Relationship between the South China Sea summer monsoon onset and tropical cyclone genesis over the western North Pacific

This study investigated the relationship between the onset date of the South China Sea summer monsoon (SCSSM) and tropical cyclone (TC) genesis over the western North Pacific (WNP). The inter-annual WNP TC genesis numbers in May is significantly negatively correlated with the onset date of the SCSSM for the epoch of 1979-2015. In the early (late) onset SCSSM years, more (less) TCs tend to be generated. The monsoon trough would enter the WNP earlier in the early SCSSM years and its easternmost location would extend to the east of 140 degrees E. This process would enhance the barotropic eddy energy conversions, which would convert more mean kinetic energy into eddy kinetic energy and supply more energy for TC genesis in the WNP in May. A predicted early (late) onset of the SCSSM might correlate with more WNP TC genesis in May.