HR: 0800h
AN: A31A-0048    [Abstracts]
TI: Solar cycle modulation of the Southern Annular mode
AU: * Kuroda, Y
EM: kuroda@mri-jma.go.jp
AF: Meteorological Research Institute, 1-1 Nagamine, Tsukuba, 305-0052 Japan
AU: Kodera, K
EM: kodera@mri-jma.go.jp
AF: Meteorological Research Institute, 1-1 Nagamine, Tsukuba, 305-0052 Japan
AB: Effect of the 11-year solar cycle on the activity of the October/November Southern Annular Mode (SAM) is examined by the analysis of the ERA40 reanalysis data from 1968 to 2001. It is found that year-to-year variability of October-November mean SAM signal significantly differ according to the solar activity: In the high solar years, signal of the SAM extends up to the upper stratosphere during October to December and the activity below lower stratosphere lasts until following early winter. Whereas in the low solar years, signal of the SAM is confined only inside the troposphere from October to December and it breaks off in January. These situations are parallel to that observed in the winter mean North Atlantic Oscillation found by previous studies [Kodera 2002, 2003; Ogi et al., 2003]. The origin of the difference is discussed based on both the observed data and model simulation.
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3362 Stratosphere/troposphere interactions
DE: 1620 Climate dynamics (3309)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting