Interdecadal Variation of the Antarctic Circumpolar Wave Based on the 20CRV3 Dataset

As a large-scale ocean–atmosphere coupling system in the Southern Hemisphere, the Antarctic Circumpolar Wave (ACW) greatly impacts the global climate. However, the interdecadal variation of the ACW has rarely been studied due to the lack of long-term data. In this research, the latest 20th Century Reanalysis Version 3 dataset is used to analyze the interdecadal variations of sea level pressure (SLP) and sea surface temperature (SST) signals in the ACW during 1836–2015. The results indicate that the ACW has not always been present in the recent 180 years, and it has remarkable interdecadal variations. Specifically, the ACW was hard to distinguish before the 1870s. The SLP anomalies propagated eastwards over the South Pacific and South Atlantic during part of the 1880s–1940s. The SST anomalies also have an eastward propagation in the 1880s–1960s. The most active period of the SLP signal is in the 1950s–1990s, while that of the SST signal is in the 1980s–1990s. The ACW has not been significant since the 21st century. The interdecadal variation of the SLP may be related to the variations of the long-term Southern Annular Mode and Pacific-South American pattern, while the interdecadal variation of the SST is more associated with the ENSO.