A coupled interannual oscillation system

ＩＮＴＲＯＤＵＣＴＩＯＮＥｌＮｉ ｎｏ ＳｏｕｔｈｅｒｎＯｓｃｉｌｌａｔｉｏｎ (ＥＮＳＯ)ｉｓｔｈｅｉｎｔｅｒａｎｎｕａｌｉｎｔｅｒａｃｔｉｏｎｏｆｏｃｅａｎ ａｔｍｏｓｐｈｅｒｅｉｎｔｈｅｔｒｏｐｉｃａｌ(ｅｓｐｅｃｉａｌｌｙｅｑｕａｔｏｒｉａｌ)Ｐａｃｉｆｉｃ .Ｉｔｉｓａｌｓｏｒｅｃｏｇｎｉｚｅｄａｓｂｅｉｎｇｔｈｅｄｏｍｉｎａｎｔｍｅｃｈａｎｉｓｍｏｆｔｈｅｅａｒｔｈ’ｓｉｎｔｅｒａｎｎｕａｌｃｌｉｍａｔｅｃｈａｎｇｅ.Ｓｅｖｅｒａｌｃｏｎｃｅｐｔｕａｌ (ｓｉｍｐｌｅ)ｍｏｄｅｌｓｗｅｒｅｐｒｏｐ…     

琉球群岛以东的西边界流与东海黑潮流量时空特征的研究

通过最新的高分辨率再分析海洋数据资料,对于东海黑潮以及琉球群岛以东海域的海流进行了研究。结果表明琉球群岛以东西边界流最大流速出现在600~1200 m深度的地形坡度最大处,大小约为0.2 m/s。由于冲绳岛以南庆良间水道的水交换对于东海黑潮流量有重要的影响,东海黑潮的平均流量从南向北逐渐递增,平均流量为28×106~35×106m3/s;琉球群岛以东的西边界流流量则比东海黑潮小一个量级,平均值小于其变化的方差;由于受庆良间水道海流的影响,冲绳岛东侧的流量要远小于奄美大岛东侧的流量。同一纬度大洋中西传的Rossby波对琉球群岛以东的西边界流有较大影响,因此琉球群岛以东西边界流的流量有大约100 d的显著变化周期。庆良间水道以南的东海黑潮由于主要受台湾以东黑潮流量的控制,也有大约100 d的显著变化周期,庆良间水道以北的东海黑潮则没有该特征。     

热带三大洋海-气耦合主模态及其相互作用的研究进展

从地球气候系统的角度,回顾了国内外热带太平洋、大西洋和印度洋海洋-大气相互作用研究,特别是有关这三大洋海-气耦合主模态研究已取得的成就;提出了热带印度洋、大西洋在被热带太平洋“充电”的同时,如何通过大气桥“放电”,从而改变热带太平洋海洋动力过程是目前面临的重要科学问题.指出了海洋动力过程在三大洋相互作用中的重要性.     

多层准地转基本流的扰动发展与非线性稳定性

进一步考察了初值与模式中参数共同扰动的情形 ;在初始扰动场仅依赖于初始扰动位势涡度、初始扰动边界速度环量与扰动参数的条件下 ,给出了扰动能量、扰动位涡拟能精确的显式估计 ;并在Lyapunov意义下广义非线性稳定性概念的基础上 ,得到了对应于Arnold第二定理的非线性稳定性判据。     

菲律宾以西海域的高温暖水与南海夏季风爆发

采用改进的甚高分辨率辐射计(AVHRR)、热带降水测量卫星(TRMM)、快速散射计(QuikSCAT)等最新高分辨率的卫星遥感资料和美国国家环境预报中心和气象研究中心(NCEP/NCAR)多年平均再分析资料,揭示出气候态下菲律宾以西海域30℃以上高温暖水的出现和面积突增可以作为南海夏季风爆发的先兆,高温暖水具有生命期短的特征。研究指出高温暖水导致的局地对流在南海夏季风爆发中起着重要作用,高温暖水的年际变化与南海夏季风爆发时间早晚关系密切。     

THE MEANDER OF KUROSHIO AND OSCILLATION IN A COUPLED OCEAN-ATMOSPHERE MODEL

A numerical experiment of an asynchronous coupled ocean-atmosphere model has been described in this paper.Atwo-layer global atmosphere general circulation model(OSU/IAP-AGCM)and a two-layer North Pacific Oceangeneral circulation model(NPOGCM)developed by Liu et al.(1992)are used in numerical experiment.The sea surfacetemperature anomaly(SSTA)corresponding to the meander of the Kuroshio is treated as the initial perturbation in thePacific Ocean and the abnormal phenomena caused by the disturbance and the interaction between atmosphere andocean,have been studied.The numerical experiment showed that the SST anomaly in the North Pacific could induce a new 30—60 dayoscillation through the coupling between atmosphere and ocean and the interaction between the meander of theKuroshio and atmosphere circulation is a positive feedback process.     

