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Progress of MJO prediction at CMA from Phase I to Phase II of the Sub-Seasonal to Seasonal prediction Project

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Advances in Atmospheric Sciences 2023年第10期40卷 1799-1815页

作者： Junchen YAO Xiangwen LIU Tongwen WU Jinghui YAN Qiaoping LI Weihua JIE Center for earth system modeling and prediction of china meteorological administration Beijing 100081China

As one of the participants in the Subseasonal to Seasonal(S2S)prediction Project,the china meteorological administration(CMA)has adopted several model versions to participate in the S2S *** study evaluates the models’capability to simulate and predict the Madden-Julian Oscillation(MJO).Three versions of the Beijing Climate Center Climate system Model(BCC-CSM)are used to conduct historical simulations and re-forecast experiments(referred to as EXP1,EXP1-M,and EXP2,respectively).In simulating MJO characteristics,the newly-developed high-resolution BCC-CSM outperforms its *** terms of MJO prediction,the useful prediction skill of the MJO index is enhanced from 15 days in EXP1 to 22 days in EXP1-M,and further to 24 days in *** the first forecast week,the better initial condition in EXP2 largely contributes to the enhancement of MJO prediction ***,during forecast weeks 2–3,EXP2 shows little advantage compared with EXP1-M because the increased skill at MJO initial phases 6–7 is largely offset by the degraded skill at MJO initial phases 2–*** at initial phases 2–3,EXP1-M skillfully captures the wind field and Kelvin-wave response to MJO convection,leading to the highest prediction skill of the *** results reveal that,during the participation of the CMA models in the S2S Project,both the improved model initialization and updated model physics played positive roles in improving MJO *** efforts should focus on improving the model physics to better simulate MJO convection over the Maritime Continent and further improve MJO prediction at long lead times.

关键词： Madden-Julian Oscillation(MJO) Subseasonal to Seasonal(S2S) prediction skill improvement initial phase

Pre-Processing,Quality Assurance,and Use of Global Atmospheric Motion Vector Observations in CRA

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Journal of meteorological Research 2022年第6期36卷 947-962页

作者： Minyan WANG Shuang YAO Lipeng JIANG Tao ZHANG Chunxiang SHI Ting ZHU National meteorological Information centre China Meteorological AdministrationBeijing 100081 CMA earth system modeling and prediction centre China Meteorological Administration(CMA)Beijing 100081

Assimilation of atmospheric motion vectors(AMVs)is important in the initialization of the atmospheric state in numerical weather prediction models,especially over oceans and at high latitudes where conventional data are *** paper presents a detailed description of the pre-processing,quality assurance,and use of global AMVs in china’s first generation of the 40-yr(1979-2018)CRA global atmospheric reanalysis product.A new AMV archive is integrated from near real-time operational Global Telecommunication system data and reprocessed AMV datasets released or produced mainly during 2014-2016 according to a priority *** avoid the misuse of data with systematic quality problems,the observations of all 18 types of AMVs from 54 satellites are pre-evaluated over the whole time *** pre-evaluation system developed by the CRA team is based on the NCEP Gridpoint Statistical Interpolation(GSI)three-dimensional variational assimilation system and the ERA-Interim reanalysis *** AMVs in the new AMV archive are denser than the AMVs prepared for the Climate Forecast system Reanalysis product,the bias and root-mean-square values are smaller,and the time series are *** new AMV archive is assimilated in the CRA product based on the NCEP GSI assimilation procedure and quality control configuration with reference to the pre-evaluation *** is the first time that the reprocessed AMVs from Fengyun-2 satellites from June 2005 to July 2017 are assimilated in a reanalysis *** assimilation features inspire confidence in the accuracy and stability of these *** mean root-mean-square values of the observation minus analysis infrared,water vapor,and visible AMV were 1.5-3.4,2.7-3.6,and 1.3-2.1 m s-1,*** experience of integrating,pre-evaluating,and assimilating AMV observations is valuable for the next generation of reanalysis products.

