Sensitivity of Nonlinearity on the ENSO Cycle in a Simple Air-sea Coupled Model          下载免费PDF全文

LIN Wan-Tao 《大气和海洋科学快报》2009,2(1):1-6

In this paper,the influence of the El NioSouthern Oscillation (ENSO) cycle on the sensitivity of nonlinear factors in the numerical simulation is investigated by conducting numerical experiments in a simple air-sea coupled model for ENSO prediction.Two sets of experiments are conducted in which zonal nonlinear factors,meridional nonlinear factors,or both are incorporated into the governing equations for the atmosphere or ocean.The results suggest that the ENSO cycle is very sensitive to the nonlinear factor of the governing equation for the atmosphere or ocean.Thus,incorporating nonlinearity into air-sea coupled models is of exclusive importance for improving ENSO simulation.  相似文献   

一个全球耦合模式的ENSO后报试验          下载免费PDF全文

YAN Li  YU Yong-Qiang  WANG Bin  LI Li-Juan  WANG Pan-Xing 《大气和海洋科学快报》2009,2(1):7-13

A group of seasonal hindcast experiments are conducted using a coupled model known as the Flexible Global Ocean-Atmosphere-Land System Modelgamil1.11 (FGOALS-g1.11) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (LASG).Two steps are included in our ElNi o-Southern Oscillation (ENSO) hindcast experiments.The first step is to integrate the coupled GCM with the Sea Surface Temperature (SST) strongly nudged towards the observation from 1971 to 2006.The second step is to remove the SST nudging term.The authors carried out a one-year hindcast by adopting the initial values from SST nudging experiments from the first step on January 1st,April 1st,July 1st,and October 1st from 1982 to 2005.In the SST nudging experiment,the model can reproduce the observed equatorial thermocline anomalies and zonal wind stress anomalies in the Pacific,which demonstrates that the SST nudging approach can provide realistic atmospheric and oceanic initial conditions for seasonal prediction experiments.The model also demonstrates a high Anomaly Correlation Coefficient (ACC) score for SST in most of the tropical Pacific,Atlantic Ocean,and some Indian Ocean regions with a 3-month lead.Compared with the persistence ACC score,this model shows much higher ACC scores for the Ni o-3.4 index for a 9-month lead.  相似文献   

A Reconstructed Wind Stress Dataset for Climate Research over the Tropical Pacific during a 153-Year Period          下载免费PDF全文

ZHENG Fei  DU Juan  ZHU Jiang 《大气和海洋科学快报》2009,2(5):277-283

There are close relationships between the sea surface temperature (SST) and the surface wind over the tropical Pacific.To study the past climate variability over the tropical Pacific,the long-term monthly wind stress anomalies over the tropical Pacific for the period of 1856–2008 are reconstructed with an SVD (singular value decomposition)-based statistical atmospheric model,where the wind stress anomalies are slave and directly correspond to the SST anomalies.The verification results show that the reconstructed wind stress data have high correlations and a small root mean square (RMS) error with the three reanalysis/simulated surface wind datasets from the last 50 years.In addition,the simulated SST anomalies from an intermediate oceanic model (IOM),which is forced by the reconstructed wind stress,can simulate the realistic interannual and decadal variability of the ENSO (El Nio-Southern Oscillation);this indicates that this new long-term wind stress dataset is useful for various climate studies,especially for the large-scale interannual and decadal variability.  相似文献   

