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Atmospheric and Oceanic Science Letters 2014年第5期7卷 447-452页

作者： ZHAO Peng duan wan-suo State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

Initial errors and model errors are the source of prediction errors. In this study, the authors compute the conditional nonlinear optimal perturbation （CNOP）-type initial errors and nonlinear forcing singular vector （NFSV）- type tendency errors of the Zebiak-Cane model with respect to El Nifio events and analyze their combined effect on the prediction errors for E1 Nino events. The CNOP- type initial error （NFSV-type tendency error） represents the initial errors （model errors） that have the largest effect on prediction uncertainties for E1 Nifio events under the perfect model （perfect initial conditions） scenario. How- ever, when the CNOP-type initial errors and the NFSV- type tendency errors are simultaneously considered in the model, the prediction errors caused by them are not am- plified as the authors expected. Specifically, the predic- tion errors caused by the combined mode of CNOP-type initial errors and NFSV-type tendency errors are a little larger than those caused by the NFSV-type tendency er- rors. This fact emphasizes a need to investigate the opti- mal combined mode of initial errors and tendency errors that cause the largest prediction error for E1 Nifio events.

关键词： predictability initial error model error optimal perturbation

The Spatial Patterns of Initial Errors Related to the “Winter Predictability Barrier” of the Indian Ocean Dipole

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Atmospheric and Oceanic Science Letters 2014年第5期7卷 406-410页

作者： FENG Rong duan wan-suo The National Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG) Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

In this study, using the Geophysical Fluid Dynamics Laboratory Climate Model version 2pl （GFDL CM2pl） coupled model, the winter predictability barrier （WPB） is found to exist in the model not only in the growing phase but also the Indian Ocean dipole （IOD） decaying phase of positive events due to the effect of initial errors. In particular, the WPB is stronger in the growing phase than in the decaying phase. These results indicate that initial errors can cause the WPB. The domi- nant patterns of the initial errors that cause the occurrence of the WPB often present an eastern-western dipole both in the surface and subsurface temperature components. These initial errors tend to concentrate in a few areas, and these areas may represent the sensitive areas of the predictions of positive IOD events. By increasing observations over these areas and eliminating initial errors here, the WPB phenomenon may be largely weakened and the forecast skill greatly improved.

关键词： Indian Ocean dipole winter predictabilitybarrier initial errors sensitive areas

Time-Dependent Nonlinear Forcing Singular Vector-Type Tendency Error of the Zebiak-Cane Model

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Atmospheric and Oceanic Science Letters 2014年第5期7卷 395-399页

作者： ZHAO Peng duan wan-suo State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

Based on the Zebiak-Cane model, the timedependent nonlinear forcing singular vector （NFSV）-type tendency errors with components of 4 and 12 （denoted by NFSV-4 and NFSV-12） are calculated for predetermined El Nifio events and compared with the constant NFSV （denoted by NFSV-1） from their patterns and resultant prediction errors. Specifically, NFSV-1 has a zonal dipolar sea surface temperature anomaly （SSTA） pattern with negative anomalies in the equatorial eastern Pacific and positive anomalies in the equatorial central-western Pa- cific. Although the first few components in NFSV-4 and NFSV-12 present patterns similar to NFSV-1, they tend to extend their dipoles farther westward; meanwhile, the positive anomalies gradually cover much smaller regions with the lag times. In addition, the authors calculate the predic- tion errors caused by the three kinds of NFSVs, and the results indicate that the prediction error induced by NFSV-12 is the largest, followed by the NFSV-4. However, when compared with the prediction errors caused by random tendency errors, the NFSVs generate significantly larger prediction errors. It is therefore shown that the spatial structure of tendency errors is important for producing large prediction errors. Furthermore, in exploring the tendency errors that cause the largest prediction error for E1 Nifio events, the timedependent NFSV should be evaluated.

关键词： predictability model error optimal perturbation

Interannual Relationship between the Winter Aleutian Low and Rainfall in the Following Summer in South China

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Atmospheric and Oceanic Science Letters 2015年第5期8卷 271-276页

作者： SONG Lin-Ye duan wan-suo State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

Using observations and reanalysis data, this study investigates the interannual relationship between the winter Aleutian Low(AL) and the rainfall anomalies in the following summer in South China(SC). Results show that the winter AL is significantly positively(negatively) correlated with the SC rainfall anomalies in the following July(August). Specifically, SC rainfall anomalies have a tendency to be positive(negative) in July(August) when the preceding winter AL is stronger than normal. The winter AL-related atmospheric circulation anomalies in the following summer are also examined. When the winter AL is stronger, there is a significant anticyclonic(cyclonic) circulation anomaly over the subtropical western North Pacific in the following July(August). Southerly(northerly) wind anomalies to the west of this anomalous anticyclonic(cyclonic) circulation increase(decrease) the northward moisture transportation and contribute to the positive(negative) rainfall anomalies over SC in July(August). This study indicates that the AL in the preceding winter can be used as a potential predictor of the rainfall anomalies in the following July and August over SC.