关键词： reanalysis CRA(china’s first generation of 40-yr global atmospheric ReAnalysis product) atmospheric motion vector integration assimilation reprocessed data

Stochastically Perturbed Parameterizations for the Process-Level Representation of Model Uncertainties in the CMA Global Ensemble prediction system

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Journal of meteorological Research 2022年第5期36卷 733-749页

作者： Fei PENG Xiaoli LI Jing CHEN CMA earth system modeling and prediction centre China Meteorological Administration(CMA)Beijing 100081 State Key Laboratory of Severe Weather China Meteorological AdministrationBeijing 100081 National meteorological centre China Meteorological AdministrationBeijing 100081

To represent model uncertainties at the physical process level in the china meteorological administration global ensemble prediction system(CMA-GEPS),a stochastically perturbed parameterization(SPP)scheme is developed by perturbing 16 parameters or variables selected from three physical parameterization schemes for the planetary boundary layer,cumulus convection,and cloud *** chosen quantity is perturbed independently with temporally and spatially correlated perturbations sampled from log-normal *** of the SPP scheme on CMA-GEPS are investigated comprehensively by using the stochastically perturbed parametrization tendencies(SPPT)scheme as a *** the absence of initial-condition perturbations,perturbation structures introduced by the two schemes are investigated by analyzing the ensemble spread of three forecast variables’physical tendencies and perturbation energy in ensembles generated by the separate use of SPP and *** is revealed that both schemes yield different perturbation structures and can simulate different sources of model *** initialcondition perturbations are activated,the influences of the two schemes on the performance of CMA-GEPS are assessed by calculating verification scores for both upper-air and surface *** improvements in ensemble reliability and probabilistic skill introduced by SPP and SPPT are mainly located in the ***,the vast majority of the reliability improvements(including increases in ensemble spread and reductions in outliers)are statistically significant,and a smaller proportion of the improvements in probabilistic skill(i.e.,decreases in continuously ranked probability score)reach statistical *** with SPPT,SPP generally has more beneficial impacts on200-hPa and 2-m temperature,along with 925-hPa and 2-m specific humidity,during the whole 15-day forecast *** other examined variables,such as 850-hPa zonal wind,850-hPa temperature,and

关键词： model uncertainty global ensemble forecast stochastic physics parameter perturbation perturbation structure

Effect of 2-m Temperature Data Assimilation in the CMA-MESO 3DVAR system

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Journal of meteorological Research 2023年第2期37卷 218-233页

作者： Zhifang XU Lin ZHANG Ruichun WANG Jiandong GONG CMA earth system modeling and prediction centre China Meteorological Administration(CMA)Beijing100081 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing100081 National meteorological centre China Meteorological AdministrationBeijing100081

Assimilation of surface observations including 2-m temperature(T_(2m))in numerical weather prediction(NWP)models remains a challenging problem owing to differences between the elevation of model terrain and that of actual observation *** results can be improved only if surface observations are assimilated *** this study,a T_(2m)data assimilation scheme that carefully considers misrepresentation of model and station terrain was established by using the three-dimensional variational data assimilation(3DVAR)system of the china meteorological administration mesoscale model(CMA-MESO).The corresponding forward observation operator,tangent linear operator,and adjoint operator for the T_(2m)observations under three terrain mismatch treatments were *** T_(2m)data were assimilated in the same method as that adopted for temperature sounding data with additional representative errors,when station terrain was 100 m higher than model terrain;otherwise,the T_(2m)data were assimilated by using the surface similarity theory assimilation ***,if station terrain was lower than model terrain,additional representative errors were stipulated and *** of a rainfall case showed that the observation innovation and analysis residuals both exhibited Gaussian distribution and that the analysis increment was ***,it was found that on completion of the data assimilation cycle,T_(2m)data assimilation obviously influenced the temperature,wind,and relative humidity fields throughout the troposphere,with the greatest impact evident in the lower layers,and that both the area and the intensity of rainfall were better forecasted,especially for the first ***-term continuous experiments for 2–28 February and 5–20 July 2020,further verified that T_(2m)data assimilation reduced deviations not only in T_(2m)but also in 10-m wind *** importantly,the precipitation equitable threat scores were improved over the two exp

关键词： 2-m temperature china meteorological administration mesoscale model(CMA-MESO) assimilation three-dimensional variational(3DVAR)data assimilation kilometer-scale

New Version of the CMA-GFS Dynamical Core Based on the Predictor–Corrector Time Integration Scheme

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Journal of meteorological Research 2023年第3期37卷 273-285页

作者： Xueshun SHEN Yong SU Hongliang ZHANG Jianglin HU CMA earth system modeling and prediction centre China Meteorological Administration(CMA)Beijing 100081 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

The operational numerical weather prediction system established by the china meteorological administration(CMA),based on the Global/Regional Assimilation and prediction system(GRAPES)model,adopts the classical semi-implicit semi-Lagrangian(SISL)time integration *** paper describes a major upgrade to the dynamical core of the CMA global forecast system(CMA-GFS),which was successfully incorporated into operation in *** the upgrade,the classical SISL is further developed into a predictor–corrector scheme,a three-dimensional(3D)reference profile instead of the original isothermal reference profile is applied when implementing the semi-implicit algorithm,and a hybrid terrain-following vertical coordinate system is also *** new version of the dynamical core greatly improves the model performance,the time integration reaches second-order accuracy,the time step can be extended by 50%,and the efficiency is greatly improved(by approximately 30%).Atmospheric circulation simulation is systematically improved,and deviations in temperature,wind,and humidity are *** new version of the dynamical core provides a solid foundation for further development of the entire operational system of the CMA.

