北太平洋海温Victoria模态与ENSO年际关系的非对称特征

Asymmetric characteristics of interannual relationship between Victoria mode of North Pacific SST and ENSO

利用美国NOAA海表温度资料,重点分析了北太平洋海温异常EOF第二模态Victoria模态(VM)与ENSO年际关系的非对称特征。研究发现,VM和ENSO在年代际尺度上相关性较弱,而在年际尺度上有很好的相关关系,两者同期为负相关,VM超前1 a为正相关。然而,正负VM事件与ENSO冷暖位相在年际尺度上的联系存在着一定的非对称性。正VM事件与同年冬季热带中东太平洋海温异常的联系较弱,但次年常有厄尔尼诺事件发生;相比较而言,负VM事件在同年一般都有厄尔尼诺事件伴随发生,而与次年冬季热带中东太平洋海温没有显著联系,且很少有ENSO事件发生。由此可见,正VM事件对次年厄尔尼诺的发生发展似乎有促进作用,可作为ENSO前期预报因子之一,而负VM事件不能作为ENSO的前期预报因子。

Based on the sea surface temperature(SST)data from NOAA in USA,the asymmetric characteristics of interannual relationship between ENSO and Victoria mode(VM;EOF2of North Pacific SST anomalies in winter(DJF))were emphatically analyzed.Results show that the correlation between VM and ENSO is weak on the decadal scale,but strong on the interannual scale.VM has significant negative correlation with ENSO in the same year,and has strong positive correlation with ENSO in the following year.However,there is a certain asymmetry in the relationship between the positive/negative VM events and ENSO warm/cold phases on the interannual scale.The relationship between the positive VM events and the SST anomalies in the tropical central and eastern Pacific in the same winter is weak,but El Ni?o events often occur in the following year.In contrast,the negative VM events are usually accompanied by El Ni?o events in the same years,but there is no significant relationship between the negative VM events and the SST anomalies in the tropical central and eastern Pacific in the following winter and there are few ENSO events.It can be seen that the positive VM event seems to promote the occurrence and development of El Ni?o in the next year and can be used as one of the early prediction factors of ENSO,while the negative VM event cannot be used as the early prediction factor of ENSO.