近50年中国冬季气温对ENSO响应的时空稳定性分析研究   总被引：2，自引：0，他引：2  

韩文韬  卫捷  沈新勇 《气候与环境研究》2014,19(1):97-106

根据1962~2010年中国160站的月平均气温资料、Ni?o3.4区海洋Ni?o指数(ONI)资料以及相应的NECP/NCAR再分析资料,采用相关分析、滑动相关分析、滑动t检验、合成分析等方法,探讨了最近50年中国冬季气温对ENSO响应的时空稳定性问题。结果表明:中国冬季气温异常对ENSO的响应有着显著的地域性差异以及年代际变化,其中东北和西南地区的相关关系不稳定度比较大,而在中国东部地区则比较稳定。东北与西南地区在20世纪70年代中后期以后,冬季气温对ENSO的响应迅速减弱,甚至发生了反向变化,而东部地区这种关系近50年并没有较强的突变。相应的亚洲高空大气环流对ENSO的响应也具有明显的空间差异和阶段性变化,其特征与中国冬季气温对ENSO的响应特征基本对应。从大气环流角度解释中国冬季气温对ENSO的响应发生阶段性减弱的可能机制:ENSO通过经向Hadley环流影响中高纬度大气环流,由于70年代中后期以后亚洲经向Hadley环流的下沉支发生显著减弱,使得东亚大气环流对ENSO的响应减弱,进而导致中国冬季气温对ENSO的响应减弱。  相似文献   

热带对流活动及其与ENSO关系的非线性特征     

沈桂凤  吴洪宝  韦莹莹  刘学华 《南京气象学院学报》2008,31(2):183-191

用非线性主成分分析方法和NCAR／NCEP长波辐射资料（OLR）,研究了热带对流异常及其与ENSO的关系。结果表明热带对流活动在时空上呈现出明显的非线性特征,它是热带对流活动对ENSO的非线性响应;热带对流异常的强度在E1 Nino时期比在La Nina时期强,且异常的中心位置偏东,表现出明显的时空上的不对称性。  相似文献   

西北太平洋秋季热带气旋发生规律分析     

石蓉蓉  雷媛  胡波 《浙江气象》2008,29(3)

针对2007年秋季热带气旋异常偏多的情况,从拉尼娜现象、南方涛动特征指数（SOI）、夏季风和海温等方面进行原因分析,对秋季热带气旋的发生规律进行初步的探讨和研究,发现在拉尼娜现象开始年秋季热带气旋生成偏多,在拉尼娜延续年生成个数偏少的规律,以及8—11月SOI偏高、海温偏高或秋季夏季风偏强均有利于秋季热带气旋的生成。  相似文献   

东亚冬季风对ENSO事件的响应特征   总被引：23，自引：5，他引：18  

何溪澄  丁一汇  何金海 《大气科学》2008,32(2):335-344

基于美国NOAA在ENSO诊断分析中使用的海洋Ni?o指数 （Oceanic Ni?o Index, 简称ONI）,将1950～2005年冬季分成强El Ni?o、强La Ni?a、弱El Ni?o、弱La Ni?a和没有发生ENSO事件5类,用分类合成方法研究了冬季东亚大气环流对ENSO事件的响应。结果表明,在低纬度,大气环流对ENSO事件的响应具有较明显的准线性特征,即大气对海洋暖事件与冷事件的响应大致是反位相的,对弱ENSO事件的响应与强ENSO事件相似但强度较弱。中高纬度大气环流与ENSO事件也有一定的联系,但同等强度暖事件与冷事件下大气环流距平场上的系统分布没有呈现明显的反位相,表明大气对海温异常的响应是复杂的。强El Ni?o事件时大气的响应信号显著,主要表现在东亚中高纬西风气流增强, 亚洲北部地区气温偏高,距平风场上的切变线从长江中下游向东伸展,菲律宾海距平反气旋西北侧的偏南气流和南支槽前西南气流加强,其共同作用使南海和中国东南沿海出现显著的偏南风距平;强La Nia事件时,长江中下游向东伸展的脊线不明显,中国南方至南海处于偏北风距平区,但通过统计检验的范围减小;弱El Ni?o事件时,菲律宾海距平反气旋西北侧的西南气流偏东,与南支槽前西南气流分开,使得华南和南海的偏南风距平没有强El Ni?o时显著; 弱La Ni?a事件时,西风带纬向气流减弱,亚洲北部地区气温偏低。对ONI指数与亚洲北部温度指数（NTI）的散点图的分析显示,9个强El Ni?o冬季中有8年亚洲北部温度距平偏高,7个弱El Ni?o冬季中只有1年温度偏高;8个强La Ni?a冬季有4年温度偏低,12个弱La Ni?a冬季中有11年温度偏低;亚洲强暖冬和强冷冬的发生与ENSO事件的联系不紧密。  相似文献   

Upwelling signals in radiocarbon from early 20th-century Peruvian bay scallop (Argopecten purpuratus) shells     

