The Influence of Interdecadal Changes in Boreal Winter Teleconnections Around the 1980s on Planetary Waves and Stratospheric Sudden Warmings

This study investigated the influence of the interdecadal changes in the Pacific-North America (PNA) and Western Pacific (WP) teleconnections on the planetary waves and stratospheric sudden warmings (SSWs), based on the National Center for Environmental Prediction reanalysis and Japanese 55-year reanalysis. Before the 1980s, there were more negative PNA & negative WP combinations (−PNA&−WP), and after the 1980s, there were more +PNA&+WP. +PNA&−WP and −PNA&+WP had no significant interdecadal changes before and after the 1980s. The interdecadal changes in the teleconnection combinations may be related to the Pacific Decadal Oscillation (PDO). During +PNA&+WP (−PNA&−WP), the planetary waves with wavenumber 1 have the maximum (minimum) wave energy and propagating more (less) to the stratosphere, causing a greater (lesser) frequency of SSWs. Thus, the interdecadal changes in the teleconnection combinations are one of the important factors which could contribute to the possible increase in SSWs after the 1980s. Since there are no satellite observations on the stratosphere before 1979, there are still many uncertainties in the interdecadal changes in SSWs.