The CPV structure for both SSWs before and after the splitting. Left column shows CPV structures for 8 January 2009 (upper plot) and 24 January 2009 (bottom plot). Right column shows CPV structures for 30 December 2012 (upper plot) and 5 January 2013 (bottom plot). Arrows show the direction of jet streams, and colors show total velocity. Points on bottom plots show positions of Russian ionosondes.