大气对南极冰异常的遥响应及其季节内振荡

运用ＩＡＰＡＧＣＭ模式证实了大气对南极冰异常的强迫遥响应是激发产生全球大气季节内振荡的重要机制，进而着重考察了候平均偏差结果的时间序列，并且通过带通滤波处理，特别分析了响应场中３０～６０ｄ低频振荡的特征及其活动。通过分析发现：大气对南极冰减退的响应是一种具有３０～６０ｄ周期的低频遥响应，并呈现出清楚的二维Ｒｏｓｓｂｙ波列特征；强迫场中的３０～６０ｄ季节内振荡具有着同实际大气中的低频振荡相类似的垂直结构和传播特征。大气响应场中３０～６０ｄ振荡能量在垂直方向上随高度的增加而增加，在纬向上表现出明显的区域性特征，即季节内振荡的最大动能区（由于ＣＩＳＫ机制）分布在大洋内；ＥＵＰ，ＰＮＡ，ＡＳＡ和ＲＳＡ波列可能是全球大气低频扰动传播的主要路径，３０～６０ｄ低频扰动在波列路径上的传播具有很大的一致性和系统性，从而使中高纬和热带地区、以及南北半球的３０～６０ｄ大气振荡相互联系起来，而且可以认为，赤道中太平洋和赤道中大西洋地区是南北半球３０～６０ｄ低频振荡间相互作用和相互联系的重要通道。

THE ATMOSPHERIC TELERESPONSE TO ANOMALES IN THE ANTARCTIC SEA ICE AND INTRASEASONAL OSCILLATIONS

By using IAPAGCM,it is proved that the anomaly in the antarctic ice is one of the important mechanisms to cause intraseasonal oscillation in the global atmosphere. The time sequence of pontadly mean depature field is analized in this paper using the band pass filtering scheme. With special attention to the characteristics of 30-60 day oscillation in the response field,it was found that: The global atmosphere behaves long time teleresponse to an anomalous external forcing from the antarctic sea ice,whose period ranges from thirty to sixty days.30-60 day oscillation plays an important role in the forcing field,whose vertical structure and zonal propogation characteristics in the model atmosphere is similar to that in real atmosphere. 30-60 day oscillation energy in response field increases with height.Longitudinal variation of the energy appears regional characteristics.The maximum energy of intraseasonal oscillation emerges over the ocean because of CISK mechanism. The wavetrains of EUP,PNA,ASA and RSA,perhaps, are the main propogation routes of the low frequency perturbation in the atmospheric circulation.Consequently the 30-60 day oscillation in the region of middle high and low latitude or in the Northern and Southern Hemisphere keeps in contact with each other.It is suggested,that,the middle equatorial Pacific and Atlantic are the paths through which 30-60 day oscillations in the Northern and Southern Hemisphere interact.