Interdecadal Change in the Antarctic Circumpolar Wave during 1951--2010

In this study, we defined an index of the Antarctic Circumploar Wave (ACW) and analyzed its variability for the period 1951--2010. A regime shift of the circumpolar westerly in the Southern Ocean and an interdecadal change of the ACW, which occurred around the mid-1970s, were identified. Associated with these changes, the variations of the ACW show three distinct sub-periods: 1951--1973, 1974--1980, and 1981--2010. They are characterized by different speeds, amplitudes, and wave structures. We briefly investigated possible mechanisms responsible for the different behaviors of the ACW during the three periods.