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Strategy and methodology of dynamical analogue prediction

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Science china Earth sciences 2007年第10期50卷 1589-1599页

作者： ren hongli1,2?2? & chou jifan1 1 college of atmospheric sciences, lanzhou university, lanzhou 73.000, china 2 Laboratory for Climate Studies, National Climate Center, china Meteorological Administration, Beijing 100081, china college of atmospheric sciences Lanzhou University Lanzhou 730000 China Laboratory for Climate Studies National Climate Center China Meteorological Administration Beijing 100081 China college of atmospheric sciences Lanzhou University Lanzhou 730000 China

In order to effectively improve numerical prediction level by using current models and data, the strategy and methodology of dynamical analogue prediction (DAP) is deeply studied in the present paper. A new idea to predict the prediction errors of dynamical model on the basis of historical analogue information is put forward so as to transform the dynamical prediction problem into the estimation problem of prediction errors. In terms of such an idea, a new prediction method of final analogue correction of errors (FACE) is developed. Furthermore, the FACE is applied to extra-seasonal prediction experiments on an operational atmosphere-ocean coupled general circulation model. Prediction results of summer mean circulation and total precipitation show that the FACE can to some extent reduce prediction errors, recover prediction variances, and improve prediction skills. Besides, sensitive experiments also show that predictions based on the FACE are evidently influenced by the number of analogues, analogue-selected variables and analogy metric.

关键词： dynamical analogue prediction, prediction strategy, analogue correction of errors, extra-seasonal prediction

A quasi-geostrophic wavelet-spectrum model for barotropic atmosphere and its numerical solution

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Progress in Natural Science:Materials International 2004年第11期 48-54页

作者： DAI Xingang 1,2*, WANG Ping 3 and chou jifan 2 (1. Key Laboratory of Regional Climate-Environment for Temperate East Asia, Institute of atmospheric Physics, Chinese Academy of sciences, START Regional Center for Temperate East Asia, Beijing 100029, china 2. Department of atmospheric sciences, lanzhou university, lanzhou 73.000, china 3. college of Physics, Peking university, Beijing 100871, china) KeyLaboratoryofRegionalClimate-EnvironmentforTemperateEastAsia InstituteofAtmosphericPhysicsChineseAcademyofSciencesSTARTRegionalCenterforTemperateEastAsiaBeijing100029China collegeofPhysics PekingUniversity.Beijing100871China Departmentofatmosphericsciences LanzhouUniversityLanzhou730000.China

A quasi-geostrophic wavelet-spectrum model of barotropic atmosphere has been constructed by wavelet-Galerkin method with the periodic orthogonal wavelet bases. In this study a wavelet grid-spectrum transform method is designed to decrease the tremendous computation of the nonlinear interaction term in the model, and a two-dimensional Helmholtz equation from the model in a wavelet spectrum form is derived, and a solution with high precision under the periodic boundary condition is obtained. The numerical investigation manifests that the wavelet-spectrum model (WSM) could keep on running for a long time under the forcing of heating and topography. Although its numerical solution is compatible with the grid model (GM), the WSM is of a higher precision and faster convergence rate than GM's. A stationary solution comes forth when the model is forced only by the surface heating, whereas a quasi-periodic oscillation with a period about 15 days appears as considering the topography in the model. The latter oscillation, to some extent, is very similar to the Rossby index cycle of atmosphere over middle and high latitudes.

关键词： plane barotropic atmosphere wavelet-spectrum model wavelet grid-spectrum transform.

Large-scale low-frequency rainfall regimes and their transition modes in summertime over china

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Chinese Science Bulletin 2006年第11期51卷 1355-1367页

作者： ren hongli ZHANG Peiqun chou jifan LI Weijing GAO Li college of atmospheric sciences Lanzhou University Lanzhou 730000 China Laboratory for Climate Studies National Climate Centre China Meteorological Administration Beijing 100081 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Seven large-scale low-frequency rainfall regimes (LFRRs) in summertime are identified for china in a 10-dimensional phase space by using a 40-year daily precipitation dataset. Corresponding to the local extrema of observed probability density in phase space, the LFRRs are characterized by the persistence and transitions that reflect the spread and jump features of low-frequency rainfall centers. The LFRRs are generally consistent with summer monsoon rainbelts on the intraseasonal timescale, and there exist the preferred transition relationships between the LFRRs. Four LFRRs’ transition modes (LFRRTMs), which are the dominant components of the interannual and intraseasonal variability of sum- mer rainfall in china, are further induced. Analyses of atmospheric circulation system show that the anomalies of the subtropical high over the western Pacific (SHWP) and blockings in mid-high latitudes, the low-latitude circulation anomalies, and the wavetrains over the East Asia-Pacific region (EAPWs), play crucial roles in the occurrence and transitions of the LFRRs. Moreover, the evolution of the SHWP and blockings, the distribution and movement of the EAPWs, and the intraseasonal variability of the East Asian-Pacific jet stream may be principal factors of the formations of the LFRRTMs.

