An Analysis of the Characteristics of Monsoon Onset over the Bay of Bengal and the South China Sea in 2010

Based on NCEP/NCAR daily reanalysis and the Tropical Rainfall Measuring Mission data,the background atmospheric circulation and the characteristics of meteorological elements during the period of the Bay of Bengal monsoon(BOBM) and the South China Sea(SCS) monsoon(SCSM) in 2010 are studied.The impacts of the BOBM onset on the SCSM onset and the relationship between the two monsoons are also analyzed.The two main results are as follows:(1) The BOBM onset obviously occurs earlier than the SCSM onset in 2010,which is a typical onset process of the Asian monsoon.During the BOBM’s onset,northward jump,and eastward expansion,convective precipitation and southwest winds occurred over the SCS,which resulted in the onset of the SCSM.(2) The relationship among strong convection,heavy rainfall,and vertical circulation configuration is obtained during the monsoon onsets over the BOB and SCS,and it is concluded that the South Asian High plays an important role in this period.