关键词： Aleutian Low South China rainfall atmospheric circ

The“Spring Predictability Barrier” Phenomenon of ENSO Predictions Generated with the FGOALS-g Model

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Atmospheric and Oceanic Science Letters 2010年第2期3卷 87-92页

作者： WEI Chao duan wan-suo LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Using the sea surface temperature （SST） predicted for the equatorial Pacific Ocean by the Flexible Global Ocean-Atmosphere-Land System Model-gamil （FGOALS-g）, an analysis of the prediction errors was performed for the seasonally dependent predictability of SST anomalies both for neutral years and for the growth/decay phase of El Nino/La Nina events. The study results indicated that for the SST predictions relating to the growth phase and the decay phase of El Nino events, the prediction errors have a seasonally dependent evolution. The largest increase in errors occurred in the spring season, which indicates that a prominent spring predictability barrier （SPB） occurs during an El Nino-Southern Oscillation （ENSO） warming episode. Furthermore, the SPB associated with the growth-phase prediction is more prominent than that associated with the decay-phase prediction. However, for the neutral years and for the growth and decay phases of La Nifia events, the SPB phenomenon was less prominent. These results indicate that the SPB phenomenon depends extensively on the ENSO events themselves. In particular, the SPB depends on the phases of the ENSO events. These results may provide useful knowledge for improving ENSO forecasting.

关键词： ENSO event spring predictability barrier prediction error predictability

The Amplitude-Duration Relation of Observed El Nio Events

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Atmospheric and Oceanic Science Letters 2012年第5期5卷 367-372页

作者： Wu Yu-Jie duan wan-suo State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric_ Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The authors demonstrate that the E1 Nifio events in the pre- and post-1976 periods show two ampli- tude-duration relations. One is that the stronger E1 Nifio events have longer durations, which is robust for the moderate E1 Nifio events; the other is that the stronger E1 Nifio events have shorter durations but for strong E1 Nifio events. By estimating the sign and amplitude of the nonlinear dynamical heating （NDH） anomalies, the au- thors illustrate that the NDH anomalies are negligible for moderate E1 Nifio events but large for strong E1 Nifio events. In particular, the large NDH anomalies for strong E1 Nifio events are positive during the growth and mature phases, which favor warmer E1 Nifio events. During the decay phase, however, the negative NDH anomalies start to arise and become increasingly significant with the evolution of the E1 Nifio events, in which the negative NDH anomalies dampen the sea surface temperature anomalies （SSTA） and cause the E1 Nifio events to reach the SST normal state earlier. This pattern suggests that the nonlinearity tends to increase the intensities of strong E1 Nifio events and shorten their duration, which, together with the previous results showing a positive correlation between the strength of E1 Nifio events and the signifi- cance of the effect of nonlinear advection on the events （especially the suppression of nonlinearity on the SSTA during the decay phase）, shows that the strong E1 Nifio events tend to have the amplitude-duration relation of the stronger E1 Nifio events with shorter durations. This result also lends support to the assertion that moderate E1 Nifio events possess the amplitude-duration relation of stronger E1 Nifio events with longer durations.

关键词： climatic oscillation E1 Nifio events amplitude duration

Ensemble Forecast for Tropical Cyclone Based on CNOP-P Method:A Case Study of WRF Model and Two Typhoons

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Journal of Tropical Meteorology 2022年第2期28卷 121-138页

作者： YUAN Shi-jin SHI Bo ZHAO Zi-jun MU Bin ZHOU Fei-fan duan wan-suo School of Software Engineering Tongji UniversityShanghai 201804 China Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 China University of Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 China

In this paper,we set out to study the ensemble forecast for tropical *** case study is based on the Conditional Nonlinear Optimal Perturbation related to Parameter(CNOP-P)method and the WRF model to improve the prediction accuracy for track and intensity,and two different typhoons are selected as cases for *** first select perturbed parameters in the YSU and WSM6 schemes,and then solve CNOP-Ps with simulated annealing algorithm for single parameters as well as the combination of multiple ***,perturbations are imposed on default parameter values to generate the ensemble *** whole proposed procedures are referred to as the PerturbedParameter Ensemble(PPE).We also conduct two experiments,which are control forecast and ensemble forecast,termed Ctrl and perturbed-physics ensemble(PPhyE)respectively,to demonstrate the performance for *** the article,we compare the effects of three experiments on tropical cyclones in aspects of track and intensity,*** track,the prediction errors of PPE are *** ensemble mean of PPE filters the unpredictable situation and retains the reasonably predictable components of the ensemble *** for intensity,ensemble mean values of the central minimum sea-level pressure and the central maximum wind speed are closer to CMA data during most of the simulation *** predicted values of the PPE ensemble members included the intensity of CMA data when the typhoon made *** PPE also shows uncertainty in the ***,we also analyze the track and intensity from physical variable fields of *** results show PPE outperforms the other two benchmarks in track and intensity prediction.

