NAME =  Johnny Chan  
ORGANIZATION =  City University of Hong Kong  
ADDRESS =  Tat Chee Av. Kowloon, Hong Kong  
COUNTRY =  China  
PHONE =  852-2788-7820  
FAX =  852-2788-7830  
E-MAIL =  johnny.chan@cityu.edu.hk  
POSTER_ONLY =  no  
THEME =  T3  
DATE =  31-Aug-04-10:21:57  
ABSID = T3JC31Aug04102157 
TITLE = Variations of the South China Sea summer monsoon: from interdecadal to intraseasonal 
AUTHOR_1 = Johnny Chan 
INSTITUTION_1 = City University of Hong Kong 
PRESENTER = AUTHOR_1 
AUTHOR_2 = Wen Zhou 
INSTITUTION_2 = City University of Hong Kong 
ABSTRACT = An examination of the variations of the onset date and rainfall associated with the South China Sea summer monsoon (SCSSM) reveals that these variations have time scales from interdecadal to interannual as well as intraseasonal.  Variations on each of these time scales are related to similar variations of the planetary-scale atmospheric circulations as well as the oceanographic conditions in the Pacific and Indian Oceans.  It is shown that many of the variations of SCSSM can be physically explained by these large-scale variations.

Specifically, much of the interdecadal variations of the monsoon rainfall can be largely explained by a superposition of the Pacific Decadal Oscillation and the El Niņo/Southern Oscillation (ENSO).  The interannual variations of the onset date and intensity of the SCSSM appear to be strongly related to the ENSO through the modifications of the atmospheric circulations by the oceanographic variations.  The timing of the onset is found to be controlled by the passage of a 30-60-day oscillation and its superposition with a westward-propagating 10-20-day oscillation.  These oscillations also explain the maintenance and break of the SCSSM.