近百年ENSO事件与营口夏季降水关系

根据近百年来发生的ENSO事件，确定ENSO事件影响年。统计分析ENSO事件影响年与营口夏季降水关系，并进行相关性检验。     

近65年ENSO事件强度变化及时频特征研究

利用海洋尼诺指数(ONI)、南方涛动指数(SOI)和多变量ENSO指数(MEI)等ENSO特征值分析了1951年1月—2016年5月近65年ENSO事件的强度与时频特征,并将其强度划分为5个等级。结果表明:近65年共发生22次暖事件（El Ni?o）和13次冷事件（La Ni?a）;对ENSO特征值进行频次分析发现,强El Ni?o月份所占比例比强La Ni?a多;使用连续小波、交叉小波和小波相干分析得出,ENSO循环主要具有2~7 a的周期,还具有10~16 a的年代际变化。      

热带海表温度及北大西洋涛动与ENSO事件的相关分析

采用交叉小波变换方法分析了热带SST、NAO与ENSO事件之间的多时间尺度相关特征。结果表明，热带SST与ENSO事件在2～7年和30年以上尺度的周期振荡上存在着显著的同位相正相关，其中以4年尺度周期的方差贡献最大，时域中热带SST冷暖变化的时间与ENSO冷暖交替的时间一一对应；北大西洋SST与ENSO事件在4年和15年尺度周期振荡上表现为方差贡献较大的正相关；NAO与ENSO事件相关较弱，在2～7年和10～24年尺度上表现为负相关，而25年以上尺度为正相关，时域中NAO强弱变化与ENSO冷暖交替的对应关系并不完全一致。     

防火墙在陕西气象信息网络中的应用

本文利用ENSO事件资料，结合吕梁地区1957年至2000年汛期(6月至8月)降水资料，分析了ENSO事件影响年的汛期降水特征，得出了ENSO事件起始季节、强度、持续时间与吕梁汛期降水的关系是密切的。     

HHT新技术及其对ENSO的诊断

年际及年代际时间变率是当代气候研究的重要问题之一。通过对近百年Nino3区月平均海面温度（SST）资料做HHT多时间尺度分析，结果表明：SST的变化包含了7个不同时间尺度的准周期振荡和一个世纪尺度的气候态，SST的主周期发生了一次显著的变化：1891-1943年主周期是准2a，1944-2002年的主周期是3～4a；分析不同模态对ENSO事件的作用表明：3～4a和6～8a分量决定了ENSO事件发生，具有相位锁定的作用，而其余尺度上的分量起着振幅和持续时间的调制作用；近百年来，冷、暖气候态变化对ENSO的冷、暖事件的影响并不显著；一些研究认为的1977年以来的“暖态有利于ENSO暖事件发生”的主要原因是：准18～20a、40a和平均气候态三个时间尺度振荡的共同作用在1977-2002年期间呈强暖相位的缘故。自20世纪90年代末期，这三个尺度的共同作用在暖相位的振幅显著的减弱，对ENSO暖事件的影响可能会减小，这在ENSO的预报中应该引起注意。     

影响化州的寒潮强冷空气特征及其与ENSO事件的关系

利用化州1959年以来的气温资料与ENSO资料,分析了化州近54a中寒潮及强冷空气爆发的天气气候特征和在全球大气环流和天气气候异常的大背景下,ENSO事件对影响化州的寒潮及强冷空气异常活动产生的作用,得到一些相关性的结论.统计分析表明,化州出现寒潮的拉尼娜影响年,其时拉尼娜事件爆发型均为东部型,强度中等或偏强,而化州出现寒潮的厄尔尼诺影响年,其时厄尔尼诺事件爆发型均为中部型,强度中等或偏弱.化州寒潮和强冷空气活动多的年份一般出现在中等或弱的厄尔尼诺事件期间或非ENSO年期间.少寒潮和强冷空气活动容易发生在拉尼娜事件影响年期间以及非ENSO事件影响年期间.     

