热带太平洋海域低频海平面异常信号研究

ON SEA LEVEL ANOMALIES OF LOW FREQUENCY SIGNALS IN TROPICAL PACIFIC OCEAN

基于1992年11月—2007年5月的高度计资料,分析了热带太平洋海域年际变化的海平面异常,发现:1)周期为24～42个月的海平面异常携带着较完整的ENSO信息;2)SLA_2442的循环不仅存在于强厄尔尼诺时期,也存在于弱厄尔尼诺时期,甚至会发生在非厄尔尼诺时期;3)在各循环中,南北半球都存在SLA_2442信号的循环回路,呈皆扁"O"形,但关于赤道不对称,其纬向通道分别位于赤道、9.86°N和8°S附近。

On the basis of the altimeter data between October 1992 and May 2007, the interannual variations of sea level anomalies （SLA） of the tropical Pacific Ocean are investigated. It is found that ： 1 ） Sea level anomalies during the period of 24 - 42 months （SLA_2442） are associated with the interannual variations of ENSO ; 2） SLA _2442 circuit exists not only during strong ENSO terms like the E1 Nino of 1997/1998, but also with weak E1 Nifio events, such as the E1 Nino of 1994/1995, and even in normal years; 3） Each circuit of SLA_2442 signals is cyclonic in both of the north and south hemispheres, whose pattern looks like an ＂0＂, but not symmetrical. In addition, the circuit pathways are near 0°, 9.86°N and 8°S,respectively.