ENSO动力学与预测   总被引：10，自引：2，他引：10       下载免费PDF全文

张人禾  周广庆  巢纪平 《大气科学》2003,27(4):674-688

发生在热带太平洋地区的ENSO现象是海气相互作用的集中表现,是年际气候变化中的最强信号.由于它的发生会在全球许多地区引起严重的气候异常,极大地影响着这些地区的工农业生产和人民生活,因此,对ENSO的机理及其预测的研究一直是大气海洋界的一个热点研究课题.中国科学院大气物理研究所在ENSO的机理及其预测等方面进行了大量的研究,取得了许多研究成果.作者将对中国科学院大气物理研究所在这方面的一些研究成果进行回顾和介绍.  相似文献   

STUDY ON THE AIR-SEA INTERACTION ON THE INTERANNUAL TIME SCALE IN THE SOUTH CHINA SEA^*     

Wang Dongxiao  Zhou Faxiu  Qin Zenghao 《Acta Meteorologica Sinica》1997,11(1):45-56

In this paper we document the correlationship between sea surface temperature(SST) and low level-winds such as sea level wind and 850 hPa wind in the South China Sea(SCS) based on COADS(1958-1987) and ECMWF objective analysis data(1973-1986).Further statistical analyses tell us that there is a fixed SCS basin mode for variations both of SST and low-level winds in the region on the interannual time scale due to air-sea interactions.A simplified,coupled model that is designed following the McCreary and Anderson's(1985) model and includes the feedback between the upper ocean and the circulation of East Asian monsoon demonstrates an interannual oscillation in the coupled air-sea system,which is similar to the observations in the SCS.  相似文献   

透明胞外聚合颗粒物碳输运新途径   总被引：2，自引：1，他引：1  

孙军  郭聪聪  张桂成 《海洋学报》2019,41(8):125-130

目前大家普遍认为，透明胞外聚合颗粒物(Transparent Exopolymer Particles，TEP)因其独特的凝聚效应导致碳通量向海底输出。但是，近几年的研究表明TEP不仅影响了碳沉降途径，其本身能够悬浮甚至向海水表层迁移，导致其在海洋微表层(Surface Micro-layer, SML)积累，最终显著影响海洋表层碳通量。TEP和其他颗粒物聚集形成凝聚物后，其运动趋势则由凝聚物中TEP的含量占比，即最终颗粒物密度所决定。一个新的值得注意的现象是，密度低的TEP通过与其他微粒聚合形成表面活性物质(Surface-active Substances, SAS)，会在海洋–大气界面形成薄膜，显著影响海–气CO₂交换通量，甚至对全球气候变化造成影响。  相似文献   

基于经验模态分解和小波分解估算海气通量涡相关计算中的截断时间尺度     

姜浩  赵中阔  樊伟  宋金宝 《海洋与湖沼》2018,49(6):1138-1150

基于时长38天的海表风场实测数据,应用经验模态分解(EmpiricalModeDecomposition,EMD)和小波分解(Wavelet Decomposition, WD)这两种数据处理方法首先对涡相关法中的截断时间尺度(CutoffTimescale,CTS)进行估算,结果显示:基于EMD与WD方法估算出的CTS一般都在40秒左右(EMD的结果略小),远远小于传统涡相关法中CTS的取值(固定为10分钟),且EMD和WD的使用使得每一段数据都能够根据自身的湍流特点而获得合适的CTS; EMD方法和WD方法有效的去除了计算结果中的非湍部分,且对通量传输方向的刻画也更加合理,极大提高了通量的计算精度,所得通量与传统方法计算的通量偏差平均值高达45%;研究还对EMD和WD的优缺点进行了对比分析,结果表明EMD相比于WD有更高的自主性,而WD对信号的分离程度则更高。  相似文献   