关键词： ensemble forecast Conditional Nonlinear Optimal Perturbation related to Parameter(CNOP-P) WRF parameter perturbation ensemble members simulated annealing algorithm

非线性优化方法在大气和海洋科学数值研究中的若干应用

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应用数学和力学 2005年第5期26卷 585-594页

作者：段晚锁穆穆中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室北京100029

　控制大气和海洋运动的模式是复杂的非线性模式,在考虑到线性奇异向量和线性奇异值只能描述切线性模式有效时段内小扰动发展的情况下,介绍了作者们近年来用非线性优化方法数值研究大气和海洋科学的有关工作,其中包括非线性奇异向量和... 详细信息

　控制大气和海洋运动的模式是复杂的非线性模式,在考虑到线性奇异向量和线性奇异值只能描述切线性模式有效时段内小扰动发展的情况下,介绍了作者们近年来用非线性优化方法数值研究大气和海洋科学的有关工作,其中包括非线性奇异向量和非线性奇异值、条件非线性最优扰动、以及它们在数值天气和气候可预报性研究中的应用·　结果表明,上述非线性优化方法在很大程度上揭示了大气和海洋运动的非线性特征;此外,对可预报性问题的新分类也做了详细介绍,即最大可预报时间、最大预报误差和最大允许初始误差·　这种分类的应用背景是针对数值天气预报和气候预测产品的评价;最后,讨论了数值模式敏感性分析的非线性优化方法,该方法在一定条件下可以定量识别模式误差和初始误差。

关键词：非线性优化天气气候可预报性敏感性分析

用非线性最优化方法研究El Nio可预报性的进展与前瞻

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大气科学 2006年第5期30卷 759-766页

作者：段晚锁穆穆中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室北京100029

综述用非线性优化方法研究厄尔尼诺(El Ni^no)南方涛动(ENSO)事件可预报性的进展。针对ENSO可预报性研究中的热点问题———“前期征兆”、“春季可预报性障碍”,以及如何量化研究ENSO可预报性和ENSO的不对称性问题,作者在近年来的工作... 详细信息

综述用非线性优化方法研究厄尔尼诺(El Ni^no)南方涛动(ENSO)事件可预报性的进展。针对ENSO可预报性研究中的热点问题———“前期征兆”、“春季可预报性障碍”,以及如何量化研究ENSO可预报性和ENSO的不对称性问题,作者在近年来的工作中先后用理论模式和中等复杂程度ENSO模式研究了ENSO可预报性的动力学,揭示了ENSO的若干重要非线性特征。主要结果如下:(1)条件非线性最优扰动(CNOP)(局部CNOP)比线性奇异向量更易发展成ENSO事件,扮演了ENSO的最优前期征兆。这些ENSO事件关于气候平均态是不对称的。理论分析表明,非线性温度平流过程是造成这种不对称性的重要原因。1980~2002年的海洋再分析资料验证了上述理论结果。(2)ENSO事件CNOP型初始误差的发展有明显的季节依赖性,该误差导致了ENSO事件最显著的春季可预报性障碍(SPB)现象。ENSO事件SPB的发生不仅依赖于气候平均态,而且依赖于ENSO事件本身及其初始误差模态,是三者综合作用的结果。(3)建立了关于ENSO可预报性的最大可预报时间下界、最大预报误差上界和最大允许初始误差下界的三类可预报性问题,分别从三个方面揭示了ENSO事件的春季可预报性障碍现象,比较有效地量化了其可预报性。(4)通过CNOP方法,揭示了非线性温度平流在年代际尺度ENSO不对称性研究中的重要作用,解释了ENSO不对称性的年代际变化,基于所用ENSO模式给出了ENSO不对称性年代际变化的机制。最后,展望了非线性优化方法在ENSO可预报性中应用的前景,并期望该方法能拓展到ENSO第二类可预报性问题的研究中。

关键词：非线性 El Nin^~o 可预报性非线性优化

数值模式误差对降水四维变分资料同化及预报的影响

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气候与环境研究 2006年第5期11卷 605-615页

作者：王铁段晚锁郑琴中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室中国人民解放军理工大学理学院南京211101

利用一个无量纲的水汽发展方程,针对同化时间窗口内出现和不出现降水两种情况,分析了不同模式误差和初始误差对降水四维变分资料同化预报效果的影响。结果表明,应用四维变分资料同化方法进行降水预报前,应该充分考虑数值模式中的误差,... 详细信息

利用一个无量纲的水汽发展方程,针对同化时间窗口内出现和不出现降水两种情况,分析了不同模式误差和初始误差对降水四维变分资料同化预报效果的影响。结果表明,应用四维变分资料同化方法进行降水预报前,应该充分考虑数值模式中的误差,才能得到比较满意的同化及预报结果。假定同化窗口内获得的比湿观测场是准确的,当不存在模式误差时,四维变分资料同化方法可以有效地消除初始场误差,找到比湿真实初始场;而存在模式误差时,四维变分资料同化后的模式初始场会偏离真实的比湿初始场,并且模式误差越大,偏离程度越严重。在一些模式误差情况下,由于模式误差在同化窗口及延伸预报时段的作用不同,进行四维变分资料同化处理后,尽管累积降水量的预报结果在同化时间窗口内优于同化前的预报,而在最终预报时刻反而差于同化前。

关键词：累积降水初始误差模式误差四维变分资料同化