南海夏季风爆发过程合成分析

在与1982／1983年强ENSO过程比较的基础上，揭示了1997／1998年ENSO暖事件发展迅速、强度极大、结束突然等关键性特点，进一步分析了这次暖事件爆发过程中热带印度洋和西太平洋大气季节内振荡的变化特点。并对1997／1998年ENSO过程中海洋和大气演变特征进行深入的诊断分析，对于认识ENSO机制，提高ENSO预报水平具有十分重要的科学意义。     

厄尔尼诺与广西致洪暴雨的关系

分析了ENSO事件的出现与广西致雨的关系，结果表明了两者关系密切，广西的致洪雨基本上都出现于ENSO事件年或ENSO事件结束后的一年时,ENSO咸件的出现频率随年代的变化与广西致洪暴雨出现频率随年代的变化非常吻合，此外，还就厄尔尼诺对广西致洪暴雨形成的可能机制进行探讨。     

ENSO事件对招远地区气温的影响

使用太平洋海表温度资料、南方涛动指数和招远国家气象观测站气温常规观测资料,对1981-2010年ENSO事件与气温的影响及相关性进行分析。结果表明:ENSO事件强度呈现剧烈起伏波动的特点。年平均气温呈现在波动中明显上升的趋势,冬季最为显著。ENSO事件的强度与年平均气温的变化呈明显的正相关性。春季气温和ENSO强度两者间呈正相关特征,暖事件年的前一年,气温明显偏低,暖事件年气温升高明显;夏季气温和ENSO事件强度主要呈正相关特征,但90年代末期后,气温和事件强度呈负相关特性;在秋季暖事件年气温偏低,冷事件年气温偏高;冬季气温与ENSO事件强度呈明显正相关特性,中等强度的ENSO事件对冬季气温的影响更大。     

近百年ENSO事件与营口夏季降水关系

根据近百年来发生的ENSO事件 ,确定ENSO事件影响年。统计分析ENSO事件影响年与营口夏季降水关系 ,并进行相关性检验     

FGOALS-g模式关于ENSO事件的春季预报障碍现象

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 Niño/La Niña events. The study results indicated that for the SST predictions relating to the growth phase and the decay phase of El Niño 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 Niño-Southern Oscillation (ENSO) warming episode. Furthermore, the SPB associated with the growth-phase prediction is higher than that associated with the decay-phase prediction. However, for the neutral years and for the growth and decay phases of La Niña 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.     

Understanding the wet season variations over Florida

The wet season of Florida is well defined and is invariably centered in the boreal summer season of June–July–August. In this observational study we objectively define the Length of the Wet Season (LOWS) for Florida and examine its variations with respect to El Niño and the Southern Oscillation (ENSO) and the Atlantic Warm Pool (AWP). Our study reveals that ENSO variability has a profound influence on the LOWS especially over south Florida and parts of panhandle Florida prior to 1976. In the post-1976 era the influence of ENSO has significantly diminished. Our results show that in this pre-1976 era, warm (cold) ENSO events in the boreal winter are followed by long (short) LOWS over the region. This variation is consistent with warm (cold) ENSO events influencing early (late) onset of the wet season in the region. There is significant relationship of the LOWS in south and northeast Florida with the variation of the AWP. Unlike the teleconnection with ENSO the relationship of the demise of the wet season with AWP is stronger in the post-1976 period compared to the pre-1976 period. Furthermore the variability of the LOWS has increased in the post-1976 period.     

