Decadal changes of ENSO persistence barrier in SST and ocean heat content indices: 1958–2001
Decadal changes of ENSO persistence barrier in SST and ocean heat content indices: 1958–2001
复制标题
DOI：
10.1029/2006jd007654
复制
发表时间：
2007-07
影响因子：
--
通讯作者：
Jin‐Yi Yu;H. Kao
中科院分区：
文献类型：
--
作者：
Jin‐Yi Yu;H. Kao
利用1958-2001年的观测资料和海洋资料同化产品，研究了厄尔尼诺-南方涛动(ENSO)持续性障碍在不同的海表面温度(SST)和海洋热含量(OHC)指数中的年代际变化。结果表明，赤道太平洋东部和中部的海温指数表现出明显不同的年代际屏障变率。东太平洋海温指数(NINO1+2和NINO3)的变率较大，其持续性障碍在1976/1977和1989/1990年间突变。相比之下，中太平洋海温指数(NINO3.4和NINO4)经历了很少的年代际障碍变化，在过去的40年里，它们的持续性障碍在春季得到了修复。赤道太平洋平均的纬向平均OHC指数表现出与东太平洋SST指数相似的年代际障碍变化，并且总是领先NINO_3 SST障碍约一个季节。在1976/1977年前，SST持续性障碍首先出现在东太平洋，1976/1977和1989/1990年间，首先出现在中太平洋，1989/1990年后，东太平洋和中太平洋几乎同时出现。这些时间与这三个时段观测到的ENSO海温异常的西传、东传和原地分布相吻合。这些结果表明，赤道太平洋ENSO SST异常可以认为由两个不同的过程组成：一个是中太平洋过程，它的相变和障碍总是发生在春季，另一个是东太平洋过程，它的相变和障碍从十年到十年变化，并受到赤道太平洋平均温跃层深度变化的影响。
Decadal changes of El Nino-Southern Oscillation (ENSO) persistence barriers in various indices of sea surface temperature (SST) and ocean heat content (OHC) are examined in this study using observations and ocean data assimilation products for the period 1958–2001. It is found that the SST indices in the eastern and central equatorial Pacific exhibit very different decadal barrier variability. The variability is large for the eastern Pacific SST indices (NINO1+2 and NINO3) whose persistence barriers shifted abruptly in 1976/1977 and 1989/1990. In contrast, the central Pacific SST indices (NINO3.4 and NINO4) experienced little decadal barrier variability and have had their persistence barriers fixed in spring in the past four decades. The zonal mean OHC index averaged over the equatorial Pacific shows decadal barrier changes similar to those in the eastern Pacific SST indices and always leads the NINO3 SST barrier by about one season. It is noticed that the SST persistence barrier appeared first in the eastern Pacific before 1976/1977, first in the central Pacific between 1976/1977 and 1989/1990, and almost simultaneous in both the eastern and central Pacific after 1989/1990. These timings coincide with the westward propagating, eastward propagating, and standing pattern of ENSO SST anomalies observed in these three periods. These results suggest that ENSO SST anomalies in the equatorial Pacific can be considered to consist of two different processes: a central Pacific process whose phase transition (such as onset) and barrier always happen in spring, and an eastern Pacific process whose phase transition and barrier change from decade to decade and are influenced by changes in the mean thermocline depth along the equatorial Pacific.