Journal
CLIMATE DYNAMICS
Volume 45, Issue 3-4, Pages 1117-1128Publisher
SPRINGER
DOI: 10.1007/s00382-014-2361-8
Keywords
Mega-ENSO; North Atlantic Oscillation; Interdecadal variability
Categories
Funding
- Ministry of Science and Technology of China [2015CB453201, 2015CB953904]
- National Natural Science Foundation of China [91437216, 41205066]
Ask authors/readers for more resources
Mega-El Nino-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO), as two principal components of the global air-sea coupling system, may have synchronous or out-synchronous fluctuations during different epochs. Understanding such connection change is instrumental for climate prediction, particularly the decadal prediction. Results in this study show that mega-ENSO has experienced a notable inter-decadal change in its linkage with the winter NAO during the past 56 years: mega-ENSO was significantly correlated with the NAO during 19571981 (or synchronous epoch), while such correlation has broken down since 1982 (or out-synchronous epoch). This marked change might be attributed to a sea surface temperature (SST) forcing change in the North Atlantic, based on the observational and numerical evidences in this study. The synchronous epoch is concurrent with the anomalous tropical North Atlantic (TNA) SST forcing, whereas the out-synchronous epoch is associated with the anomalous extra-tropical North Atlantic (XNA) SST forcing. Two possible reasons may explain how the synchronous behaviors between mega-ENSO and the NAO were tied to the TNA SST anomaly (SSTA). There is a positive feedback between the TNA SSTA and the NAO-like atmosphere anomalies, which helps to prolong the NAO impacts from the developing phase through mature phase of mega-ENSO. Additionally, the TNA SSTA itself may induce a NAO-like atmosphere anomaly. Since 1982, the TNA SSTA has been replaced by the XNA SSTA and the latter primarily favors a NAO-neutral state in the atmosphere, which ends the synchronous epoch.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available