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Application of Backward Nonlinear Local Lyapunov Exponent Method to Assessing the Relative Impacts of initial condition and Model Errors on Local Backward Predictability

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Advances in Atmospheric Sciences 2021年第9期38卷 1486-1496页

作者： Xuan LI Jie FENG Ruiqiang DING Jianping LI Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Frontiers Science Center for Deep Ocean Multispheres and Earth System(FDOMES)/Key Laboratory of Physical Oceanography/Institute for Advanced Ocean Studies Ocean University of ChinaQingdao 266100China Laboratory for Ocean Dynamics and Climate Pilot Qingdao National Laboratory for Marine Science and Technology(QNLM)Qingdao 266237China

initial condition and model errors both contribute to the loss of atmospheric ***,it remains debatable which type of error has the larger impact on the prediction lead time of specific *** this study,we perform a theoretical study to investigate the relative effects of initial condition and model errors on local prediction lead time of given states in the Lorenz *** the backward nonlinear local Lyapunov exponent method,the prediction lead time,also called local backward predictability limit(LBPL),of given states induced by the two types of errors can be quantitatively *** show that the structure of the Lorenz attractor leads to a layered distribution of LBPLs of *** an individual circular orbit,the LBPLs are roughly the same,whereas they are different on different *** spatial distributions of LBPLs show that the relative effects of initial condition and model errors on local backward predictability depend on the locations of given states on the dynamical trajectory and the error *** the error magnitude is fixed,the differences between the LBPLs vary with the locations of given *** larger differences are mainly located on the inner trajectories of *** the error magnitudes are different,the dissimilarities in LBPLs are diverse for the same given state.

关键词： initial condition model errors error magnitude error location LBPL

Why Are Arctic Sea Ice Concentration in September and Its Interannual Variability Well Predicted over the Barents–East Siberian Seas by CFSv2?

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Journal of Meteorological Research 2024年第1期38卷 53-68页

作者： Yifan XIE Ke FAN Hongqing YANG School of Atmospheric Sciences Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082

To further understand the prediction skill for the interannual variability of the sea ice concentration(SIC)in specific regions of the Arctic,this paper evaluates the NCEP Climate Forecast System version 2(CFSv2),in predicting the autumn SIC and its interannual variability over the Barents–East Siberian Seas(BES).It is found that CFSv2 presents much better prediction skill for the September SIC over BES than the Arctic as a whole at 1–6-month leads,and high prediction skill for the interannual variability of the SIC over BES is displayed at 1–2-month leads after removing the linear ***2 can reasonably reproduce the relationship between the SIC over BES in September and such factors as the surface air temperature(SAT),200-hPa geopotential height,sea surface temperature(SST),and North Atlantic *** addition,it is found that the prescribed SIC initial condition in August as an input to CFSv2 is also ***,the above atmospheric and oceanic factors,as well as an accurate initial condition of SIC,all contribute to a high prediction skill for SIC over BES in *** on a statistical prediction method,the contributions from individual predictability sources are further *** high prediction skill of CFSv2 for the interannual variability of SIC over BES is largely attributable to its accurate predictions of the SAT and SST,as well as a better initial condition of SIC.

关键词： sea ice concentration the Barents-East Siberian Seas Climate Forecast System version 2(CFSv2) prediction skill predictability source atmospheric and oceanic factors initial condition

CONTINUOUS DEPENDENCE OF THE SOLUTIONS OF IMPULSIVE DIFFERENTIAL EQUATIONS ON THE initial conditionS AND BARRIER CURVES

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Acta Mathematica Scientia 2012年第3期32卷 1035-1052页

作者： K.G.Dishlieva Faculty of Applied Mathematics and Informatics Technical University of SofiaSofia1756Bulgaria

The basic objects of investigation in this article are nonlinear impulsive dif- ferential equations. The impulsive moments coincide with the moments of meeting of the integral curve and some of the so-called barrier curves. For such type of equations, suf- ficient conditions are found under which the solutions are continuously dependent on the perturbations with respect to the initial conditions and barrier curves. The results are applied to a mathematical model of population dynamics.