关键词：夏季降雨相空间低频降雨体系大尺度预报

Rainfall spectrum change in North china and its possible mechanism

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Progress in Natural Science:Materials International 2004年第7期 46-52页

作者： DAI Xingang 1,2*, WANG Ping 3, ZHANG Peiqun 4 and chou jifan 1(1. college of Resources and Environmental sciences, lanzhou university, lanzhou 73.000, china 2. State Key Laboratory LASG, Institute of atmospheric Physics, Chinese Academy of sciences, Beijing 100029, china 3. college of Physics, Peking university, Beijing 100871, china 4. National Climate Center, Beijing 100081, china) college of Resources and Environmental sciences，lanzhou university，lanzhou 73.000，china State Key Laboratory LASG，Institute of atmospheric Physics，Chinese Academy of sciences，Beijing 100029，china college of Physics，Peking university，Beijing 100871，china National Climate Center，Beijing 100081，china college of Resources and Environmental sciences，lanzhou university，lanzhou 73.000，china

The seasonal distribution of the rainfall in North china has changed greatly since 1977, with more rainfall in spring and less in July, August, and September (JAS). Wavelet analysis showed that the JAS rainfall underwent an abrupt spectrum change in the mid-1960s. Its interannual variability has declined while the interdecadal component has become the dominant mode, associated with the dry climate. Correlation analysis found that the JAS rainfall is negatively correlated with the departures of the 500 hPa geopotential height significantly over the northwest and southwest of china, and positively correlated with the summer monsoon over eastern china. Therefore, the interdecadal ascending of the air pressure in northwestern china and the monsoon decaying over East Asia in the past 20 years may be the two major causes of North china drought.

关键词： North china drought wavelet spectrum abruption monsoon geopotential height interdecadal change.

Theory of three-pattern decomposition of global atmospheric circulation

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Science china Earth sciences 2020年第9期63卷 1248-1267页

作者： Shujuan HU Bingqian ZHOU Chenbin GAO Zhihang XU Qingwan WANG jifan chou Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

This paper reviews the three-pattern decomposition of global atmospheric circulation(3P-DGAC)developed in recent years,including the decomposition model and the dynamical equations of global horizontal,meridional,and zonal *** with the traditional two-dimensional(2D)circulation decomposition method,the 3P-DGAC can effectively decompose the actual vertical vorticity into two components that are caused by the horizontal circulation and convergent/divergent movement(associated with the meridional and zonal circulations).It also decomposes the vertical velocity into the components of the meridional vertical circulation and the zonal vertical circulation,thus providing a new method to study the dynamical influences of convergent/divergent motions on the evolution of actual vertical vorticity and an accurate description of local vertical *** 3P-DGAC is a three-dimensional(3D)circulation decomposition method based on the main characteristics of the actual atmospheric *** horizontal,meridional,and zonal circulations after the 3P-DGAC are the global generalization of Rossby waves in the middle-high latitudes and Hadley and Walker circulations in low ***,the three-pattern decomposition model and its dynamical equations provide novel theoretical tools for studying complex interactions between middle-high and low latitude circulations as well as the physical mechanisms of the abnormal evolution of large-scale atmospheric circulations under the background of global warming.

关键词： Horizontal circulation Meridional circulation Zonal circulation Three-pattern decomposition of global atmospheric circulation(3P-DGAC) Dynamical equations

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统计-动力相结合的相似误差订正法

气象学报 2005年第6期63卷 988-993页

作者：任宏利丑纪范兰州大学大气科学学院兰州730000

根据大气相似性原理,提出了利用历史资料的相似信息估计模式误差的反问题,并发展了一种相似误差订正(ACE)方法。该方法将统计和动力两种方法有机结合,在不改变现有数值预报模式的前提下,既充分利用了动力学发展的成就,又能够有效提取大... 详细信息

根据大气相似性原理,提出了利用历史资料的相似信息估计模式误差的反问题,并发展了一种相似误差订正(ACE)方法。该方法将统计和动力两种方法有机结合,在不改变现有数值预报模式的前提下,既充分利用了动力学发展的成就,又能够有效提取大量历史资料中的相似信息,达到减小模式误差、改进当前预报的目的。而且,ACE方法能够针对当前预报的特殊性来区分所利用过去资料的特殊性,提取历史相似信息间接求解反问题。定性分析表明,ACE方法与以往相似-动力模式原理是等价的,但无需重新建立复杂的相似离差预报模式,更具可行性和业务应用前景。在理想化的极限情形下,当数值模式或历史相似完全准确时,ACE方法的预报结果将分别蜕变为动力或统计学方法的预报结果。

