**Equatorial and subtropical waves and the onset of the South East Asian monsoon

This study uses data from the 1998 South China Sea Monsoon Experiment (SCSMEX) as well as NCEP reanalysis data from 1979 to 1998. From this data set, spectral analysis and band-pass filtering of outgoing longwave radiation (OLR), zonal and meridional winds are done to determine dominant wave modes in the South China Sea (SCS) during the summer monsoon period. Further analysis is used to derive criteria for determining the onset date of the SCS monsoon as well as ascertain the importance of particular wave modes with respect to the onset.