THREE-DIMENSIONAL BAROCLINIC NUMERICAL SIMULATION OF THE SOUTH CHINA SEA CIRCULATION＇S SEASONAL CHARACTERISTICS II. MIDDLE AND DEEP CIRCULATION

A three-dimensional baroclinic shelf sea model‘ s numerical simulation of the South China Sea (SCS) middle and deep layer circulation structure showed that: 1. In the SCS middle and deep layer, a seulhward boundary current exists along the east shore of the Indo-China Peninsula all year long.A cyclonic eddy (gyre) is formed by the current in the above sea areas except in the middle layer in spring, when an anticyclonic eddy exists on the eastern side of the current. In the deep layer, a larges-cale anticyclonic eddy often exists in the sea areas between the Zhongsha Islands and west shore of southern Luzon Island. 2. In the middle layer in snmmer and autumn, and in the deep layer in autumn and winter, there is an anticyclonic eddy (gyre) in the northeastern SCS, while in the middle layer in winter and spring, and in the deep layer in spring and snmmer, there is a cyclonic one. 3. In the middle layer,there is a weak northeastward current in the Nansha Trough in spring and snmmer, while in autumn and winter it evolves inl~ an anticyclonic eddy ( gyre), which then spreads westward l~ the whole western Nansha Islands sea areas.     

分层热带海洋模式中的Rossby波和Kelvin波——初始混合层深度异常与大气热力强迫激发波动

利用一个两层半的热带海洋模式,采用数值实验的方法研究了热带海洋对于初始海洋混合层深度异常和大气季节内时间尺度热力强迫激发产生的Ｒｏｓｓｂｙ波和Ｋｅｌｖｉｎ波。研究表明,初始海洋混合层深度异常和大气热力强迫,可以在两层半热带海洋模式中激发产生东向传播具有Ｋｅｌｖｉｎ波性质的波动和具有Ｒｏｓｓｂｙ波性质的波动。热力强迫激发产生海洋Ｒｏｓｓｂｙ波和Ｋｅｌｖｉｎ波所需时间长于初始海洋混合层深度异常和大气季节内动力强迫激发产生两波所需时间,与大气季节内动力强迫激发的Ｒｏｓｓｂｙ波相比,初始深度异常与大气热力强迫激发产生Ｒｏｓｓｂｙ波具有不同的热力性质。     

冬季黑潮延伸体海域云水含量的年际变化

利用卫星观测的海面高度资料、海表温度资料和再分析大气资料,考察了冬季黑潮延伸体海域云水含量的年际变化。结果表明:尽管大气环流有明显的年际变化,海洋锋对其上云水含量的"锚定"作用(锋面南侧云水含量多,北侧少)始终存在,同时云水量值有明显的年际变化,该变化主要受背景大气环流的影响,当西北风加强(减弱)带来偏冷(暖)偏干(湿)的空气团时,锋面南侧云水少(多)。按照云水含量多少进行合成分析的结果表明:来自大陆的冬季西北风南下,在遇到海洋锋锋南侧的暖水面时,空气抬升导致的大气跨锋面的次级环流和对应锋面南(北)辐合(辐散)在一定程度上(约25%)受背景大气环流变化的影响。在背景大尺度的西北风强(弱)时,大气中水汽含量较少(多),凝结放热较弱(强),黑潮延伸体海洋锋南侧南侧上升,北侧下沉的次级环流偏弱(强)。     

DYNAMICS OF NONLINEAR BAROCLINIC EKMAN BOUNDARY LAYER

By the geostrophic momentum approximation, the wind structure and vertical motion within the nonlinear baroclinic Ekman layer matching with the surface layer are deterrmned. A comparison of the Ekman solution with the classical one is made. It is demonstrated that the contributions of barocfiaity, stratification and nonlinear effects to the wind profile within the layer are all of definite importance.