百余年的ENSO事件与北京汛期旱涝的统计关系

利用王绍武等人最近对近百年ＥＮＳＯ事件及强度的研究结果,对ＥＮＳＯ事件与北京汛期相当暴雨日数的统计关系进行分析,表明,ＥＮＳＯ事件与北京沁期旱涝存在较复杂的统计关系,ＥＮＳＯ事件的性质,强度,起始季节和持续时间长短等与汛期旱涝的对应关系是复杂的。根据１８６７－１９９８年的ＥＮＳＯ事件和同期北京汛期相当暴雨日数资料,给出一些统计结果。     

STUDIES ON RELATIONSHIPS BETWEEN ENSO AND LANDFALLING TROPICAL CYCLONES IN CHINA

The data of landfalling tropical cyclones (TCs) in China and ENSO events and the NinoZ index during 1951 to 2005 were used to study the relationships between ENSO and landfalling TCs in China. ENSO events from July to September have obvious effects on landfalling TCs in China. When El Nio persists throughout the months, the frequency of landfalling TCs is less than normal, the season of landfalling TCs is shorter, the annually first landfall is later, the annually last landfall is earlier, and the mean int...     

Seasonal variability of Indonesian rainfall in ECHAM4 simulations and in the reanalyses: The role of ENSO

Summary A study of the skill of the ECHAM version 4 atmospheric general circulation model and two reanalyses in simulating Indonesian rainfall is presented with comparisons to 30 years of rain gauge data. The reanalyses are those performed by the European Centre for Medium-Range Weather Forecasts and of the National Centers for Environmental Prediction jointly with National Center for Atmospheric Research. This study investigates the skill of the reanalyses and ECHAM4 with regard to three climate regions of Indonesia, the annual and interannual variability of rainfall and its responses to El Ni?o-Southern Oscillation (ENSO) events. The study is conducted at two spectral resolutions, T42 and T106. The skill of rainfall simulations in Indonesia depends on the region, month and season, and the distribution of land and sea. Higher simulation skills are confined to years with ENSO events. With the exception of the northwest region of Indonesia, the rainfall from June (Molucca) and July (south Indonesia) to November is influenced by ENSO, and is more sensitive to El Ni?o than La Ni?a events. Observations show that the Moluccan region is more sensitive to ENSO, receives a longer ENSO impact and receives the earliest ENSO impact in June, which continues through to December. It is found that the reanalyses and the climate model simulate seasonal variability better than monthly variability. The seasonal skill is highest in June/July/August, followed by September/October/November, December/January/February and March/April/May. The correlations usually break down in April (for monthly analysis) or in the boreal spring (for seasonal analysis). This period seems to act as a persistent barrier to Indonesian rainfall predictability and skill. In general, the performance of ECHAM4 is poor, but in ENSO sensitive regions and during ENSO events, it is comparable to the reanalyses.     

四个耦合模式ENSO后报试验的“春季预报障碍”

用CliPAS计划中3个气候模式和中国科学院大气物理研究所耦合模式FGOALS-g短期气候异常回报试验结果,将动力和统计方法相结合,考察了1982—2003年厄尔尼诺/拉尼娜事件发展期和衰减期海表温度春季可预报性障碍现象。结果表明,所考察的耦合模式对ENSO事件预报的误差发展存在明显的季节依赖性,最大误差增长通常发生在春季,发生显著的可预报性障碍现象。进一步分析发现厄尔尼诺事件和拉尼娜事件在发展期的季节预报障碍现象比衰减期明显,以厄尔尼诺事件发展期春季可预报性障碍现象最为显著,拉尼娜事件衰减期季节预报障碍现象不显著。研究还发现,预报误差的增长在ENSO事件冷暖位相具有显著的非对称性,发展期暖位相预报误差强于冷位相,而衰减期冷位相的预报误差比暖位相大。通过回归分析,诊断了海-气相互作用的强度,发现耦合系统在春季最不稳定,使预报误差最易在春季发展,从而导致可预报性障碍。     

