全球百年海表面温度年际和年代际变化特征分析

利用100 a(1903—2002年)HadiSST的逐月资料,将全球海表面温度异常(SSTA)作为整体进行经验正交函数分解(EOF分解),提取了控制各大洋SSTA的主导模态和各大洋之间的联合模态,分析了相应的空间分布和时间序列。研究结果表明:SSTA变化最剧烈的海区是赤道中东太平洋、西北大西洋湾流海区和北太平洋黑潮延伸体海区。热带太平洋厄尔尼诺和南方涛动是主导模态并具有2~7 a周期的年际变化;SSTA变化第二主模态和第三主模态都是以大约70 a为周期的年代际变化为主的跨大洋联合模态。第二主模态的空间分布主要表现为中纬度北太平洋和北大西洋反位相、热带太平洋与大西洋反位相的太平洋-大西洋双偶极子型分布。SSTA变化的第三模态主要呈现南北半球海洋反位相的特征,为北太平洋-北大西洋-南大洋联合模态。第四模态基本上是反映各个不同海域特有的局地海洋-大气相互作用模态,该模态的时间序列具有1~4 a周期的年际变化和约9 a周期的年代际变化。

The analysis of interannual and interdecadal characteristics of global sea surface temperature during 1902-2003

Based on the monthly HadiSST SSTA(sea surface temperature anomaly) in recent 100 years (from 1903 to 2002), the spatial and temporal variation characteristics of global SSTA are analyzed by using the method of Empirical Orthogonal Function (EOF),the first main mode of global SSTA and other joint modes between different oceans are respectively obtained. It is shown that the maximum changes of SSTA appear in equatorial eastern Pacific, Gulf Stream zone in northwestern Atlantic and Kuroshio extension zone in north Pacific; ENSO in tropical Pacific is the first main mode with periods of 2~7 years; the second main mode and third main mode are joint modes between different oceans with an interdecadal period of about 70 years. The second mode is a Pacific-Atlantic double dipole mode with one out-of-phase dipole in north Pacific and north Atlantic, the other in tropical Pacific and tropical Atlantic. The third mode is a North Pacific-North Atlantic-Southern Ocean mode with out-of-phase between northern and southern hemispheres. The forth mode reflects local ocean-atmosphere interaction patterns in different zones and the time series in this mode presents interannual periods of 1~4 years and an interdecadal period of about 9 years .