SCGT spreads to the east along southern hemisphere mid-latitudes and its interaction with circulation in South Asia and subtropical zone in East Asia area. 

8-phase spread figure of 20-30d oscillation dry and wet anomaly in northern hemisphere South and East Asia in summer: South Asia tropical precipitation zone’s (1) beginning, (2) maturity, (3) formation an d ( 4) spread to the east and north to the lower Yangtze region, in (5)-(8) phases, the opposite rainfall anomaly zone changes similarly with each phase lasts for about 3 days (Yang，2009) 

Function of SCGT 

(1) SCGT changes regional precipitation regime; 

(2) SCGT strengthens/weakens South and East Asia’s cyclonic activities; 

(3) SCGT adjusts the East Asian subtropical monsoon system (outburst/end, suspend and strength).