2008年南海季风爆发前后西沙海域海气通量变化特征   总被引：4，自引：1，他引：3  

孙启振  陈锦年  闫俊岳  张秀芝  黄磊  王长科  姚华栋  赵学华  陈长丘 《海洋学报》2010,32(4):12-23

基于2008年4至5月在南海西沙永兴岛进行的海气通量观测试验资料和NCEP资料,应用COARE3.0通量算法计算了海气通量,分析了季风爆发前后西沙海域天气变化特点和海气通量对南海季风爆发的响应。结果表明:2008年南海季风首先于5月第1候在南海南部爆发,受热带气旋等因素的影响,北部海区季风爆发推迟到5月18日。季风爆发和热带气旋活动对西沙海域的风速和海气通量影响较大,其中热带气旋的影响更强烈。热带气旋来临之前,潜热通量、感热通量以及动量通量均较小;在气旋活动及此后的季风爆发时期,大风使潜热通量和动量通量显著增强,感热通量则在降水期间变化明显;动量通量的最大值出现在热带气旋活动期间,其在此过程中的均值是观测初期均值的3倍以上。在整个观测过程中,潜热通量明显大于感热通量,后者是前者的16∶1。不同类型天气过程中,潜热通量的日变化相似,而感热通量的日变化有差异。湍流交换系数与风速有较好的相关关系。  相似文献   

Weak ENSO Asymmetry Due to Weak Nonlinear Air–Sea Interaction in CMIP5 Climate Models   总被引：1，自引：0，他引：1  

Yan Sun  Fan Wang  De-Zheng Sun 《大气科学进展》2016,33(3):352-364

State-of-the-art climate models have long-standing intrinsic biases that limit their simulation and projection capabilities.Significantly weak ENSO asymmetry and weakly nonlinear air–sea interaction over the tropical Pacific was found in CMIP5(Coupled Model Intercomparison Project, Phase 5) climate models compared with observation. The results suggest that a weak nonlinear air–sea interaction may play a role in the weak ENSO asymmetry. Moreover, a weak nonlinearity in air–sea interaction in the models may be associated with the biases in the mean climate—the cold biases in the equatorial central Pacific. The excessive cold tongue bias pushes the deep convection far west to the western Pacific warm pool region and suppresses its development in the central equatorial Pacific. The deep convection has difficulties in further moving to the eastern equatorial Pacific, especially during extreme El Ni o events, which confines the westerly wind anomaly to the western Pacific. This weakens the eastern Pacific El Ni o events, especially the extreme El Ni o events, and thus leads to the weakened ENSO asymmetry in climate models. An accurate mean state structure(especially a realistic cold tongue and deep convection) is critical to reproducing ENSO events in climate models. Our evaluation also revealed that ENSO statistics in CMIP5 climate models are slightly improved compared with those of CMIP3. The weak ENSO asymmetry in CMIP5 is closer to the observation. It is more evident in CMIP5 that strong ENSO activities are usually accompanied by strong ENSO asymmetry, and the diversity of ENSO amplitude is reduced.  相似文献   

