A mechanism of the onset of the Australian summer monsoon

摘要: [1] An onset mechanism of the Australian summer monsoon that incorporates possible air-sea feedback processes is investigated using National Centers for Environmental Prediction /National Center Atmospheric Research daily reanalysis data aided by an ocean general circulation model. Rapid intensification land-ocean thermal contrast during premonsoon period results in a well-organized continental-scale shallow vertical over continent. The dynamically coupled both with thermally induced low at lower level below 850 hPa and high 600–700 level. Intensified low-level westerly anomalies increased solar radiation less cloudy air subsidence periphery increasing sea surface temperature (SST) along northern coast Australia. concurrent leads to dry intrusion into layer � 700 Arafura Sea Coral through horizontal advective processes. A combination SST increase creates more convectively unstable condition. When convective instability intensified while suppresses convection, arrival large-scale disturbances ascending motion (such as Madden-Julian oscillation) domain where enhanced triggers deep cumulus implying monsoon. proposed this study may apply not only but also other systems have continental masses subtropics. INDEX TERMS: 1625 Global Change: Geomorphology weathering (1824, 1886); 3339 Meteorology Dynamics: Ocean/atmosphere interactions (0312, 4504); 3374 Tropical meteorology; KEYWORDS: monsoon, onset, instability, low,