关键词： Global/Regional Assimilation and prediction system(GRAPES) china meteorological administration global forecast system(CMA-GFS) predictor-corrector three-dimensional(3D)reference profile

CRA-40/Atmosphere—The First-Generation Chinese Atmospheric Reanalysis(1979–2018):system Description and Performance Evaluation

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Journal of meteorological Research 2023年第1期37卷 1-19页

作者： Zhiquan LIU Lipeng JIANG Chunxiang SHI Tao ZHANG Zijiang ZHOU Jie LIAO Shuang YAO Jingwei LIU Minyan WANG Huiying WANG Xiao LIANG Zhisen ZHANG Yan YAO Ting ZHU Zhe CHEN Wenhui XU Lijuan CAO Hui JIANG Kaixi HU National meteorological Information centre China Meteorological Administration(CMA)Beijing 100081China National Center for Atmospheric Research BoulderCO 80301USA CMA earth system modeling and prediction centre China Meteorological AdministrationBeijing 100081China

Atmospheric reanalysis reproduces the past atmospheric conditions through assimilation of historical meteorological observations with fixed version of a numerical weather prediction(NWP)model and data assimilation(DA)*** is widely used in weather,climate,and even business-related research and *** paper reports the development of CMA’s first-generation global atmospheric reanalysis(RA)covering 1979–2018(CRA-40;CRA refers to CMA-RA).CRA-40 is produced by using the Global Spectral Model(GSM)/Gridpoint Statistical Interpolation(GSI)at a 6-h time interval and a TL574 spectral(34-km)resolution with the model top at 0.27 hPa.A large number of reprocessed satellite data and widely collected conventional observations were assimilated during the reanalyzing process,including the reprocessed atmospheric motion vector(AMV)products from FY-2C/D/E/G satellites,dense conventional observations(at about 120 radiosonde and 2400 synoptic stations)over china,as well as MWHS-2 and GNSS-RO observations from *** reanalysis fitting to observations is improved over time,especially for surface pressure with root-mean-square error reduced from 1.05 hPa in 1979 to 0.8 hPa,and for upper air temperature from 1.65 K in 1979 to 1.35 K,in *** patterns of global analysis increments for temperature,specific humidity,and zonal wind are consistent with the changes in the observing *** surface temperature from the model’s 6-h forecast reflects the global warming trend *** CRA-40 precipitation pattern matches well with those of GPCP and other ***-40 also successfully captures the QBO and its vertical and temporal development,hemispherical atmospheric circulation change,and moisture transport by the East Asian summer *** is now operationally running in near real time as a climate data assimilation system in CMA.

关键词： CMA reanalysis(CRA) observations data assimilation(DA) forecast model

An Initial Perturbation Method for the Multiscale Singular Vector in Global Ensemble prediction

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Advances in Atmospheric Sciences 2024年第3期41卷 545-563页

作者： Xin LIU Jing CHEN Yongzhu LIU Zhenhua HUO Zhizhen XU Fajing CHEN Jing WANG Yanan MA Yumeng HAN School of Atmospheric Sciences Nanjing University of Information Science&TechnologyNanjing 210044China Chinese Academy of meteorological Sciences Beijing 100081China CMA earth system modeling and prediction centre(CEMC) Beijing 100081China Key Laboratory of earth system modeling and prediction of china meteorological administration Beijing 100081China Tianjin meteorological Observatory Tianjin 300074China china meteorological administration Xiong’an Atmospheric Boundary Layer Key Laboratory Hebei 071799China

