Diagnostic Study of Apparent Heat Sources and Moisture Sinks in the South China Sea and Its Adjacent Areas during the Onset of 1998 SCS Monsoon

The apparent heat sources () and moisture sinks () are calculated based on the reanalyzed data of the South China Sea Monsoon Experiment (SCSMEX) from May 1 to August 31, 1998. It is found that the formation and distribution of the atmospheric heat sources are important for the monsoon onset. The earlier onset of the SCS monsoon is the result of enduring atmospheric heating in the Indo-China Pe-ninsula and South China areas. The atmospheric heating firstly appears in the Indo-China Peninsula area and the sensible heat is the major one. The 30-50 day periodic oscillation of atmospheric heat sources be-tween the SCS area and the western Pacific warm pool has a reverse phase distribution before the middle of July and the low frequency oscillation of heat sources in SCS area has an obvious longitudinal propagation. The 30-50 day low frequency oscillation has vital modificatory effects on the summer monsoon evolution during 1998.