关键词： Impulsive differential equations initial condition barrier curves continuous dependence population dynamics

Distributed Solving Linear Algebraic Equations with Switched Fractional Order Dynamics

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Journal of Systems Science & Complexity 2023年第2期36卷 613-631页

作者： YU Wenqiang CHENG Songsong HE Shuping Anhui Engineering Laboratory of Human-Robot Integration System and Intelligent Equipment School of Electrical Engineering and AutomationAnhui UniversityHefei 230601China

This paper proposes a novel distributed optimization algorithm with fractional order dynamics to solve linear algebraic ***,the authors proposed“Consensus+Projection”flow with fractional order dynamics,which has more design freedom and the potential to obtain a better convergent performance than that of conventional first order ***,the authors prove that the proposed algorithm is convergent under certain iteration order and ***,the authors develop iteration order switching scheme with initial condition design to improve the convergence performance of the proposed ***,the authors illustrate the effectiveness of the proposed method with several numerical examples.

关键词： Distributed optimization fractional order dynamics initial condition iteration order linear equations

Predictability and dynamics of the rapid intensification of Super Typhoon Lekima (2019)

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Frontiers of Earth Science 2022年第1期16卷 132-143页

作者： Mengting XU Hong LI Jingyao LUO Hairong BEN Yijie ZHU Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China Key Laboratory of Numerical Modeling for Tropical Cyclones China Meteorological AdministrationShanghai 200030China Taizhou Meteorological Bureau Taizhou 318000China

This study explores the effect of the initial axisymmetric wind structure and moisture on the predictability of the peak intensity of Typhoon Lekima(2019)through a 20-member ensemble forecast using the WRF *** ensemble members are separated into Strong and Weak groups according to the maximum 10-m wind speed at 48 *** our study of Lekima(2019),the initial intensity defined by maximum 10-m wind speed is not a good predictor of the intensity *** peak intensity uncertainty is sensitive to the initial primary circulation outside the radius of maximum wind(RMW)and the initial secondary *** greater absolute angular momentum(AAM)beyond the RMW directly related to stronger primary circulation,and stronger radial inflow,Strong group is found to have larger AAM import in lowlevel,helping to spin up the *** moisture in innercore is also critical to the intensity predictability through the development of inner-core *** aggregation and merger of convection,leading to the TC intensification,is influenced by both radial advection and gradient of system-scale vortex *** sensitivity experiments are conducted to study the effect of model uncertainty in terms of model horizontal grid resolution on intensity *** horizontal grid resolution greatly impacts the predictability of Lekima’s intensity,and the finer resolution is helpful to simulate the intensification and capture the observed peak value.

关键词： tropical cyclone intensity predictability rapid intensification initial condition model resolution

Application of ERA5 Reanalysis to the Construction of initial conditions for WACCM Simulations

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空间科学学报 2018年第4期38卷 460-468页

作者： WANG Yegui JING Wenqi CUI Yuanyuan CAI Qifa LAN Weiren FANG Hanxian WENG Libin NIU Jun College of Meteorology and Oceanography National University of Defense Technology Nanjing 211101 Institute of Atmospheric Physics Chinese Academy of Science Beijing 100029 Meteorological Observatory of 94758 Troops Ningde 355103 Hebei Met

This study uses ECMWF fifth-generation reanalysis, ERA5, which extends to the mesopause, to construct the initial conditions(IC) for WACCM(Whole Atmosphere Community Climate Model) simulations. Because the biases between ERA5 and Sounding of the Atmosphere using Broadband Emission Radiometry(SABER) temperature data are within ±5 K below the lower mesosphere,ERA5 reanalysis is used to construct IC in the lower atmosphere. Four experiments are performed to simulate a Stratospheric Sudden Warming(SSW) event from 5 to 15 February 2016. The simulation using the WACCM default climatic IC cannot represent the sharp meteorological variation during SSW. In contrast, the 0～4 d forecast results driven by ERA5-constructed IC is consistent with ERA5 reanalysis below the middle mesosphere. Comparing with WACCM climatology ICs scheme, the ICs constructing method based on ERA5 reanalysis can obtain 67%, 40%, 22%, 4% and 6% reduction of temperature forecast RMSE at 10 hPa, 1 hPa, 0.1 hPa, 0.01 hPa and 0.001 hPa respectively. However,such improvement is not shown in the lower thermosphere.