Ensemble prediction is widely used to represent the uncertainty of single deterministic Numerical Weather prediction(NWP) caused by errors in initial conditions(ICs). The traditional Singular Vector(SV) initial perturbation method tends only to capture synoptic scale initial uncertainty rather than mesoscale uncertainty in global ensemble prediction. To address this issue, a multiscale SV initial perturbation method based on the china meteorological administration Global Ensemble prediction system(CMA-GEPS) is proposed to quantify multiscale initial uncertainty. The multiscale SV initial perturbation approach entails calculating multiscale SVs at different resolutions with multiple linearized physical processes to capture fast-growing perturbations from mesoscale to synoptic scale in target areas and combining these SVs by using a Gaussian sampling method with amplitude coefficients to generate initial perturbations. Following that, the energy norm,energy spectrum, and structure of multiscale SVs and their impact on GEPS are analyzed based on a batch experiment in different seasons. The results show that the multiscale SV initial perturbations can possess more energy and capture more mesoscale uncertainties than the traditional single-SV method. Meanwhile, multiscale SV initial perturbations can reflect the strongest dynamical instability in target areas. Their performances in global ensemble prediction when compared to single-scale SVs are shown to(i) improve the relationship between the ensemble spread and the root-mean-square error and(ii) provide a better probability forecast skill for atmospheric circulation during the late forecast period and for short-to medium-range precipitation. This study provides scientific evidence and application foundations for the design and development of a multiscale SV initial perturbation method for the GEPS.

关键词： multiscale uncertainty singular vector initial perturbation global ensemble prediction system

Vector Radiative Transfer in a Vertically Inhomogeneous Scattering and Emitting ***Ⅰ:A New Discrete Ordinate Method

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Journal of meteorological Research 2024年第5期38卷 209-224页

作者： Ziqiang ZHU Fuzhong WENG Yang HAN Chinese Academy of meteorological Sciences China Meteorological AdministrationBeijing 100081 University of Chinese Academy of Sciences Beijing 100049 CMA earth system modeling and prediction centre China Meteorological Administration(CMA)Beijing 100081 State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

The original vector discrete ordinate radiative transfer(VDISORT)model takes into account Stokes radiance vector but derives its solution assuming azimuthal symmetric surface reflective matrix and atmospheric scattering phase matrix,such as the phase matrix derived from spherical particles or randomly oriented non-spherical *** this study,a new VDISORT is developed for general atmospheric scattering and boundary *** vector is decomposed into both sinusoidal and cosinusoidal harmonic modes,and the radiance at arbitrary viewing geometry is solved directly by adding two zero-weighted points in the Gaussian quadrature *** complex eigenvalues in homogeneous solutions are also taken into full *** accuracy of VDISORT model is comprehensively validated by four cases:Rayleigh scattering case,the spherical particle scattering case with the Legendre expansion coefficients of 0th-13th orders of the phase matrix(hereinafter L13),L13 with a polarized source,and the randomoriented oblate particle scattering case with the Legendre expansion coefficients of 0th-11th orders of the phase matrix(hereinafter L11).In all cases,the simulated radiances agree well with the benchmarks,with absolute biases less than 0.0065,0.0006,and 0.0008 for Rayleigh,unpolarized L13,and L11,*** a polarized bidirectional reflection distribution function(pBRDF)matrix is used as the lower boundary condition,VDISORT is now able to handle fully coupled atmospheric and surface polarimetric radiative transfer processes.

关键词： radiative transfer discrete ordinate polarization Stokes vector vector discrete ordinate radiative transfer(VDISORT)

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Classification analysis of prediction skill among ensemble members in MJO subseasonal predictions——based on the results of the CAMS-CSM subseasonal prediction system

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Atmospheric and Oceanic Science Letters 2024年第4期17卷 8-14页

作者： Yihao Peng Xiaolei Liu Jingzhi Su Xinli Liu State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijingChina Center for earth system modeling and prediction of CMA(CEMC) BeijingChina Key Laboratory of earth system modeling and prediction china meteorological administration BeijingChina

由于模式误差和初始误差所致,次季节-季节预报技巧整体偏低.国际上多数模式都采用集合预报的方式来提高次季节预报的准确率.热带大气季节内振荡(MJO)作为次季节尺度可预报性的重要来源,其预测水平取决于模式性能和MJO事件本身的物理特性... 详细信息

由于模式误差和初始误差所致,次季节-季节预报技巧整体偏低.国际上多数模式都采用集合预报的方式来提高次季节预报的准确率.热带大气季节内振荡(MJO)作为次季节尺度可预报性的重要来源,其预测水平取决于模式性能和MJO事件本身的物理特性.根据中国气象科学研究院气候系统模式次季节预测系统的回报结果,结合不同类型MJO事件的特征,对模式集合成员间的预报技巧进行了分类和比较.在集合成员预报技巧普遍较高的一类MJO事件中,对流异常信号持续时间较长,强度较大,强对流异常中心主要位于印度洋区域,并逐渐东传至西太平洋.在集合成员预报技巧多数较差的MJO事件中,对流异常信号的强度最弱,维持时间最短.在集合成员预报技巧优劣参半的类别中,MJO往往持续时间较短,强度较低,在后续传播过程中,对流异常中心多停驻在海洋性大陆区域.

关键词：次季节-季节预测预报技巧热带大气季节内振荡