Pacific decadal oscillation remotely forced by the equatorial Pacific and the Atlantic Oceans
Pacific decadal oscillation remotely forced by the equatorial Pacific and the Atlantic Oceans
复制标题
DOI：
10.1007/s00382-020-05295-2
复制
发表时间：
2020-06-06
期刊：
影响因子：
4.6
通讯作者：
Mochizuki, Takashi
中科院分区：
文献类型：
--
作者：
Johnson, Zachary F.;Chikamoto, Yoshimitsu;Mochizuki, Takashi
太平洋年代际振荡（PDO）是太平洋海表温度年代际变化的主导模态，主要由北太平洋区域海气相互作用和热带太平洋、大西洋等远距离强迫共同作用而产生。由于这种机制的组合，一个问题仍然是有多少PDO的变异性源于这些地区。为了更好地了解PDO的变化，赤道太平洋和大西洋的PDO的影响进行了几个3维部分海洋资料同化试验与两个全球气候模式：CESM1.0和MIROC3.2m。在这些部分同化实验中，气候模型受到观察到的温度和盐度异常的约束，一个仅在大西洋盆地，另一个仅在赤道太平洋盆地，但允许在其他地区自由发展。这些实验表明，除了热带太平洋的作用，在驱动PDO的变化，大西洋可以通过调节热带太平洋气候通过两个拟议的过程影响PDO的变化。一个是赤道路径，其中热带大西洋海表温度（SST）的变率导致在赤道太平洋的厄尔尼诺样SST的响应，通过重组的全球步行者环流。另一个是北热带路径，其中与大西洋年代际振荡相关的低频SST变率在赤道以北的热带南极-太平洋扇区引起松野-吉尔型大气响应。这些结果提供了一个定量评估，表明PDO方差的12-29%来自大西洋和40-44%来自热带太平洋。其余的27-48%的变化被推断为来自其他过程，如北太平洋的区域海洋-大气相互作用和可能来自印度洋的遥相关。
The Pacific Decadal Oscillation (PDO), the leading mode of Pacific decadal sea surface temperature variability, arises mainly from combinations of regional air-sea interaction within the North Pacific Ocean and remote forcing, such as from the tropical Pacific and the Atlantic. Because of such a combination of mechanisms, a question remains as to how much PDO variability originates from these regions. To better understand PDO variability, the equatorial Pacific and the Atlantic impacts on the PDO are examined using several 3-dimensional partial ocean data assimilation experiments conducted with two global climate models: the CESM1.0 and MIROC3.2m. In these partial assimilation experiments, the climate models are constrained by observed temperature and salinity anomalies, one solely in the Atlantic basin and the other solely in the equatorial Pacific basin, but are allowed to evolve freely in other regions. These experiments demonstrate that, in addition to the tropical Pacific's role in driving PDO variability, the Atlantic can affect PDO variability by modulating the tropical Pacific climate through two proposed processes. One is the equatorial pathway, in which tropical Atlantic sea surface temperature (SST) variability causes an El Nino-like SST response in the equatorial Pacific through the reorganization of the global Walker circulation. The other is the north tropical pathway, where low-frequency SST variability associated with the Atlantic Multidecadal Oscillation induces a Matsuno-Gill type atmospheric response in the tropical Atlantic-Pacific sectors north of the equator. These results provide a quantitative assessment suggesting that 12-29% of PDO variance originates from the Atlantic Ocean and 40-44% from the tropical Pacific. The remaining 27-48% of the variance is inferred to arise from other processes such as regional ocean-atmosphere interactions in the North Pacific and possibly teleconnections from the Indian Ocean.