Toward the development of prediction models for the primary Caribbean dry season

Summary Two statistical models are created for the Caribbean during its dry season. Canonical correlation analysis (CCA) confirms that there is a robust El Ni?o Southern Oscillation (ENSO) signal in the region during the dry season and that the mode manifests itself as oppositely signed precipitation anomalies over the north and south Caribbean. The south-eastern Caribbean becomes dry in response to a warm event. The first statistical model consequently uses a rainfall index averaged over the south-eastern Caribbean as the predictand. A model which retains an ENSO proxy as one of two predictors shows reasonable skill with hindcast predictions for the region. A second model is created using a Jamaican rainfall index as predictand. Jamaica falls in the transition zone i.e. between the oppositely signed north-south precipitation anomalies characteristic of the ENSO dry season mode. In this case no ENSO related predictor is retained in the final model. Composite analysis of select atmospheric variables for anomalously high and low rainfall years (for the dry season) give an understanding of the dynamics of the Caribbean dry season during phases of the ENSO, particularly those which lead to the creation of the transition zone. Authors’ address: Tannecia S. Stephenson, A. Anthony Chen, Michael A. Taylor, Department of Physics, University of the West Indies, Mona, Jamaica.     

ENSO循环与太平洋-北美型遥相关事件的关系

利用1950~2009年的Nio3.4指数和冬季5个月逐日太平洋-北美型遥相关(PNA)指数,对ENSO冷、暖位相及中性年份冬季发生的PNA事件进行了统计分析,结果发现PNA事件个数有显著的差异。ENSO暖位相年份冬季的PNA+事件个数是PNA-事件个数的4.13倍,而冷位相年份的PNA-事件个数是PNA+事件个数的2.73倍。PNA事件指数和PNA事件对应的300 hPa流函数场合成分析结果显示ENSO暖(冷)位相年份的PNA+(PNA-)事件的强度较小,生命史较长,PNA-(PNA+)事件的强度较大生命史较短,位于北太平洋上空的南北向偶极子结构仅出现在PNA+事件过程的成熟阶段。同时,聚类分析也发现,ENSO暖(冷)位相年份的PNA+(PNA-)型的比例大于PNA-(PNA+)型,PNA+型波列结构中有太平洋区域的南北向偶极子结构,而PNA-波列结构中没有,与合成分析结果一致。通过计算北太平洋的300 hPa基本流发现,ENSO循环暖位相年份的副热带急流位置比ENSO循环冷位相年份的偏北,这解释了ENSO循环冷暖位相年份PNA+事件和PNA-事件发生频率的差异。由于中性年份也存在PNA事件,ENSO循环对PNA事件的强度与发生频率有一定的调制作用。     

The Optimal Precursors for ENSO Events Depicted Using the Gradientdefinition-based Method in an Intermediate Coupled Model

The predictability of El Ni?o?Southern Oscillation (ENSO) has been an important area of study for years. Searching for the optimal precursor (OPR) of ENSO occurrence is an effective way to understand its predictability. The CNOP (conditional nonlinear optimal perturbation), one of the most effective ways to depict the predictability of ENSO, is adopted to study the optimal sea surface temperature (SST) precursors (SST-OPRs) of ENSO in the IOCAS ICM (intermediate coupled model developed at the Institute of Oceanology, Chinese Academy of Sciences). To seek the SST-OPRs of ENSO in the ICM, non-ENSO events simulated by the ICM are chosen as the basic state. Then, the gradient-definition-based method (GD method) is employed to solve the CNOP for different initial months of the basic years to obtain the SST-OPRs. The experimental results show that the obtained SST-OPRs present a positive anomaly signal in the western-central equatorial Pacific, and obvious differences exist in the patterns between the different seasonal SST-OPRs along the equatorial western-central Pacific, showing seasonal dependence to some extent. Furthermore, the non-El Ni?o events can eventually evolve into El Ni?o events when the SST-OPRs are superimposed on the corresponding seasons; the peaks of the Ni?o3.4 index occur at the ends of the years, which is consistent with the evolution of the real El Ni?o. These results show that the GD method is an effective way to obtain SST-OPRs for ENSO events in the ICM. Moreover, the OPRs for ENSO depicted using the GD method provide useful information for finding the early signal of ENSO in the ICM.