authenticity of the information can be further identified by thermal *** fluorescent organohydrogel can act as an effective anti-counterfeiting label to improve the information security and protect the information from being cracked.

关键词： Fluorescent organohydrogel Anti-counterfeiting Stimulus responsive Encryption-decryption Dynamic fluorescence