Synoptic-scale modulation of convection during the Australian summer monsoon

Abstract

Time-longitude representations of Japanese Geostationary Meteorology Satellite (GMS) infrared imagery indicate the existence of major synoptic-scale banding of convection within the Australian summer monsoon. The bands can be interpreted as active and break phases of major convective activity within the monsoon. Some low-level wind surges in the South China Sea produced a modulation in the convection activity within the preexisting bands but did not seem to be associated with their formation. The organization of the convection into synoptic-scale bands was associated with the Southern Hemisphere 200 mb flow. Areas of enhanced convective banding were east of upper-level tropospheric troughs. The troughs and associated subtropical jet streaks had amplified from the south, interacting and enhancing the monsoonal convection. West of the trough, in the region of subsiding air, the convection was suppressed. -from Authors