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Comparisons of Two Ensemble Mean Methods in Measuring the Average Error Growth and the Predictability

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Acta meteorologica Sinica 2011年第4期25卷 395-404页

作者： DING Ruiqiang li jianping State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029

In this paper, taking the Lorenz system as an example, we compare the influences of the arithmetic mean and the geometric mean on measuring the global and local average error growth. The results show that the geometric mean error （GME） has a smoother growth than the arithmetic mean error （AME） for the global average error growth, and the GME is directly related to the maximal Lyapunov exponent, but the AME is not, as already noted by Krishnamurthy in 1993. Besides these, the GME is shown to be more appropriate than the AME in measuring the mean error growth in terms of the probability distribution of errors. The physical meanings of the saturation levels of the AME and the GME are also shown to be different. However, there is no obvious difference between the local average error growth with the arithmetic mean and the geometric mean, indicating that the choices of the AME or the GME have no influence on the measure of local average predictability.

关键词： predictability arithmetic mean geometric mean Lorenz system

Vector mode based optical direct detection orthogonal frequency division multiplexing transmission in short-reach optical link

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Frontiers of Optoelectronics 2019年第1期12卷 41-51页

作者： jianping li Zhaohui li Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 510632China State Key Laboratory of Optoelectronic Materials and Technologies and School of Electronics and Information Technology Sun Yat-sen UniversityGuangzhou 510275China

As one solution to implement the largecapacity space division multiplexing(SDM)transmission systems,the mode division multiplexing(MDM)has gained much attention *** vector mode(VM),which is the eigenmode of the optical fiber,has also been adopted to realize the optical communications including the transmission over free-space optical(FSO)and optical fiber *** the concerns on the short-reach optical interconnects,the low cost and high integration technologies should be *** detection(DD)with higher-order modulation formats in combination of MDM technologies could offer an available trade-off in system performance and *** review demonstrations of FSO and fiber high-speed data transmission based on the VM MDM(VMDM)*** special VMs,cylindrical vector beams(CVB),have been generated by the q-plate(QP)and characterized *** then they were used to implement the VMDM transmission with direct-detection orthogonal frequency division multiplexing(DD-OFDM).These demonstrations show the potential of VMDM-DD-OFDM technology in the large-capacity short-reach transmission links.

关键词： space division multiplexing (SDM) mode division multiplexing (MDM) few-mode fiber (FMF) vector mode (VM) cylindrical vector beam (CVB) orthogonal frequency division multiplexing (OFDM) direct detection (DD) optical interconnect

Quantitative Comparison of Predictabilities of Warm and Cold Events Using the Backward Nonlinear Local Lyapunov Exponent Method

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Advances in Atmospheric Sciences 2020年第9期37卷 951-958页

作者： Xuan li Ruiqiang DING jianping li Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China Key Laboratory of Physical Oceanography Institute for Advanced Ocean StudiesOcean University of China and Qingdao National Laboratory for Marine Science and TechnologyQingdao 266100China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China Key Laboratory of Physical Oceanography/Institute for Advanced Ocean Studies Ocean University of China and Qingdao National Laboratory for Marine Science and TechnologyQingdao 266100China

The backward nonlinear local Lyapunov exponent method(BNLLE)is applied to quantify the predictability of warm and cold events in the Lorenz *** show that the maximum prediction lead times of warm and cold events present obvious layered structures in phase *** maximum prediction lead times of each warm(cold)event on individual circles concentric with the distribution of warm(cold)regime events are roughly the same,whereas the maximum prediction lead time of events on other circles are *** results show that warm events are more predictable than cold events.