关键词： ERA5 reanalysis SABER WACCM initial condition Stratospheric Sudden Warming(SSW)

Transient chaos in smooth memristor oscillator

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Chinese Physics B 2010年第3期19卷 158-163页

作者：包伯成刘中许建平 Department of Electronic Engineering Nanjing University of Science and Technology School of Electrical and Information Engineering Jiangsu Teachers University of Technology School of Electrical Engineering Southwest Jiaotong University

This paper presents a new smooth memristor oscillator, which is derived from Chua＇s oscillator by replacing Chua＇s diode with a flux-controlled memristor and a negative conductance. Novel parameters and initial conditions are dependent upon dynamical behaviours such as transient chaos and stable chaos with an intermittence period and are found in the smooth memristor oscillator. By using dynamical analysis approaches including time series, phase portraits and bifurcation diagrams, the dynamical behaviours of the proposed memristor oscillator are effectively investigated in this paper.

关键词： dynamical behaviour initial condition memristor oscillator transient chaos

Improved unequal interval grey model and its applications

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Journal of Systems Engineering and Electronics 2011年第3期22卷 445-451页

作者： Yuhong Wang Yaoguo Dang Xujin Pu School of Business Jiangnan UniversityWuxi 214122P.R.China College of Economics and Management Nanjing University of Aeronautics and AstronauticsNanjing 210016P.R.China

A new method to improve prediction precision of GM（1,1） model with unequal time interval is *** grey derivative is multiplied by a parameter to guarantee the time response function satisfying approximately exponential function *** simplify the process of parametric estimation,an approximate value is taken for the multiplied *** the estimators of coefficient of development and grey action quantity can be *** the same time,the principle of the new information priority is also *** take the last item of the first-order accumulated generation operator（1-AGO） on raw data sequence as the initial condition in the time response *** the new information can be taken full advantage of through the improved initial *** properties of this new model are also *** presented method is actually a combination of improvement of grey derivative and improvement of the initial *** results of an example indicate that the proposed method can improve prediction precision prominently.

关键词： grey derivative initial condition GM(1 1) model unequal interval.

Impact of Spin-up Forcing on Vegetation States Simulated by a Dynamic Global Vegetation Model Coupled with a Land Surface Model

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Advances in Atmospheric Sciences 2011年第4期28卷 775-788页

作者：李芳曾晓东宋翔田东晓邵璞张东凌 Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 Graduate University of Chinese Academy of Sciences Beijing 100049

A dynamic global vegetation model （DGVM） coupled with a land surface model （LSM） is generally initialized using a spin-up process to derive a physically-consistent initial condition. Spin-up forcing, which is the atmospheric forcing used to drive the coupled model to equilibrium solutions in the spin-up process, varies across earlier studies. In the present study, the impact of the spin-up forcing in the initialization stage on the fractional coverages （FCs） of plant functional type （PFT） in the subsequent simulation stage are assessed in seven classic climate regions by a modified Community Land Model’s Dynamic Global Vegetation Model （CLM-DGVM）. Results show that the impact of spin-up forcing is considerable in all regions except the tropical rainforest climate region （TR） and the wet temperate climate region （WM）. In the tropical monsoon climate region （TM）, the TR and TM transition region （TR-TM）, the dry temperate climate region （DM）, the highland climate region （H）, and the boreal forest climate region （BF）, where FCs are affected by climate non-negligibly, the discrepancies in initial FCs, which represent long-term cumulative response of vegetation to different climate anomalies, are large. Moreover, the large discrepancies in initial FCs usually decay slowly because there are trees or shrubs in the five regions. The intrinsic growth timescales of FCs for tree PFTs and shrub PFTs are long, and the variation of FCs of tree PFTs or shrub PFTs can affect that of grass PFTs.

关键词： vegetation initial condition spin-up forcing Dynamic Global Vegetation Model Land Surface Model