Southern Hemisphere Summer Monsoon Circulation during the 1978-79 WMONEX

[摘要] The onset of the 1978-79 Southern Hemisphere summer monsoon at around 23 to 27 December was initiated by a series of events that occurred away from the Indonesia-Australia region. Low-level monsoon westerlies were first established over the western South Pacific (160°E-170°W, 0°-10°S) in response to the intensification of the tradewinds over the North Pacific and cross-equatorial northerlies near 170°E. The monsoon became fully established with the westward expansion of this low-level westerly regime into the Indonesian-Arafura Sea region.The western South Pacific was also a key area for the initiation of the "break" monsoon that prevailed from around 8 to 17 February. The initial phase shift from a westerly ("active") to a predominantly easterly ("break") regime occurred over this region as a result of vorticity advection due to northerly divergent winds (low-level Hadley circulation) and planetary boundary layer friction effects.

[学科分类] 大气科学