关键词： backward nonlinear local Lyapunov exponent maximum prediction lead time layered structure statistical result

Determination of the Backward Predictability limit and Its Relationship with the Forward Predictability limit

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Advances in Atmospheric Sciences 2019年第6期36卷 669-677页

作者： Xuan li Ruiqiang DING jianping li State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences College of Earth Science University of Chinese Academy of Sciences Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technology College of Global Change and Earth System Sciences (GCESS) Beijing Normal University

In this work, two types of predictability are proposed—forward and backward predictability—and then applied in the nonlinear local Lyapunov exponent approach to the Lorenz63 and Lorenz96 models to quantitatively estimate the local forward and backward predictability limits of states in phase space. The forward predictability mainly focuses on the forward evolution of initial errors superposed on the initial state over time, while the backward predictability is mainly concerned with when the given state can be predicted before this state happens. From the results, there is a negative correlation between the local forward and backward predictability limits. That is, the forward predictability limits are higher when the backward predictability limits are lower, and vice versa. We also find that the sum of forward and backward predictability limits of each state tends to fluctuate around the average value of sums of the forward and backward predictability limits of sufficient ***, the average value is constant when the states are sufficient. For different chaotic systems, the average value is dependent on the chaotic systems and more complex chaotic systems get a lower average value. For a single chaotic system,the average value depends on the magnitude of initial perturbations. The average values decrease as the magnitudes of initial perturbations increase.

关键词： nonlinear local Lyapunov exponent forward and backward predictability limit negative correlation average value

Determining the Spectrum of the Nonlinear Local Lyapunov Exponents in a Multidimensional Chaotic System

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Advances in Atmospheric Sciences 2017年第9期34卷 1027-1034页

作者： Ruiqiang DING jianping li Baosheng li State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technology College of Global Change and Earth System Sciences Beijing Normal University University of Chinese Academy of Sciences

For an n-dimensional chaotic system, we extend the definition of the nonlinear local Lyapunov exponent （NLLE） from one- to n-dimensional spectra, and present a method for computing the NLLE spectrum. The method is tested on three chaotic systems with different complexity. The results indicate that the NLLE spectrum realistically characterizes the growth rates of initial error vectors along different directions from the linear to nonlinear phases of error growth. This represents an improvement over the traditional Lyapunov exponent spectrum, which only characterizes the error growth rates during the linear phase of error growth. In addition, because the NLLE spectrum can effectively separate the slowly and rapidly growing perturbations, it is shown to be more suitable for estimating the predictability of chaotic systems, as compared to the traditional Lyapunov exponent spectrum.

关键词： Lyapunov exponent nonlinear local Lyapunov exponent predictability

Investigation on low total temperature combustion characteristics of kerosene-fueled supersonic combustor

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Chinese Journal of Aeronautics 2022年第7期35卷 192-208页

作者： jianping li Kai WANG Guiqian JIAO Zilong liAO Jindong li School of Engine and Energy Northwestern Polytechnical UniversityXi’an 710072China

In this paper,the combustion characteristics of kerosene-fueled supersonic combustor under the conditions of Mach number 2.0,the total temperature at 700 K and the total pressure at 520 k Pa(simulated flight Mach number at 3.5)were studied by using the flame stabilizing method of cavity and strut from three aspects such as blockage ratios,kerosene equivalence ratios,location and quantity of injection *** results showed that:(A)The combustor with the strut realized the independent and stable combustion of *** combustion-induced back pressure in the block test with blockage ratio of 20%and 10%destroyed the inlet flow conditions;while the blockage ratio was 7.3%and 5%,the incoming flow conditions when kerosene was burned stably were not destroyed.(B)The kerosene Equivalence Ratio(ER)was more likely to be disturbed upstream than the induced back pressure when it rose,and an excessively high-ER would reduce the combustion efficiency;when the equivalence ratio was constant,the combustion efficiency of the blockage ratio of 7.3%was higher than the blockage ratio of 5%.The combustion efficiencies were 0.86(ER=0.13)and 0.78(ER=0.19)when the blockage ratio was 5%,respectively;the combustion efficiencies were 0.89(ER=0.16)and 0.82(ER=0.19)when the blockage ratio was 7.3%,respectively;the combustion efficiencies were 0.51(ER=0.25),0.81(ER=0.3),0.65(ER=0.34)and0.62(ER=0.42)when the blockage ratio was 20%,respectively.(C)The porous injection provided behind the strut was beneficial to the atomization of kerosene and improved the combustion efficiency of kerosene;the second injection after the cavity would reduce the combustion efficiency due to insufficient oxygen and combustion *** study expanded the working range of ramjet and provided a reference fuel injection scheme for Turbine-Based Combined Cycle(TBCC)engine.