LINKAGE BETWEEN INDIAN OCEAN DIPOLE AND TWO TYPES OF El NI?O AND ITS POSSIBLE MECHANISMS     

董笛  何金海  李建平 《热带气象学报(英文版)》2016,22(2):172-181

After compositing three representative ENSO indices,El Nio events have been divided into an eastern pattern(EP) and a central pattern(CP).By using EOF,correlation and composite analysis,the relationship and possible mechanisms between Indian Ocean Dipole(IOD) and two types of El Nio were investigated.IOD events,originating from Indo-Pacific scale air-sea interaction,are composed of two modes,which are associated with EP and CP El Ni o respectively.The IOD mode related to EP El Nio events(named as IOD1) is strongest at the depth of 50 to 150 m along the equatorial Indian Ocean.Besides,it shows a quasi-symmetric distribution,stronger in the south of the Equator.The IOD mode associated with CP El Nio(named as IOD2) has strongest signal in tropical southern Indian Ocean surface.In terms of mechanisms,before EP El Nio peaks,anomalous Walker circulation produces strong anomalous easterlies in equatorial Indian Ocean,resulting in upwelling in the east,decreasing sea temperature there;a couple of anomalous anticyclones(stronger in the south) form off the Equator where warm water accumulates,and thus the IOD1 occurs.When CP El Nio develops,anomalous Walker circulation is weaker and shifts its center to the west,therefore anomalous easterlies in equatorial Indian Ocean is less strong.Besides,the anticyclone south of Sumatra strengthens,and the southerlies east of it bring cold water from higher latitudes and northerlies west of it bring warm water from lower latitudes to the 15° to 25°S zone.Meanwhile,there exists strong divergence in the east and convergence in the west part of tropical southern Indian Ocean,making sea temperature fall and rise separately.Therefore,IOD2 lies farther south.  相似文献   

The biogeochemical sulfur cycle in the marine boundary layer over the Northeast Pacific Ocean   总被引：1，自引：0，他引：1  

T. S. Bates  J. E. Johnson  P. K. Quinn  P. D. Goldan  W. C. Kuster  D. C. Covert  C. J. Hahn 《Journal of Atmospheric Chemistry》1990,10(1):59-81

The major components of the marine boundary layer biogeochemical sulfur cycle were measured simultaneously onshore and off the coast of Washington State, U.S.A. during May 1987. Seawater dimethylsulfide (DMS) concentrations on the continental shelf were strongly influenced by coastal upwelling. Concentration further offshore were typical of summer values (2.2 nmol/L) at this latitude. Although seawater DMS concentrations were high on the biologically productive continental shelf (2–12 nmol/L), this region had no measurable effect on atmospheric DMS concentrations. Atmospheric DMS concentrations (0.1–12 nmol/m³), however, were extremely dependent upon wind speed and boundary layer height. Although there appeared to be an appreciable input of non-sea-salt sulfate to the marine boundary layer from the free troposphere, the local flux of DMS from the ocean to the atmosphere was sufficient to balance the remainder of the sulfur budget.  相似文献   

REGIONAL DIFFERENCES OF TEMPORAL-SPATIAL CHARACTERISTICS OF AIR-SEA INTERACTIONS IN TROPICAL OCEANS   总被引：3，自引：0，他引：3  

王盘兴  何金海  郭品文  马丽萍 《Acta Meteorologica Sinica》2001,(4)

The singular value decomposition (SVD) of air-sea interaction in the tropical western,central,and eastern Pacific,and the tropical Atlantic and Indian Oceans has been conducted by using theNCEP/NCAR 40-year reanalysis 1000 hPa monthly wind field and COADS monthly sea surfacetemperature (SST).Comparisons of the results suggest that these areas can be divided into threetypes from the viewpoint of air-sea interaction:tropical central-eastern Pacific belongs to monistictype,in which ENSO is the sole important process;tropical western Pacific and Indian Oceansbelong to dualistic type,in which in addition to ENSO.there should be an another importantprocess;tropical Atlantic Ocean belongs to pluralistic type,in which the process is complicatedand the ENSO cycle is not evident.  相似文献   

热带太平洋线性海气耦合系统的主模与ENSO   总被引：2，自引：0，他引：2  

谢倩  杨修群 《大气科学》1996,20(5):547-555

本文利用包含海洋表面边界层、线性海洋大气动力学以及完整的关于不均匀气候态线性化SST预报方程的热带太平洋海气耦合模式， 在真实的气候背景态和参数域内，研究了海气耦合系统的特征值问题，确定了线性耦合系统主模的特征周期及其稳定性特征，进而揭示了主模和ENSO的关系。结果表明:准两年振荡是线性海气耦合系统中的最不稳定模态，且只有该模态类似于ENSO水平结构。因此，准两年振荡很可能是海气耦合系统固有的最根本性的振荡过程。本文也对准两年振荡的形成与年循环的关系以及它在ENSO时间尺度形成中的作用进行了讨论。  相似文献