关键词：统计-动力相结合反问题数值预报相似误差订正法

Dynamic-statistics combined forecast scheme based on the abrupt decadal change component of summer precipitation in East Asia

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Science china Earth sciences 2015年第2期58卷 404-419页

作者： GONG ZhiQiang ZHAO JunHu FENG GuoLin chou jifan Laboratory for Climate Studies National Climate Research Center CMA college of atmospheric Science Lanzhou University

Based on the 1983~2011 CMAP data,the precipitation anomaly in East Asia and its nearby sea regions（hereafter called East Asia for short） demonstrates the ＂＋-＋＂ pattern before 1999 and the ＂-＋-＂ pattern afterwards; this decadal change is contained principally in the corresponding EOF3 ***,the NCC_CGCM forecast results are quite different,which reveal the ＂＋-＋-＂ pattern before 1999 and the ＂-＋-＋＂ pattern ***,the probability of improving NCC_CGCM＇s forecast accuracy based on these key SST areas is discussed,and the dynamic-statistics combined forecast scheme is constructed for increasing the information of decadal change contained in the summer precipitation in East *** independent sample forecast results indicate that this forecasting scheme can effectively modify the NCC_CGCM＇s decadal change information contained in the summer precipitation in East Asia（especially in the area of 30°N–55°N）.The ACC is 0.25 and ACR is 61% for the forecasting result based on the V SST area,and the mean ACC is 0.03 and ACR is 51% for the seven key areas,which are better than NCC_CGCM＇s system error correction results（ACC is -0.01 and ACR is 49%）.Besides,the modified forecast results also provide the information that the precipitation anomaly in East Asia mainly shows the ＂＋-＋＂ pattern before 1999 and the ＂-＋-＂ pattern afterwards.

关键词： abrupt decadal change dynamic-statistics combined forecast scheme summer precipitation East Asia sea surface temperature

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Forecast scheme and strategy for extended-range predictable components

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Science china Earth sciences 2013年第4期56卷 878-889页

作者： ZHENG ZhiHai HUANG JianPing FENG GuoLin chou jifan National Climate Center China Meteorological Administration college of atmospheric sciences Lanzhou University

Although extended-range forecasting has exceeded the limit of daily predictability of weather,there are still partially predictable characteristics of meteorological fields in such forecasts.A targeted forecast scheme and strategy for extended-range predictable components is *** on chaotic characteristics of the atmosphere,predictable components and unpredictable random components are separated by using the standpoint of error growth in a numerical *** predictable components are defined as those with slow error growth at a given range,which are not sensitive to small errors in initial conditions. A numerical model for predictable components(NMPC)is established,by filtering random components with poor *** aim is to maintain predictable components and avoid the influence of rapidly growing forecast errors on small scales. Meanwhile,the analogue-dynamical approach(ADA)is used to correct forecast errors of predictable components,to decrease model error and statistically take into account the influence of random *** scheme is applied to operational dynamical extended-range forecast(DERF)model of the National Climate Center of china Meteorological Administration (NCC/CMA).Prediction results show that the scheme can improve forecast skill of predictable components to some extent, especially in high predictability *** skill at zonal wave zero is improved more than for ultra-long waves and synoptic-scale *** show good agreement with predictability of spatial *** a result,the scheme can reduce forecast errors and improve forecast skill,which favors operational use.

关键词： extended-range forecast predictability predictable components analogue-dynamical approach

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Prediction of Precipitation during Summer Monsoon with Self-memorial Model

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Advances in atmospheric sciences 2001年第5期18卷 701-709页

作者：封国林曹鸿兴高新全董文杰丑纪范 Mathematics and Physics college Yangzhou University Chinese Academy of Meteorological Science 46 Baishiqiaolu Department of Meteorological Science Lanzhou University Institute of atmospheric Physics Chinese Academy of Sciences

In view of the fact that the atmospheric motion is an irreversible process, a memory function which can recall the observation data in the past is introduced, moreover, a special concept of self-memorization of the atmospheric motion is proposed, and a so-called self-memorization equation of the atmospheric motion has been derived. Based on the self-memorization principle, a numerical model for decadal forecast is established by means of the thermodynamic equation and the precipitation equation. The verification scores of the hindcasts of the model in the period from 1 to 12 years are much higher than that of monthly weather forecasts at present.

关键词： numerical model climatic prediction memory