关键词： Blockage ratio Combustion characteristics Combustion efficiency Kerosene equivalence ratio Low temperature

Intermodel Diversity of Simulated Long-term Changes in the Austral Winter Southern Annular Mode:Role of the Southern Ocean Dipole

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Advances in Atmospheric Sciences 2021年第3期38卷 375-386页

作者： Fei ZHENG jianping li Shuailei YAO State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 10029China 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

The Southern Annular Mode(SAM)plays an important role in regulating Southern Hemisphere extratropical ***-of-the-art models exhibit intermodel spread in simulating long-term changes in the *** from Atmospheric Model Intercomparison Project(AMIP)experiments from 28 models archived in CMIP5 show that the intermodel spread in the linear trend in the austral winter(June−July−August)SAM is significant,with an intermodel standard deviation of 0.28(10 yr)−1,larger than the multimodel ensemble mean of 0.18(10 yr)−*** study explores potential factors underlying the model difference from the aspect of extratropical sea surface temperature(SST).Extratropical SST anomalies related to the SAM exhibit a dipole-like structure between middle and high latitudes,referred to as the Southern Ocean Dipole(SOD).The role of SOD-like SST anomalies in influencing the SAM is found in the AMIP *** performance in simulating the SAM trend is linked with model skill in reflecting the SOD−SAM *** with stronger linkage between the SOD and the SAM tend to simulate a stronger SAM *** explained variance is about 40%in the AMIP *** results suggest improved simulation of the SOD−SAM relationship may help reproduce long-term changes in the SAM.

关键词： Southern Annular Mode Southern Ocean Dipole intermodel spread air−sea interactions

Some Mathematical and Numerical Issues in Geophysical FluidD ynamics and Climate Dynamics

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Communications in Computational Physics 2008年第4期3卷 759-793页

作者： jianping li Shouhong Wang State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG) Institute of Atmospheric Physics(IAP)Chinese Academy of Sciences(CAS)P.O.Box 9804Beijing 100029China Department of Mathematics Indiana UniversityBloomingtonIN 47405USA

In this article,we address both recent advances and open questions in some mathematical and computational issues in geophysical fluid dynamics(GFD)and climate *** main focus is on 1)the primitive equations(PEs)models and their related mathematical and computational issues,2)climate variability,predictability and successive bifurcation,and 3)a new dynamical systems theory and its applications to GFD and climate dynamics.

关键词： Geophysical fluid dynamics climate dynamics low-frequency variability attractor bifurcation dynamic transition well-posedness.

Influence of the Preceding Austral Summer Southern Hemisphere Annular Mode on the Amplitude of ENSO Decay

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Advances in Atmospheric Sciences 2017年第11期34卷 1358-1379页

作者： Fei ZHENG jianping li Ruiqiang DING State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China Laboratory for Regional Oceanography and Numerical Modeling Qingdao National Laboratory for Marine Science and Technologyqingdao 266237China Plateau Atmosphere and Environment Key Laboratory of Sichuan Province Chengdu University of Information Technologychengdu 610103China

There is increasing evidence of the possible role of extratropical forcing in the evolution of ENSO. The Southern Hemi- sphere Annular Mode （SAM） is the dominant mode of atmospheric circulation in the Southern Hemisphere extratropics. This study shows that the austral summer （December-January-February; DJF） SAM may also influence the amplitude of ENSO decay during austral autumn （March-April-May; MAM）. The mechanisms associated with this SAM-ENSO relationship can be briefly summarized as follows： The SAM is positively （negatively） correlated with SST in the Southern Hemisphere middle （high） latitudes. This dipole-like SST anomaly pattern is referred to as the Southern Ocean Dipole （SOD）. The DJF SOD, caused by the DJF SAM, could persist until MAM and then influence atmospheric circulation, including trade winds, over the Nifio3.4 area. Anomalous trade winds and SST anomalies over the Nifio3.4 area related to the DJF SAM are further developed through the Bjerkness feedback, which eventually results in a cooling （warming） over the Nifio3.4 area followed by the positive （negative） DJF SAM.

关键词： Southern Hemisphere Annular Mode ENSO Southern Ocean Dipole