Kevin B. Jones  Gregory W.L. Hodgins  Miguel F. Etayo-Cadavid  C. Fred T. Andrus 《Quaternary Research》2009,72(3):452-456

We quantified Δ¹⁴C, δ¹⁸O, and δ¹³C cycles along ontogeny within four bay scallop (Argopecten purpuratus) shells collected from Callao Bay, Salaverry, and Sechura Bay, Peru following the 1907–1908 non-El Niño years and the 1925–1926 El Niño. Δ¹⁴C and δ¹³C generally covary; Δ¹⁴C and δ¹⁸O vary inversely. Simultaneous decreases in Δ¹⁴C and increases in δ¹⁸O in non-El Niño shells are followed by constant Δ¹⁴C and gradually decreasing δ¹⁸O, which we interpret as evidence for discrete marine upwelling events followed by warming of the initially cold upwelled water. Upwelling changes from El Niño events are detectable with difficulty in mollusk shell Δ¹⁴C.  相似文献   

Uncertainties in climate change prediction: El Niño-Southern Oscillation and monsoons     

Heiko Paeth  Anja Scholten  Petra Friederichs  Andreas Hense 《Global and Planetary Change》2008,60(3-4):265-288

The sensitivity of climate phenomena in the low latitudes to enhanced greenhouse conditions is a scientific issue of high relevance to billions of people in the poorest countries of the globe. So far, most studies dealt with individual model results. In the present analysis, we refer to 79 coupled ocean–atmosphere simulations from 12 different climate models under 6 different IPCC scenarios. The basic question is as to what extent various state-of-the-art climate models agree in predicting changes in the main features of El Niño-Southern Oscillation (ENSO) and the monsoon climates in South Asia and West Africa. The individual model runs are compared with observational data in order to judge whether the spatio-temporal characteristics of ENSO are well reproduced. The model experiments can be grouped into multi-model ensembles. Thus, climate change signals in the classical index time series, in the principal components and in the time series of interannual variability can be evaluated against the background of internal variability and model uncertainty.There are large differences between the individual model predictions until the end of the 21st century, especially in terms of monsoon rainfall and the Southern Oscillation index (SOI). The majority of the models tends to project La Niña-like anomalies in the SOI and an intensification of the summer monsoon precipitation in India and West Africa. However, the response barely exceeds the level of natural variability and the systematic intermodel variations are larger than the impact of different IPCC scenarios. Nonetheless, there is one prominent climate change signal, which stands out from model variations and internal noise: All forced model experiments agree in predicting a substantial warming in the eastern tropical Pacific. This oceanic heating does not necessarily lead to a modification of ENSO towards more frequent El Niño and/or La Niña events. It simply represents a change in the background state of ENSO. Indeed, we did not find convincing multi-model evidence for a modification of the wavelet spectra in terms of ENSO or the monsoons. Some models suggest an intensification of the annual cycle but this signal is fairly model-dependent. Thus, large model uncertainty still exists with respect to the future behaviour of climate in the low latitudes. This has to be taken into account when addressing climate change signals in individual model experiments and ensembles.  相似文献   

新疆洪旱灾害与大尺度气候强迫因子的联系   总被引：13，自引：6，他引：7  

姜逢清  杨跃辉 《干旱区地理》2004,27(2):148-153

通过对新疆洪灾灾害历史资料和太阳黑子、ENSO事件年数据以及北大西洋涛动指数的分析,表明在太阳黑子极低值年或不活跃年,新疆易发生重大洪灾,而在太阳黑子低值年或相对不活跃年,新疆也易发生重大旱灾。近200a来,新疆重大洪旱灾害绝大部分都发生在太阳黑子的低谷时期。ENSO事件对新疆夏季降水的影响效应明显。因而该事件对新疆的洪旱灾害也产生了影响。对近50年来灾害统计资料分析显示,与拉尼娜年相比,在厄尔尼诺年新疆更易发生洪旱灾害。20世纪后半段新疆洪旱灾害指数与北大西洋涛动指数进行对比可以发现．夏季NAO指数与新疆洪水灾害之间存在大致上的反相关系。而冬季NAO指数与新疆干旱灾害之间存在比较明显的反相关系。  相似文献